gluon/docs/dev/site_library.rst
2018-07-07 11:43:37 +02:00

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gluon.site library
==================
The *gluon.site* library allows convenient access to the site configuration
from Lua scripts. Example:
.. code-block:: lua
local site = require 'gluon.site'
print(site.wifi24.ap.ssid())
The *site* object in this example does not directly represent the *site.conf* data structure;
instead, it is wrapped in a way that makes it more convenient to access deeply nested elements.
To access the the underlying values, they must be unwrapped using the function call notation
(the ``()`` after ``site.wifi24.ap.ssid`` in the example).
The wrapper objects have two advantages over simple Lua tables:
* Accessing non-existing values is never an error: ``site.wifi24.ap.ssid()`` will simply
return *nil* if ``site.wifi24`` or ``site.wifi24.ap`` do not exist
* Default values: A default value can be passed to the unwrapping function call:
.. code-block:: lua
print(site.wifi24.ap.ssid('Default'))
will return *'Default'* instead of *nil* when the value is unset.
Note that *nil* values and unset values are equivalent in Lua.
A simple way to access the whole site configuration as a simple table
is to unwrap the top-level site object:
.. code-block:: lua
local site_table = site()