% mechanize -- Documentation

Full API documentation is in the docstrings and the documentation of
[`urllib2`](http://docs.python.org/release/2.6/library/urllib2.html).  The
documentation in these web pages is in need of reorganisation at the moment,
after the merge of ClientCookie and ClientForm into mechanize.


Tests and examples
------------------

### Examples ###

The [front page](./) has some introductory examples.

The `examples` directory in the source packages contains a couple of silly,
but working, scripts to demonstrate basic use of the module.

See also the [forms examples](./forms.html) (these examples use the forms API
independently of `mechanize.Browser`).


### Tests ###

To run the tests:

    python test.py

There are some tests that try to fetch URLs from the internet.  To include
those in the test run:

    python test.py discover --tag internet


The `urllib2` interface
-----------------------

mechanize exports the complete interface of `urllib2`.  See the [`urllib2`
documentation](http://docs.python.org/release/2.6/library/urllib2.html).  For
example:

~~~~{.python}
import mechanize
response = mechanize.urlopen("http://www.example.com/")
print response.read()
~~~~


Compatibility
-------------

These notes explain the relationship between mechanize, ClientCookie,
ClientForm, `cookielib` and `urllib2`, and which to use when.  If you're just
using mechanize, and not any of those other libraries, you can ignore this
section.

 #. mechanize works with Python 2.4, Python 2.5, Python 2.6, and Python 2.7.

 #. When using mechanize, anything you would normally import from `urllib2`
    should be imported from `mechanize` instead.

 #. Use of mechanize classes with `urllib2` (and vice-versa) is no longer
    supported.  However, existing classes implementing the `urllib2 Handler`
    interface are likely to work unchanged with mechanize.

 #. mechanize now only imports `urllib2.URLError` and `urllib2.HTTPError` from
    `urllib2`.  The rest is forked.  I intend to merge fixes from Python trunk
    frequently.

 #. ClientForm is no longer maintained as a separate package.  The code is
    now part of mechanize, and its interface is now exported through module
    mechanize (since mechanize 0.2.0).  Old code can simply be changed to
    `import mechanize as ClientForm` and should continue to work.

 #. ClientCookie is no longer maintained as a separate package.  The code is
    now part of mechanize, and its interface is now exported through module
    mechanize (since mechanize 0.1.0).  Old code can simply be changed to
    `import mechanize as ClientCookie` and should continue to work.

 #. The cookie handling parts of mechanize are in Python 2.4 standard library
    as module `cookielib` and extensions to module `urllib2`.  mechanize does
    not currently use `cookielib`, due to the presence of thread
    synchronisation code in `cookielib` that is not present in the mechanize
    fork of `cookielib`.

API differences between mechanize and `urllib2`:

 #. mechanize provides additional features.

 #. `mechanize.urlopen` differs in its behaviour: it handles cookies, whereas
    `urllib2.urlopen` does not.  To make a `urlopen` function with the
    `urllib2` behaviour:

~~~~{.python}
import mechanize
handler_classes = [mechanize.ProxyHandler,
                   mechanize.UnknownHandler,
                   mechanize.HTTPHandler,
                   mechanize.HTTPDefaultErrorHandler,
                   mechanize.HTTPRedirectHandler,
                   mechanize.FTPHandler,
                   mechanize.FileHandler,
                   mechanize.HTTPErrorProcessor]
opener = mechanize.OpenerDirector()
for handler_class in handler_classes:
    opener.add_handler(handler_class())
urlopen = opener.open
~~~~

 #. Since Python 2.6, `urllib2` uses a `.timeout` attribute on `Request`
    objects internally.  However, `urllib2.Request` has no timeout constructor
    argument, and `urllib2.urlopen()` ignores this parameter.
    `mechanize.Request` has a `timeout` constructor argument which is used to
    set the attribute of the same name, and `mechanize.urlopen()` does not
    ignore the timeout attribute.


UserAgent vs UserAgentBase
--------------------------

`mechanize.UserAgent` is a trivial subclass of `mechanize.UserAgentBase`,
adding just one method, `.set_seekable_responses()` (see the [documentation on
seekable responses](./doc.html#seekable-responses)).

The reason for the extra class is that `mechanize.Browser` depends on seekable
response objects (because response objects are used to implement the browser
history).


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