7.7.3 HiddenFieldSessionMixin

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7.7.3 HiddenFieldSessionMixin

Saves session state to a hidden field named `__albstate__` at the end of every form produced by `<al-form>` tags.

Inherits from the `SessionBase` class so you must call the constructor if you subclass this class.

`encode_session`( | )

  Extends the base class `encode_session()` method to `zlib.compress()` and `base64.encodestring()` the result. This makes the session data suitable for placing in a hidden field in the HTML.

`load_session`( | )

  This is called from the `Application` class `load_session()` method. The session state is retrieved from the browser request, decoded and decompressed then passed to the `decode_session()` method.

`save_session`( | )

  This is called from the `Application` class `save_session()` method at the end of the request processing sequence. The method does nothing because the session state is saved in hidden fields in the HTML.

`form_close`( | )

  Called just before the `<al-form>` tag is closed. If the session is flagged to be saved a hidden field named `__albstate__` is written to the output.

  Note that this method is also present in the `RecorderMixin`, so if you inherit from the `HiddenFieldSessionMixin` class you must define a `form_close()` method in the derived class which calls this method in both of the super classes.