Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1 | :mod:`urllib.request` --- extensible library for opening URLs |
| 2 | ============================================================= |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 3 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 4 | .. module:: urllib.request |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 5 | :synopsis: Next generation URL opening library. |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 6 | .. moduleauthor:: Jeremy Hylton <jeremy@alum.mit.edu> |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 7 | .. sectionauthor:: Moshe Zadka <moshez@users.sourceforge.net> |
| 8 | |
| 9 | |
Georg Brandl | 0f7ede4 | 2008-06-23 11:23:31 +0000 | [diff] [blame] | 10 | The :mod:`urllib.request` module defines functions and classes which help in |
| 11 | opening URLs (mostly HTTP) in a complex world --- basic and digest |
| 12 | authentication, redirections, cookies and more. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 13 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 14 | The :mod:`urllib.request` module defines the following functions: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 15 | |
| 16 | |
| 17 | .. function:: urlopen(url[, data][, timeout]) |
| 18 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 19 | Open the URL *url*, which can be either a string or a |
| 20 | :class:`Request` object. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 21 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 22 | *data* may be a string specifying additional data to send to the |
| 23 | server, or ``None`` if no such data is needed. Currently HTTP |
| 24 | requests are the only ones that use *data*; the HTTP request will |
| 25 | be a POST instead of a GET when the *data* parameter is provided. |
| 26 | *data* should be a buffer in the standard |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 27 | :mimetype:`application/x-www-form-urlencoded` format. The |
Georg Brandl | 7fe2c4a | 2008-12-05 07:32:56 +0000 | [diff] [blame] | 28 | :func:`urllib.parse.urlencode` function takes a mapping or sequence |
| 29 | of 2-tuples and returns a string in this format. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 30 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 31 | The optional *timeout* parameter specifies a timeout in seconds for |
| 32 | blocking operations like the connection attempt (if not specified, |
| 33 | the global default timeout setting will be used). This actually |
| 34 | only works for HTTP, HTTPS, FTP and FTPS connections. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 35 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 36 | This function returns a file-like object with two additional methods from |
| 37 | the :mod:`urllib.response` module |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 38 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 39 | * :meth:`geturl` --- return the URL of the resource retrieved, |
| 40 | commonly used to determine if a redirect was followed |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 41 | |
Georg Brandl | 2dd0104 | 2009-02-27 16:46:46 +0000 | [diff] [blame] | 42 | * :meth:`info` --- return the meta-information of the page, such as headers, |
Benjamin Peterson | d23f822 | 2009-04-05 19:13:16 +0000 | [diff] [blame] | 43 | in the form of an :class:`http.client.HTTPMessage` instance (see `Quick |
Georg Brandl | 2dd0104 | 2009-02-27 16:46:46 +0000 | [diff] [blame] | 44 | Reference to HTTP Headers <http://www.cs.tut.fi/~jkorpela/http.html>`_) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 45 | |
| 46 | Raises :exc:`URLError` on errors. |
| 47 | |
Georg Brandl | 2dd0104 | 2009-02-27 16:46:46 +0000 | [diff] [blame] | 48 | Note that ``None`` may be returned if no handler handles the request (though |
| 49 | the default installed global :class:`OpenerDirector` uses |
| 50 | :class:`UnknownHandler` to ensure this never happens). |
| 51 | |
| 52 | The legacy ``urllib.urlopen`` function from Python 2.6 and earlier has been |
| 53 | discontinued; :func:`urlopen` corresponds to the old ``urllib2.urlopen``. |
| 54 | Proxy handling, which was done by passing a dictionary parameter to |
| 55 | ``urllib.urlopen``, can be obtained by using :class:`ProxyHandler` objects. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 56 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 57 | .. function:: install_opener(opener) |
| 58 | |
| 59 | Install an :class:`OpenerDirector` instance as the default global opener. |
| 60 | Installing an opener is only necessary if you want urlopen to use that opener; |
| 61 | otherwise, simply call :meth:`OpenerDirector.open` instead of :func:`urlopen`. |
| 62 | The code does not check for a real :class:`OpenerDirector`, and any class with |
| 63 | the appropriate interface will work. |
| 64 | |
| 65 | |
| 66 | .. function:: build_opener([handler, ...]) |
| 67 | |
| 68 | Return an :class:`OpenerDirector` instance, which chains the handlers in the |
| 69 | order given. *handler*\s can be either instances of :class:`BaseHandler`, or |
| 70 | subclasses of :class:`BaseHandler` (in which case it must be possible to call |
| 71 | the constructor without any parameters). Instances of the following classes |
| 72 | will be in front of the *handler*\s, unless the *handler*\s contain them, |
| 73 | instances of them or subclasses of them: :class:`ProxyHandler`, |
| 74 | :class:`UnknownHandler`, :class:`HTTPHandler`, :class:`HTTPDefaultErrorHandler`, |
| 75 | :class:`HTTPRedirectHandler`, :class:`FTPHandler`, :class:`FileHandler`, |
| 76 | :class:`HTTPErrorProcessor`. |
| 77 | |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 78 | If the Python installation has SSL support (i.e., if the :mod:`ssl` module can be imported), |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 79 | :class:`HTTPSHandler` will also be added. |
| 80 | |
Georg Brandl | e6bcc91 | 2008-05-12 18:05:20 +0000 | [diff] [blame] | 81 | A :class:`BaseHandler` subclass may also change its :attr:`handler_order` |
| 82 | member variable to modify its position in the handlers list. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 83 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 84 | .. function:: urlretrieve(url[, filename[, reporthook[, data]]]) |
| 85 | |
| 86 | Copy a network object denoted by a URL to a local file, if necessary. If the URL |
| 87 | points to a local file, or a valid cached copy of the object exists, the object |
| 88 | is not copied. Return a tuple ``(filename, headers)`` where *filename* is the |
| 89 | local file name under which the object can be found, and *headers* is whatever |
| 90 | the :meth:`info` method of the object returned by :func:`urlopen` returned (for |
| 91 | a remote object, possibly cached). Exceptions are the same as for |
| 92 | :func:`urlopen`. |
| 93 | |
| 94 | The second argument, if present, specifies the file location to copy to (if |
| 95 | absent, the location will be a tempfile with a generated name). The third |
| 96 | argument, if present, is a hook function that will be called once on |
| 97 | establishment of the network connection and once after each block read |
| 98 | thereafter. The hook will be passed three arguments; a count of blocks |
| 99 | transferred so far, a block size in bytes, and the total size of the file. The |
| 100 | third argument may be ``-1`` on older FTP servers which do not return a file |
| 101 | size in response to a retrieval request. |
| 102 | |
| 103 | If the *url* uses the :file:`http:` scheme identifier, the optional *data* |
| 104 | argument may be given to specify a ``POST`` request (normally the request type |
| 105 | is ``GET``). The *data* argument must in standard |
| 106 | :mimetype:`application/x-www-form-urlencoded` format; see the :func:`urlencode` |
| 107 | function below. |
| 108 | |
| 109 | :func:`urlretrieve` will raise :exc:`ContentTooShortError` when it detects that |
| 110 | the amount of data available was less than the expected amount (which is the |
| 111 | size reported by a *Content-Length* header). This can occur, for example, when |
| 112 | the download is interrupted. |
| 113 | |
| 114 | The *Content-Length* is treated as a lower bound: if there's more data to read, |
| 115 | urlretrieve reads more data, but if less data is available, it raises the |
| 116 | exception. |
| 117 | |
| 118 | You can still retrieve the downloaded data in this case, it is stored in the |
| 119 | :attr:`content` attribute of the exception instance. |
| 120 | |
| 121 | If no *Content-Length* header was supplied, urlretrieve can not check the size |
| 122 | of the data it has downloaded, and just returns it. In this case you just have |
| 123 | to assume that the download was successful. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 124 | |
| 125 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 126 | .. data:: _urlopener |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 127 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 128 | The public functions :func:`urlopen` and :func:`urlretrieve` create an instance |
| 129 | of the :class:`FancyURLopener` class and use it to perform their requested |
| 130 | actions. To override this functionality, programmers can create a subclass of |
| 131 | :class:`URLopener` or :class:`FancyURLopener`, then assign an instance of that |
| 132 | class to the ``urllib._urlopener`` variable before calling the desired function. |
| 133 | For example, applications may want to specify a different |
| 134 | :mailheader:`User-Agent` header than :class:`URLopener` defines. This can be |
| 135 | accomplished with the following code:: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 136 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 137 | import urllib.request |
Christian Heimes | 292d351 | 2008-02-03 16:51:08 +0000 | [diff] [blame] | 138 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 139 | class AppURLopener(urllib.request.FancyURLopener): |
| 140 | version = "App/1.7" |
| 141 | |
| 142 | urllib._urlopener = AppURLopener() |
Christian Heimes | 292d351 | 2008-02-03 16:51:08 +0000 | [diff] [blame] | 143 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 144 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 145 | .. function:: urlcleanup() |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 146 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 147 | Clear the cache that may have been built up by previous calls to |
| 148 | :func:`urlretrieve`. |
Christian Heimes | 292d351 | 2008-02-03 16:51:08 +0000 | [diff] [blame] | 149 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 150 | .. function:: pathname2url(path) |
Christian Heimes | 292d351 | 2008-02-03 16:51:08 +0000 | [diff] [blame] | 151 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 152 | Convert the pathname *path* from the local syntax for a path to the form used in |
| 153 | the path component of a URL. This does not produce a complete URL. The return |
| 154 | value will already be quoted using the :func:`quote` function. |
Christian Heimes | 292d351 | 2008-02-03 16:51:08 +0000 | [diff] [blame] | 155 | |
| 156 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 157 | .. function:: url2pathname(path) |
| 158 | |
| 159 | Convert the path component *path* from an encoded URL to the local syntax for a |
| 160 | path. This does not accept a complete URL. This function uses :func:`unquote` |
| 161 | to decode *path*. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 162 | |
| 163 | The following classes are provided: |
| 164 | |
Christian Heimes | 292d351 | 2008-02-03 16:51:08 +0000 | [diff] [blame] | 165 | .. class:: Request(url[, data][, headers][, origin_req_host][, unverifiable]) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 166 | |
| 167 | This class is an abstraction of a URL request. |
| 168 | |
| 169 | *url* should be a string containing a valid URL. |
| 170 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 171 | *data* may be a string specifying additional data to send to the |
| 172 | server, or ``None`` if no such data is needed. Currently HTTP |
| 173 | requests are the only ones that use *data*; the HTTP request will |
| 174 | be a POST instead of a GET when the *data* parameter is provided. |
| 175 | *data* should be a buffer in the standard |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 176 | :mimetype:`application/x-www-form-urlencoded` format. The |
Georg Brandl | 7fe2c4a | 2008-12-05 07:32:56 +0000 | [diff] [blame] | 177 | :func:`urllib.parse.urlencode` function takes a mapping or sequence |
| 178 | of 2-tuples and returns a string in this format. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 179 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 180 | *headers* should be a dictionary, and will be treated as if |
| 181 | :meth:`add_header` was called with each key and value as arguments. |
| 182 | This is often used to "spoof" the ``User-Agent`` header, which is |
| 183 | used by a browser to identify itself -- some HTTP servers only |
| 184 | allow requests coming from common browsers as opposed to scripts. |
| 185 | For example, Mozilla Firefox may identify itself as ``"Mozilla/5.0 |
| 186 | (X11; U; Linux i686) Gecko/20071127 Firefox/2.0.0.11"``, while |
| 187 | :mod:`urllib`'s default user agent string is |
| 188 | ``"Python-urllib/2.6"`` (on Python 2.6). |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 189 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 190 | The final two arguments are only of interest for correct handling |
| 191 | of third-party HTTP cookies: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 192 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 193 | *origin_req_host* should be the request-host of the origin |
| 194 | transaction, as defined by :rfc:`2965`. It defaults to |
| 195 | ``http.cookiejar.request_host(self)``. This is the host name or IP |
| 196 | address of the original request that was initiated by the user. |
| 197 | For example, if the request is for an image in an HTML document, |
| 198 | this should be the request-host of the request for the page |
Georg Brandl | 2442015 | 2008-05-26 16:32:26 +0000 | [diff] [blame] | 199 | containing the image. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 200 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 201 | *unverifiable* should indicate whether the request is unverifiable, |
| 202 | as defined by RFC 2965. It defaults to False. An unverifiable |
| 203 | request is one whose URL the user did not have the option to |
| 204 | approve. For example, if the request is for an image in an HTML |
| 205 | document, and the user had no option to approve the automatic |
| 206 | fetching of the image, this should be true. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 207 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 208 | .. class:: URLopener([proxies[, **x509]]) |
| 209 | |
| 210 | Base class for opening and reading URLs. Unless you need to support opening |
| 211 | objects using schemes other than :file:`http:`, :file:`ftp:`, or :file:`file:`, |
| 212 | you probably want to use :class:`FancyURLopener`. |
| 213 | |
| 214 | By default, the :class:`URLopener` class sends a :mailheader:`User-Agent` header |
| 215 | of ``urllib/VVV``, where *VVV* is the :mod:`urllib` version number. |
| 216 | Applications can define their own :mailheader:`User-Agent` header by subclassing |
| 217 | :class:`URLopener` or :class:`FancyURLopener` and setting the class attribute |
| 218 | :attr:`version` to an appropriate string value in the subclass definition. |
| 219 | |
| 220 | The optional *proxies* parameter should be a dictionary mapping scheme names to |
| 221 | proxy URLs, where an empty dictionary turns proxies off completely. Its default |
| 222 | value is ``None``, in which case environmental proxy settings will be used if |
| 223 | present, as discussed in the definition of :func:`urlopen`, above. |
| 224 | |
| 225 | Additional keyword parameters, collected in *x509*, may be used for |
| 226 | authentication of the client when using the :file:`https:` scheme. The keywords |
| 227 | *key_file* and *cert_file* are supported to provide an SSL key and certificate; |
| 228 | both are needed to support client authentication. |
| 229 | |
| 230 | :class:`URLopener` objects will raise an :exc:`IOError` exception if the server |
| 231 | returns an error code. |
| 232 | |
| 233 | .. method:: open(fullurl[, data]) |
| 234 | |
| 235 | Open *fullurl* using the appropriate protocol. This method sets up cache and |
| 236 | proxy information, then calls the appropriate open method with its input |
| 237 | arguments. If the scheme is not recognized, :meth:`open_unknown` is called. |
| 238 | The *data* argument has the same meaning as the *data* argument of |
| 239 | :func:`urlopen`. |
| 240 | |
| 241 | |
| 242 | .. method:: open_unknown(fullurl[, data]) |
| 243 | |
| 244 | Overridable interface to open unknown URL types. |
| 245 | |
| 246 | |
| 247 | .. method:: retrieve(url[, filename[, reporthook[, data]]]) |
| 248 | |
| 249 | Retrieves the contents of *url* and places it in *filename*. The return value |
| 250 | is a tuple consisting of a local filename and either a |
| 251 | :class:`email.message.Message` object containing the response headers (for remote |
| 252 | URLs) or ``None`` (for local URLs). The caller must then open and read the |
| 253 | contents of *filename*. If *filename* is not given and the URL refers to a |
| 254 | local file, the input filename is returned. If the URL is non-local and |
| 255 | *filename* is not given, the filename is the output of :func:`tempfile.mktemp` |
| 256 | with a suffix that matches the suffix of the last path component of the input |
| 257 | URL. If *reporthook* is given, it must be a function accepting three numeric |
| 258 | parameters. It will be called after each chunk of data is read from the |
| 259 | network. *reporthook* is ignored for local URLs. |
| 260 | |
| 261 | If the *url* uses the :file:`http:` scheme identifier, the optional *data* |
| 262 | argument may be given to specify a ``POST`` request (normally the request type |
| 263 | is ``GET``). The *data* argument must in standard |
| 264 | :mimetype:`application/x-www-form-urlencoded` format; see the :func:`urlencode` |
| 265 | function below. |
| 266 | |
| 267 | |
| 268 | .. attribute:: version |
| 269 | |
| 270 | Variable that specifies the user agent of the opener object. To get |
| 271 | :mod:`urllib` to tell servers that it is a particular user agent, set this in a |
| 272 | subclass as a class variable or in the constructor before calling the base |
| 273 | constructor. |
| 274 | |
| 275 | |
| 276 | .. class:: FancyURLopener(...) |
| 277 | |
| 278 | :class:`FancyURLopener` subclasses :class:`URLopener` providing default handling |
| 279 | for the following HTTP response codes: 301, 302, 303, 307 and 401. For the 30x |
| 280 | response codes listed above, the :mailheader:`Location` header is used to fetch |
| 281 | the actual URL. For 401 response codes (authentication required), basic HTTP |
| 282 | authentication is performed. For the 30x response codes, recursion is bounded |
| 283 | by the value of the *maxtries* attribute, which defaults to 10. |
| 284 | |
| 285 | For all other response codes, the method :meth:`http_error_default` is called |
| 286 | which you can override in subclasses to handle the error appropriately. |
| 287 | |
| 288 | .. note:: |
| 289 | |
| 290 | According to the letter of :rfc:`2616`, 301 and 302 responses to POST requests |
| 291 | must not be automatically redirected without confirmation by the user. In |
| 292 | reality, browsers do allow automatic redirection of these responses, changing |
| 293 | the POST to a GET, and :mod:`urllib` reproduces this behaviour. |
| 294 | |
| 295 | The parameters to the constructor are the same as those for :class:`URLopener`. |
| 296 | |
| 297 | .. note:: |
| 298 | |
| 299 | When performing basic authentication, a :class:`FancyURLopener` instance calls |
| 300 | its :meth:`prompt_user_passwd` method. The default implementation asks the |
| 301 | users for the required information on the controlling terminal. A subclass may |
| 302 | override this method to support more appropriate behavior if needed. |
| 303 | |
| 304 | The :class:`FancyURLopener` class offers one additional method that should be |
| 305 | overloaded to provide the appropriate behavior: |
| 306 | |
| 307 | .. method:: prompt_user_passwd(host, realm) |
| 308 | |
| 309 | Return information needed to authenticate the user at the given host in the |
| 310 | specified security realm. The return value should be a tuple, ``(user, |
| 311 | password)``, which can be used for basic authentication. |
| 312 | |
| 313 | The implementation prompts for this information on the terminal; an application |
| 314 | should override this method to use an appropriate interaction model in the local |
| 315 | environment. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 316 | |
| 317 | .. class:: OpenerDirector() |
| 318 | |
| 319 | The :class:`OpenerDirector` class opens URLs via :class:`BaseHandler`\ s chained |
| 320 | together. It manages the chaining of handlers, and recovery from errors. |
| 321 | |
| 322 | |
| 323 | .. class:: BaseHandler() |
| 324 | |
| 325 | This is the base class for all registered handlers --- and handles only the |
| 326 | simple mechanics of registration. |
| 327 | |
| 328 | |
| 329 | .. class:: HTTPDefaultErrorHandler() |
| 330 | |
| 331 | A class which defines a default handler for HTTP error responses; all responses |
| 332 | are turned into :exc:`HTTPError` exceptions. |
| 333 | |
| 334 | |
| 335 | .. class:: HTTPRedirectHandler() |
| 336 | |
| 337 | A class to handle redirections. |
| 338 | |
| 339 | |
| 340 | .. class:: HTTPCookieProcessor([cookiejar]) |
| 341 | |
| 342 | A class to handle HTTP Cookies. |
| 343 | |
| 344 | |
| 345 | .. class:: ProxyHandler([proxies]) |
| 346 | |
| 347 | Cause requests to go through a proxy. If *proxies* is given, it must be a |
| 348 | dictionary mapping protocol names to URLs of proxies. The default is to read the |
| 349 | list of proxies from the environment variables :envvar:`<protocol>_proxy`. |
Christian Heimes | e25f35e | 2008-03-20 10:49:03 +0000 | [diff] [blame] | 350 | To disable autodetected proxy pass an empty dictionary. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 351 | |
| 352 | |
| 353 | .. class:: HTTPPasswordMgr() |
| 354 | |
| 355 | Keep a database of ``(realm, uri) -> (user, password)`` mappings. |
| 356 | |
| 357 | |
| 358 | .. class:: HTTPPasswordMgrWithDefaultRealm() |
| 359 | |
| 360 | Keep a database of ``(realm, uri) -> (user, password)`` mappings. A realm of |
| 361 | ``None`` is considered a catch-all realm, which is searched if no other realm |
| 362 | fits. |
| 363 | |
| 364 | |
| 365 | .. class:: AbstractBasicAuthHandler([password_mgr]) |
| 366 | |
| 367 | This is a mixin class that helps with HTTP authentication, both to the remote |
| 368 | host and to a proxy. *password_mgr*, if given, should be something that is |
| 369 | compatible with :class:`HTTPPasswordMgr`; refer to section |
| 370 | :ref:`http-password-mgr` for information on the interface that must be |
| 371 | supported. |
| 372 | |
| 373 | |
| 374 | .. class:: HTTPBasicAuthHandler([password_mgr]) |
| 375 | |
| 376 | Handle authentication with the remote host. *password_mgr*, if given, should be |
| 377 | something that is compatible with :class:`HTTPPasswordMgr`; refer to section |
| 378 | :ref:`http-password-mgr` for information on the interface that must be |
| 379 | supported. |
| 380 | |
| 381 | |
| 382 | .. class:: ProxyBasicAuthHandler([password_mgr]) |
| 383 | |
| 384 | Handle authentication with the proxy. *password_mgr*, if given, should be |
| 385 | something that is compatible with :class:`HTTPPasswordMgr`; refer to section |
| 386 | :ref:`http-password-mgr` for information on the interface that must be |
| 387 | supported. |
| 388 | |
| 389 | |
| 390 | .. class:: AbstractDigestAuthHandler([password_mgr]) |
| 391 | |
| 392 | This is a mixin class that helps with HTTP authentication, both to the remote |
| 393 | host and to a proxy. *password_mgr*, if given, should be something that is |
| 394 | compatible with :class:`HTTPPasswordMgr`; refer to section |
| 395 | :ref:`http-password-mgr` for information on the interface that must be |
| 396 | supported. |
| 397 | |
| 398 | |
| 399 | .. class:: HTTPDigestAuthHandler([password_mgr]) |
| 400 | |
| 401 | Handle authentication with the remote host. *password_mgr*, if given, should be |
| 402 | something that is compatible with :class:`HTTPPasswordMgr`; refer to section |
| 403 | :ref:`http-password-mgr` for information on the interface that must be |
| 404 | supported. |
| 405 | |
| 406 | |
| 407 | .. class:: ProxyDigestAuthHandler([password_mgr]) |
| 408 | |
| 409 | Handle authentication with the proxy. *password_mgr*, if given, should be |
| 410 | something that is compatible with :class:`HTTPPasswordMgr`; refer to section |
| 411 | :ref:`http-password-mgr` for information on the interface that must be |
| 412 | supported. |
| 413 | |
| 414 | |
| 415 | .. class:: HTTPHandler() |
| 416 | |
| 417 | A class to handle opening of HTTP URLs. |
| 418 | |
| 419 | |
| 420 | .. class:: HTTPSHandler() |
| 421 | |
| 422 | A class to handle opening of HTTPS URLs. |
| 423 | |
| 424 | |
| 425 | .. class:: FileHandler() |
| 426 | |
| 427 | Open local files. |
| 428 | |
| 429 | |
| 430 | .. class:: FTPHandler() |
| 431 | |
| 432 | Open FTP URLs. |
| 433 | |
| 434 | |
| 435 | .. class:: CacheFTPHandler() |
| 436 | |
| 437 | Open FTP URLs, keeping a cache of open FTP connections to minimize delays. |
| 438 | |
| 439 | |
| 440 | .. class:: UnknownHandler() |
| 441 | |
| 442 | A catch-all class to handle unknown URLs. |
| 443 | |
| 444 | |
| 445 | .. _request-objects: |
| 446 | |
| 447 | Request Objects |
| 448 | --------------- |
| 449 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 450 | The following methods describe :class:`Request`'s public interface, |
| 451 | and so all may be overridden in subclasses. It also defines several |
| 452 | public attributes that can be used by clients to inspect the parsed |
| 453 | request. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 454 | |
Jeremy Hylton | e257316 | 2009-03-31 14:38:13 +0000 | [diff] [blame] | 455 | .. attribute:: Request.full_url |
| 456 | |
| 457 | The original URL passed to the constructor. |
| 458 | |
| 459 | .. attribute:: Request.type |
| 460 | |
| 461 | The URI scheme. |
| 462 | |
| 463 | .. attribute:: Request.host |
| 464 | |
| 465 | The URI authority, typically a host, but may also contain a port |
| 466 | separated by a colon. |
| 467 | |
| 468 | .. attribute:: Request.origin_req_host |
| 469 | |
| 470 | The original host for the request, without port. |
| 471 | |
| 472 | .. attribute:: Request.selector |
| 473 | |
| 474 | The URI path. If the :class:`Request` uses a proxy, then selector |
| 475 | will be the full url that is passed to the proxy. |
| 476 | |
| 477 | .. attribute:: Request.data |
| 478 | |
| 479 | The entity body for the request, or None if not specified. |
| 480 | |
| 481 | .. attribute:: Request.unverifiable |
| 482 | |
| 483 | boolean, indicates whether the request is unverifiable as defined |
| 484 | by RFC 2965. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 485 | |
| 486 | .. method:: Request.add_data(data) |
| 487 | |
| 488 | Set the :class:`Request` data to *data*. This is ignored by all handlers except |
| 489 | HTTP handlers --- and there it should be a byte string, and will change the |
| 490 | request to be ``POST`` rather than ``GET``. |
| 491 | |
| 492 | |
| 493 | .. method:: Request.get_method() |
| 494 | |
| 495 | Return a string indicating the HTTP request method. This is only meaningful for |
| 496 | HTTP requests, and currently always returns ``'GET'`` or ``'POST'``. |
| 497 | |
| 498 | |
| 499 | .. method:: Request.has_data() |
| 500 | |
| 501 | Return whether the instance has a non-\ ``None`` data. |
| 502 | |
| 503 | |
| 504 | .. method:: Request.get_data() |
| 505 | |
| 506 | Return the instance's data. |
| 507 | |
| 508 | |
| 509 | .. method:: Request.add_header(key, val) |
| 510 | |
| 511 | Add another header to the request. Headers are currently ignored by all |
| 512 | handlers except HTTP handlers, where they are added to the list of headers sent |
| 513 | to the server. Note that there cannot be more than one header with the same |
| 514 | name, and later calls will overwrite previous calls in case the *key* collides. |
| 515 | Currently, this is no loss of HTTP functionality, since all headers which have |
| 516 | meaning when used more than once have a (header-specific) way of gaining the |
| 517 | same functionality using only one header. |
| 518 | |
| 519 | |
| 520 | .. method:: Request.add_unredirected_header(key, header) |
| 521 | |
| 522 | Add a header that will not be added to a redirected request. |
| 523 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 524 | |
| 525 | .. method:: Request.has_header(header) |
| 526 | |
| 527 | Return whether the instance has the named header (checks both regular and |
| 528 | unredirected). |
| 529 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 530 | |
| 531 | .. method:: Request.get_full_url() |
| 532 | |
| 533 | Return the URL given in the constructor. |
| 534 | |
| 535 | |
| 536 | .. method:: Request.get_type() |
| 537 | |
| 538 | Return the type of the URL --- also known as the scheme. |
| 539 | |
| 540 | |
| 541 | .. method:: Request.get_host() |
| 542 | |
| 543 | Return the host to which a connection will be made. |
| 544 | |
| 545 | |
| 546 | .. method:: Request.get_selector() |
| 547 | |
| 548 | Return the selector --- the part of the URL that is sent to the server. |
| 549 | |
| 550 | |
| 551 | .. method:: Request.set_proxy(host, type) |
| 552 | |
| 553 | Prepare the request by connecting to a proxy server. The *host* and *type* will |
| 554 | replace those of the instance, and the instance's selector will be the original |
| 555 | URL given in the constructor. |
| 556 | |
| 557 | |
| 558 | .. method:: Request.get_origin_req_host() |
| 559 | |
| 560 | Return the request-host of the origin transaction, as defined by :rfc:`2965`. |
| 561 | See the documentation for the :class:`Request` constructor. |
| 562 | |
| 563 | |
| 564 | .. method:: Request.is_unverifiable() |
| 565 | |
| 566 | Return whether the request is unverifiable, as defined by RFC 2965. See the |
| 567 | documentation for the :class:`Request` constructor. |
| 568 | |
| 569 | |
| 570 | .. _opener-director-objects: |
| 571 | |
| 572 | OpenerDirector Objects |
| 573 | ---------------------- |
| 574 | |
| 575 | :class:`OpenerDirector` instances have the following methods: |
| 576 | |
| 577 | |
| 578 | .. method:: OpenerDirector.add_handler(handler) |
| 579 | |
| 580 | *handler* should be an instance of :class:`BaseHandler`. The following methods |
| 581 | are searched, and added to the possible chains (note that HTTP errors are a |
| 582 | special case). |
| 583 | |
| 584 | * :meth:`protocol_open` --- signal that the handler knows how to open *protocol* |
| 585 | URLs. |
| 586 | |
| 587 | * :meth:`http_error_type` --- signal that the handler knows how to handle HTTP |
| 588 | errors with HTTP error code *type*. |
| 589 | |
| 590 | * :meth:`protocol_error` --- signal that the handler knows how to handle errors |
| 591 | from (non-\ ``http``) *protocol*. |
| 592 | |
| 593 | * :meth:`protocol_request` --- signal that the handler knows how to pre-process |
| 594 | *protocol* requests. |
| 595 | |
| 596 | * :meth:`protocol_response` --- signal that the handler knows how to |
| 597 | post-process *protocol* responses. |
| 598 | |
| 599 | |
| 600 | .. method:: OpenerDirector.open(url[, data][, timeout]) |
| 601 | |
| 602 | Open the given *url* (which can be a request object or a string), optionally |
Alexandre Vassalotti | 5f8ced2 | 2008-05-16 00:03:33 +0000 | [diff] [blame] | 603 | passing the given *data*. Arguments, return values and exceptions raised are |
| 604 | the same as those of :func:`urlopen` (which simply calls the :meth:`open` |
| 605 | method on the currently installed global :class:`OpenerDirector`). The |
| 606 | optional *timeout* parameter specifies a timeout in seconds for blocking |
Georg Brandl | f78e02b | 2008-06-10 17:40:04 +0000 | [diff] [blame] | 607 | operations like the connection attempt (if not specified, the global default |
| 608 | timeout setting will be usedi). The timeout feature actually works only for |
| 609 | HTTP, HTTPS, FTP and FTPS connections). |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 610 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 611 | |
| 612 | .. method:: OpenerDirector.error(proto[, arg[, ...]]) |
| 613 | |
| 614 | Handle an error of the given protocol. This will call the registered error |
| 615 | handlers for the given protocol with the given arguments (which are protocol |
| 616 | specific). The HTTP protocol is a special case which uses the HTTP response |
| 617 | code to determine the specific error handler; refer to the :meth:`http_error_\*` |
| 618 | methods of the handler classes. |
| 619 | |
| 620 | Return values and exceptions raised are the same as those of :func:`urlopen`. |
| 621 | |
| 622 | OpenerDirector objects open URLs in three stages: |
| 623 | |
| 624 | The order in which these methods are called within each stage is determined by |
| 625 | sorting the handler instances. |
| 626 | |
| 627 | #. Every handler with a method named like :meth:`protocol_request` has that |
| 628 | method called to pre-process the request. |
| 629 | |
| 630 | #. Handlers with a method named like :meth:`protocol_open` are called to handle |
| 631 | the request. This stage ends when a handler either returns a non-\ :const:`None` |
| 632 | value (ie. a response), or raises an exception (usually :exc:`URLError`). |
| 633 | Exceptions are allowed to propagate. |
| 634 | |
| 635 | In fact, the above algorithm is first tried for methods named |
| 636 | :meth:`default_open`. If all such methods return :const:`None`, the algorithm |
| 637 | is repeated for methods named like :meth:`protocol_open`. If all such methods |
| 638 | return :const:`None`, the algorithm is repeated for methods named |
| 639 | :meth:`unknown_open`. |
| 640 | |
| 641 | Note that the implementation of these methods may involve calls of the parent |
| 642 | :class:`OpenerDirector` instance's :meth:`.open` and :meth:`.error` methods. |
| 643 | |
| 644 | #. Every handler with a method named like :meth:`protocol_response` has that |
| 645 | method called to post-process the response. |
| 646 | |
| 647 | |
| 648 | .. _base-handler-objects: |
| 649 | |
| 650 | BaseHandler Objects |
| 651 | ------------------- |
| 652 | |
| 653 | :class:`BaseHandler` objects provide a couple of methods that are directly |
| 654 | useful, and others that are meant to be used by derived classes. These are |
| 655 | intended for direct use: |
| 656 | |
| 657 | |
| 658 | .. method:: BaseHandler.add_parent(director) |
| 659 | |
| 660 | Add a director as parent. |
| 661 | |
| 662 | |
| 663 | .. method:: BaseHandler.close() |
| 664 | |
| 665 | Remove any parents. |
| 666 | |
| 667 | The following members and methods should only be used by classes derived from |
| 668 | :class:`BaseHandler`. |
| 669 | |
| 670 | .. note:: |
| 671 | |
| 672 | The convention has been adopted that subclasses defining |
| 673 | :meth:`protocol_request` or :meth:`protocol_response` methods are named |
| 674 | :class:`\*Processor`; all others are named :class:`\*Handler`. |
| 675 | |
| 676 | |
| 677 | .. attribute:: BaseHandler.parent |
| 678 | |
| 679 | A valid :class:`OpenerDirector`, which can be used to open using a different |
| 680 | protocol, or handle errors. |
| 681 | |
| 682 | |
| 683 | .. method:: BaseHandler.default_open(req) |
| 684 | |
| 685 | This method is *not* defined in :class:`BaseHandler`, but subclasses should |
| 686 | define it if they want to catch all URLs. |
| 687 | |
| 688 | This method, if implemented, will be called by the parent |
| 689 | :class:`OpenerDirector`. It should return a file-like object as described in |
| 690 | the return value of the :meth:`open` of :class:`OpenerDirector`, or ``None``. |
| 691 | It should raise :exc:`URLError`, unless a truly exceptional thing happens (for |
| 692 | example, :exc:`MemoryError` should not be mapped to :exc:`URLError`). |
| 693 | |
| 694 | This method will be called before any protocol-specific open method. |
| 695 | |
| 696 | |
| 697 | .. method:: BaseHandler.protocol_open(req) |
| 698 | :noindex: |
| 699 | |
| 700 | This method is *not* defined in :class:`BaseHandler`, but subclasses should |
| 701 | define it if they want to handle URLs with the given protocol. |
| 702 | |
| 703 | This method, if defined, will be called by the parent :class:`OpenerDirector`. |
| 704 | Return values should be the same as for :meth:`default_open`. |
| 705 | |
| 706 | |
| 707 | .. method:: BaseHandler.unknown_open(req) |
| 708 | |
| 709 | This method is *not* defined in :class:`BaseHandler`, but subclasses should |
| 710 | define it if they want to catch all URLs with no specific registered handler to |
| 711 | open it. |
| 712 | |
| 713 | This method, if implemented, will be called by the :attr:`parent` |
| 714 | :class:`OpenerDirector`. Return values should be the same as for |
| 715 | :meth:`default_open`. |
| 716 | |
| 717 | |
| 718 | .. method:: BaseHandler.http_error_default(req, fp, code, msg, hdrs) |
| 719 | |
| 720 | This method is *not* defined in :class:`BaseHandler`, but subclasses should |
| 721 | override it if they intend to provide a catch-all for otherwise unhandled HTTP |
| 722 | errors. It will be called automatically by the :class:`OpenerDirector` getting |
| 723 | the error, and should not normally be called in other circumstances. |
| 724 | |
| 725 | *req* will be a :class:`Request` object, *fp* will be a file-like object with |
| 726 | the HTTP error body, *code* will be the three-digit code of the error, *msg* |
| 727 | will be the user-visible explanation of the code and *hdrs* will be a mapping |
| 728 | object with the headers of the error. |
| 729 | |
| 730 | Return values and exceptions raised should be the same as those of |
| 731 | :func:`urlopen`. |
| 732 | |
| 733 | |
| 734 | .. method:: BaseHandler.http_error_nnn(req, fp, code, msg, hdrs) |
| 735 | |
| 736 | *nnn* should be a three-digit HTTP error code. This method is also not defined |
| 737 | in :class:`BaseHandler`, but will be called, if it exists, on an instance of a |
| 738 | subclass, when an HTTP error with code *nnn* occurs. |
| 739 | |
| 740 | Subclasses should override this method to handle specific HTTP errors. |
| 741 | |
| 742 | Arguments, return values and exceptions raised should be the same as for |
| 743 | :meth:`http_error_default`. |
| 744 | |
| 745 | |
| 746 | .. method:: BaseHandler.protocol_request(req) |
| 747 | :noindex: |
| 748 | |
| 749 | This method is *not* defined in :class:`BaseHandler`, but subclasses should |
| 750 | define it if they want to pre-process requests of the given protocol. |
| 751 | |
| 752 | This method, if defined, will be called by the parent :class:`OpenerDirector`. |
| 753 | *req* will be a :class:`Request` object. The return value should be a |
| 754 | :class:`Request` object. |
| 755 | |
| 756 | |
| 757 | .. method:: BaseHandler.protocol_response(req, response) |
| 758 | :noindex: |
| 759 | |
| 760 | This method is *not* defined in :class:`BaseHandler`, but subclasses should |
| 761 | define it if they want to post-process responses of the given protocol. |
| 762 | |
| 763 | This method, if defined, will be called by the parent :class:`OpenerDirector`. |
| 764 | *req* will be a :class:`Request` object. *response* will be an object |
| 765 | implementing the same interface as the return value of :func:`urlopen`. The |
| 766 | return value should implement the same interface as the return value of |
| 767 | :func:`urlopen`. |
| 768 | |
| 769 | |
| 770 | .. _http-redirect-handler: |
| 771 | |
| 772 | HTTPRedirectHandler Objects |
| 773 | --------------------------- |
| 774 | |
| 775 | .. note:: |
| 776 | |
| 777 | Some HTTP redirections require action from this module's client code. If this |
| 778 | is the case, :exc:`HTTPError` is raised. See :rfc:`2616` for details of the |
| 779 | precise meanings of the various redirection codes. |
| 780 | |
| 781 | |
Georg Brandl | 9617a59 | 2009-02-13 10:40:43 +0000 | [diff] [blame] | 782 | .. method:: HTTPRedirectHandler.redirect_request(req, fp, code, msg, hdrs, newurl) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 783 | |
| 784 | Return a :class:`Request` or ``None`` in response to a redirect. This is called |
| 785 | by the default implementations of the :meth:`http_error_30\*` methods when a |
| 786 | redirection is received from the server. If a redirection should take place, |
| 787 | return a new :class:`Request` to allow :meth:`http_error_30\*` to perform the |
Georg Brandl | 9617a59 | 2009-02-13 10:40:43 +0000 | [diff] [blame] | 788 | redirect to *newurl*. Otherwise, raise :exc:`HTTPError` if no other handler |
| 789 | should try to handle this URL, or return ``None`` if you can't but another |
| 790 | handler might. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 791 | |
| 792 | .. note:: |
| 793 | |
| 794 | The default implementation of this method does not strictly follow :rfc:`2616`, |
| 795 | which says that 301 and 302 responses to ``POST`` requests must not be |
| 796 | automatically redirected without confirmation by the user. In reality, browsers |
| 797 | do allow automatic redirection of these responses, changing the POST to a |
| 798 | ``GET``, and the default implementation reproduces this behavior. |
| 799 | |
| 800 | |
| 801 | .. method:: HTTPRedirectHandler.http_error_301(req, fp, code, msg, hdrs) |
| 802 | |
Georg Brandl | 9617a59 | 2009-02-13 10:40:43 +0000 | [diff] [blame] | 803 | Redirect to the ``Location:`` or ``URI:`` URL. This method is called by the |
| 804 | parent :class:`OpenerDirector` when getting an HTTP 'moved permanently' response. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 805 | |
| 806 | |
| 807 | .. method:: HTTPRedirectHandler.http_error_302(req, fp, code, msg, hdrs) |
| 808 | |
| 809 | The same as :meth:`http_error_301`, but called for the 'found' response. |
| 810 | |
| 811 | |
| 812 | .. method:: HTTPRedirectHandler.http_error_303(req, fp, code, msg, hdrs) |
| 813 | |
| 814 | The same as :meth:`http_error_301`, but called for the 'see other' response. |
| 815 | |
| 816 | |
| 817 | .. method:: HTTPRedirectHandler.http_error_307(req, fp, code, msg, hdrs) |
| 818 | |
| 819 | The same as :meth:`http_error_301`, but called for the 'temporary redirect' |
| 820 | response. |
| 821 | |
| 822 | |
| 823 | .. _http-cookie-processor: |
| 824 | |
| 825 | HTTPCookieProcessor Objects |
| 826 | --------------------------- |
| 827 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 828 | :class:`HTTPCookieProcessor` instances have one attribute: |
| 829 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 830 | .. attribute:: HTTPCookieProcessor.cookiejar |
| 831 | |
Georg Brandl | 2442015 | 2008-05-26 16:32:26 +0000 | [diff] [blame] | 832 | The :class:`http.cookiejar.CookieJar` in which cookies are stored. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 833 | |
| 834 | |
| 835 | .. _proxy-handler: |
| 836 | |
| 837 | ProxyHandler Objects |
| 838 | -------------------- |
| 839 | |
| 840 | |
| 841 | .. method:: ProxyHandler.protocol_open(request) |
| 842 | :noindex: |
| 843 | |
| 844 | The :class:`ProxyHandler` will have a method :meth:`protocol_open` for every |
| 845 | *protocol* which has a proxy in the *proxies* dictionary given in the |
| 846 | constructor. The method will modify requests to go through the proxy, by |
| 847 | calling ``request.set_proxy()``, and call the next handler in the chain to |
| 848 | actually execute the protocol. |
| 849 | |
| 850 | |
| 851 | .. _http-password-mgr: |
| 852 | |
| 853 | HTTPPasswordMgr Objects |
| 854 | ----------------------- |
| 855 | |
| 856 | These methods are available on :class:`HTTPPasswordMgr` and |
| 857 | :class:`HTTPPasswordMgrWithDefaultRealm` objects. |
| 858 | |
| 859 | |
| 860 | .. method:: HTTPPasswordMgr.add_password(realm, uri, user, passwd) |
| 861 | |
| 862 | *uri* can be either a single URI, or a sequence of URIs. *realm*, *user* and |
| 863 | *passwd* must be strings. This causes ``(user, passwd)`` to be used as |
| 864 | authentication tokens when authentication for *realm* and a super-URI of any of |
| 865 | the given URIs is given. |
| 866 | |
| 867 | |
| 868 | .. method:: HTTPPasswordMgr.find_user_password(realm, authuri) |
| 869 | |
| 870 | Get user/password for given realm and URI, if any. This method will return |
| 871 | ``(None, None)`` if there is no matching user/password. |
| 872 | |
| 873 | For :class:`HTTPPasswordMgrWithDefaultRealm` objects, the realm ``None`` will be |
| 874 | searched if the given *realm* has no matching user/password. |
| 875 | |
| 876 | |
| 877 | .. _abstract-basic-auth-handler: |
| 878 | |
| 879 | AbstractBasicAuthHandler Objects |
| 880 | -------------------------------- |
| 881 | |
| 882 | |
| 883 | .. method:: AbstractBasicAuthHandler.http_error_auth_reqed(authreq, host, req, headers) |
| 884 | |
| 885 | Handle an authentication request by getting a user/password pair, and re-trying |
| 886 | the request. *authreq* should be the name of the header where the information |
| 887 | about the realm is included in the request, *host* specifies the URL and path to |
| 888 | authenticate for, *req* should be the (failed) :class:`Request` object, and |
| 889 | *headers* should be the error headers. |
| 890 | |
| 891 | *host* is either an authority (e.g. ``"python.org"``) or a URL containing an |
| 892 | authority component (e.g. ``"http://python.org/"``). In either case, the |
| 893 | authority must not contain a userinfo component (so, ``"python.org"`` and |
| 894 | ``"python.org:80"`` are fine, ``"joe:password@python.org"`` is not). |
| 895 | |
| 896 | |
| 897 | .. _http-basic-auth-handler: |
| 898 | |
| 899 | HTTPBasicAuthHandler Objects |
| 900 | ---------------------------- |
| 901 | |
| 902 | |
| 903 | .. method:: HTTPBasicAuthHandler.http_error_401(req, fp, code, msg, hdrs) |
| 904 | |
| 905 | Retry the request with authentication information, if available. |
| 906 | |
| 907 | |
| 908 | .. _proxy-basic-auth-handler: |
| 909 | |
| 910 | ProxyBasicAuthHandler Objects |
| 911 | ----------------------------- |
| 912 | |
| 913 | |
| 914 | .. method:: ProxyBasicAuthHandler.http_error_407(req, fp, code, msg, hdrs) |
| 915 | |
| 916 | Retry the request with authentication information, if available. |
| 917 | |
| 918 | |
| 919 | .. _abstract-digest-auth-handler: |
| 920 | |
| 921 | AbstractDigestAuthHandler Objects |
| 922 | --------------------------------- |
| 923 | |
| 924 | |
| 925 | .. method:: AbstractDigestAuthHandler.http_error_auth_reqed(authreq, host, req, headers) |
| 926 | |
| 927 | *authreq* should be the name of the header where the information about the realm |
| 928 | is included in the request, *host* should be the host to authenticate to, *req* |
| 929 | should be the (failed) :class:`Request` object, and *headers* should be the |
| 930 | error headers. |
| 931 | |
| 932 | |
| 933 | .. _http-digest-auth-handler: |
| 934 | |
| 935 | HTTPDigestAuthHandler Objects |
| 936 | ----------------------------- |
| 937 | |
| 938 | |
| 939 | .. method:: HTTPDigestAuthHandler.http_error_401(req, fp, code, msg, hdrs) |
| 940 | |
| 941 | Retry the request with authentication information, if available. |
| 942 | |
| 943 | |
| 944 | .. _proxy-digest-auth-handler: |
| 945 | |
| 946 | ProxyDigestAuthHandler Objects |
| 947 | ------------------------------ |
| 948 | |
| 949 | |
| 950 | .. method:: ProxyDigestAuthHandler.http_error_407(req, fp, code, msg, hdrs) |
| 951 | |
| 952 | Retry the request with authentication information, if available. |
| 953 | |
| 954 | |
| 955 | .. _http-handler-objects: |
| 956 | |
| 957 | HTTPHandler Objects |
| 958 | ------------------- |
| 959 | |
| 960 | |
| 961 | .. method:: HTTPHandler.http_open(req) |
| 962 | |
| 963 | Send an HTTP request, which can be either GET or POST, depending on |
| 964 | ``req.has_data()``. |
| 965 | |
| 966 | |
| 967 | .. _https-handler-objects: |
| 968 | |
| 969 | HTTPSHandler Objects |
| 970 | -------------------- |
| 971 | |
| 972 | |
| 973 | .. method:: HTTPSHandler.https_open(req) |
| 974 | |
| 975 | Send an HTTPS request, which can be either GET or POST, depending on |
| 976 | ``req.has_data()``. |
| 977 | |
| 978 | |
| 979 | .. _file-handler-objects: |
| 980 | |
| 981 | FileHandler Objects |
| 982 | ------------------- |
| 983 | |
| 984 | |
| 985 | .. method:: FileHandler.file_open(req) |
| 986 | |
| 987 | Open the file locally, if there is no host name, or the host name is |
| 988 | ``'localhost'``. Change the protocol to ``ftp`` otherwise, and retry opening it |
| 989 | using :attr:`parent`. |
| 990 | |
| 991 | |
| 992 | .. _ftp-handler-objects: |
| 993 | |
| 994 | FTPHandler Objects |
| 995 | ------------------ |
| 996 | |
| 997 | |
| 998 | .. method:: FTPHandler.ftp_open(req) |
| 999 | |
| 1000 | Open the FTP file indicated by *req*. The login is always done with empty |
| 1001 | username and password. |
| 1002 | |
| 1003 | |
| 1004 | .. _cacheftp-handler-objects: |
| 1005 | |
| 1006 | CacheFTPHandler Objects |
| 1007 | ----------------------- |
| 1008 | |
| 1009 | :class:`CacheFTPHandler` objects are :class:`FTPHandler` objects with the |
| 1010 | following additional methods: |
| 1011 | |
| 1012 | |
| 1013 | .. method:: CacheFTPHandler.setTimeout(t) |
| 1014 | |
| 1015 | Set timeout of connections to *t* seconds. |
| 1016 | |
| 1017 | |
| 1018 | .. method:: CacheFTPHandler.setMaxConns(m) |
| 1019 | |
| 1020 | Set maximum number of cached connections to *m*. |
| 1021 | |
| 1022 | |
| 1023 | .. _unknown-handler-objects: |
| 1024 | |
| 1025 | UnknownHandler Objects |
| 1026 | ---------------------- |
| 1027 | |
| 1028 | |
| 1029 | .. method:: UnknownHandler.unknown_open() |
| 1030 | |
| 1031 | Raise a :exc:`URLError` exception. |
| 1032 | |
| 1033 | |
| 1034 | .. _http-error-processor-objects: |
| 1035 | |
| 1036 | HTTPErrorProcessor Objects |
| 1037 | -------------------------- |
| 1038 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1039 | .. method:: HTTPErrorProcessor.unknown_open() |
| 1040 | |
| 1041 | Process HTTP error responses. |
| 1042 | |
| 1043 | For 200 error codes, the response object is returned immediately. |
| 1044 | |
| 1045 | For non-200 error codes, this simply passes the job on to the |
| 1046 | :meth:`protocol_error_code` handler methods, via :meth:`OpenerDirector.error`. |
Georg Brandl | 0f7ede4 | 2008-06-23 11:23:31 +0000 | [diff] [blame] | 1047 | Eventually, :class:`HTTPDefaultErrorHandler` will raise an |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1048 | :exc:`HTTPError` if no other handler handles the error. |
| 1049 | |
Georg Brandl | 0f7ede4 | 2008-06-23 11:23:31 +0000 | [diff] [blame] | 1050 | |
| 1051 | .. _urllib-request-examples: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1052 | |
| 1053 | Examples |
| 1054 | -------- |
| 1055 | |
| 1056 | This example gets the python.org main page and displays the first 100 bytes of |
| 1057 | it:: |
| 1058 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1059 | >>> import urllib.request |
| 1060 | >>> f = urllib.request.urlopen('http://www.python.org/') |
Collin Winter | c79461b | 2007-09-01 23:34:30 +0000 | [diff] [blame] | 1061 | >>> print(f.read(100)) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1062 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> |
| 1063 | <?xml-stylesheet href="./css/ht2html |
| 1064 | |
| 1065 | Here we are sending a data-stream to the stdin of a CGI and reading the data it |
| 1066 | returns to us. Note that this example will only work when the Python |
| 1067 | installation supports SSL. :: |
| 1068 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1069 | >>> import urllib.request |
| 1070 | >>> req = urllib.request.Request(url='https://localhost/cgi-bin/test.cgi', |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1071 | ... data='This data is passed to stdin of the CGI') |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1072 | >>> f = urllib.request.urlopen(req) |
Collin Winter | c79461b | 2007-09-01 23:34:30 +0000 | [diff] [blame] | 1073 | >>> print(f.read()) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1074 | Got Data: "This data is passed to stdin of the CGI" |
| 1075 | |
| 1076 | The code for the sample CGI used in the above example is:: |
| 1077 | |
| 1078 | #!/usr/bin/env python |
| 1079 | import sys |
| 1080 | data = sys.stdin.read() |
Collin Winter | c79461b | 2007-09-01 23:34:30 +0000 | [diff] [blame] | 1081 | print('Content-type: text-plain\n\nGot Data: "%s"' % data) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1082 | |
| 1083 | Use of Basic HTTP Authentication:: |
| 1084 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1085 | import urllib.request |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1086 | # Create an OpenerDirector with support for Basic HTTP Authentication... |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1087 | auth_handler = urllib.request.HTTPBasicAuthHandler() |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1088 | auth_handler.add_password(realm='PDQ Application', |
| 1089 | uri='https://mahler:8092/site-updates.py', |
| 1090 | user='klem', |
| 1091 | passwd='kadidd!ehopper') |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1092 | opener = urllib.request.build_opener(auth_handler) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1093 | # ...and install it globally so it can be used with urlopen. |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1094 | urllib.request.install_opener(opener) |
| 1095 | urllib.request.urlopen('http://www.example.com/login.html') |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1096 | |
| 1097 | :func:`build_opener` provides many handlers by default, including a |
| 1098 | :class:`ProxyHandler`. By default, :class:`ProxyHandler` uses the environment |
| 1099 | variables named ``<scheme>_proxy``, where ``<scheme>`` is the URL scheme |
| 1100 | involved. For example, the :envvar:`http_proxy` environment variable is read to |
| 1101 | obtain the HTTP proxy's URL. |
| 1102 | |
| 1103 | This example replaces the default :class:`ProxyHandler` with one that uses |
Georg Brandl | 2ee470f | 2008-07-16 12:55:28 +0000 | [diff] [blame] | 1104 | programmatically-supplied proxy URLs, and adds proxy authorization support with |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1105 | :class:`ProxyBasicAuthHandler`. :: |
| 1106 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1107 | proxy_handler = urllib.request.ProxyHandler({'http': 'http://www.example.com:3128/'}) |
| 1108 | proxy_auth_handler = urllib.request.HTTPBasicAuthHandler() |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1109 | proxy_auth_handler.add_password('realm', 'host', 'username', 'password') |
| 1110 | |
| 1111 | opener = build_opener(proxy_handler, proxy_auth_handler) |
| 1112 | # This time, rather than install the OpenerDirector, we use it directly: |
| 1113 | opener.open('http://www.example.com/login.html') |
| 1114 | |
| 1115 | Adding HTTP headers: |
| 1116 | |
| 1117 | Use the *headers* argument to the :class:`Request` constructor, or:: |
| 1118 | |
Georg Brandl | 029986a | 2008-06-23 11:44:14 +0000 | [diff] [blame] | 1119 | import urllib.request |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1120 | req = urllib.request.Request('http://www.example.com/') |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1121 | req.add_header('Referer', 'http://www.python.org/') |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1122 | r = urllib.request.urlopen(req) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1123 | |
| 1124 | :class:`OpenerDirector` automatically adds a :mailheader:`User-Agent` header to |
| 1125 | every :class:`Request`. To change this:: |
| 1126 | |
Georg Brandl | 029986a | 2008-06-23 11:44:14 +0000 | [diff] [blame] | 1127 | import urllib.request |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1128 | opener = urllib.request.build_opener() |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1129 | opener.addheaders = [('User-agent', 'Mozilla/5.0')] |
| 1130 | opener.open('http://www.example.com/') |
| 1131 | |
| 1132 | Also, remember that a few standard headers (:mailheader:`Content-Length`, |
| 1133 | :mailheader:`Content-Type` and :mailheader:`Host`) are added when the |
| 1134 | :class:`Request` is passed to :func:`urlopen` (or :meth:`OpenerDirector.open`). |
| 1135 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1136 | .. _urllib-examples: |
| 1137 | |
| 1138 | Here is an example session that uses the ``GET`` method to retrieve a URL |
| 1139 | containing parameters:: |
| 1140 | |
| 1141 | >>> import urllib.request |
| 1142 | >>> import urllib.parse |
| 1143 | >>> params = urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0}) |
| 1144 | >>> f = urllib.request.urlopen("http://www.musi-cal.com/cgi-bin/query?%s" % params) |
| 1145 | >>> print(f.read()) |
| 1146 | |
| 1147 | The following example uses the ``POST`` method instead:: |
| 1148 | |
| 1149 | >>> import urllib.request |
| 1150 | >>> import urllib.parse |
| 1151 | >>> params = urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0}) |
| 1152 | >>> f = urllib.request.urlopen("http://www.musi-cal.com/cgi-bin/query", params) |
| 1153 | >>> print(f.read()) |
| 1154 | |
| 1155 | The following example uses an explicitly specified HTTP proxy, overriding |
| 1156 | environment settings:: |
| 1157 | |
| 1158 | >>> import urllib.request |
| 1159 | >>> proxies = {'http': 'http://proxy.example.com:8080/'} |
| 1160 | >>> opener = urllib.request.FancyURLopener(proxies) |
| 1161 | >>> f = opener.open("http://www.python.org") |
| 1162 | >>> f.read() |
| 1163 | |
| 1164 | The following example uses no proxies at all, overriding environment settings:: |
| 1165 | |
| 1166 | >>> import urllib.request |
| 1167 | >>> opener = urllib.request.FancyURLopener({}) |
| 1168 | >>> f = opener.open("http://www.python.org/") |
| 1169 | >>> f.read() |
| 1170 | |
| 1171 | |
| 1172 | :mod:`urllib.request` Restrictions |
| 1173 | ---------------------------------- |
| 1174 | |
| 1175 | .. index:: |
| 1176 | pair: HTTP; protocol |
| 1177 | pair: FTP; protocol |
| 1178 | |
| 1179 | * Currently, only the following protocols are supported: HTTP, (versions 0.9 and |
| 1180 | 1.0), FTP, and local files. |
| 1181 | |
| 1182 | * The caching feature of :func:`urlretrieve` has been disabled until I find the |
| 1183 | time to hack proper processing of Expiration time headers. |
| 1184 | |
| 1185 | * There should be a function to query whether a particular URL is in the cache. |
| 1186 | |
| 1187 | * For backward compatibility, if a URL appears to point to a local file but the |
| 1188 | file can't be opened, the URL is re-interpreted using the FTP protocol. This |
| 1189 | can sometimes cause confusing error messages. |
| 1190 | |
| 1191 | * The :func:`urlopen` and :func:`urlretrieve` functions can cause arbitrarily |
| 1192 | long delays while waiting for a network connection to be set up. This means |
| 1193 | that it is difficult to build an interactive Web client using these functions |
| 1194 | without using threads. |
| 1195 | |
| 1196 | .. index:: |
| 1197 | single: HTML |
| 1198 | pair: HTTP; protocol |
| 1199 | |
| 1200 | * The data returned by :func:`urlopen` or :func:`urlretrieve` is the raw data |
| 1201 | returned by the server. This may be binary data (such as an image), plain text |
| 1202 | or (for example) HTML. The HTTP protocol provides type information in the reply |
| 1203 | header, which can be inspected by looking at the :mailheader:`Content-Type` |
| 1204 | header. If the returned data is HTML, you can use the module |
| 1205 | :mod:`html.parser` to parse it. |
| 1206 | |
| 1207 | .. index:: single: FTP |
| 1208 | |
| 1209 | * The code handling the FTP protocol cannot differentiate between a file and a |
| 1210 | directory. This can lead to unexpected behavior when attempting to read a URL |
| 1211 | that points to a file that is not accessible. If the URL ends in a ``/``, it is |
| 1212 | assumed to refer to a directory and will be handled accordingly. But if an |
| 1213 | attempt to read a file leads to a 550 error (meaning the URL cannot be found or |
| 1214 | is not accessible, often for permission reasons), then the path is treated as a |
| 1215 | directory in order to handle the case when a directory is specified by a URL but |
| 1216 | the trailing ``/`` has been left off. This can cause misleading results when |
| 1217 | you try to fetch a file whose read permissions make it inaccessible; the FTP |
| 1218 | code will try to read it, fail with a 550 error, and then perform a directory |
| 1219 | listing for the unreadable file. If fine-grained control is needed, consider |
| 1220 | using the :mod:`ftplib` module, subclassing :class:`FancyURLOpener`, or changing |
| 1221 | *_urlopener* to meet your needs. |
| 1222 | |
Georg Brandl | 0f7ede4 | 2008-06-23 11:23:31 +0000 | [diff] [blame] | 1223 | |
| 1224 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1225 | :mod:`urllib.response` --- Response classes used by urllib. |
| 1226 | =========================================================== |
Georg Brandl | 0f7ede4 | 2008-06-23 11:23:31 +0000 | [diff] [blame] | 1227 | |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1228 | .. module:: urllib.response |
| 1229 | :synopsis: Response classes used by urllib. |
| 1230 | |
| 1231 | The :mod:`urllib.response` module defines functions and classes which define a |
Georg Brandl | 0f7ede4 | 2008-06-23 11:23:31 +0000 | [diff] [blame] | 1232 | minimal file like interface, including ``read()`` and ``readline()``. The |
| 1233 | typical response object is an addinfourl instance, which defines and ``info()`` |
| 1234 | method and that returns headers and a ``geturl()`` method that returns the url. |
Senthil Kumaran | aca8fd7 | 2008-06-23 04:41:59 +0000 | [diff] [blame] | 1235 | Functions defined by this module are used internally by the |
| 1236 | :mod:`urllib.request` module. |
| 1237 | |