__init__.py

OpenWFE是一个开放源码的Java工作流引擎。它是一个完整的业务处理管理套件：一个引擎

#
# Copyright (c) 2005, John Mettraux, OpenWFE.org
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without 
# modification, are permitted provided that the following conditions are met:
# 
# . Redistributions of source code must retain the above copyright notice, this
#   list of conditions and the following disclaimer.  
# 
# . Redistributions in binary form must reproduce the above copyright notice, 
#   this list of conditions and the following disclaimer in the documentation 
#   and/or other materials provided with the distribution.
# 
# . Neither the name of the "OpenWFE" nor the names of its contributors may be
#   used to endorse or promote products derived from this software without
#   specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
# POSSIBILITY OF SUCH DAMAGE.
#
# $Id: __init__.py 2098 2005-09-06 17:05:37Z jmettraux $
#

"""

    A base class for interacting with an OpenWFE REST service

"""

import base64
from time import sleep
from urllib2 import urlopen
from urllib2 import Request
from openwfe.workitem import codec


#
# the number of times unsuccesful requests are retried
#
#RETRY = 14
RETRY = 3

HTTP_EOL = '\r\n'
DOUBLE_HTTP_EOL = HTTP_EOL + HTTP_EOL



class RestSession:
    """
        The basics of a REST session.
        Do not instantiate directly.
    """

    def _computeUrl (self, action, storeName, **params):
        if storeName: 
            url = '%s/%s' % (self.url, storeName)
        else:
            url = self.url
        url = '%s?session=%s&action=%s' % (url, self.sessionId, action)
        for k in params.keys():
            url += '&%s=%s' % (k, params[k])
        return str(url)


    def _get (self, action, storeName=None, **params):
        return urlopen(self._computeUrl(action, storeName, **params))


    def _getXml (self, action, storeName=None, **params):
        for l in self._get(action, storeName, **params).readlines(): 
            print l[:-1]


    def _post (self, action, storeName, data, **params):
        url = self._computeUrl(action, storeName, **params)
        #
        #print "urlopen('%s', '%s')" % (url, data)
        #
        if data: data = data + DOUBLE_HTTP_EOL
        return urlopen(url, data)


    def _doPost (self, action, storeName, data, **params):
        #printFirstLine(data)
        r = None
        retry = 0
        while 1:
            try:
                r = self._post(action, storeName, data, **params)
                break
            except:
                if retry == RETRY-1: sleep(1)
                if retry > RETRY: raise
                #print '============================ retry = %i' % retry
                retry = retry + 1

        return codec.decode(r)

        # debug
        #import codecs
        #r = codecs.EncodedFile(r, 'iso-8859-1')
        #rd = r.read()
        #f = codecs.open('/home/jmettraux/tmp/python.out', 'w', 'iso-8859-1')
        #f.write(rd)
        #f.flush()
        #f.close()
        #return codec.decode(rd)


    def _postXml (self, action, storeName, data, **params):
        for l in self._post(action, storeName, data, **params).readlines(): 
            print l[:-1]


    def close (self):
        """
            Terminates the worksession. 
            You should take care of using this method, it frees ressources
            in the worklist.
        """
        self._doPost('endWorkSession', None, None)



#
# some methods

def getSession (url, username, password):
    """
        Connects to the given url, login and return the new sessionId if any.
    """

    hs = {}
    hs['Authorization'] = 'Basic %s' % \
        base64.encodestring('%s:%s' % (username, password))
    hs['RestClient'] = \
        '$Id: __init__.py 2098 2005-09-06 17:05:37Z jmettraux $'

    request = Request(url, headers=hs)

    f = urlopen(request)

    return codec.decode(f)