1 2 :mod:`user` --- User-specific configuration hook 3 ================================================ 4 5 .. module:: user 6 :synopsis: A standard way to reference user-specific modules. 7 :deprecated: 8 9 .. deprecated:: 2.6 10 The :mod:`user` module has been removed in Python 3. 11 12 .. index:: 13 pair: .pythonrc.py; file 14 triple: user; configuration; file 15 16 As a policy, Python doesn't run user-specified code on startup of Python 17 programs. (Only interactive sessions execute the script specified in the 18 :envvar:`PYTHONSTARTUP` environment variable if it exists). 19 20 However, some programs or sites may find it convenient to allow users to have a 21 standard customization file, which gets run when a program requests it. This 22 module implements such a mechanism. A program that wishes to use the mechanism 23 must execute the statement :: 24 25 import user 26 27 .. index:: builtin: execfile 28 29 The :mod:`user` module looks for a file :file:`.pythonrc.py` in the user's home 30 directory and if it can be opened, executes it (using :func:`execfile`) in its 31 own (the module :mod:`user`'s) global namespace. Errors during this phase are 32 not caught; that's up to the program that imports the :mod:`user` module, if it 33 wishes. The home directory is assumed to be named by the :envvar:`HOME` 34 environment variable; if this is not set, the current directory is used. 35 36 The user's :file:`.pythonrc.py` could conceivably test for ``sys.version`` if it 37 wishes to do different things depending on the Python version. 38 39 A warning to users: be very conservative in what you place in your 40 :file:`.pythonrc.py` file. Since you don't know which programs will use it, 41 changing the behavior of standard modules or functions is generally not a good 42 idea. 43 44 A suggestion for programmers who wish to use this mechanism: a simple way to let 45 users specify options for your package is to have them define variables in their 46 :file:`.pythonrc.py` file that you test in your module. For example, a module 47 :mod:`spam` that has a verbosity level can look for a variable 48 ``user.spam_verbose``, as follows:: 49 50 import user 51 52 verbose = bool(getattr(user, "spam_verbose", 0)) 53 54 (The three-argument form of :func:`getattr` is used in case the user has not 55 defined ``spam_verbose`` in their :file:`.pythonrc.py` file.) 56 57 Programs with extensive customization needs are better off reading a 58 program-specific customization file. 59 60 Programs with security or privacy concerns should *not* import this module; a 61 user can easily break into a program by placing arbitrary code in the 62 :file:`.pythonrc.py` file. 63 64 Modules for general use should *not* import this module; it may interfere with 65 the operation of the importing program. 66 67 68 .. seealso:: 69 70 Module :mod:`site` 71 Site-wide customization mechanism. 72 73
