web/lib/django/core/management/base.py
changeset 0 0d40e90630ef
child 29 cc9b7e14412b
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/django/core/management/base.py	Wed Jan 20 00:34:04 2010 +0100
@@ -0,0 +1,431 @@
+"""
+Base classes for writing management commands (named commands which can
+be executed through ``django-admin.py`` or ``manage.py``).
+
+"""
+
+import os
+import sys
+from optparse import make_option, OptionParser
+
+import django
+from django.core.exceptions import ImproperlyConfigured
+from django.core.management.color import color_style
+
+try:
+    set
+except NameError:
+    from sets import Set as set     # For Python 2.3
+
+class CommandError(Exception):
+    """
+    Exception class indicating a problem while executing a management
+    command.
+
+    If this exception is raised during the execution of a management
+    command, it will be caught and turned into a nicely-printed error
+    message to the appropriate output stream (i.e., stderr); as a
+    result, raising this exception (with a sensible description of the
+    error) is the preferred way to indicate that something has gone
+    wrong in the execution of a command.
+    
+    """
+    pass
+
+def handle_default_options(options):
+    """
+    Include any default options that all commands should accept here
+    so that ManagementUtility can handle them before searching for
+    user commands.
+    
+    """
+    if options.settings:
+        os.environ['DJANGO_SETTINGS_MODULE'] = options.settings
+    if options.pythonpath:
+        sys.path.insert(0, options.pythonpath)
+
+class BaseCommand(object):
+    """
+    The base class from which all management commands ultimately
+    derive.
+
+    Use this class if you want access to all of the mechanisms which
+    parse the command-line arguments and work out what code to call in
+    response; if you don't need to change any of that behavior,
+    consider using one of the subclasses defined in this file.
+
+    If you are interested in overriding/customizing various aspects of
+    the command-parsing and -execution behavior, the normal flow works
+    as follows:
+
+    1. ``django-admin.py`` or ``manage.py`` loads the command class
+       and calls its ``run_from_argv()`` method.
+
+    2. The ``run_from_argv()`` method calls ``create_parser()`` to get
+       an ``OptionParser`` for the arguments, parses them, performs
+       any environment changes requested by options like
+       ``pythonpath``, and then calls the ``execute()`` method,
+       passing the parsed arguments.
+
+    3. The ``execute()`` method attempts to carry out the command by
+       calling the ``handle()`` method with the parsed arguments; any
+       output produced by ``handle()`` will be printed to standard
+       output and, if the command is intended to produce a block of
+       SQL statements, will be wrapped in ``BEGIN`` and ``COMMIT``.
+
+    4. If ``handle()`` raised a ``CommandError``, ``execute()`` will
+       instead print an error message to ``stderr``.
+
+    Thus, the ``handle()`` method is typically the starting point for
+    subclasses; many built-in commands and command types either place
+    all of their logic in ``handle()``, or perform some additional
+    parsing work in ``handle()`` and then delegate from it to more
+    specialized methods as needed.
+
+    Several attributes affect behavior at various steps along the way:
+    
+    ``args``
+        A string listing the arguments accepted by the command,
+        suitable for use in help messages; e.g., a command which takes
+        a list of application names might set this to '<appname
+        appname ...>'.
+
+    ``can_import_settings``
+        A boolean indicating whether the command needs to be able to
+        import Django settings; if ``True``, ``execute()`` will verify
+        that this is possible before proceeding. Default value is
+        ``True``.
+
+    ``help``
+        A short description of the command, which will be printed in
+        help messages.
+
+    ``option_list``
+        This is the list of ``optparse`` options which will be fed
+        into the command's ``OptionParser`` for parsing arguments.
+
+    ``output_transaction``
+        A boolean indicating whether the command outputs SQL
+        statements; if ``True``, the output will automatically be
+        wrapped with ``BEGIN;`` and ``COMMIT;``. Default value is
+        ``False``.
+
+    ``requires_model_validation``
+        A boolean; if ``True``, validation of installed models will be
+        performed prior to executing the command. Default value is
+        ``True``. To validate an individual application's models
+        rather than all applications' models, call
+        ``self.validate(app)`` from ``handle()``, where ``app`` is the
+        application's Python module.
+    
+    """
+    # Metadata about this command.
+    option_list = (
+        make_option('-v', '--verbosity', action='store', dest='verbosity', default='1',
+            type='choice', choices=['0', '1', '2'],
+            help='Verbosity level; 0=minimal output, 1=normal output, 2=all output'),
+        make_option('--settings',
+            help='The Python path to a settings module, e.g. "myproject.settings.main". If this isn\'t provided, the DJANGO_SETTINGS_MODULE environment variable will be used.'),
+        make_option('--pythonpath',
+            help='A directory to add to the Python path, e.g. "/home/djangoprojects/myproject".'),
+        make_option('--traceback', action='store_true',
+            help='Print traceback on exception'),
+    )
+    help = ''
+    args = ''
+
+    # Configuration shortcuts that alter various logic.
+    can_import_settings = True
+    requires_model_validation = True
+    output_transaction = False # Whether to wrap the output in a "BEGIN; COMMIT;"
+
+    def __init__(self):
+        self.style = color_style()
+
+    def get_version(self):
+        """
+        Return the Django version, which should be correct for all
+        built-in Django commands. User-supplied commands should
+        override this method.
+        
+        """
+        return django.get_version()
+
+    def usage(self, subcommand):
+        """
+        Return a brief description of how to use this command, by
+        default from the attribute ``self.help``.
+        
+        """
+        usage = '%%prog %s [options] %s' % (subcommand, self.args)
+        if self.help:
+            return '%s\n\n%s' % (usage, self.help)
+        else:
+            return usage
+
+    def create_parser(self, prog_name, subcommand):
+        """
+        Create and return the ``OptionParser`` which will be used to
+        parse the arguments to this command.
+        
+        """
+        return OptionParser(prog=prog_name,
+                            usage=self.usage(subcommand),
+                            version=self.get_version(),
+                            option_list=self.option_list)
+
+    def print_help(self, prog_name, subcommand):
+        """
+        Print the help message for this command, derived from
+        ``self.usage()``.
+        
+        """
+        parser = self.create_parser(prog_name, subcommand)
+        parser.print_help()
+
+    def run_from_argv(self, argv):
+        """
+        Set up any environment changes requested (e.g., Python path
+        and Django settings), then run this command.
+        
+        """
+        parser = self.create_parser(argv[0], argv[1])
+        options, args = parser.parse_args(argv[2:])
+        handle_default_options(options)
+        self.execute(*args, **options.__dict__)
+
+    def execute(self, *args, **options):
+        """
+        Try to execute this command, performing model validation if
+        needed (as controlled by the attribute
+        ``self.requires_model_validation``). If the command raises a
+        ``CommandError``, intercept it and print it sensibly to
+        stderr.
+        
+        """
+        # Switch to English, because django-admin.py creates database content
+        # like permissions, and those shouldn't contain any translations.
+        # But only do this if we can assume we have a working settings file,
+        # because django.utils.translation requires settings.
+        if self.can_import_settings:
+            try:
+                from django.utils import translation
+                translation.activate('en-us')
+            except ImportError, e:
+                # If settings should be available, but aren't,
+                # raise the error and quit.
+                sys.stderr.write(self.style.ERROR(str('Error: %s\n' % e)))
+                sys.exit(1)
+        try:
+            if self.requires_model_validation:
+                self.validate()
+            output = self.handle(*args, **options)
+            if output:
+                if self.output_transaction:
+                    # This needs to be imported here, because it relies on settings.
+                    from django.db import connection
+                    if connection.ops.start_transaction_sql():
+                        print self.style.SQL_KEYWORD(connection.ops.start_transaction_sql())
+                print output
+                if self.output_transaction:
+                    print self.style.SQL_KEYWORD("COMMIT;")
+        except CommandError, e:
+            sys.stderr.write(self.style.ERROR(str('Error: %s\n' % e)))
+            sys.exit(1)
+
+    def validate(self, app=None, display_num_errors=False):
+        """
+        Validates the given app, raising CommandError for any errors.
+        
+        If app is None, then this will validate all installed apps.
+        
+        """
+        from django.core.management.validation import get_validation_errors
+        try:
+            from cStringIO import StringIO
+        except ImportError:
+            from StringIO import StringIO
+        s = StringIO()
+        num_errors = get_validation_errors(s, app)
+        if num_errors:
+            s.seek(0)
+            error_text = s.read()
+            raise CommandError("One or more models did not validate:\n%s" % error_text)
+        if display_num_errors:
+            print "%s error%s found" % (num_errors, num_errors != 1 and 's' or '')
+
+    def handle(self, *args, **options):
+        """
+        The actual logic of the command. Subclasses must implement
+        this method.
+        
+        """
+        raise NotImplementedError()
+
+class AppCommand(BaseCommand):
+    """
+    A management command which takes one or more installed application
+    names as arguments, and does something with each of them.
+
+    Rather than implementing ``handle()``, subclasses must implement
+    ``handle_app()``, which will be called once for each application.
+    
+    """
+    args = '<appname appname ...>'
+
+    def handle(self, *app_labels, **options):
+        from django.db import models
+        if not app_labels:
+            raise CommandError('Enter at least one appname.')
+        try:
+            app_list = [models.get_app(app_label) for app_label in app_labels]
+        except (ImproperlyConfigured, ImportError), e:
+            raise CommandError("%s. Are you sure your INSTALLED_APPS setting is correct?" % e)
+        output = []
+        for app in app_list:
+            app_output = self.handle_app(app, **options)
+            if app_output:
+                output.append(app_output)
+        return '\n'.join(output)
+
+    def handle_app(self, app, **options):
+        """
+        Perform the command's actions for ``app``, which will be the
+        Python module corresponding to an application name given on
+        the command line.
+        
+        """
+        raise NotImplementedError()
+
+class LabelCommand(BaseCommand):
+    """
+    A management command which takes one or more arbitrary arguments
+    (labels) on the command line, and does something with each of
+    them.
+
+    Rather than implementing ``handle()``, subclasses must implement
+    ``handle_label()``, which will be called once for each label.
+
+    If the arguments should be names of installed applications, use
+    ``AppCommand`` instead.
+    
+    """
+    args = '<label label ...>'
+    label = 'label'
+
+    def handle(self, *labels, **options):
+        if not labels:
+            raise CommandError('Enter at least one %s.' % self.label)
+
+        output = []
+        for label in labels:
+            label_output = self.handle_label(label, **options)
+            if label_output:
+                output.append(label_output)
+        return '\n'.join(output)
+
+    def handle_label(self, label, **options):
+        """
+        Perform the command's actions for ``label``, which will be the
+        string as given on the command line.
+        
+        """
+        raise NotImplementedError()
+
+class NoArgsCommand(BaseCommand):
+    """
+    A command which takes no arguments on the command line.
+
+    Rather than implementing ``handle()``, subclasses must implement
+    ``handle_noargs()``; ``handle()`` itself is overridden to ensure
+    no arguments are passed to the command.
+
+    Attempting to pass arguments will raise ``CommandError``.
+    
+    """
+    args = ''
+
+    def handle(self, *args, **options):
+        if args:
+            raise CommandError("Command doesn't accept any arguments")
+        return self.handle_noargs(**options)
+
+    def handle_noargs(self, **options):
+        """
+        Perform this command's actions.
+        
+        """
+        raise NotImplementedError()
+
+def copy_helper(style, app_or_project, name, directory, other_name=''):
+    """
+    Copies either a Django application layout template or a Django project
+    layout template into the specified directory.
+
+    """
+    # style -- A color style object (see django.core.management.color).
+    # app_or_project -- The string 'app' or 'project'.
+    # name -- The name of the application or project.
+    # directory -- The directory to which the layout template should be copied.
+    # other_name -- When copying an application layout, this should be the name
+    #               of the project.
+    import re
+    import shutil
+    other = {'project': 'app', 'app': 'project'}[app_or_project]
+    if not re.search(r'^[_a-zA-Z]\w*$', name): # If it's not a valid directory name.
+        # Provide a smart error message, depending on the error.
+        if not re.search(r'^[_a-zA-Z]', name):
+            message = 'make sure the name begins with a letter or underscore'
+        else:
+            message = 'use only numbers, letters and underscores'
+        raise CommandError("%r is not a valid %s name. Please %s." % (name, app_or_project, message))
+    top_dir = os.path.join(directory, name)
+    try:
+        os.mkdir(top_dir)
+    except OSError, e:
+        raise CommandError(e)
+
+    # Determine where the app or project templates are. Use
+    # django.__path__[0] because we don't know into which directory
+    # django has been installed.
+    template_dir = os.path.join(django.__path__[0], 'conf', '%s_template' % app_or_project)
+
+    for d, subdirs, files in os.walk(template_dir):
+        relative_dir = d[len(template_dir)+1:].replace('%s_name' % app_or_project, name)
+        if relative_dir:
+            os.mkdir(os.path.join(top_dir, relative_dir))
+        for i, subdir in enumerate(subdirs):
+            if subdir.startswith('.'):
+                del subdirs[i]
+        for f in files:
+            if not f.endswith('.py'):
+                # Ignore .pyc, .pyo, .py.class etc, as they cause various
+                # breakages.
+                continue
+            path_old = os.path.join(d, f)
+            path_new = os.path.join(top_dir, relative_dir, f.replace('%s_name' % app_or_project, name))
+            fp_old = open(path_old, 'r')
+            fp_new = open(path_new, 'w')
+            fp_new.write(fp_old.read().replace('{{ %s_name }}' % app_or_project, name).replace('{{ %s_name }}' % other, other_name))
+            fp_old.close()
+            fp_new.close()
+            try:
+                shutil.copymode(path_old, path_new)
+                _make_writeable(path_new)
+            except OSError:
+                sys.stderr.write(style.NOTICE("Notice: Couldn't set permission bits on %s. You're probably using an uncommon filesystem setup. No problem.\n" % path_new))
+
+def _make_writeable(filename):
+    """
+    Make sure that the file is writeable. Useful if our source is
+    read-only.
+    
+    """
+    import stat
+    if sys.platform.startswith('java'):
+        # On Jython there is no os.access()
+        return
+    if not os.access(filename, os.W_OK):
+        st = os.stat(filename)
+        new_permissions = stat.S_IMODE(st.st_mode) | stat.S_IWUSR
+        os.chmod(filename, new_permissions)