source file: /Library/Python/2.3/site-packages/CherryPy-3.0.1-py2.3.egg/cherrypy/lib/cptools.py
file stats: 205 lines, 39 executed: 19.0% covered
1. """Functions for builtin CherryPy tools.""" 2. 3. import md5 4. import re 5. 6. import cherrypy 7. from cherrypy.lib import http as _http 8. 9. 10. # Conditional HTTP request support # 11. 12. def validate_etags(autotags=False): 13. """Validate the current ETag against If-Match, If-None-Match headers. 14. 15. If autotags is True, an ETag response-header value will be provided 16. from an MD5 hash of the response body (unless some other code has 17. already provided an ETag header). If False (the default), the ETag 18. will not be automatic. 19. 20. WARNING: the autotags feature is not designed for URL's which allow 21. methods other than GET. For example, if a POST to the same URL returns 22. no content, the automatic ETag will be incorrect, breaking a fundamental 23. use for entity tags in a possibly destructive fashion. Likewise, if you 24. raise 304 Not Modified, the response body will be empty, the ETag hash 25. will be incorrect, and your application will break. 26. See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.24 27. """ 28. response = cherrypy.response 29. 30. # Guard against being run twice. 31. if hasattr(response, "ETag"): 32. return 33. 34. status, reason, msg = _http.valid_status(response.status) 35. 36. etag = response.headers.get('ETag') 37. 38. # Automatic ETag generation. See warning in docstring. 39. if (not etag) and autotags: 40. if status == 200: 41. etag = response.collapse_body() 42. etag = '"%s"' % md5.new(etag).hexdigest() 43. response.headers['ETag'] = etag 44. 45. response.ETag = etag 46. 47. # "If the request would, without the If-Match header field, result in 48. # anything other than a 2xx or 412 status, then the If-Match header 49. # MUST be ignored." 50. if status >= 200 and status <= 299: 51. request = cherrypy.request 52. 53. conditions = request.headers.elements('If-Match') or [] 54. conditions = [str(x) for x in conditions] 55. if conditions and not (conditions == ["*"] or etag in conditions): 56. raise cherrypy.HTTPError(412, "If-Match failed: ETag %r did " 57. "not match %r" % (etag, conditions)) 58. 59. conditions = request.headers.elements('If-None-Match') or [] 60. conditions = [str(x) for x in conditions] 61. if conditions == ["*"] or etag in conditions: 62. if request.method in ("GET", "HEAD"): 63. raise cherrypy.HTTPRedirect([], 304) 64. else: 65. raise cherrypy.HTTPError(412, "If-None-Match failed: ETag %r " 66. "matched %r" % (etag, conditions)) 67. 68. def validate_since(): 69. """Validate the current Last-Modified against If-Modified-Since headers. 70. 71. If no code has set the Last-Modified response header, then no validation 72. will be performed. 73. """ 74. response = cherrypy.response 75. lastmod = response.headers.get('Last-Modified') 76. if lastmod: 77. status, reason, msg = _http.valid_status(response.status) 78. 79. request = cherrypy.request 80. 81. since = request.headers.get('If-Unmodified-Since') 82. if since and since != lastmod: 83. if (status >= 200 and status <= 299) or status == 412: 84. raise cherrypy.HTTPError(412) 85. 86. since = request.headers.get('If-Modified-Since') 87. if since and since == lastmod: 88. if (status >= 200 and status <= 299) or status == 304: 89. if request.method in ("GET", "HEAD"): 90. raise cherrypy.HTTPRedirect([], 304) 91. else: 92. raise cherrypy.HTTPError(412) 93. 94. 95. # Tool code # 96. 97. def proxy(base=None, local='X-Forwarded-Host', remote='X-Forwarded-For', 98. scheme='X-Forwarded-Proto'): 99. """Change the base URL (scheme://host[:port][/path]). 100. 101. For running a CP server behind Apache, lighttpd, or other HTTP server. 102. 103. If you want the new request.base to include path info (not just the host), 104. you must explicitly set base to the full base path, and ALSO set 'local' 105. to '', so that the X-Forwarded-Host request header (which never includes 106. path info) does not override it. 107. 108. cherrypy.request.remote.ip (the IP address of the client) will be 109. rewritten if the header specified by the 'remote' arg is valid. 110. By default, 'remote' is set to 'X-Forwarded-For'. If you do not 111. want to rewrite remote.ip, set the 'remote' arg to an empty string. 112. """ 113. 114. request = cherrypy.request 115. 116. if scheme: 117. scheme = request.headers.get(scheme, None) 118. if not scheme: 119. scheme = request.base[:request.base.find("://")] 120. 121. if local: 122. base = request.headers.get(local, base) 123. if not base: 124. port = cherrypy.request.local.port 125. if port == 80: 126. base = 'localhost' 127. else: 128. base = 'localhost:%s' % port 129. 130. if base.find("://") == -1: 131. # add http:// or https:// if needed 132. base = scheme + "://" + base 133. 134. request.base = base 135. 136. if remote: 137. xff = request.headers.get(remote) 138. if xff: 139. if remote == 'X-Forwarded-For': 140. # See http://bob.pythonmac.org/archives/2005/09/23/apache-x-forwarded-for-caveat/ 141. xff = xff.split(',')[-1].strip() 142. request.remote.ip = xff 143. 144. 145. def ignore_headers(headers=('Range',)): 146. """Delete request headers whose field names are included in 'headers'. 147. 148. This is a useful tool for working behind certain HTTP servers; 149. for example, Apache duplicates the work that CP does for 'Range' 150. headers, and will doubly-truncate the response. 151. """ 152. request = cherrypy.request 153. for name in headers: 154. if name in request.headers: 155. del request.headers[name] 156. 157. 158. def response_headers(headers=None): 159. """Set headers on the response.""" 160. for name, value in (headers or []): 161. cherrypy.response.headers[name] = value 162. response_headers.failsafe = True 163. 164. 165. def referer(pattern, accept=True, accept_missing=False, error=403, 166. message='Forbidden Referer header.'): 167. """Raise HTTPError if Referer header does not pass our test. 168. 169. pattern: a regular expression pattern to test against the Referer. 170. accept: if True, the Referer must match the pattern; if False, 171. the Referer must NOT match the pattern. 172. accept_missing: if True, permit requests with no Referer header. 173. error: the HTTP error code to return to the client on failure. 174. message: a string to include in the response body on failure. 175. """ 176. try: 177. match = bool(re.match(pattern, cherrypy.request.headers['Referer'])) 178. if accept == match: 179. return 180. except KeyError: 181. if accept_missing: 182. return 183. 184. raise cherrypy.HTTPError(error, message) 185. 186. 187. class SessionAuth(object): 188. """Assert that the user is logged in.""" 189. 190. session_key = "username" 191. 192. def check_username_and_password(self, username, password): 193. pass 194. 195. def anonymous(self): 196. """Provide a temporary user name for anonymous users.""" 197. pass 198. 199. def on_login(self, username): 200. pass 201. 202. def on_logout(self, username): 203. pass 204. 205. def on_check(self, username): 206. pass 207. 208. def login_screen(self, from_page='..', username='', error_msg=''): 209. return """<html><body> 210. Message: %(error_msg)s 211. <form method="post" action="do_login"> 212. Login: <input type="text" name="username" value="%(username)s" size="10" /><br /> 213. Password: <input type="password" name="password" size="10" /><br /> 214. <input type="hidden" name="from_page" value="%(from_page)s" /><br /> 215. <input type="submit" /> 216. </form> 217. </body></html>""" % {'from_page': from_page, 'username': username, 218. 'error_msg': error_msg} 219. 220. def do_login(self, username, password, from_page='..'): 221. """Login. May raise redirect, or return True if request handled.""" 222. error_msg = self.check_username_and_password(username, password) 223. if error_msg: 224. body = self.login_screen(from_page, username, error_msg) 225. cherrypy.response.body = body 226. if cherrypy.response.headers.has_key("Content-Length"): 227. # Delete Content-Length header so finalize() recalcs it. 228. del cherrypy.response.headers["Content-Length"] 229. return True 230. else: 231. cherrypy.session[self.session_key] = cherrypy.request.login = username 232. self.on_login(username) 233. raise cherrypy.HTTPRedirect(from_page or "/") 234. 235. def do_logout(self, from_page='..'): 236. """Logout. May raise redirect, or return True if request handled.""" 237. sess = cherrypy.session 238. username = sess.get(self.session_key) 239. sess[self.session_key] = None 240. if username: 241. cherrypy.request.login = None 242. self.on_logout(username) 243. raise cherrypy.HTTPRedirect(from_page) 244. 245. def do_check(self): 246. """Assert username. May raise redirect, or return True if request handled.""" 247. sess = cherrypy.session 248. request = cherrypy.request 249. 250. username = sess.get(self.session_key) 251. if not username: 252. sess[self.session_key] = username = self.anonymous() 253. if not username: 254. cherrypy.response.body = self.login_screen(cherrypy.url(qs=request.query_string)) 255. if cherrypy.response.headers.has_key("Content-Length"): 256. # Delete Content-Length header so finalize() recalcs it. 257. del cherrypy.response.headers["Content-Length"] 258. return True 259. cherrypy.request.login = username 260. self.on_check(username) 261. 262. def run(self): 263. request = cherrypy.request 264. path = request.path_info 265. if path.endswith('login_screen'): 266. return self.login_screen(**request.params) 267. elif path.endswith('do_login'): 268. return self.do_login(**request.params) 269. elif path.endswith('do_logout'): 270. return self.do_logout(**request.params) 271. else: 272. return self.do_check() 273. 274. 275. def session_auth(**kwargs): 276. sa = SessionAuth() 277. for k, v in kwargs.iteritems(): 278. setattr(sa, k, v) 279. return sa.run() 280. session_auth.__doc__ = """Session authentication hook. 281. 282. Any attribute of the SessionAuth class may be overridden via a keyword arg 283. to this function: 284. 285. """ + "\n".join(["%s: %s" % (k, type(getattr(SessionAuth, k)).__name__) 286. for k in dir(SessionAuth) if not k.startswith("__")]) 287. 288. 289. def log_traceback(): 290. """Write the last error's traceback to the cherrypy error log.""" 291. from cherrypy import _cperror 292. cherrypy.log(_cperror.format_exc(), "HTTP") 293. 294. def log_request_headers(): 295. """Write request headers to the cherrypy error log.""" 296. h = [" %s: %s" % (k, v) for k, v in cherrypy.request.header_list] 297. cherrypy.log('\nRequest Headers:\n' + '\n'.join(h), "HTTP") 298. 299. def redirect(url='', internal=True): 300. """Raise InternalRedirect or HTTPRedirect to the given url.""" 301. if internal: 302. raise cherrypy.InternalRedirect(url) 303. else: 304. raise cherrypy.HTTPRedirect(url) 305. 306. def trailing_slash(missing=True, extra=False): 307. """Redirect if path_info has (missing|extra) trailing slash.""" 308. request = cherrypy.request 309. pi = request.path_info 310. 311. if request.is_index is True: 312. if missing: 313. if not pi.endswith('/'): 314. new_url = cherrypy.url(pi + '/', request.query_string) 315. raise cherrypy.HTTPRedirect(new_url) 316. elif request.is_index is False: 317. if extra: 318. # If pi == '/', don't redirect to ''! 319. if pi.endswith('/') and pi != '/': 320. new_url = cherrypy.url(pi[:-1], request.query_string) 321. raise cherrypy.HTTPRedirect(new_url) 322. 323. def flatten(): 324. """Wrap response.body in a generator that recursively iterates over body. 325. 326. This allows cherrypy.response.body to consist of 'nested generators'; 327. that is, a set of generators that yield generators. 328. """ 329. import types 330. def flattener(input): 331. for x in input: 332. if not isinstance(x, types.GeneratorType): 333. yield x 334. else: 335. for y in flattener(x): 336. yield y 337. response = cherrypy.response 338. response.body = flattener(response.body) 339. 340. 341. def accept(media=None): 342. """Return the client's preferred media-type (from the given Content-Types). 343. 344. If 'media' is None (the default), no test will be performed. 345. 346. If 'media' is provided, it should be the Content-Type value (as a string) 347. or values (as a list or tuple of strings) which the current request 348. can emit. The client's acceptable media ranges (as declared in the 349. Accept request header) will be matched in order to these Content-Type 350. values; the first such string is returned. That is, the return value 351. will always be one of the strings provided in the 'media' arg (or None 352. if 'media' is None). 353. 354. If no match is found, then HTTPError 406 (Not Acceptable) is raised. 355. Note that most web browsers send */* as a (low-quality) acceptable 356. media range, which should match any Content-Type. In addition, "...if 357. no Accept header field is present, then it is assumed that the client 358. accepts all media types." 359. 360. Matching types are checked in order of client preference first, 361. and then in the order of the given 'media' values. 362. 363. Note that this function does not honor accept-params (other than "q"). 364. """ 365. if not media: 366. return 367. if isinstance(media, basestring): 368. media = [media] 369. 370. # Parse the Accept request header, and try to match one 371. # of the requested media-ranges (in order of preference). 372. ranges = cherrypy.request.headers.elements('Accept') 373. if not ranges: 374. # Any media type is acceptable. 375. return media[0] 376. else: 377. # Note that 'ranges' is sorted in order of preference 378. for element in ranges: 379. if element.qvalue > 0: 380. if element.value == "*/*": 381. # Matches any type or subtype 382. return media[0] 383. elif element.value.endswith("/*"): 384. # Matches any subtype 385. mtype = element.value[:-1] # Keep the slash 386. for m in media: 387. if m.startswith(mtype): 388. return m 389. else: 390. # Matches exact value 391. if element.value in media: 392. return element.value 393. 394. # No suitable media-range found. 395. ah = cherrypy.request.headers.get('Accept') 396. if ah is None: 397. msg = "Your client did not send an Accept header." 398. else: 399. msg = "Your client sent this Accept header: %s." % ah 400. msg += (" But this resource only emits these media types: %s." % 401. ", ".join(media)) 402. raise cherrypy.HTTPError(406, msg) 403.