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Diffstat (limited to 'trunk/freebase/api/session.py')
| -rw-r--r-- | trunk/freebase/api/session.py | 391 |
1 files changed, 391 insertions, 0 deletions
diff --git a/trunk/freebase/api/session.py b/trunk/freebase/api/session.py new file mode 100644 index 0000000..b3ec825 --- /dev/null +++ b/trunk/freebase/api/session.py @@ -0,0 +1,391 @@ +# ======================================================================== +# Copyright (c) 2007, Metaweb Technologies, Inc. +# 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. +# +# THIS SOFTWARE IS PROVIDED BY METAWEB TECHNOLOGIES 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 METAWEB +# TECHNOLOGIES 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. +# ======================================================================== + +# +# declarations for external metaweb api. +# +# +# from metaweb.api import HTTPMetawebSession +# +# mss = HTTPMetawebSession('sandbox.freebase.com') +# print mss.mqlread([dict(name=None, type='/type/type')]) +# +# +# + +import os, sys, re +import urllib2 +import cookielib +import simplejson +from urllib import quote as urlquote +import pprint +import socket + +import logging +log = logging.getLogger() +log.setLevel(logging.DEBUG) +console = logging.StreamHandler() +console.setLevel(logging.INFO) +# add the handler to the root logger +log.addHandler(console) + + +__all__ = ['MetawebError', 'MetawebSession', 'HTTPMetawebSession'] + +__version__ = '0.1' + +import simplejson.encoder +simplejson.JSONEncoder.item_separator = ',' +simplejson.JSONEncoder.key_separator = ':' +#delattr(simplejson.encoder.ESCAPE_DCT, '/') + +def urlencode_weak(s): + return urlquote(s, safe='{}[],"/:$') + + +# from http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/361668 +class attrdict(dict): + """A dict whose items can also be accessed as member variables. + + >>> d = attrdict(a=1, b=2) + >>> d['c'] = 3 + >>> print d.a, d.b, d.c + 1 2 3 + >>> d.b = 10 + >>> print d['b'] + 10 + + # but be careful, it's easy to hide methods + >>> print d.get('c') + 3 + >>> d['get'] = 4 + >>> print d.get('a') + Traceback (most recent call last): + TypeError: 'int' object is not callable + """ + def __init__(self, *args, **kwargs): + dict.__init__(self, *args, **kwargs) + self.__dict__ = self + + + +# TODO expose the common parts of the result envelope +class MetawebError(Exception): + """ + an error report from the metaweb service. + """ + pass + + + +# TODO right now this is a completely unnecessary superclass. +# is there enough common behavior between session types +# to justify it? +class MetawebSession(object): + """ + MetawebSession is the base class for MetawebSession, subclassed for + different connection types. Only http is available externally. + + This is more of an interface than + """ + + # interface definition here... + + +class HTTPMetawebSession(MetawebSession): + """ + a MetawebSession is a request/response queue. + + this version uses the HTTP api, and is synchronous. + """ + # share cookies across sessions, so that different sessions can + # see each other's writes immediately. + _cookies = cookielib.CookieJar() + _cookiespy = urllib2.HTTPCookieProcessor(_cookies) + + def __init__(self, service_url, username=None, password=None, prev_session=None): + """ + create a new MetawebSession for interacting with the Metaweb. + + a new session will inherit state from prev_session if present, + """ + super(HTTPMetawebSession, self).__init__() + + assert not service_url.endswith('/') + if not '/' in service_url: # plain host:port + service_url = 'http://' + service_url + + self.service_url = service_url + + self.username = username + self.password = password + + self.tid = None + + if prev_session: + self.service_url = prev.service_url + + def _httpreq(self, service_path, method='GET', body=None, form=None, + headers=None, **kws): + """ + make an http request to the service. + + form arguments are encoded in the url, even for POST, if a non-form + content-type is given for the body. + """ + + if method == 'POST': + assert body is not None or form is not None + elif method == 'GET': + assert body is None + else: + assert 0, 'unknown method %s' % method + + log.debug('HTTPREQ: %s %s %s %s', service_path, method, kws, self._cookies) + + url = self.service_url + service_path + + if headers is None: + headers = [] + + # XXX This is a lousy way to parse Content-Type, where is + # the library? + ct = None + for k,v in headers: + if k.lower() == 'content-type': + ct = v.split(';')[0] + break + + if body is not None: + # if body is provided, content-type had better be too + assert ct is not None + + if form is not None: + qstr = '&'.join(['%s=%s' % (urlencode_weak(k), urlencode_weak(v)) + for k,v in form.items()]) + if method == 'POST': + # put the args on the url if we're putting something else + # in the body. this is used to add args to raw uploads. + if body is not None: + url += '?' + qstr + else: + if ct is None: + # XXX encoding and stuff + ct = 'application/x-www-form-urlencoded' + headers.append(('content-type', ct)) + + if ct == 'multipart/form-encoded': + # XXX fixme + raise NotImplementedError + elif ct == 'application/x-www-form-urlencoded': + body = qstr + else: + # for all methods other than POST, use the url + url += '?' + qstr + + req = urllib2.Request(url, body, dict(headers), **kws) + + self.opener = urllib2.build_opener(self._cookiespy) + + # assure the service that this isn't a CSRF form submission + self.opener.addheaders = [('User-agent', + 'python freebase.api-%s' % __version__), + ('X-Metaweb-Request', 'Python')] + + if self.tid is not None: + self.opener.addheaders.append(('X-Metaweb-TID', self.tid)) + + try: + if headers: + self.opener.addheaders += headers + resp = self.opener.open(req) + + except socket.error, e: + log.error('SOCKET FAILURE: %s', e.fp.read()) + raise MetawebError, 'failed contacting %s: %s' % (url, str(e)) + + except urllib2.HTTPError, e: + if e.code == 400 and e.info().type == 'application/json': + r = self._readjson(e.fp) + for msg in r.messages: + if msg.get('level', 'error') == 'error': + raise MetawebError(u'%s %s %r' % (msg.get('code',''), msg.message, msg.info)) + + # some 400 we don't recognize. hmm. + raise MetawebError(u'%r' % r) + raise MetawebError, 'request failed: %s: %r %r' % (url, str(e), e.fp.read()) + + for header in resp.info().headers: + log.debug('HTTP HEADER %s', header) + name, value = re.split("[:\n\r]", header, 1) + if name.lower() == 'x-metaweb-tid': + self.tid = value.strip() + #if name.lower().startswith('set-cookie'): + # if value.startswith(' metaweb-user'): + # pass + # else: + # self.saved_headers[name] = value.strip() + # log.debug('HTTP VALUE %s', value) + + return resp + + def _readjson(self, fp): + # TODO really this should be accomplished by hooking + # simplejson to create attrdicts instead of dicts. + def struct2attrdict(st): + """ + copy a json structure, turning all dicts into attrdicts. + + copying descends instances of dict and list, including subclasses. + """ + if isinstance(st, dict): + return attrdict([(k,struct2attrdict(v)) for k,v in st.items()]) + if isinstance(st, list): + return [struct2attrdict(li) for li in st] + return st + + json = fp.read() + if json == '': + log.error('the empty string is not valid json') + raise MetawebError('the empty string is not valid json') + + try: + r = simplejson.loads(json) + except ValueError, e: + log.error('error parsing json string %r' % json) + raise MetawebError, 'error parsing JSON string: %s' % e + + return struct2attrdict(r) + + def _mqlresult(self, r): + if r.code != '/api/status/ok': + for msg in r.messages: + log.error('mqlread failed: %s %s' % (msg.code, msg.message)) + raise MetawebError, 'query failed: %s' % r.messages[0].code + + return r.result + + def login(self): + """sign in to the service""" + + assert self.username is not None + assert self.password is not None + + log.debug('LOGIN USERNAME: %s', self.username) + + try: + resp = self._httpreq('/api/account/login', 'POST', + form=dict(username=self.username, + password=self.password)) + except urllib2.HTTPError, e: + raise MetawebError("login error: %s", e) + + r = self._readjson(resp) + + if r.code != '/api/status/ok': + raise MetawebError(u'%s %r' % (r.get('code',''), r.messages)) + + log.debug('LOGIN RESP: %r', r) + log.debug('LOGIN INFO: %s', resp.info()) + log.debug('LOGIN COOKIES: %s', self._cookies) + + + def mqlreaditer(self, sq): + """read a structure query""" + + cursor = True + + while 1: + subq = dict(query=[sq], cursor=cursor, escape=False) + qstr = simplejson.dumps(dict(c0=subq)) + + service = '/api/service/mqlread' + + resp = self._httpreq(service, form=dict(queries=qstr)) + r = self._readjson(resp) + r = r['c0'] + + for item in self._mqlresult(r): + yield item + + if r['cursor']: + cursor = r['cursor'] + else: + break + + def mqlread(self, sq): + """read a structure query""" + subq = dict(query=sq, cursor=True, escape=False) + qstr = simplejson.dumps(dict(c0=subq)) + + log.debug('MQLREAD: %s', qstr) + + service = '/api/service/mqlread' + + resp = self._httpreq(service, form=dict(queries=qstr)) + r = self._readjson(resp) + r = r['c0'] + return self._mqlresult(r) + + def trans(self, guid): + """translate blob from guid """ + url = '/api/trans/raw/' + urlquote(guid) + resp = self._httpreq(url) + content = resp.read() + return content + + def mqlwrite(self, sq): + """do a mql write""" + query = dict(query=sq, escape=False) + qstr = simplejson.dumps(query) + + log.debug('MQLWRITE: %s', qstr) + + service = '/api/service/mqlwrite' + resp = self._httpreq(service, 'POST', + form=dict(query=qstr)) + r = self._readjson(resp) + return self._mqlresult(r) + + def upload(self, body, content_type): + """upload to the metaweb""" + + log.debug('UPLOAD %s', content) + + service = '/api/service/upload' + resp = self._httpreq(service, 'POST', + headers={'content-type': content_type}, + body=qstr) + r = self._readjson(resp) + return self._mqlresult(r) + + +if __name__ == '__main__': + mss = HTTPMetawebSession('sandbox.freebase.com') + + print mss.mqlread([dict(name=None, type='/type/type')]) |