help: Respect language preference when showing user manual

Retrieve the manual page or download PDF manual in user's preferred language.

Signed-off-by: Joseph Nuthalapati <njoseph@riseup.net>
[sunil@medhas.org Merge URL format since view is the same]
[sunil@medhas.org Refactor language extraction]
[sunil@medhas.org Minor refactorings]
Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

plinth/modules/help/help.py

@@ -20,12 +20,15 @@ Help app for FreedomBox.
 
 import mimetypes
 import os
+import pathlib
 import subprocess
 
 from apt.cache import Cache
 from django.core.files.base import File
-from django.http import Http404, HttpResponse
+from django.http import Http404, HttpResponse, HttpResponseRedirect
 from django.template.response import TemplateResponse
+from django.urls import reverse
+from django.utils.translation import get_language_from_request
 from django.utils.translation import ugettext as _
 from django.utils.translation import ugettext_lazy
 
@@ -118,15 +121,27 @@ def about(request):
     return TemplateResponse(request, 'help_about.html', context)
 
 
-def manual(request, page='freedombox-manual.part.html'):
+def manual(request, lang=None, page=None):
     """Serve the manual page from the 'doc' directory"""
-    try:
-        page = '{}.part.html'.format(
-            page) if not page.endswith('html') else page
-        with open(os.path.join(cfg.doc_dir, page), 'r',
-                  encoding='utf-8') as input_file:
-            content = input_file.read()
-    except IOError:
+    language_code = get_language_from_request(request)
+
+    if not lang or lang == '-':
+        kwargs = {'lang': language_code}
+        if page:
+            return HttpResponseRedirect(
+                reverse('help:manual-page', kwargs=dict(kwargs, page=page)))
+
+        return HttpResponseRedirect(reverse('help:manual', kwargs=kwargs))
+
+    def read_file(language_code, page):
+        """Read the page from disk and return contents or None."""
+        page_file = pathlib.Path(cfg.doc_dir) / 'manual' / language_code / page
+        return page_file.read_text() if page_file.exists() else None
+
+    page = page or 'freedombox-manual'
+    page = f'{page}.part.html'
+    content = read_file(language_code, page) or read_file(language_code, 'en')
+    if not content:
         raise Http404
 
     return TemplateResponse(
@@ -138,17 +153,26 @@ def manual(request, page='freedombox-manual.part.html'):
 
 def download_manual(request):
     """Serve the PDF version of the manual from the 'doc' directory"""
-    files = [
-        os.path.join(cfg.doc_dir, file_name)
-        for file_name in ['freedombox-manual.pdf.gz', 'freedombox-manual.pdf']
-        if os.path.isfile(os.path.join(cfg.doc_dir, file_name))
-    ]
+    language_code = get_language_from_request(request)
 
-    if not files:
+    def get_manual_file_name(language_code):
+        for file_name in ['freedombox-manual.pdf.gz', 'freedombox-manual.pdf']:
+            name = os.path.join(cfg.doc_dir, 'manual', language_code,
+                                file_name)
+            if os.path.isfile(name):
+                return name
+
+        return None
+
+    manual_file_name = get_manual_file_name(
+        language_code) or get_manual_file_name('en')
+
+    if not manual_file_name:
         raise Http404
 
-    (content_type, encoding) = mimetypes.guess_type(files[0])
-    with open(files[0], 'rb') as file_handle:
+    (content_type, encoding) = mimetypes.guess_type(manual_file_name)
+
+    with open(manual_file_name, 'rb') as file_handle:
         response = HttpResponse(File(file_handle), content_type=content_type)
         if encoding:
             response['Content-Encoding'] = encoding

plinth/modules/help/urls.py

@@ -32,10 +32,12 @@ urlpatterns = [
     url(r'^help/contribute/$', non_admin_view(views.contribute),
         name='contribute'),
     url(r'^help/manual/$', non_admin_view(views.manual), name='manual'),
-    url(r'^help/manual/download/$', non_admin_view(views.download_manual),
+    url(r'^help/manual/(?P<lang>\w*(-\w*)?)/$', non_admin_view(views.manual),
+        name='manual'),
+    url(r'^help/manual/(?P<lang>\w*(-\w*)?)/(?P<page>[\w-]+)$',
+        non_admin_view(views.manual), name='manual-page'),
+    url(r'^help/manual-download/$', non_admin_view(views.download_manual),
         name='download-manual'),
-    url(r'^help/manual/(?P<page>[\w-]+)?/?$', non_admin_view(views.manual),
-        name='manual-page'),
     url(r'^help/status-log/$', non_admin_view(views.status_log),
         name='status-log'),
 ]

plinth/modules/power/templates/power_restart.html

@@ -38,7 +38,7 @@
 
   {% if manual_page %}
     <p class="manual-page">
-      <a href="{% url 'help:manual-page' manual_page %}">
+      <a href="{% url 'help:manual-page' lang='-' page=manual_page %}">
         {% trans 'Learn more...' %}
       </a>
     </p>

plinth/modules/power/templates/power_shutdown.html

@@ -37,7 +37,7 @@
 
   {% if manual_page %}
     <p class="manual-page">
-      <a href="{% url 'help:manual-page' manual_page %}">
+      <a href="{% url 'help:manual-page' lang='-' page=manual_page %}">
         {% trans 'Learn more...' %}
       </a>
     </p>

plinth/templates/app.html

@@ -39,7 +39,7 @@
 
   {% if manual_page %}
     <p class="manual-page">
-      <a href="{% url 'help:manual-page' manual_page %}">
+      <a href="{% url 'help:manual-page' lang='-' page=manual_page %}">
         {% trans 'Learn more...' %}
       </a>
     </p>

plinth/templates/setup.html

@@ -44,7 +44,7 @@
 
   {% if setup_helper.module.manual_page %}
     <p class="manual-page">
-      <a href="{% url 'help:manual-page' setup_helper.module.manual_page %}">
+      <a href="{% url 'help:manual-page' lang='-' page=setup_helper.module.manual_page %}">
         {% trans 'Learn more...' %}
       </a>
     </p>

plinth/templates/simple_app.html

@@ -34,7 +34,7 @@
 
   {% if manual_page %}
     <p class="manual-page">
-      <a href="{% url 'help:manual-page' manual_page %}">
+      <a href="{% url 'help:manual-page' lang='-' page=manual_page %}">
         {% trans 'Learn more...' %}
       </a>
     </p>

plinth/web_server.py

@@ -71,10 +71,12 @@ def init():
 
     _mount_static_directory('/usr/share/javascript', '/javascript')
 
-    manual_dir = os.path.join(cfg.doc_dir, 'images')
-    manual_url = '/'.join([cfg.server_dir, 'help/manual/images']) \
-        .replace('//', '/')
-    _mount_static_directory(manual_dir, manual_url)
+    langs = os.listdir(os.path.join(cfg.doc_dir, 'manual'))
+    for lang in langs:
+        manual_dir = os.path.join(cfg.doc_dir, 'manual', lang, 'images')
+        manual_url = '/'.join([cfg.server_dir, f'help/manual/{lang}/images']) \
+                        .replace('//', '/')
+        _mount_static_directory(manual_dir, manual_url)
 
     for module_name, module in module_loader.loaded_modules.items():
         module_path = os.path.dirname(module.__file__)