Pithos_GSS » Java GSS CLI Client

#!/usr/bin/python

# Bindings for GRNET's "Pithos" storage system's REST API

# Author: Apollon Oikonomopoulos (apollon@noc.grnet.gr)

# Distributed under the terms of GNU General Public License v3

import urllib

import base64

from httplib2 import Http

from hmac import HMAC

from hashlib import sha1

from time import strftime

from simplejson import JSONEncoder, JSONDecoder

class AuthenticationError(Exception):

    def __init__(self, value):

        self.parameter = value

    def __str__(self):

        return repr(self.parameter)

class PithosObject:

    def __init__(self, name, uri, pithos):

        self.name = name

        self.uri = uri

        self.pithos = pithos

class PithosGroup(PithosObject):

    def get_members(self):

        data = self.pithos.get_resource(self.uri)

        members = self.pithos.jsondecoder.decode(data)

        return map(lambda x: x.replace(self.uri + '/', '', 1), members)

    def stat(self):

        return len(self.read())

    def read(self):

        return "\n".join(self.getMembers())

    def __repr__(self):

        return "<PithosGroup: '" + self.name + "'>"

class PithosFile(PithosObject):

    def __init__(self, name, uri, pithos):

        self.position = 0

        PithosObject.__init__(self, name, uri, pithos)

    def __repr__(self):

        return "<PithosFile: '" + self.name + "'>"

    def get_metadata(self):

        metadata = self.pithos.get_resource(self.uri, "HEAD")

        metadata = self.pithos.jsondecoder.decode(metadata)

        return metadata

    def read(self, length=None):

        headers = {}

        if length:

            headers['Range'] = 'bytes %d-%d' % (self.position, self.position + length - 1)

        elif self.position > 0:

            headers['Range'] = 'bytes %d-' % self.position

        buf = self.pithos.get_resource(self.uri, headers=headers)

        self.position += len(buf)

        return buf

    def seek(self,position):

        self.position = position

class PithosDir(PithosObject):

    def __repr__(self):

        return "<PithosDir: '" + self.name + "'>"

    def stat(self):

        metadata = self.pithos.get_resource(self.uri)

        metadata = self.pithos.jsondecoder.decode(metadata)

        return metadata

    def list(self):

        metadata = self.pithos.get_resource(self.uri)

        metadata = self.pithos.jsondecoder.decode(metadata)

        print metadata

        files = []

        folders = []

        for file in metadata['files']:

            files.append(PithosFile(file['name'], file['uri'], self.pithos))

        for dir in metadata['folders']:

            folders.append(PithosDir(dir['name'], dir['uri'], self.pithos))

        return files + folders

class Pithos:

    def __init__(self, username, token, url="pithos.grnet.gr"):

        self.username = username

        self.token = base64.decodestring(token)

        self.url = url

        self.connection = Http()

        self.jsonencoder = JSONEncoder()

        self.jsondecoder = JSONDecoder()

        self._get_root_elements()

        print self.accountdata['username']

        print self.accountdata['name']

        print self.accountdata['quota']['bytesRemaining']

    def _get_root_elements(self):

        reply = self.get_resource('/')

        self.accountdata = self.jsondecoder.decode(reply)

    def get_resource(self, resource, method="GET", headers={}):

        if resource.startswith('http://'):

            resource = resource.replace('http://pithos.grnet.gr/pithos/rest/' + self.username, '', 1)

        else:

            resource = urllib.quote(resource)

        print 'Getting ' + resource

        current_time = strftime("%a, %d %b %Y %H:%M:%S %z")

        digest = HMAC(self.token, digestmod=sha1)

        digest.update(method + current_time + '/' + self.username + resource)

        headers['Authorization'] =  self.username + " " + \

            base64.encodestring(digest.digest()).strip()

        headers['user-agent'] = 'zythos'

        headers['X-GSS-Date'] = current_time

        response, content = self.connection.request(

            "http://pithos.grnet.gr/pithos/rest/" + self.username + resource, 

            method, headers=headers

        )

        print response

        if method == "HEAD":

            return response['x-gss-metadata']

        return content

    def get_groups(self):

        groups = self.get_resource(self.accountdata['groups'])

        groups = self.jsondecoder.decode(groups)

        return map(lambda x: PithosGroup(x['name'], x['uri'], self), groups)

    def get_group(self,name):

        return PithosGroup(name, self.accountdata['groups'] + '/' + name, self)

    def get_files(self):

        listing = self.get_resource(self.accountdata['files'])

        listing = self.jsondecoder.decode(listing)

        return map(lambda x: PithosFile(x['name'], x['uri'], self), listing['files']) + \

            map(lambda x: PithosDir(x['name'], x['uri'], self), listing['folders'])

    def get_file(self,path):

        return PithosFile(path.split('/')[-1], 

            self.accountdata['files'] + '/' + urllib.quote(path), self)