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1 #!/usr/bin/python2.4 | |
2 # | |
3 # Copyright (C) 2010 Google Inc. | |
4 # | |
5 # Licensed under the Apache License, Version 2.0 (the "License"); | |
6 # you may not use this file except in compliance with the License. | |
7 # You may obtain a copy of the License at | |
8 # | |
9 # http://www.apache.org/licenses/LICENSE-2.0 | |
10 # | |
11 # Unless required by applicable law or agreed to in writing, software | |
12 # distributed under the License is distributed on an "AS IS" BASIS, | |
13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
14 # See the License for the specific language governing permissions and | |
15 # limitations under the License. | |
16 | |
17 """Model objects for requests and responses. | |
18 | |
19 Each API may support one or more serializations, such | |
20 as JSON, Atom, etc. The model classes are responsible | |
21 for converting between the wire format and the Python | |
22 object representation. | |
23 """ | |
24 | |
25 __author__ = 'jcgregorio@google.com (Joe Gregorio)' | |
26 | |
27 import gflags | |
28 import logging | |
29 import urllib | |
30 | |
31 from errors import HttpError | |
32 from oauth2client.anyjson import simplejson | |
33 | |
34 FLAGS = gflags.FLAGS | |
35 | |
36 gflags.DEFINE_boolean('dump_request_response', False, | |
37 'Dump all http server requests and responses. ' | |
38 ) | |
39 | |
40 | |
41 def _abstract(): | |
42 raise NotImplementedError('You need to override this function') | |
43 | |
44 | |
45 class Model(object): | |
46 """Model base class. | |
47 | |
48 All Model classes should implement this interface. | |
49 The Model serializes and de-serializes between a wire | |
50 format such as JSON and a Python object representation. | |
51 """ | |
52 | |
53 def request(self, headers, path_params, query_params, body_value): | |
54 """Updates outgoing requests with a serialized body. | |
55 | |
56 Args: | |
57 headers: dict, request headers | |
58 path_params: dict, parameters that appear in the request path | |
59 query_params: dict, parameters that appear in the query | |
60 body_value: object, the request body as a Python object, which must be | |
61 serializable. | |
62 Returns: | |
63 A tuple of (headers, path_params, query, body) | |
64 | |
65 headers: dict, request headers | |
66 path_params: dict, parameters that appear in the request path | |
67 query: string, query part of the request URI | |
68 body: string, the body serialized in the desired wire format. | |
69 """ | |
70 _abstract() | |
71 | |
72 def response(self, resp, content): | |
73 """Convert the response wire format into a Python object. | |
74 | |
75 Args: | |
76 resp: httplib2.Response, the HTTP response headers and status | |
77 content: string, the body of the HTTP response | |
78 | |
79 Returns: | |
80 The body de-serialized as a Python object. | |
81 | |
82 Raises: | |
83 apiclient.errors.HttpError if a non 2xx response is received. | |
84 """ | |
85 _abstract() | |
86 | |
87 | |
88 class BaseModel(Model): | |
89 """Base model class. | |
90 | |
91 Subclasses should provide implementations for the "serialize" and | |
92 "deserialize" methods, as well as values for the following class attributes. | |
93 | |
94 Attributes: | |
95 accept: The value to use for the HTTP Accept header. | |
96 content_type: The value to use for the HTTP Content-type header. | |
97 no_content_response: The value to return when deserializing a 204 "No | |
98 Content" response. | |
99 alt_param: The value to supply as the "alt" query parameter for requests. | |
100 """ | |
101 | |
102 accept = None | |
103 content_type = None | |
104 no_content_response = None | |
105 alt_param = None | |
106 | |
107 def _log_request(self, headers, path_params, query, body): | |
108 """Logs debugging information about the request if requested.""" | |
109 if FLAGS.dump_request_response: | |
110 logging.info('--request-start--') | |
111 logging.info('-headers-start-') | |
112 for h, v in headers.iteritems(): | |
113 logging.info('%s: %s', h, v) | |
114 logging.info('-headers-end-') | |
115 logging.info('-path-parameters-start-') | |
116 for h, v in path_params.iteritems(): | |
117 logging.info('%s: %s', h, v) | |
118 logging.info('-path-parameters-end-') | |
119 logging.info('body: %s', body) | |
120 logging.info('query: %s', query) | |
121 logging.info('--request-end--') | |
122 | |
123 def request(self, headers, path_params, query_params, body_value): | |
124 """Updates outgoing requests with a serialized body. | |
125 | |
126 Args: | |
127 headers: dict, request headers | |
128 path_params: dict, parameters that appear in the request path | |
129 query_params: dict, parameters that appear in the query | |
130 body_value: object, the request body as a Python object, which must be | |
131 serializable by simplejson. | |
132 Returns: | |
133 A tuple of (headers, path_params, query, body) | |
134 | |
135 headers: dict, request headers | |
136 path_params: dict, parameters that appear in the request path | |
137 query: string, query part of the request URI | |
138 body: string, the body serialized as JSON | |
139 """ | |
140 query = self._build_query(query_params) | |
141 headers['accept'] = self.accept | |
142 headers['accept-encoding'] = 'gzip, deflate' | |
143 if 'user-agent' in headers: | |
144 headers['user-agent'] += ' ' | |
145 else: | |
146 headers['user-agent'] = '' | |
147 headers['user-agent'] += 'google-api-python-client/1.0' | |
148 | |
149 if body_value is not None: | |
150 headers['content-type'] = self.content_type | |
151 body_value = self.serialize(body_value) | |
152 self._log_request(headers, path_params, query, body_value) | |
153 return (headers, path_params, query, body_value) | |
154 | |
155 def _build_query(self, params): | |
156 """Builds a query string. | |
157 | |
158 Args: | |
159 params: dict, the query parameters | |
160 | |
161 Returns: | |
162 The query parameters properly encoded into an HTTP URI query string. | |
163 """ | |
164 if self.alt_param is not None: | |
165 params.update({'alt': self.alt_param}) | |
166 astuples = [] | |
167 for key, value in params.iteritems(): | |
168 if type(value) == type([]): | |
169 for x in value: | |
170 x = x.encode('utf-8') | |
171 astuples.append((key, x)) | |
172 else: | |
173 if getattr(value, 'encode', False) and callable(value.encode): | |
174 value = value.encode('utf-8') | |
175 astuples.append((key, value)) | |
176 return '?' + urllib.urlencode(astuples) | |
177 | |
178 def _log_response(self, resp, content): | |
179 """Logs debugging information about the response if requested.""" | |
180 if FLAGS.dump_request_response: | |
181 logging.info('--response-start--') | |
182 for h, v in resp.iteritems(): | |
183 logging.info('%s: %s', h, v) | |
184 if content: | |
185 logging.info(content) | |
186 logging.info('--response-end--') | |
187 | |
188 def response(self, resp, content): | |
189 """Convert the response wire format into a Python object. | |
190 | |
191 Args: | |
192 resp: httplib2.Response, the HTTP response headers and status | |
193 content: string, the body of the HTTP response | |
194 | |
195 Returns: | |
196 The body de-serialized as a Python object. | |
197 | |
198 Raises: | |
199 apiclient.errors.HttpError if a non 2xx response is received. | |
200 """ | |
201 self._log_response(resp, content) | |
202 # Error handling is TBD, for example, do we retry | |
203 # for some operation/error combinations? | |
204 if resp.status < 300: | |
205 if resp.status == 204: | |
206 # A 204: No Content response should be treated differently | |
207 # to all the other success states | |
208 return self.no_content_response | |
209 return self.deserialize(content) | |
210 else: | |
211 logging.debug('Content from bad request was: %s' % content) | |
212 raise HttpError(resp, content) | |
213 | |
214 def serialize(self, body_value): | |
215 """Perform the actual Python object serialization. | |
216 | |
217 Args: | |
218 body_value: object, the request body as a Python object. | |
219 | |
220 Returns: | |
221 string, the body in serialized form. | |
222 """ | |
223 _abstract() | |
224 | |
225 def deserialize(self, content): | |
226 """Perform the actual deserialization from response string to Python | |
227 object. | |
228 | |
229 Args: | |
230 content: string, the body of the HTTP response | |
231 | |
232 Returns: | |
233 The body de-serialized as a Python object. | |
234 """ | |
235 _abstract() | |
236 | |
237 | |
238 class JsonModel(BaseModel): | |
239 """Model class for JSON. | |
240 | |
241 Serializes and de-serializes between JSON and the Python | |
242 object representation of HTTP request and response bodies. | |
243 """ | |
244 accept = 'application/json' | |
245 content_type = 'application/json' | |
246 alt_param = 'json' | |
247 | |
248 def __init__(self, data_wrapper=False): | |
249 """Construct a JsonModel. | |
250 | |
251 Args: | |
252 data_wrapper: boolean, wrap requests and responses in a data wrapper | |
253 """ | |
254 self._data_wrapper = data_wrapper | |
255 | |
256 def serialize(self, body_value): | |
257 if (isinstance(body_value, dict) and 'data' not in body_value and | |
258 self._data_wrapper): | |
259 body_value = {'data': body_value} | |
260 return simplejson.dumps(body_value) | |
261 | |
262 def deserialize(self, content): | |
263 body = simplejson.loads(content) | |
264 if self._data_wrapper and isinstance(body, dict) and 'data' in body: | |
265 body = body['data'] | |
266 return body | |
267 | |
268 @property | |
269 def no_content_response(self): | |
270 return {} | |
271 | |
272 | |
273 class RawModel(JsonModel): | |
274 """Model class for requests that don't return JSON. | |
275 | |
276 Serializes and de-serializes between JSON and the Python | |
277 object representation of HTTP request, and returns the raw bytes | |
278 of the response body. | |
279 """ | |
280 accept = '*/*' | |
281 content_type = 'application/json' | |
282 alt_param = None | |
283 | |
284 def deserialize(self, content): | |
285 return content | |
286 | |
287 @property | |
288 def no_content_response(self): | |
289 return '' | |
290 | |
291 | |
292 class MediaModel(JsonModel): | |
293 """Model class for requests that return Media. | |
294 | |
295 Serializes and de-serializes between JSON and the Python | |
296 object representation of HTTP request, and returns the raw bytes | |
297 of the response body. | |
298 """ | |
299 accept = '*/*' | |
300 content_type = 'application/json' | |
301 alt_param = 'media' | |
302 | |
303 def deserialize(self, content): | |
304 return content | |
305 | |
306 @property | |
307 def no_content_response(self): | |
308 return '' | |
309 | |
310 | |
311 class ProtocolBufferModel(BaseModel): | |
312 """Model class for protocol buffers. | |
313 | |
314 Serializes and de-serializes the binary protocol buffer sent in the HTTP | |
315 request and response bodies. | |
316 """ | |
317 accept = 'application/x-protobuf' | |
318 content_type = 'application/x-protobuf' | |
319 alt_param = 'proto' | |
320 | |
321 def __init__(self, protocol_buffer): | |
322 """Constructs a ProtocolBufferModel. | |
323 | |
324 The serialzed protocol buffer returned in an HTTP response will be | |
325 de-serialized using the given protocol buffer class. | |
326 | |
327 Args: | |
328 protocol_buffer: The protocol buffer class used to de-serialize a | |
329 response from the API. | |
330 """ | |
331 self._protocol_buffer = protocol_buffer | |
332 | |
333 def serialize(self, body_value): | |
334 return body_value.SerializeToString() | |
335 | |
336 def deserialize(self, content): | |
337 return self._protocol_buffer.FromString(content) | |
338 | |
339 @property | |
340 def no_content_response(self): | |
341 return self._protocol_buffer() | |
342 | |
343 | |
344 def makepatch(original, modified): | |
345 """Create a patch object. | |
346 | |
347 Some methods support PATCH, an efficient way to send updates to a resource. | |
348 This method allows the easy construction of patch bodies by looking at the | |
349 differences between a resource before and after it was modified. | |
350 | |
351 Args: | |
352 original: object, the original deserialized resource | |
353 modified: object, the modified deserialized resource | |
354 Returns: | |
355 An object that contains only the changes from original to modified, in a | |
356 form suitable to pass to a PATCH method. | |
357 | |
358 Example usage: | |
359 item = service.activities().get(postid=postid, userid=userid).execute() | |
360 original = copy.deepcopy(item) | |
361 item['object']['content'] = 'This is updated.' | |
362 service.activities.patch(postid=postid, userid=userid, | |
363 body=makepatch(original, item)).execute() | |
364 """ | |
365 patch = {} | |
366 for key, original_value in original.iteritems(): | |
367 modified_value = modified.get(key, None) | |
368 if modified_value is None: | |
369 # Use None to signal that the element is deleted | |
370 patch[key] = None | |
371 elif original_value != modified_value: | |
372 if type(original_value) == type({}): | |
373 # Recursively descend objects | |
374 patch[key] = makepatch(original_value, modified_value) | |
375 else: | |
376 # In the case of simple types or arrays we just replace | |
377 patch[key] = modified_value | |
378 else: | |
379 # Don't add anything to patch if there's no change | |
380 pass | |
381 for key in modified: | |
382 if key not in original: | |
383 patch[key] = modified[key] | |
384 | |
385 return patch | |
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