root / pykota / trunk / pykota / utils.py @ 3367

# -*- coding: UTF-8 -*-
#
# PyKota : Print Quotas for CUPS
#
# (c) 2003, 2004, 2005, 2006, 2007, 2008 Jerome Alet <alet@librelogiciel.com>
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# $Id$
#

"""This module defines some utility functions which make no sense as methods."""

import sys
import os
import pwd
import locale
import gettext
from types import UnicodeType

from pykota.errors import PyKotaCommandLineError

def initlocale(lang="", cset=None) :
    """Initializes the locale stuff."""
    try :
        locale.setlocale(locale.LC_ALL, (lang, cset))
    except (locale.Error, IOError) :
        locale.setlocale(locale.LC_ALL, None)
    (language, charset) = locale.getlocale()
    language = language or "C"
    try :
        charset = charset or locale.getpreferredencoding()
    except locale.Error :    
        charset = sys.stdout.encoding or sys.getfilesystemencoding()

    if (not charset) or charset in ("ASCII", "ANSI_X3.4-1968") :
        charset = "UTF-8"
        
    return (language, charset)

def setenv(varname, value, charset) :
    """Sets an environment variable."""
    if value is None :
        value = "None"
    os.environ[varname] = value.encode(charset, "replace")    
    
def initgettext(lang, cset) :
    """Initializes gettext translations for PyKota."""
    try :
        try :
            trans = gettext.translation("pykota", \
                                        languages=["%s.%s" % (lang, 
                                                              cset)], 
                                        codeset=cset)
        except TypeError : # Python <2.4
            trans = gettext.translation("pykota", 
                                        languages=["%s.%s" % (lang, 
                                                              cset)])
        trans.install(unicode=True)
    except :
        gettext.NullTranslations().install(unicode=True)
        
def getpreferredlanguage() :
    """Returns the preferred language."""
    languages = os.environ.get("HTTP_ACCEPT_LANGUAGE", "")
    langs = [l.strip().split(';')[0] for l in languages.split(",")]
    return langs[0].replace("-", "_")
    
def getpreferredcharset() :
    """Returns the preferred charset."""
    charsets = os.environ.get("HTTP_ACCEPT_CHARSET", "UTF-8")
    charsets = [l.strip().split(';')[0] for l in charsets.split(",")]
    return charsets[0]

def reinitcgilocale() :        
    """Reinitializes the locale and gettext translations for CGI scripts, according to browser's preferences."""
    initgettext(*initlocale(getpreferredlanguage(), getpreferredcharset()))
    
def N_(message) :
    """Fake translation marker for translatable strings extraction."""
    return message

def databaseToUnicode(text) :
    """Converts from database format (UTF-8) to unicode.
    
       We use "replace" to accomodate legacy datas which may not
       have been recorded correctly.
    """
    if text is not None :
        if not isinstance(text, UnicodeType) :
            return text.decode("UTF-8", "replace")
        else :    
            # MySQL already returns unicode objects
            return text
    else : 
        return None
    
def unicodeToDatabase(text) :
    """Converts from unicode to database format (UTF-8)."""
    if text is not None : 
        return text.encode("UTF-8")
    else :    
        return None
            
def getdefaultcharset() :            
    """Returns the default charset to use."""
    return sys.stdout.encoding or locale.getlocale()[1] or "ANSI_X3.4-1968"
    
def logerr(text) :
    """Logs an unicode text to stderr."""
    sys.stderr.write(text.encode(getdefaultcharset(), "replace"))
    sys.stderr.flush()
    
def loginvalidparam(opt, value, defaultvalue=None, additionalinfo=None) :
    """Logs an error when an invalid parameter to a command line option
       is encountered.
    """   
    message = _("Invalid value '%(value)s' for the %(opt)s command line option") \
                                % locals()
    if defaultvalue is not None :                            
        message += ", using default '%(defaultvalue)s' instead" % locals()
    if additionalinfo :
        logerr("%s (%s)\n" % (message, additionalinfo))
    else :    
        logerr("%s\n" % message)
            
def crashed(message="Bug in PyKota") :    
    """Minimal crash method."""
    import traceback
    from pykota.version import __version__
    lines = []
    for line in traceback.format_exception(*sys.exc_info()) :
        line = line.decode(getdefaultcharset(), "replace")
        lines.extend([l for l in line.split("\n") if l])
    msg = "ERROR: ".join(["%s\n" % l for l in (["ERROR: PyKota v%s" % __version__, message] + lines)])
    logerr(msg)
    return msg
    
def run(optparser, workclass, requireargs=False) :
    """Runs a PyKota command line tool."""
    appname = os.path.basename(sys.argv[0])
    retcode = 0
    (options, arguments) = optparser.parse_args()                   
    if requireargs and not arguments :
        logerr("%s\n" % (_("%(appname)s requires arguments, please use --help") \
                            % locals()))
        retcode = -1
    application = None    
    try :
        try :
            application = workclass()
            application.deferredInit()
            retcode = application.main(arguments, options)
        except KeyboardInterrupt :        
            logerr("\nInterrupted with Ctrl+C !\n")
            retcode = -3
        except PyKotaCommandLineError, msg :    
            logerr("%s : %s\n" % (sys.argv[0], msg))
            retcode = -2
        except SystemExit :        
            pass
        except :
            title = _("%(appname)s failed") % locals()
            try :
                application.crashed(title)
            except :    
                crashed(title)
            retcode = -1
    finally :    
        try :
            application.storage.close()
        except :    
            pass
            
    sys.exit(retcode)