Synnefo » Pithos

# Copyright 2011 GRNET S.A. All rights reserved.

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import logging

import uuid

from django.http import HttpResponse

from pithos.api.faults import (Fault, BadRequest, ItemNotFound, RangeNotSatisfiable)

from pithos.api.util import (put_object_meta, validate_modification_preconditions,

    validate_matching_preconditions, get_range, ObjectWrapper, api_method)

from pithos.backends import backend

logger = logging.getLogger(__name__)

def object_demux(request, v_account, v_container, v_object):

    if request.method == 'HEAD':

        return object_meta(request, v_account, v_container, v_object)

    elif request.method == 'GET':

        return object_read(request, v_account, v_container, v_object)

    else:

        return method_not_allowed(request)

# TODO: Use a version of api_method that does not check for a token.

@api_method('HEAD')

def object_meta(request, v_account, v_container, v_object):

    # Normal Response Codes: 204

    # Error Response Codes: serviceUnavailable (503),

    #                       itemNotFound (404),

    #                       unauthorized (401),

    #                       badRequest (400)

    try:

        meta = backend.get_object_meta(v_account, v_container, v_object)

    except NameError:

        raise ItemNotFound('Object does not exist')

    if 'X-Object-Public' not in meta:

        raise ItemNotFound('Object does not exist')

    response = HttpResponse(status=204)

    put_object_meta(response, meta)

    return response

@api_method('GET')

def object_read(request, v_account, v_container, v_object):

    # Normal Response Codes: 200, 206

    # Error Response Codes: serviceUnavailable (503),

    #                       rangeNotSatisfiable (416),

    #                       preconditionFailed (412),

    #                       itemNotFound (404),

    #                       unauthorized (401),

    #                       badRequest (400),

    #                       notModified (304)

    try:

        meta = backend.get_object_meta(v_account, v_container, v_object)

    except NameError:

        raise ItemNotFound('Object does not exist')

    if 'X-Object-Public' not in meta:

        raise ItemNotFound('Object does not exist')

    # Evaluate conditions.

    validate_modification_preconditions(request, meta)

    try:

        validate_matching_preconditions(request, meta)

    except NotModified:

        response = HttpResponse(status=304)

        response['ETag'] = meta['hash']

        return response

    try:

        size, hashmap = backend.get_object_hashmap(v_account, v_container, v_object)

    except NameError:

        raise ItemNotFound('Object does not exist')

    # Range handling.

    ranges = get_range(request, size)

    if ranges is None:

        ranges = [(0, size)]

        ret = 200

    else:

        check = [True for offset, length in ranges if

                    length <= 0 or length > size or

                    offset < 0 or offset >= size or

                    offset + length > size]

        if len(check) > 0:

            raise RangeNotSatisfiable('Requested range exceeds object limits')        

        ret = 206

    if ret == 206 and len(ranges) > 1:

        boundary = uuid.uuid4().hex

    else:

        boundary = ''

    wrapper = ObjectWrapper(v_account, v_container, v_object, ranges, size, hashmap, boundary)

    response = HttpResponse(wrapper, status=ret)

    put_object_meta(response, meta)

    if ret == 206:

        if len(ranges) == 1:

            offset, length = ranges[0]

            response['Content-Length'] = length # Update with the correct length.

            response['Content-Range'] = 'bytes %d-%d/%d' % (offset, offset + length - 1, size)

        else:

            del(response['Content-Length'])

            response['Content-Type'] = 'multipart/byteranges; boundary=%s' % (boundary,)

    return response

@api_method()

def method_not_allowed(request):

    raise ItemNotFound('Object does not exist')