~azzar1/unity/add-show-desktop-key

# IVLE - Informatics Virtual Learning Environment

# Copyright (C) 2007-2009 The University of Melbourne

#

# 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 2 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, write to the Free Software

# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

# Author: Nick Chadwick

import inspect

import os.path

import urllib

import genshi.template

from ivle.webapp.media import media_url

from ivle.webapp.core import Plugin as CorePlugin

from ivle.webapp.base.views import BaseView

from ivle.webapp.base.plugins import ViewPlugin, OverlayPlugin

from ivle.webapp.errors import HTTPError, Unauthorized

from ivle.webapp.publisher import NoPath

from ivle.webapp.breadcrumbs import Breadcrumber

class GenshiLoaderMixin(object):

    """Mixin for classes which need to render Genshi templates.

    A TemplateLoader is shared between all instances, so templates are

    cached across multiple instances and therefore also requests.

    """

    _loader = None

    def __init__(self, *args, **kwargs):

        super(GenshiLoaderMixin, self).__init__(*args, **kwargs)

        # We use a single loader for all views, so we can cache the

        # parsed templates. auto_reload is convenient and has a minimal

        # performance penalty, so we'll leave it on.

        if GenshiLoaderMixin._loader is None:

            GenshiLoaderMixin._loader = genshi.template.TemplateLoader(

                ".", auto_reload=True,

                max_cache_size=100)

class XHTMLView(GenshiLoaderMixin, BaseView):

    """

    A view which provides a base class for views which need to return XHTML

    It is expected that apps which use this view will be written using Genshi

    templates.

    """

    template = 'template.html'

    allow_overlays = True

    breadcrumb_text = None

    def __init__(self, *args, **kwargs):

        super(XHTMLView, self).__init__(*args, **kwargs)

        self.overlay_blacklist = []

        self.plugin_scripts = {}

        self.plugin_styles = {}

        self.scripts_init = []

        self.extra_breadcrumbs = []

        self.overlay_blacklist = []

    def get_context_ancestry(self, req):

        return req.publisher.get_ancestors(self.context)

    def filter(self, stream, ctx):

        return stream

    def render(self, req):

        req.content_type = 'text/html' # TODO: Detect application/xhtml+xml

        # View template

        viewctx = genshi.template.Context()

        self.populate(req, viewctx)

        # The template is found in the directory of the module containing the

        # view.

        app_template = os.path.join(os.path.dirname(

                        inspect.getmodule(self).__file__), self.template) 

        tmpl = self._loader.load(app_template)

        app = self.filter(tmpl.generate(viewctx), viewctx)

        view_scripts = []

        for plugin in self.plugin_scripts:

            for path in self.plugin_scripts[plugin]:

                view_scripts.append(media_url(req, plugin, path))

        view_styles = []

        for plugin in self.plugin_styles:

            for path in self.plugin_styles[plugin]:

                view_styles.append(media_url(req, plugin, path))

        # Global template

        ctx = genshi.template.Context()

        overlay_bits = self.render_overlays(req) if req.user else [[]]*4

        ctx['overlays'] = overlay_bits[0]

        ctx['styles'] = [media_url(req, CorePlugin, 'ivle.css')]

        ctx['styles'] += view_styles

        ctx['styles'] += overlay_bits[1]

        ctx['scripts'] = [media_url(req, CorePlugin, path) for path in

                           ('util.js', 'json2.js', 'md5.js')]

        ctx['scripts'].append(media_url(req, '+external/jquery', 'jquery.js'))

        ctx['scripts'] += view_scripts

        ctx['scripts'] += overlay_bits[2]

        ctx['scripts_init'] = self.scripts_init + overlay_bits[3]

        ctx['app_template'] = app

        ctx['title_img'] = media_url(req, CorePlugin,

                                     "images/chrome/root-breadcrumb.png")

        try:

            ancestry = self.get_context_ancestry(req)

        except NoPath:

            ancestry = []

        crumber = Breadcrumber(req)

        ctx['breadcrumbs'] = []

        if not req.publicmode:

            for ancestor in ancestry:

                crumb = crumber.crumb(ancestor)

                if crumb is None:

                    continue

                if hasattr(crumb, 'extra_breadcrumbs_before'):

                    ctx['breadcrumbs'].extend(crumb.extra_breadcrumbs_before)

                ctx['breadcrumbs'].append(crumb)

                if hasattr(crumb, 'extra_breadcrumbs_after'):

                    ctx['breadcrumbs'].extend(crumb.extra_breadcrumbs_after)

            # If the view has specified text for a breadcrumb, add one.

            if self.breadcrumb_text:

                ctx['breadcrumbs'].append(ViewBreadcrumb(req, self))

            # Allow the view to add its own fake breadcrumbs.

            ctx['breadcrumbs'].extend(self.extra_breadcrumbs)

        self.populate_headings(req, ctx)

        tmpl = self._loader.load(os.path.join(os.path.dirname(__file__), 

                                                        'ivle-headings.html'))

        req.write(tmpl.generate(ctx).render('xhtml', doctype='xhtml'))

    def populate(self, req, ctx):

        raise NotImplementedError()

    def populate_headings(self, req, ctx):

        ctx['favicon'] = None

        ctx['root_dir'] = req.config['urls']['root']

        ctx['public_host'] = req.config['urls']['public_host']

        ctx['svn_base'] = req.config['urls']['svn_addr']

        ctx['write_javascript_settings'] = req.write_javascript_settings

        if req.user:

            ctx['login'] = req.user.login

            ctx['logged_in'] = True

            ctx['nick'] = req.user.nick

        else:

            ctx['login'] = None

            ctx['logged_in'] = False

        ctx['publicmode'] = req.publicmode

        if hasattr(self, 'help'):

            ctx['help_path'] = self.help

        ctx['apps_in_tabs'] = []

        for plugin in req.config.plugin_index[ViewPlugin]:

            if not hasattr(plugin, 'tabs'):

                continue

            for tab in plugin.tabs:

                # tab is a tuple: name, title, desc, icon, path, weight, admin

                # (Admin is optional, defaults to false)

                new_app = {}

                new_app['this_app'] = hasattr(self, 'tab') \

                                      and tab[0] == self.tab

                # Icon name

                if tab[3] is not None:

                    new_app['has_icon'] = True

                    icon_url = media_url(req, plugin, tab[3])

                    new_app['icon_url'] = icon_url

                    if new_app['this_app']:

                        ctx['favicon'] = icon_url

                else:

                    new_app['has_icon'] = False

                # The following check is here, so it is AFTER setting the

                # icon, but BEFORE actually installing the tab in the menu

                if len(tab) > 6 and tab[6]:

                    # Admin-only tab

                    if not (req.user and req.user.admin):

                        break

                new_app['path'] = req.make_path(tab[4])

                new_app['desc'] = tab[2]

                new_app['name'] = tab[1]

                new_app['weight'] = tab[5]

                ctx['apps_in_tabs'].append(new_app)

        ctx['apps_in_tabs'].sort(key=lambda tab: tab['weight'])

    def render_overlays(self, req):

        """Generate XML streams for the overlays.

        Returns a list of streams. Populates the scripts, styles, and 

        scripts_init.

        """

        overlays = []

        styles = []

        scripts = []

        scripts_init = []

        if not self.allow_overlays:

            return (overlays, styles, scripts, scripts_init)

        for plugin in req.config.plugin_index[OverlayPlugin]:

            for overclass in plugin.overlays:

                if overclass in self.overlay_blacklist:

                    continue

                overlay = overclass(req)

                #TODO: Re-factor this to look nicer

                for mplugin in overlay.plugin_scripts:

                    for path in overlay.plugin_scripts[mplugin]:

                        scripts.append(media_url(req, mplugin, path))

                for mplugin in overlay.plugin_styles:

                    for path in overlay.plugin_styles[mplugin]:

                        styles.append(media_url(req, mplugin, path))

                scripts_init += overlay.plugin_scripts_init

                overlays.append(overlay.render(req))

        return (overlays, styles, scripts, scripts_init)

    @classmethod

    def get_error_view(cls, e):

        view_map = {HTTPError:    XHTMLErrorView,

                    Unauthorized: XHTMLUnauthorizedView}

        for exccls in inspect.getmro(type(e)):

            if exccls in view_map:

                return view_map[exccls]

class XHTMLErrorView(XHTMLView):

    template = 'xhtmlerror.html'

    def __init__(self, req, context, lastobj):

        super(XHTMLErrorView, self).__init__(req, context)

        self.lastobj = lastobj

    def get_context_ancestry(self, req):

        return req.publisher.get_ancestors(self.lastobj)

    def populate(self, req, ctx):

        ctx['req'] = req

        ctx['exception'] = self.context

        req.headers_out['X-IVLE-Error'] = self.context.message

class XHTMLUnauthorizedView(XHTMLErrorView):

    template = 'xhtmlunauthorized.html'

    def __init__(self, req, exception, lastobj):

        super(XHTMLUnauthorizedView, self).__init__(req, exception, lastobj)

        if not req.publicmode and req.user is None:

            # Not logged in. Redirect to login page.

            if req.uri == '/':

                query_string = ''

            else:

                query_string = '?url=' + urllib.quote(req.uri, safe="/~")

            req.throw_redirect('/+login' + query_string)

        req.status = 403

class ViewBreadcrumb(object):

    def __init__(self, req, context):

        self.req = req

        self.context = context

    @property

    def text(self):

        return self.context.breadcrumb_text