= Code Caveats =

This section's aim is to log some tricks and caveats that you should take into
consideration while developing for Indico.

== 1. If you add a new Javascript file, remember about packing ==

If you create a new Javascript file, remember that in production files are "packed" to reduce the number of files that the browser requests.
In a development machine, you probably have activated the server's "debug" mode, so the browser is requesting your unpacked files. In production, however, "debug" is turned off.

Therefore, if you add a new .js file, remember to add the corresponding line to the proper ''.cfg'' file in ''etc/js'' (usually ''indico.cfg'').

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== 2. Usage of .getUser() within a management area ==

'''Don't assume''' that a user is always logged in just because
he is in the management area of an event. getUser() can return None
because the user could have used a modification key to login. 
So, always check that getUser() is not None.

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== 3. Do not use Python built-ins as variable names ==

This is more a general Python programming tip, but most people fall into it some time or another.

Try not to use Python built-in keywords, such as "type", "list", "dict", "vars", etc. as variable names.

Example of problem:
{{{
#!py
def mymethod(self, value, type):
    self._type = type
    ...
    if type(value) is int: #we try to use Python's built-in type function to check the type of an object
        ...
}}}
This will fail because we have redefined type when using it as a function argument; so the built-in "type" function is no longer available.

Using [/wiki/Dev/Tools#a3.PylintwithPyDev PyLint] helps detect these problems.

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== 4. Use the right i18n (internationalization) function ==

Indico's interface should be multi-language; for this, we have the _ function on the server (Python) side (import with from MaKaC.i18n import _ ), and the $T Javascript function in the client side.
Be careful not to use a Python function inside a Javascript string, for example:
{{{
#!js
var today = '<%=_("Today") %>';
}}}
will become, when rendered in English:
{{{
#!js
var today = 'Today';
}}}
But when rendered in French, it will become:
{{{
#!js
var today = 'Aujourd'hui';
}}}
This will provoke a syntax error because the string was using single quotes (').

Therefore, the correct thing to do is:
{{{
#!js
var today = $T("Today");
}}}