ref: dab539cd14726de15932b0310532212f8da29bf7
dir: /sys/src/cmd/python/Doc/lib/libuser.tex/
\section{\module{user} --- User-specific configuration hook} \declaremodule{standard}{user} \modulesynopsis{A standard way to reference user-specific modules.} \indexii{.pythonrc.py}{file} \indexiii{user}{configuration}{file} As a policy, Python doesn't run user-specified code on startup of Python programs. (Only interactive sessions execute the script specified in the \envvar{PYTHONSTARTUP} environment variable if it exists). However, some programs or sites may find it convenient to allow users to have a standard customization file, which gets run when a program requests it. This module implements such a mechanism. A program that wishes to use the mechanism must execute the statement \begin{verbatim} import user \end{verbatim} The \module{user} module looks for a file \file{.pythonrc.py} in the user's home directory and if it can be opened, executes it (using \function{execfile()}\bifuncindex{execfile}) in its own (the module \module{user}'s) global namespace. Errors during this phase are not caught; that's up to the program that imports the \module{user} module, if it wishes. The home directory is assumed to be named by the \envvar{HOME} environment variable; if this is not set, the current directory is used. The user's \file{.pythonrc.py} could conceivably test for \code{sys.version} if it wishes to do different things depending on the Python version. A warning to users: be very conservative in what you place in your \file{.pythonrc.py} file. Since you don't know which programs will use it, changing the behavior of standard modules or functions is generally not a good idea. A suggestion for programmers who wish to use this mechanism: a simple way to let users specify options for your package is to have them define variables in their \file{.pythonrc.py} file that you test in your module. For example, a module \module{spam} that has a verbosity level can look for a variable \code{user.spam_verbose}, as follows: \begin{verbatim} import user verbose = bool(getattr(user, "spam_verbose", 0)) \end{verbatim} (The three-argument form of \function{getattr()} is used in case the user has not defined \code{spam_verbose} in their \file{.pythonrc.py} file.) Programs with extensive customization needs are better off reading a program-specific customization file. Programs with security or privacy concerns should \emph{not} import this module; a user can easily break into a program by placing arbitrary code in the \file{.pythonrc.py} file. Modules for general use should \emph{not} import this module; it may interfere with the operation of the importing program. \begin{seealso} \seemodule{site}{Site-wide customization mechanism.} \end{seealso}