1 Pithos v2 Developer Guide
2 =========================
7 Pithos is a storage service implemented by GRNET (http://www.grnet.gr). Data is stored as objects, organized in containers, belonging to an account. This hierarchy of storage layers has been inspired by the OpenStack Object Storage (OOS) API and similar CloudFiles API by Rackspace. The Pithos API follows the OOS API as closely as possible. One of the design requirements has been to be able to use Pithos with clients built for the OOS, without changes.
9 However, to be able to take full advantage of the Pithos infrastructure, client software should be aware of the extensions that differentiate Pithos from OOS. Pithos objects can be updated, or appended to. Pithos will store sharing permissions per object and enforce corresponding authorization policies. Automatic version management, allows taking account and container listings back in time, as well as reading previous instances of objects.
11 The storage backend of Pithos is block oriented, permitting efficient, deduplicated data placement. The block structure of objects is exposed at the API layer, in order to encourage external software to implement advanced data management operations.
13 This document's goals are:
15 * Define the Pithos ReST API that allows the storage and retrieval of data and metadata via HTTP calls
16 * Specify metadata semantics and user interface guidelines for a common experience across client software implementations
18 The present document is meant to be read alongside the OOS API documentation. Thus, it is suggested that the reader is familiar with associated technologies, the OOS API as well as the first version of the Pithos API. This document refers to the second version of Pithos. Information on the first version of the storage API can be found at http://code.google.com/p/gss.
20 Whatever marked as to be determined (**TBD**), should not be considered by implementors.
25 ========================= ================================
27 ========================= ================================
28 0.8 (Dec 22, 2011) Update allowed versioning values.
29 \ Change policy/meta formatting in JSON/XML replies.
30 \ Document that all non-ASCII characters in headers should be URL-encoded.
31 \ Support metadata-based queries when listing objects at the container level.
32 \ Note Content-Type issue when using the internal django web server.
33 \ Add object UUID field.
34 \ Always reply with the MD5 in the ETag.
35 0.7 (Nov 21, 2011) Suggest upload/download methods using hashmaps.
36 \ Propose syncing algorithm.
37 \ Support cross-account object copy and move.
38 \ Pass token as a request parameter when using ``POST`` via an HTML form.
39 \ Optionally use source account to update object from another object.
40 \ Use container ``POST`` to upload missing blocks of data.
41 \ Report policy in account headers.
42 \ Add insufficient quota reply.
43 \ Use special meta to always report Merkle hash.
44 0.6 (Sept 13, 2011) Reply with Merkle hash as the ETag when updating objects.
45 \ Include version id in object replace/change replies.
46 \ Change conflict (409) replies format to text.
47 \ Tags should be migrated to a meta value.
48 \ Container ``PUT`` updates metadata/policy.
49 \ Report allowed actions in shared object replies.
50 \ Provide ``https://hostname/login`` for Shibboleth authentication.
51 \ Use ``hashmap`` parameter in object ``GET``/``PUT`` to use hashmaps.
52 0.5 (July 22, 2011) Object update from another object's data.
53 \ Support object truncate.
54 \ Create object using a standard HTML form.
55 \ Purge container/object history.
56 \ List other accounts that share objects with a user.
57 \ List shared containers/objects.
58 \ Update implementation guidelines.
59 \ Check preconditions when creating/updating objects.
60 0.4 (July 01, 2011) Object permissions and account groups.
61 \ Control versioning behavior and container quotas with container policy directives.
62 \ Support updating/deleting individual metadata with ``POST``.
63 \ Create object using hashmap.
64 0.3 (June 14, 2011) Large object support with ``X-Object-Manifest``.
65 \ Allow for publicly available objects via ``https://hostname/public``.
66 \ Support time-variant account/container listings.
67 \ Add source version when duplicating with ``PUT``/``COPY``.
68 \ Request version in object ``HEAD``/``GET`` requests (list versions with ``GET``).
69 0.2 (May 31, 2011) Add object meta listing and filtering in containers.
70 \ Include underlying storage characteristics in container meta.
71 \ Support for partial object updates through ``POST``.
72 \ Expose object hashmaps through ``GET``.
73 \ Support for multi-range object ``GET`` requests.
74 0.1 (May 17, 2011) Initial release. Based on OpenStack Object Storage Developer Guide API v1 (Apr. 15, 2011).
75 ========================= ================================
77 Pithos Users and Authentication
78 -------------------------------
80 Pithos keeps separate databases for users and objects.
82 Each user is uniquely identified by the ``Uniq`` field. This should be used as the user's account in the API. The API uses the ``Token`` field to authenticate a user, thus allowing cross-account requests. All API requests require a token.
84 User entries can be modified/added via the management interface available at ``https://hostname/admin``.
86 Pithos is also compatible with Shibboleth (http://shibboleth.internet2.edu/). The connection between Shibboleth and Pithos is done by ``https://hostname/login``. An application that wishes to connect to Pithos, but does not have a token, should redirect the user to the login URI.
88 The login URI accepts the following parameters:
90 ====================== =========================
91 Request Parameter Name Value
92 ====================== =========================
93 next The URI to redirect to when the process is finished
94 renew Force token renewal (no value parameter)
95 ====================== =========================
97 The login process starts by redirecting the user to an external URI (controlled by Shibboleth), where the actual authentication credentials are entered. Then, the user is redirected back to the login URI from Shibboleth, with various identification information in the request headers.
99 If the user does not exist in the database, Pithos adds the user and creates a random token. If the user exists, the token has not expired and ``renew`` is not set, the existing token is reused. Finally, the login URI redirects to the URI provided with ``next``, adding the ``user`` and ``token`` parameters, which contain the ``Uniq`` and ``Token`` fields respectively.
104 The URI requests supported by the Pithos API follow one of the following forms:
106 * Top level: ``https://hostname/v1/``
107 * Account level: ``https://hostname/v1/<account>``
108 * Container level: ``https://hostname/v1/<account>/<container>``
109 * Object level: ``https://hostname/v1/<account>/<container>/<object>``
111 All requests must include an ``X-Auth-Token`` - as a header, or a parameter.
113 The allowable request operations and respective return codes per level are presented in the remainder of this chapter. Common to all requests are the following return codes.
115 ========================= ================================
116 Return Code Description
117 ========================= ================================
118 400 (Bad Request) The request is invalid
119 401 (Unauthorized) Missing or invalid token
120 403 (Forbidden) Request not allowed
121 404 (Not Found) The requested resource was not found
122 503 (Service Unavailable) The request cannot be completed because of an internal error
123 ========================= ================================
130 ========= ==================
131 Operation Description
132 ========= ==================
133 GET Authentication (for compatibility with the OOS API) or list allowed accounts
134 ========= ==================
139 If the ``X-Auth-User`` and ``X-Auth-Key`` headers are given, a dummy ``X-Auth-Token`` and ``X-Storage-Url`` will be replied, which can be used as a guest token/namespace for testing Pithos.
141 ================ =====================
142 Return Code Description
143 ================ =====================
144 204 (No Content) The request succeeded
145 ================ =====================
147 If an ``X-Auth-Token`` is already present, the operation will be interpreted as a request to list other accounts that share objects to the user.
149 ====================== =========================
150 Request Parameter Name Value
151 ====================== =========================
152 limit The amount of results requested (default is 10000)
153 marker Return containers with name lexicographically after marker
154 format Optional extended reply type (can be ``json`` or ``xml``)
155 ====================== =========================
157 The reply is a list of account names.
158 If a ``format=xml`` or ``format=json`` argument is given, extended information on the accounts will be returned, serialized in the chosen format.
159 For each account, the information will include the following (names will be in lower case and with hyphens replaced with underscores):
161 =========================== ============================
163 =========================== ============================
164 name The name of the account
165 last_modified The last account modification date (regardless of ``until``)
166 =========================== ============================
168 Example ``format=json`` reply:
172 [{"name": "user", "last_modified": "2011-12-02T08:10:41.565891+00:00"}, ...]
174 Example ``format=xml`` reply:
178 <?xml version="1.0" encoding="UTF-8"?>
182 <last_modified>2011-12-02T08:10:41.565891+00:00</last_modified>
184 <account>...</account>
187 =========================== =====================
188 Return Code Description
189 =========================== =====================
190 200 (OK) The request succeeded
191 204 (No Content) The user has no access to other accounts (only for non-extended replies)
192 =========================== =====================
194 Will use a ``200`` return code if the reply is of type JSON/XML.
201 ========= ==================
202 Operation Description
203 ========= ==================
204 HEAD Retrieve account metadata
206 POST Update account metadata
207 ========= ==================
212 ==================== ===========================
213 Request Header Name Value
214 ==================== ===========================
215 If-Modified-Since Retrieve if account has changed since provided timestamp
216 If-Unmodified-Since Retrieve if account has not changed since provided timestamp
217 ==================== ===========================
221 ====================== ===================================
222 Request Parameter Name Value
223 ====================== ===================================
224 until Optional timestamp
225 ====================== ===================================
227 Cross-user requests are not allowed to use ``until`` and only include the account modification date in the reply.
229 ========================== =====================
230 Reply Header Name Value
231 ========================== =====================
232 X-Account-Container-Count The total number of containers
233 X-Account-Bytes-Used The total number of bytes stored
234 X-Account-Until-Timestamp The last account modification date until the timestamp provided
235 X-Account-Group-* Optional user defined groups
236 X-Account-Policy-* Account behavior and limits
237 X-Account-Meta-* Optional user defined metadata
238 Last-Modified The last account modification date (regardless of ``until``)
239 ========================== =====================
243 ================ =====================
244 Return Code Description
245 ================ =====================
246 204 (No Content) The request succeeded
247 ================ =====================
253 ==================== ===========================
254 Request Header Name Value
255 ==================== ===========================
256 If-Modified-Since Retrieve if account has changed since provided timestamp
257 If-Unmodified-Since Retrieve if account has not changed since provided timestamp
258 ==================== ===========================
262 ====================== =========================
263 Request Parameter Name Value
264 ====================== =========================
265 limit The amount of results requested (default is 10000)
266 marker Return containers with name lexicographically after marker
267 format Optional extended reply type (can be ``json`` or ``xml``)
268 shared Show only shared containers (no value parameter)
269 until Optional timestamp
270 ====================== =========================
272 The reply is a list of container names. Account headers (as in a ``HEAD`` request) will also be included.
273 Cross-user requests are not allowed to use ``until`` and only include the account/container modification dates in the reply.
275 If a ``format=xml`` or ``format=json`` argument is given, extended information on the containers will be returned, serialized in the chosen format.
276 For each container, the information will include all container metadata (names will be in lower case and with hyphens replaced with underscores):
278 =========================== ============================
280 =========================== ============================
281 name The name of the container
282 count The number of objects inside the container
283 bytes The total size of the objects inside the container
284 last_modified The last container modification date (regardless of ``until``)
285 x_container_until_timestamp The last container modification date until the timestamp provided
286 x_container_policy_* Container behavior and limits
287 x_container_meta_* Optional user defined metadata
288 =========================== ============================
290 Example ``format=json`` reply:
297 "last_modified": "2011-12-02T08:10:41.565891+00:00",
298 "x_container_policy": {"quota": "53687091200", "versioning": "auto"},
299 "x_container_meta": {"a": "b", "1": "2"}}, ...]
301 Example ``format=xml`` reply:
305 <?xml version="1.0" encoding="UTF-8"?>
306 <account name="user">
311 <last_modified>2011-12-02T08:10:41.565891+00:00</last_modified>
313 <key>quota</key><value>53687091200</value>
314 <key>versioning</key><value>auto</value>
315 </x_container_policy>
317 <key>a</key><value>b</value>
318 <key>1</key><value>2</value>
321 <container>...</container>
324 For more examples of container details returned in JSON/XML formats refer to the OOS API documentation. In addition to the OOS API, Pithos returns all fields. Policy and metadata values are grouped and returned as key-value pairs.
326 =========================== =====================
327 Return Code Description
328 =========================== =====================
329 200 (OK) The request succeeded
330 204 (No Content) The account has no containers (only for non-extended replies)
331 304 (Not Modified) The account has not been modified
332 412 (Precondition Failed) The condition set can not be satisfied
333 =========================== =====================
335 Will use a ``200`` return code if the reply is of type JSON/XML.
341 ==================== ===========================
342 Request Header Name Value
343 ==================== ===========================
344 X-Account-Group-* Optional user defined groups
345 X-Account-Meta-* Optional user defined metadata
346 ==================== ===========================
350 ====================== ============================================
351 Request Parameter Name Value
352 ====================== ============================================
353 update Do not replace metadata/groups (no value parameter)
354 ====================== ============================================
356 No reply content/headers.
358 The operation will overwrite all user defined metadata, except if ``update`` is defined.
359 To create a group, include an ``X-Account-Group-*`` header with the name in the key and a comma separated list of user names in the value. If no ``X-Account-Group-*`` header is present, no changes will be applied to groups. The ``update`` parameter also applies to groups. To delete a specific group, use ``update`` and an empty header value.
361 ================ ===============================
362 Return Code Description
363 ================ ===============================
364 202 (Accepted) The request has been accepted
365 ================ ===============================
373 ========= ============================
374 Operation Description
375 ========= ============================
376 HEAD Retrieve container metadata
378 PUT Create/update container
379 POST Update container metadata
380 DELETE Delete container
381 ========= ============================
387 ==================== ===========================
388 Request Header Name Value
389 ==================== ===========================
390 If-Modified-Since Retrieve if container has changed since provided timestamp
391 If-Unmodified-Since Retrieve if container has not changed since provided timestamp
392 ==================== ===========================
396 ====================== ===================================
397 Request Parameter Name Value
398 ====================== ===================================
399 until Optional timestamp
400 ====================== ===================================
402 Cross-user requests are not allowed to use ``until`` and only include the container modification date in the reply.
404 =========================== ===============================
405 Reply Header Name Value
406 =========================== ===============================
407 X-Container-Object-Count The total number of objects in the container
408 X-Container-Bytes-Used The total number of bytes of all objects stored
409 X-Container-Block-Size The block size used by the storage backend
410 X-Container-Block-Hash The hash algorithm used for block identifiers in object hashmaps
411 X-Container-Until-Timestamp The last container modification date until the timestamp provided
412 X-Container-Object-Meta A list with all meta keys used by objects (**TBD**)
413 X-Container-Policy-* Container behavior and limits
414 X-Container-Meta-* Optional user defined metadata
415 Last-Modified The last container modification date (regardless of ``until``)
416 =========================== ===============================
418 The keys returned in ``X-Container-Object-Meta`` are all the unique strings after the ``X-Object-Meta-`` prefix, formatted as a comma-separated list. See container ``PUT`` for a reference of policy directives. (**TBD**)
420 ================ ===============================
421 Return Code Description
422 ================ ===============================
423 204 (No Content) The request succeeded
424 ================ ===============================
430 ==================== ===========================
431 Request Header Name Value
432 ==================== ===========================
433 If-Modified-Since Retrieve if container has changed since provided timestamp
434 If-Unmodified-Since Retrieve if container has not changed since provided timestamp
435 ==================== ===========================
439 ====================== ===================================
440 Request Parameter Name Value
441 ====================== ===================================
442 limit The amount of results requested (default is 10000)
443 marker Return containers with name lexicographically after marker
444 prefix Return objects starting with prefix
445 delimiter Return objects up to the delimiter (discussion follows)
446 path Assume ``prefix=path`` and ``delimiter=/``
447 format Optional extended reply type (can be ``json`` or ``xml``)
448 meta Return objects that satisfy the key queries in the specified comma separated list (use ``<key>``, ``!<key>`` for existence queries, ``<key><op><value>`` for value queries, where ``<op>`` can be one of ``=``, ``!=``, ``<=``, ``>=``, ``<``, ``>``)
449 shared Show only shared objects (no value parameter)
450 until Optional timestamp
451 ====================== ===================================
453 The ``path`` parameter overrides ``prefix`` and ``delimiter``. When using ``path``, results will include objects ending in ``delimiter``.
455 The keys given with ``meta`` will be matched with the strings after the ``X-Object-Meta-`` prefix.
457 The reply is a list of object names. Container headers (as in a ``HEAD`` request) will also be included.
458 Cross-user requests are not allowed to use ``until`` and include the following limited set of headers in the reply:
460 =========================== ===============================
461 Reply Header Name Value
462 =========================== ===============================
463 X-Container-Block-Size The block size used by the storage backend
464 X-Container-Block-Hash The hash algorithm used for block identifiers in object hashmaps
465 X-Container-Object-Meta A list with all meta keys used by allowed objects (**TBD**)
466 Last-Modified The last container modification date
467 =========================== ===============================
469 If a ``format=xml`` or ``format=json`` argument is given, extended information on the objects will be returned, serialized in the chosen format.
470 For each object, the information will include all object metadata (names will be in lower case and with hyphens replaced with underscores):
472 ========================== ======================================
474 ========================== ======================================
475 name The name of the object
476 hash The ETag of the object
477 bytes The size of the object
478 content_type The MIME content type of the object
479 content_encoding The encoding of the object (optional)
480 content-disposition The presentation style of the object (optional)
481 last_modified The last object modification date (regardless of version)
482 x_object_hash The Merkle hash
483 x_object_uuid The object's UUID
484 x_object_version The object's version identifier
485 x_object_version_timestamp The object's version timestamp
486 x_object_modified_by The user that committed the object's version
487 x_object_manifest Object parts prefix in ``<container>/<object>`` form (optional)
488 x_object_sharing Object permissions (optional)
489 x_object_shared_by Object inheriting permissions (optional)
490 x_object_allowed_to Allowed actions on object (optional)
491 x_object_public Object's publicly accessible URI (optional)
492 x_object_meta_* Optional user defined metadata
493 ========================== ======================================
495 Extended replies may also include virtual directory markers in separate sections of the ``json`` or ``xml`` results.
496 Virtual directory markers are only included when ``delimiter`` is explicitly set. They correspond to the substrings up to and including the first occurrence of the delimiter.
497 In JSON results they appear as dictionaries with only a ``subdir`` key. In XML results they appear interleaved with ``<object>`` tags as ``<subdir name="..." />``.
498 In case there is an object with the same name as a virtual directory marker, the object will be returned.
500 Example ``format=json`` reply:
506 "hash": "d41d8cd98f00b204e9800998ecf8427e",
507 "content_type": "application/octet-stream",
508 "last_modified": "2011-12-02T08:10:41.565891+00:00",
509 "x_object_meta": {"asdf": "qwerty"},
510 "x_object_hash": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
511 "x_object_uuid": "8ed9af1b-c948-4bb6-82b0-48344f5c822c",
512 "x_object_version": 98,
513 "x_object_version_timestamp": "1322813441.565891",
514 "x_object_modified_by": "user"}, ...]
516 Example ``format=xml`` reply:
520 <?xml version="1.0" encoding="UTF-8"?>
521 <container name="pithos">
525 <hash>d41d8cd98f00b204e9800998ecf8427e</hash>
526 <content_type>application/octet-stream</content_type>
527 <last_modified>2011-12-02T08:10:41.565891+00:00</last_modified>
529 <key>asdf</key><value>qwerty</value>
531 <x_object_hash>e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855</x_object_hash>
532 <x_object_uuid>8ed9af1b-c948-4bb6-82b0-48344f5c822c</x_object_uuid>
533 <x_object_version>98</x_object_version>
534 <x_object_version_timestamp>1322813441.565891</x_object_version_timestamp>
535 <x_object_modified_by>chazapis</x_object_modified_by>
540 For more examples of container details returned in JSON/XML formats refer to the OOS API documentation. In addition to the OOS API, Pithos returns all fields. Metadata values are grouped and returned as key-value pairs.
542 =========================== ===============================
543 Return Code Description
544 =========================== ===============================
545 200 (OK) The request succeeded
546 204 (No Content) The account has no containers (only for non-extended replies)
547 304 (Not Modified) The container has not been modified
548 412 (Precondition Failed) The condition set can not be satisfied
549 =========================== ===============================
551 Will use a ``200`` return code if the reply is of type JSON/XML.
557 ==================== ================================
558 Request Header Name Value
559 ==================== ================================
560 X-Container-Policy-* Container behavior and limits
561 X-Container-Meta-* Optional user defined metadata
562 ==================== ================================
564 No reply content/headers.
566 If no policy is defined, the container will be created with the default values.
567 Available policy directives:
569 * ``versioning``: Set to ``auto`` or ``none`` (default is ``auto``)
570 * ``quota``: Size limit in KB (default is ``0`` - unlimited)
572 If the container already exists, the operation is equal to a ``POST`` with ``update`` defined.
574 ================ ===============================
575 Return Code Description
576 ================ ===============================
577 201 (Created) The container has been created
578 202 (Accepted) The request has been accepted
579 ================ ===============================
585 ==================== ================================
586 Request Header Name Value
587 ==================== ================================
588 Content-Length The size of the supplied data (optional, to upload)
589 Content-Type The MIME content type of the supplied data (optional, to upload)
590 Transfer-Encoding Set to ``chunked`` to specify incremental uploading (if used, ``Content-Length`` is ignored)
591 X-Container-Policy-* Container behavior and limits
592 X-Container-Meta-* Optional user defined metadata
593 ==================== ================================
597 ====================== ============================================
598 Request Parameter Name Value
599 ====================== ============================================
600 update Do not replace metadata/policy (no value parameter)
601 ====================== ============================================
603 No reply content/headers, except when uploading data, where the reply consists of a list of hashes for the blocks received (in a simple text format, with one hash per line).
605 The operation will overwrite all user defined metadata, except if ``update`` is defined.
606 To change policy, include an ``X-Container-Policy-*`` header with the name in the key. If no ``X-Container-Policy-*`` header is present, no changes will be applied to policy. The ``update`` parameter also applies to policy - deleted values will revert to defaults. To delete/revert a specific policy directive, use ``update`` and an empty header value. See container ``PUT`` for a reference of policy directives.
608 To upload blocks of data to the container, set ``Content-Type`` to ``application/octet-stream`` and ``Content-Length`` to a valid value (except if using ``chunked`` as the ``Transfer-Encoding``).
610 ================ ===============================
611 Return Code Description
612 ================ ===============================
613 202 (Accepted) The request has been accepted
614 ================ ===============================
620 ====================== ===================================
621 Request Parameter Name Value
622 ====================== ===================================
623 until Optional timestamp
624 ====================== ===================================
626 If ``until`` is defined, the container is "purged" up to that time (the history of all objects up to then is deleted).
628 No reply content/headers.
630 ================ ===============================
631 Return Code Description
632 ================ ===============================
633 204 (No Content) The request succeeded
634 409 (Conflict) The container is not empty
635 ================ ===============================
643 ========= =================================
644 Operation Description
645 ========= =================================
646 HEAD Retrieve object metadata
648 PUT Write object data or copy/move object
651 POST Update object metadata/data
653 ========= =================================
659 ==================== ================================
660 Request Header Name Value
661 ==================== ================================
662 If-Match Retrieve if ETags match
663 If-None-Match Retrieve if ETags don't match
664 If-Modified-Since Retrieve if object has changed since provided timestamp
665 If-Unmodified-Since Retrieve if object has not changed since provided timestamp
666 ==================== ================================
670 ====================== ===================================
671 Request Parameter Name Value
672 ====================== ===================================
673 version Optional version identifier
674 ====================== ===================================
678 ========================== ===============================
679 Reply Header Name Value
680 ========================== ===============================
681 ETag The ETag of the object
682 Content-Length The size of the object
683 Content-Type The MIME content type of the object
684 Last-Modified The last object modification date (regardless of version)
685 Content-Encoding The encoding of the object (optional)
686 Content-Disposition The presentation style of the object (optional)
687 X-Object-Hash The Merkle hash
688 X-Object-UUID The object's UUID
689 X-Object-Version The object's version identifier
690 X-Object-Version-Timestamp The object's version timestamp
691 X-Object-Modified-By The user that comitted the object's version
692 X-Object-Manifest Object parts prefix in ``<container>/<object>`` form (optional)
693 X-Object-Sharing Object permissions (optional)
694 X-Object-Shared-By Object inheriting permissions (optional)
695 X-Object-Allowed-To Allowed actions on object (optional)
696 X-Object-Public Object's publicly accessible URI (optional)
697 X-Object-Meta-* Optional user defined metadata
698 ========================== ===============================
702 ================ ===============================
703 Return Code Description
704 ================ ===============================
705 200 (No Content) The request succeeded
706 ================ ===============================
712 ==================== ================================
713 Request Header Name Value
714 ==================== ================================
715 Range Optional range of data to retrieve
716 If-Range Retrieve the missing part if entity is unchanged; otherwise, retrieve the entire new entity (used together with Range header)
717 If-Match Retrieve if ETags match
718 If-None-Match Retrieve if ETags don't match
719 If-Modified-Since Retrieve if object has changed since provided timestamp
720 If-Unmodified-Since Retrieve if object has not changed since provided timestamp
721 ==================== ================================
725 ====================== ===================================
726 Request Parameter Name Value
727 ====================== ===================================
728 format Optional extended reply type (can be ``json`` or ``xml``)
729 hashmap Optional request for hashmap (no value parameter)
730 version Optional version identifier or ``list`` (specify a format if requesting a list)
731 ====================== ===================================
733 The reply is the object's data (or part of it), except if a hashmap is requested with ``hashmap``, or a version list with ``version=list`` (in both cases an extended reply format must be specified). Object headers (as in a ``HEAD`` request) are always included.
735 Hashmaps expose the underlying storage format of the object. Note that each hash is computed after trimming trailing null bytes of the corresponding block. The ``X-Object-Hash`` header reports the single Merkle hash of the object's hashmap (refer to http://bittorrent.org/beps/bep_0030.html for more information).
737 Example ``format=json`` reply:
741 {"block_hash": "sha1", "hashes": ["7295c41da03d7f916440b98e32c4a2a39351546c", ...], "block_size": 131072, "bytes": 242}
743 Example ``format=xml`` reply:
747 <?xml version="1.0" encoding="UTF-8"?>
748 <object name="file" bytes="24223726" block_size="131072" block_hash="sha1">
749 <hash>7295c41da03d7f916440b98e32c4a2a39351546c</hash>
753 Version lists include the version identifier and timestamp for each available object version. Version identifiers can be arbitrary strings, so use the timestamp to find newer versions.
755 Example ``format=json`` reply:
759 {"versions": [[85, "1322734861.248469"], [86, "1322734905.009272"], ...]}
761 Example ``format=xml`` reply:
765 <?xml version="1.0" encoding="UTF-8"?>
767 <version timestamp="1322734861.248469">85</version>
768 <version timestamp="1322734905.009272">86</version>
769 <version timestamp="...">...</version>
772 The ``Range`` header may include multiple ranges, as outlined in RFC2616. Then the ``Content-Type`` of the reply will be ``multipart/byteranges`` and each part will include a ``Content-Range`` header.
774 ========================== ===============================
775 Reply Header Name Value
776 ========================== ===============================
777 ETag The ETag of the object
778 Content-Length The size of the data returned
779 Content-Type The MIME content type of the object
780 Content-Range The range of data included (only on a single range request)
781 Last-Modified The last object modification date (regardless of version)
782 Content-Encoding The encoding of the object (optional)
783 Content-Disposition The presentation style of the object (optional)
784 X-Object-Hash The Merkle hash
785 X-Object-UUID The object's UUID
786 X-Object-Version The object's version identifier
787 X-Object-Version-Timestamp The object's version timestamp
788 X-Object-Modified-By The user that comitted the object's version
789 X-Object-Manifest Object parts prefix in ``<container>/<object>`` form (optional)
790 X-Object-Sharing Object permissions (optional)
791 X-Object-Shared-By Object inheriting permissions (optional)
792 X-Object-Allowed-To Allowed actions on object (optional)
793 X-Object-Public Object's publicly accessible URI (optional)
794 X-Object-Meta-* Optional user defined metadata
795 ========================== ===============================
799 =========================== ==============================
800 Return Code Description
801 =========================== ==============================
802 200 (OK) The request succeeded
803 206 (Partial Content) The range request succeeded
804 304 (Not Modified) The object has not been modified
805 412 (Precondition Failed) The condition set can not be satisfied
806 416 (Range Not Satisfiable) The requested range is out of limits
807 =========================== ==============================
813 ==================== ================================
814 Request Header Name Value
815 ==================== ================================
816 If-Match Put if ETags match with current object
817 If-None-Match Put if ETags don't match with current object
818 ETag The MD5 hash of the object (optional to check written data)
819 Content-Length The size of the data written
820 Content-Type The MIME content type of the object
821 Transfer-Encoding Set to ``chunked`` to specify incremental uploading (if used, ``Content-Length`` is ignored)
822 X-Copy-From The source path in the form ``/<container>/<object>``
823 X-Move-From The source path in the form ``/<container>/<object>``
824 X-Source-Account The source account to copy/move from
825 X-Source-Version The source version to copy from
826 Content-Encoding The encoding of the object (optional)
827 Content-Disposition The presentation style of the object (optional)
828 X-Object-Manifest Object parts prefix in ``<container>/<object>`` form (optional)
829 X-Object-Sharing Object permissions (optional)
830 X-Object-Public Object is publicly accessible (optional)
831 X-Object-Meta-* Optional user defined metadata
832 ==================== ================================
836 ====================== ===================================
837 Request Parameter Name Value
838 ====================== ===================================
839 format Optional extended request type (can be ``json`` or ``xml``)
840 hashmap Optional hashmap provided instead of data (no value parameter)
841 ====================== ===================================
843 The request is the object's data (or part of it), except if a hashmap is provided (using ``hashmap`` and ``format`` parameters). If using a hashmap and all different parts are stored in the server, the object is created, otherwise the server returns Conflict (409) with the list of the missing parts (in a simple text format, with one hash per line).
845 Hashmaps should be formatted as outlined in ``GET``.
847 ========================== ===============================
848 Reply Header Name Value
849 ========================== ===============================
850 ETag The MD5 hash of the object
851 X-Object-Version The object's new version
852 ========================== ===============================
854 The ``X-Object-Sharing`` header may include either a ``read=...`` comma-separated user/group list, or a ``write=...`` comma-separated user/group list, or both separated by a semicolon (``;``). Groups are specified as ``<account>:<group>``. To publish the object, set ``X-Object-Public`` to ``true``. To unpublish, set to ``false``, or use an empty header value.
856 ============================== ==============================
857 Return Code Description
858 ============================== ==============================
859 201 (Created) The object has been created
860 409 (Conflict) The object can not be created from the provided hashmap, or there are conflicting permissions (a list of missing hashes, or a list of conflicting sharing paths will be included in the reply - in simple text format)
861 411 (Length Required) Missing ``Content-Length`` or ``Content-Type`` in the request
862 413 (Request Entity Too Large) Insufficient quota to complete the request
863 422 (Unprocessable Entity) The MD5 checksum of the data written to the storage system does not match the (optionally) supplied ETag value
864 ============================== ==============================
870 ==================== ================================
871 Request Header Name Value
872 ==================== ================================
873 If-Match Proceed if ETags match with object
874 If-None-Match Proceed if ETags don't match with object
875 Destination The destination path in the form ``/<container>/<object>``
876 Destination-Account The destination account to copy to
877 Content-Type The MIME content type of the object (optional :sup:`*`)
878 Content-Encoding The encoding of the object (optional)
879 Content-Disposition The presentation style of the object (optional)
880 X-Source-Version The source version to copy from
881 X-Object-Manifest Object parts prefix in ``<container>/<object>`` form (optional)
882 X-Object-Sharing Object permissions (optional)
883 X-Object-Public Object is publicly accessible (optional)
884 X-Object-Meta-* Optional user defined metadata
885 ==================== ================================
887 :sup:`*` *When using django locally with the supplied web server, do provide a valid Content-Type, as a type of text/plain is applied by default to all requests.*
889 Refer to ``PUT``/``POST`` for a description of request headers. Metadata is also copied, updated with any values defined. Sharing/publishing options are not copied.
891 ========================== ===============================
892 Reply Header Name Value
893 ========================== ===============================
894 X-Object-Version The object's new version
895 ========================== ===============================
899 ============================== ==============================
900 Return Code Description
901 ============================== ==============================
902 201 (Created) The object has been created
903 409 (Conflict) There are conflicting permissions (a list of conflicting sharing paths will be included in the reply - in simple text format)
904 413 (Request Entity Too Large) Insufficient quota to complete the request
905 ============================== ==============================
911 Same as ``COPY``, without the ``X-Source-Version`` request header. The ``MOVE`` operation is always applied on the latest version.
917 ==================== ================================
918 Request Header Name Value
919 ==================== ================================
920 If-Match Proceed if ETags match with object
921 If-None-Match Proceed if ETags don't match with object
922 Content-Length The size of the data written (optional, to update)
923 Content-Type The MIME content type of the object (optional, to update)
924 Content-Range The range of data supplied (optional, to update)
925 Transfer-Encoding Set to ``chunked`` to specify incremental uploading (if used, ``Content-Length`` is ignored)
926 Content-Encoding The encoding of the object (optional)
927 Content-Disposition The presentation style of the object (optional)
928 X-Source-Object Update with data from the object at path ``/<container>/<object>`` (optional, to update)
929 X-Source-Account The source account to update from
930 X-Source-Version The source version to update from (optional, to update)
931 X-Object-Bytes The updated object's final size (optional, when updating)
932 X-Object-Manifest Object parts prefix in ``<container>/<object>`` form (optional)
933 X-Object-Sharing Object permissions (optional)
934 X-Object-Public Object is publicly accessible (optional)
935 X-Object-Meta-* Optional user defined metadata
936 ==================== ================================
940 ====================== ============================================
941 Request Parameter Name Value
942 ====================== ============================================
943 update Do not replace metadata (no value parameter)
944 ====================== ============================================
946 The ``Content-Encoding``, ``Content-Disposition``, ``X-Object-Manifest`` and ``X-Object-Meta-*`` headers are considered to be user defined metadata. An operation without the ``update`` parameter will overwrite all previous values and remove any keys not supplied. When using ``update`` any metadata with an empty value will be deleted.
948 To change permissions, include an ``X-Object-Sharing`` header (as defined in ``PUT``). To publish, include an ``X-Object-Public`` header, with a value of ``true``. If no such headers are defined, no changes will be applied to sharing/public. Use empty values to remove permissions/unpublish (unpublishing also works with ``false`` as a header value). Sharing options are applied to the object - not its versions.
950 To update an object's data:
952 * Either set ``Content-Type`` to ``application/octet-stream``, or provide an object with ``X-Source-Object``. If ``Content-Type`` has some other value, it will be ignored and only the metadata will be updated.
953 * If the data is supplied in the request (using ``Content-Type`` instead of ``X-Source-Object``), a valid ``Content-Length`` header is required - except if using chunked transfers (set ``Transfer-Encoding`` to ``chunked``).
954 * Set ``Content-Range`` as specified in RFC2616, with the following differences:
956 * Client software MAY omit ``last-byte-pos`` of if the length of the range being transferred is unknown or difficult to determine.
957 * Client software SHOULD not specify the ``instance-length`` (use a ``*``), unless there is a reason for performing a size check at the server.
958 * If ``Content-Range`` used has a ``byte-range-resp-spec = *``, data will be appended to the object.
960 Optionally, truncate the updated object to the desired length with the ``X-Object-Bytes`` header.
962 A data update will trigger an ETag change. Updated ETags may happen asynchronously and appear at the server with a delay.
964 No reply content. No reply headers if only metadata is updated.
966 ========================== ===============================
967 Reply Header Name Value
968 ========================== ===============================
969 ETag The new ETag of the object (data updated)
970 X-Object-Version The object's new version
971 ========================== ===============================
975 ============================== ==============================
976 Return Code Description
977 ============================== ==============================
978 202 (Accepted) The request has been accepted (not a data update)
979 204 (No Content) The request succeeded (data updated)
980 409 (Conflict) There are conflicting permissions (a list of conflicting sharing paths will be included in the reply - in simple text format)
981 411 (Length Required) Missing ``Content-Length`` in the request
982 413 (Request Entity Too Large) Insufficient quota to complete the request
983 416 (Range Not Satisfiable) The supplied range is invalid
984 ============================== ==============================
986 The ``POST`` method can also be used for creating an object via a standard HTML form. If the request ``Content-Type`` is ``multipart/form-data``, none of the above headers will be processed. The form should have an ``X-Object-Data`` field, as in the following example. The token is passed as a request parameter. ::
988 <form method="post" action="https://pithos.dev.grnet.gr/v1/user/folder/EXAMPLE.txt?X-Auth-Token=0000" enctype="multipart/form-data">
989 <input type="file" name="X-Object-Data">
990 <input type="submit">
993 This will create/override the object with the given name, as if using ``PUT``. The ``Content-Type`` of the object will be set to the value of the corresponding header sent in the part of the request containing the data (usually, automatically handled by the browser). Metadata, sharing and other object attributes can not be set this way.
995 ========================== ===============================
996 Reply Header Name Value
997 ========================== ===============================
998 ETag The MD5 hash of the object
999 X-Object-Version The object's new version
1000 ========================== ===============================
1004 ============================== ==============================
1005 Return Code Description
1006 ============================== ==============================
1007 201 (Created) The object has been created
1008 413 (Request Entity Too Large) Insufficient quota to complete the request
1009 ============================== ==============================
1015 ====================== ===================================
1016 Request Parameter Name Value
1017 ====================== ===================================
1018 until Optional timestamp
1019 ====================== ===================================
1021 If ``until`` is defined, the object is "purged" up to that time (the history up to then is deleted).
1023 No reply content/headers.
1025 =========================== ==============================
1026 Return Code Description
1027 =========================== ==============================
1028 204 (No Content) The request succeeded
1029 =========================== ==============================
1031 Sharing and Public Objects
1032 ^^^^^^^^^^^^^^^^^^^^^^^^^^
1034 Read and write control in Pithos is managed by setting appropriate permissions with the ``X-Object-Sharing`` header. The permissions are applied using prefix-based inheritance. Thus, each set of authorization directives is applied to all objects sharing the same prefix with the object where the corresponding ``X-Object-Sharing`` header is defined. For simplicity, nested/overlapping permissions are not allowed. Setting ``X-Object-Sharing`` will fail, if the object is already "covered", or another object with a longer common-prefix name already has permissions. When retrieving an object, the ``X-Object-Shared-By`` header reports where it gets its permissions from. If not present, the object is the actual source of authorization directives.
1036 A user may ``GET`` another account or container. The result will include a limited reply, containing only the allowed containers or objects respectively. A top-level request with an authentication token, will return a list of allowed accounts, so the user can easily find out which other users share objects. The ``X-Object-Allowed-To`` header lists the actions allowed on an object, if it does not belong to the requesting user.
1038 Objects that are marked as public, via the ``X-Object-Public`` meta, are also available at the corresponding URI returned for ``HEAD`` or ``GET``. Requests for public objects do not need to include an ``X-Auth-Token``. Pithos will ignore request parameters and only include the following headers in the reply (all ``X-Object-*`` meta is hidden):
1040 ========================== ===============================
1041 Reply Header Name Value
1042 ========================== ===============================
1043 ETag The ETag of the object
1044 Content-Length The size of the data returned
1045 Content-Type The MIME content type of the object
1046 Content-Range The range of data included (only on a single range request)
1047 Last-Modified The last object modification date (regardless of version)
1048 Content-Encoding The encoding of the object (optional)
1049 Content-Disposition The presentation style of the object (optional)
1050 ========================== ===============================
1052 Public objects are not included and do not influence cross-user listings. They are, however, readable by all users.
1057 List of differences from the OOS API:
1059 * Support for ``X-Account-Meta-*`` style headers at the account level. Use ``POST`` to update.
1060 * Support for ``X-Container-Meta-*`` style headers at the container level. Can be set when creating via ``PUT``. Use ``POST`` to update.
1061 * Header ``X-Container-Object-Meta`` at the container level and parameter ``meta`` in container listings. (**TBD**)
1062 * Account and container policies to manage behavior and limits. Container behavior overrides account settings. Account quota sets the maximum bytes limit, regardless of container values.
1063 * Headers ``X-Container-Block-*`` at the container level, exposing the underlying storage characteristics.
1064 * All metadata replies, at all levels, include latest modification information.
1065 * At all levels, a ``HEAD`` or ``GET`` request may use ``If-Modified-Since`` and ``If-Unmodified-Since`` headers.
1066 * Container/object lists include all associated metadata if the reply is of type JSON/XML. Some names are kept to their OOS API equivalents for compatibility.
1067 * Option to include only shared containers/objects in listings.
1068 * Object metadata allowed, in addition to ``X-Object-Meta-*``: ``Content-Encoding``, ``Content-Disposition``, ``X-Object-Manifest``. These are all replaced with every update operation, except if using the ``update`` parameter (in which case individual keys can also be deleted). Deleting meta by providing empty values also works when copying/moving an object.
1069 * Multi-range object ``GET`` support as outlined in RFC2616.
1070 * Object hashmap retrieval through ``GET`` and the ``format`` parameter.
1071 * Object create via hashmap through ``PUT`` and the ``format`` parameter.
1072 * The object's Merkle hash is always returned in the ``X-Object-Hash`` header.
1073 * The object's UUID is always returned in the ``X-Object-UUID`` header. The UUID remains unchanged, even when the object's data or metadata changes, or the object is moved to another path (is renamed). A new UUID is assigned when creating or copying an object.
1074 * Object create using ``POST`` to support standard HTML forms.
1075 * Partial object updates through ``POST``, using the ``Content-Length``, ``Content-Type``, ``Content-Range`` and ``Transfer-Encoding`` headers. Use another object's data to update with ``X-Source-Object`` and ``X-Source-Version``. Truncate with ``X-Object-Bytes``.
1076 * Include new version identifier in replies for object replace/change requests.
1077 * Object ``MOVE`` support.
1078 * Conditional object create/update operations, using ``If-Match`` and ``If-None-Match`` headers.
1079 * Time-variant account/container listings via the ``until`` parameter.
1080 * Object versions - parameter ``version`` in ``HEAD``/``GET`` (list versions with ``GET``), ``X-Object-Version-*`` meta in replies, ``X-Source-Version`` in ``PUT``/``COPY``.
1081 * Sharing/publishing with ``X-Object-Sharing``, ``X-Object-Public`` at the object level. Cross-user operations are allowed - controlled by sharing directives. Available actions in cross-user requests are reported with ``X-Object-Allowed-To``. Permissions may include groups defined with ``X-Account-Group-*`` at the account level. These apply to the object - not its versions.
1082 * Support for prefix-based inheritance when enforcing permissions. Parent object carrying the authorization directives is reported in ``X-Object-Shared-By``.
1083 * Copy and move between accounts with ``X-Source-Account`` and ``Destination-Account`` headers.
1084 * Large object support with ``X-Object-Manifest``.
1085 * Trace the user that created/modified an object with ``X-Object-Modified-By``.
1086 * Purge container/object history with the ``until`` parameter in ``DELETE``.
1088 Clarifications/suggestions:
1090 * All non-ASCII characters in headers should be URL-encoded.
1091 * Authentication is done by another system. The token is used in the same way, but it is obtained differently. The top level ``GET`` request is kept compatible with the OOS API and allows for guest/testing operations.
1092 * Some processing is done in the variable part of all ``X-*-Meta-*`` headers. If it includes underscores, they will be converted to dashes and the first letter of all intra-dash strings will be capitalized.
1093 * A ``GET`` reply for a level will include all headers of the corresponding ``HEAD`` request.
1094 * To avoid conflicts between objects and virtual directory markers in container listings, it is recommended that object names do not end with the delimiter used.
1095 * The ``Accept`` header may be used in requests instead of the ``format`` parameter to specify the desired request/reply format. The parameter overrides the header.
1096 * Container/object lists use a ``200`` return code if the reply is of type JSON/XML. The reply will include an empty JSON/XML.
1097 * In headers, dates are formatted according to RFC 1123. In extended information listings, the ``last_modified`` field is formatted according to ISO 8601 (for OOS API compatibility). All other fields (Pithos extensions) use integer tiemstamps.
1098 * The ``Last-Modified`` header value always reflects the actual latest change timestamp, regardless of time control parameters and version requests. Time precondition checks with ``If-Modified-Since`` and ``If-Unmodified-Since`` headers are applied to this value.
1099 * A copy/move using ``PUT``/``COPY``/``MOVE`` will always update metadata, keeping all old values except the ones redefined in the request headers.
1100 * A ``HEAD`` or ``GET`` for an ``X-Object-Manifest`` object, will include modified ``Content-Length`` and ``ETag`` headers, according to the characteristics of the objects under the specified prefix. The ``Etag`` will be the MD5 hash of the corresponding ETags concatenated. In extended container listings there is no metadata processing.
1108 Hopefully this API will allow for a multitude of client implementations, each supporting a different device or operating system. All clients will be able to manipulate containers and objects - even software only designed for OOS API compatibility. But a Pithos interface should not be only about showing containers and folders. There are some extra user interface elements and functionalities that should be common to all implementations.
1110 Upon entrance to the service, a user is presented with the following elements - which can be represented as folders or with other related icons:
1112 * The ``home`` element, which is used as the default entry point to the user's "files". Objects under ``home`` are represented in the usual hierarchical organization of folders and files.
1113 * The ``trash`` element, which contains files that have been marked for deletion, but can still be recovered.
1114 * The ``shared`` element, which contains all objects shared by the user to other users of the system.
1115 * The ``others`` element, which contains all objects that other users share with the user.
1116 * The ``groups`` element, which contains the names of groups the user has defined. Each group consists of a user list. Group creation, deletion, and manipulation is carried out by actions originating here.
1117 * The ``history`` element, which allows browsing past instances of ``home`` and - optionally - ``trash``.
1119 Objects in Pithos can be:
1121 * Moved to trash and then deleted.
1122 * Shared with specific permissions.
1123 * Made public (shared with non-Pithos users).
1124 * Restored from previous versions.
1126 Some of these functions are performed by the client software and some by the Pithos server.
1128 In the first version of Pithos, objects could also be assigned custom tags. This is no longer supported. Existing deployments can migrate tags into a specific metadata value, i.e. ``X-Object-Meta-Tags``.
1130 Implementation Guidelines
1131 ^^^^^^^^^^^^^^^^^^^^^^^^^
1133 Pithos clients should use the ``pithos`` and ``trash`` containers for active and inactive objects respectively. If any of these containers is not found, the client software should create it, without interrupting the user's workflow. The ``home`` element corresponds to ``pithos`` and the ``trash`` element to ``trash``. Use ``PUT`` with the ``X-Move-From`` header, or ``MOVE`` to transfer objects from one container to the other. Use ``DELETE`` to remove from ``pithos`` without trashing, or to remove from ``trash``. When moving objects, detect naming conflicts with the ``If-Match`` or ``If-None-Match`` headers. Such conflicts should be resolved by the user.
1135 Object names should use the ``/`` delimiter to impose a hierarchy of folders and files.
1137 The ``shared`` element should be implemented as a read-only view of the ``pithos`` container, using the ``shared`` parameter when listing objects. The ``others`` element, should start with a top-level ``GET`` to retrieve the list of accounts accessible to the user. It is suggested that the client software hides the next step of navigation - the container - if it only includes ``pithos`` and forwards the user directly to the objects.
1139 Public objects are not included in ``shared`` and ``others`` listings. It is suggested that they are marked in a visually distinctive way in ``pithos`` listings (for example using an icon overlay).
1141 A special application menu, or a section in application preferences, should be devoted to managing groups (the ``groups`` element). All group-related actions are implemented at the account level.
1143 Browsing past versions of objects should be available both at the object and the container level. At the object level, a list of past versions can be included in the screen showing details or more information on the object (metadata, permissions, etc.). At the container level, it is suggested that clients use a ``history`` element, which presents to the user a read-only, time-variable view of ``pithos`` contents. This can be accomplished via the ``until`` parameter in listings. Optionally, ``history`` may include ``trash``.
1145 Uploading and downloading data
1146 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1148 By using hashmaps to upload and download objects the corresponding operations can complete much faster.
1150 In the case of an upload, only the missing blocks will be submitted to the server:
1152 * Calculate the hash value for each block of the object to be uploaded. Use the hash algorithm and block size of the destination container.
1153 * Send a hashmap ``PUT`` request for the object.
1155 * Server responds with status ``201`` (Created):
1157 * Blocks are already on the server. The object has been created. Done.
1159 * Server responds with status ``409`` (Conflict):
1161 * Server's response body contains the hashes of the blocks that do not exist on the server.
1162 * For each hash value in the server's response (or all hashes together):
1164 * Send a ``POST`` request to the destination container with the corresponding data.
1166 * Repeat hashmap ``PUT``. Fail if the server's response is not ``201``.
1168 Consulting hashmaps when downloading allows for resuming partially transferred objects. The client should retrieve the hashmap from the server and compare it with the hashmap computed from the respective local file. Any missing parts can be downloaded with ``GET`` requests with the additional ``Range`` header.
1173 Consider the following algorithm for synchronizing a local folder with the server. The "state" is the complete object listing, with the corresponding attributes.
1177 L: local state (stored state from last sync with the server)
1178 C: current state (state computed right before sync)
1184 # No remote changes, nothing to do
1186 # Update local state to match that of the server
1189 # We have local changes
1191 # No remote changes, update the server
1195 # Both we and server have changes
1197 # We were lucky, we did the same change
1200 # We have conflicting changes
1205 * States represent file hashes (it is suggested to use Merkle). Deleted or non-existing files are assumed to have a magic hash (e.g. empty string).
1206 * Updating a state (either local or remote) implies downloading, uploading or deleting the appropriate file.
1208 Recommended Practices and Examples
1209 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1211 Assuming an authentication token is obtained, the following high-level operations are available - shown with ``curl``:
1213 * Get account information ::
1216 -H "X-Auth-Token: 0000" \
1217 https://pithos.dev.grnet.gr/v1/user
1219 * List available containers ::
1222 -H "X-Auth-Token: 0000" \
1223 https://pithos.dev.grnet.gr/v1/user
1225 * Get container information ::
1228 -H "X-Auth-Token: 0000" \
1229 https://pithos.dev.grnet.gr/v1/user/pithos
1231 * Add a new container ::
1234 -H "X-Auth-Token: 0000" \
1235 https://pithos.dev.grnet.gr/v1/user/test
1237 * Delete a container ::
1239 curl -X DELETE -D - \
1240 -H "X-Auth-Token: 0000" \
1241 https://pithos.dev.grnet.gr/v1/user/test
1243 * List objects in a container ::
1246 -H "X-Auth-Token: 0000" \
1247 https://pithos.dev.grnet.gr/v1/user/pithos
1249 * List objects in a container (extended reply) ::
1252 -H "X-Auth-Token: 0000" \
1253 https://pithos.dev.grnet.gr/v1/user/pithos?format=json
1255 It is recommended that extended replies are cached and subsequent requests utilize the ``If-Modified-Since`` header.
1257 * List metadata keys used by objects in a container
1259 Will be in the ``X-Container-Object-Meta`` reply header, included in container information or object list (``HEAD`` or ``GET``). (**TBD**)
1261 * List objects in a container having a specific meta defined ::
1264 -H "X-Auth-Token: 0000" \
1265 https://pithos.dev.grnet.gr/v1/user/pithos?meta=favorites
1267 * Retrieve an object ::
1270 -H "X-Auth-Token: 0000" \
1271 https://pithos.dev.grnet.gr/v1/user/pithos/README.txt
1273 * Retrieve an object (specific ranges of data) ::
1276 -H "X-Auth-Token: 0000" \
1277 -H "Range: bytes=0-9" \
1278 https://pithos.dev.grnet.gr/v1/user/pithos/README.txt
1280 This will return the first 10 bytes. To get the first 10, bytes 30-39 and the last 100 use ``Range: bytes=0-9,30-39,-100``.
1282 * Add a new object (folder type) (**TBD**) ::
1285 -H "X-Auth-Token: 0000" \
1286 -H "Content-Type: application/directory" \
1287 https://pithos.dev.grnet.gr/v1/user/pithos/folder
1289 * Add a new object ::
1292 -H "X-Auth-Token: 0000" \
1293 -H "Content-Type: text/plain" \
1295 https://pithos.dev.grnet.gr/v1/user/pithos/folder/EXAMPLE.txt
1297 * Update an object ::
1300 -H "X-Auth-Token: 0000" \
1301 -H "Content-Length: 10" \
1302 -H "Content-Type: application/octet-stream" \
1303 -H "Content-Range: bytes 10-19/*" \
1305 https://pithos.dev.grnet.gr/v1/user/folder/EXAMPLE.txt
1307 This will update bytes 10-19 with the data specified.
1309 * Update an object (append) ::
1312 -H "X-Auth-Token: 0000" \
1313 -H "Content-Length: 10" \
1314 -H "Content-Type: application/octet-stream" \
1315 -H "Content-Range: bytes */*" \
1317 https://pithos.dev.grnet.gr/v1/user/folder/EXAMPLE.txt
1319 * Update an object (truncate) ::
1322 -H "X-Auth-Token: 0000" \
1323 -H "X-Source-Object: /folder/EXAMPLE.txt" \
1324 -H "Content-Range: bytes 0-0/*" \
1325 -H "X-Object-Bytes: 0" \
1326 https://pithos.dev.grnet.gr/v1/user/folder/EXAMPLE.txt
1328 This will truncate the object to 0 bytes.
1330 * Add object metadata ::
1333 -H "X-Auth-Token: 0000" \
1334 -H "X-Object-Meta-First: first_meta_value" \
1335 -H "X-Object-Meta-Second: second_meta_value" \
1336 https://pithos.dev.grnet.gr/v1/user/folder/EXAMPLE.txt
1338 * Delete object metadata ::
1341 -H "X-Auth-Token: 0000" \
1342 -H "X-Object-Meta-First: first_meta_value" \
1343 https://pithos.dev.grnet.gr/v1/user/folder/EXAMPLE.txt
1345 Metadata can only be "set". To delete ``X-Object-Meta-Second``, reset all metadata.
1347 * Delete an object ::
1349 curl -X DELETE -D - \
1350 -H "X-Auth-Token: 0000" \
1351 https://pithos.dev.grnet.gr/v1/user/folder/EXAMPLE.txt
projects / pithos / blob