empty.py

# coding:utf-8

__all__ = ['Empty']

from flask import Flask, render_template
import logging

basestring = getattr(__builtins__, 'basestring', str)


def _import_variable(blueprint_path, module, variable_name):
    path = '.'.join(blueprint_path.split('.') + [module])
    mod = __import__(path, fromlist=[variable_name])
    return getattr(mod, variable_name)


class Empty(Flask):

    def configure(self, config):
        """
        Loads configuration class into flask app.
        If environment variable available, overwrites class config.

        """
        self.config.update(config)
        # could/should be available in server environment
        self.config.from_envvar("APP_CONFIG", silent=True)

    def add_blueprint(self, name, kw):
        blueprint = _import_variable(name, 'views', 'app')
        self.register_blueprint(blueprint, **kw)

    def add_blueprint_list(self, bp_list):
        for blueprint_config in bp_list:
            name, kw = None, {}

            if isinstance(blueprint_config, basestring):
                name = blueprint_config
            elif isinstance(blueprint_config, (list, tuple)):
                name = blueprint_config[0]
                kw.update(blueprint_config[1])
            else:
                print "Error in BLUEPRINTS setup in config.py"
                print "Please, verify if each blueprint setup is either a string or a tuple."
                exit(1)

            self.add_blueprint(name, kw)

    def setup(self):
        self.configure_logger()
        self.configure_error_handlers()
        self.configure_database()
        self.configure_context_processors()
        self.configure_template_extensions()
        self.configure_template_filters()
        self.configure_extensions()
        self.configure_before_request()
        self.configure_views()

    def configure_logger(self):
        try:
            log_filename = self.config['LOG_FILENAME']

            # Create a file logger since we got a logdir
            log_file = logging.FileHandler(filename=log_filename)
            formatter = logging.Formatter(self.config['LOG_FORMAT'])
            log_file.setFormatter(formatter)
            log_file.setLevel(self.config['LOG_LEVEL'])
            self.logger.addHandler(log_file)
            self.logger.info("Logger started")
        except:
            print "Could not configure logger, using defaults."
            
    def configure_error_handlers(app):
        @app.errorhandler(403)
        def forbidden_page(error):
            """
            The server understood the request, but is refusing to fulfill it.
            Authorization will not help and the request SHOULD NOT be repeated.
            If the request method was not HEAD and the server wishes to make public
            why the request has not been fulfilled, it SHOULD describe the reason for
            the refusal in the entity. If the server does not wish to make this
            information available to the client, the status code 404 (Not Found)
            can be used instead.
            """
            return render_template("http/access_forbidden.html"), 403

        @app.errorhandler(404)
        def page_not_found(error):
            """
            The server has not found anything matching the Request-URI. No indication
            is given of whether the condition is temporary or permanent. The 410 (Gone)
            status code SHOULD be used if the server knows, through some internally
            configurable mechanism, that an old resource is permanently unavailable
            and has no forwarding address. This status code is commonly used when the
            server does not wish to reveal exactly why the request has been refused,
            or when no other response is applicable.
            """
            return render_template("http/page_not_found.html"), 404

        @app.errorhandler(405)
        def method_not_allowed_page(error):
            """
            The method specified in the Request-Line is not allowed for the resource
            identified by the Request-URI. The response MUST include an Allow header
            containing a list of valid methods for the requested resource.
            """
            return render_template("http/method_not_allowed.html"), 405

        @app.errorhandler(500)
        def server_error_page(error):
            return render_template("http/server_error.html"), 500

    def configure_database(self):
        """
        Database configuration should be set here
        """
        pass

    def configure_context_processors(self):
        """
        Modify templates context here
        """
        pass

    def configure_template_extensions(self):
        """
        Add jinja2 extensions here
        """
        # 'do' extension. see: http://jinja.pocoo.org/docs/extensions/#expression-statement
        self.jinja_env.add_extension('jinja2.ext.do')

    def configure_template_filters(self):
        """
        Configure filters and tags for jinja
        """
        pass

    def configure_extensions(self):
        """
        Configure extensions like mail and login here
        """
        try:
            # only works in debug mode
            from flask_debugtoolbar import DebugToolbarExtension
            DebugToolbarExtension(self)
        except ImportError, e:
            print 'debugtoolbar extension not available.'

    def configure_before_request(self):
        pass

    def configure_views(self):
        """
        You can add some simple views here for fast prototyping
        """
        pass