kiwix: Add app for Kiwix offline Wikipedia reader

Signed-off-by: Joseph Nuthalapati <njoseph@riseup.net>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>

HACKING.md

@@ -9,7 +9,7 @@ This document provides reference information for FreedomBox **contribution** hac
 1. [Submitting your changes](#submitting-your-changes)
 1. [Other related stuff](#miscelanea)
 
-It doesn't cover arquitecture, design choices, or other product internals.
+It doesn't cover architecture, design choices or other product internals.
 
 ## Picking a task to work on
 
@@ -20,8 +20,6 @@ Newcomers will find easy, self-contained tasks tagged as "beginner".
 Source code for FreedomBox Service is available from
 [salsa.debian.org](https://salsa.debian.org/freedombox-team/freedombox).
 
-
-
 ## Development environments: setting up and their usage
 
 ### Requirements for Development OS
@@ -30,9 +28,9 @@ FreedomBox is built as part of Debian GNU/Linux. However, you don't need to
 install Debian to do development for FreedomBox. FreedomBox development is
 typically done with a container or a Virtual Machine.
 
-* For running a container, you need systemd containers, Git, Python3 and a
+* To run a container, you need systemd containers, Git, Python3 and a
 sudo-enabled user. This approach is recommended.
-* For running a VM, you can work on any operating system that can install latest
+* To run a VM, you can work on any operating system that can install latest
 versions of Git, Vagrant and VirtualBox.
 
 In addition:

debian/copyright

@@ -132,6 +132,12 @@ Files: plinth/modules/janus/static/icons/janus.png
 Copyright: 2014-2022 Meetecho
 License: GPL-3 with OpenSSL exception
 
+Files: static/themes/default/icons/kiwix.png
+       static/themes/default/icons/kiwix.svg
+Copyright: 2020 The other Kiwix guy
+Comment: https://commons.wikimedia.org/wiki/File:Kiwix_logo_v3.svg
+License: CC-BY-SA-4.0
+
 Files: static/themes/default/icons/macos.png
        static/themes/default/icons/macos.svg
 Copyright: Vectors Market (https://thenounproject.com/vectorsmarket/)

plinth/modules/kiwix/__init__.py

@@ -0,0 +1,121 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+FreedomBox app for Kiwix content server.
+"""
+
+from django.utils.translation import gettext_lazy as _
+
+from plinth import app as app_module, frontpage, menu, package
+from plinth.config import DropinConfigs
+from plinth.daemon import Daemon
+from plinth.modules.apache.components import Webserver
+from plinth.modules.backups.components import BackupRestore
+from plinth.modules.kiwix import manifest
+from plinth.modules.firewall.components import Firewall, FirewallLocalProtection
+from plinth.modules.users.components import UsersAndGroups
+
+from . import manifest, privileged
+
+_description = [
+    _('Kiwix is an offline reader for web content. It is software intended '
+      'to make Wikipedia available without using the internet, but it is '
+      'potentially suitable for all HTML content. Kiwix packages are in the '
+      'ZIM file format.'),
+    _('''Kiwix can host various kinds of content:
+    <ul>
+      <li>Offline versions of websites: Wikimedia projects, Stack Exchange</li>
+      <li>Video content: Khan Academy, TED Talks, Crash Course</li>
+      <li>Educational materials: PHET, TED Ed, Vikidia</li>
+      <li>eBooks: Project Gutenberg</li>
+      <li>Magazines: Low-tech Magazine</li>
+    </ul>''')
+]
+
+SYSTEM_USER = 'kiwix'
+
+
+class KiwixApp(app_module.App):
+    """FreedomBox app for Kiwix."""
+
+    app_id = 'kiwix'
+
+    _version = 1
+
+    DAEMON = 'kiwix-server-freedombox'
+
+    def __init__(self):
+        """Create components for the app."""
+        super().__init__()
+
+        groups = {'kiwix': _('Manage Kiwix content server')}
+
+        info = app_module.Info(
+            app_id=self.app_id, version=self._version, name=_('Kiwix'),
+            icon_filename='kiwix', short_description=_('Offline Wikipedia'),
+            description=_description, manual_page='Kiwix',
+            clients=manifest.clients,
+            donation_url='https://www.kiwix.org/en/support-us/')
+        self.add(info)
+
+        menu_item = menu.Menu('menu-kiwix', info.name, info.short_description,
+                              info.icon_filename, 'kiwix:index',
+                              parent_url_name='apps')
+        self.add(menu_item)
+
+        shortcut = frontpage.Shortcut('shortcut-kiwix', info.name,
+                                      short_description=info.short_description,
+                                      icon=info.icon_filename, url='/kiwix',
+                                      clients=info.clients,
+                                      login_required=True,
+                                      allowed_groups=list(groups))
+        self.add(shortcut)
+
+        packages = package.Packages('packages-kiwix', ['kiwix-tools'])
+        self.add(packages)
+
+        dropin_configs = DropinConfigs('dropin-configs-kiwix', [
+            '/etc/apache2/conf-available/kiwix-freedombox.conf',
+        ])
+        self.add(dropin_configs)
+
+        firewall = Firewall('firewall-kiwix', info.name,
+                            ports=['http', 'https'], is_external=True)
+        self.add(firewall)
+
+        firewall_local_protection = FirewallLocalProtection(
+            'firewall-local-protection-kiwix', ['4201'])
+        self.add(firewall_local_protection)
+
+        webserver = Webserver('webserver-kiwix', 'kiwix-freedombox',
+                              urls=['https://{host}/kiwix'])
+        self.add(webserver)
+
+        daemon = Daemon('daemon-kiwix', self.DAEMON,
+                        listen_ports=[(4201, 'tcp4')])
+        self.add(daemon)
+
+        users_and_groups = UsersAndGroups('users-and-groups-kiwix',
+                                          reserved_usernames=['kiwix'],
+                                          groups=groups)
+        self.add(users_and_groups)
+
+        backup_restore = BackupRestore('backup-restore-kiwix',
+                                       **manifest.backup)
+        self.add(backup_restore)
+
+    def setup(self, old_version=None):
+        """Install and configure the app."""
+        super().setup(old_version)
+        if not old_version:
+            self.enable()
+
+    def uninstall(self):
+        """De-configure and uninstall the app."""
+        super().uninstall()
+        privileged.uninstall()
+
+
+def validate_file_name(file_name: str):
+    """Check if the content archive file has a valid extension."""
+    if not file_name.endswith(".zim"):
+        raise ValueError(f"Expected a ZIM file. Found {file_name}")

plinth/modules/kiwix/data/etc/plinth/modules-enabled/kiwix

@@ -0,0 +1 @@
+plinth.modules.kiwix

plinth/modules/kiwix/data/usr/lib/systemd/system/kiwix-server-freedombox.service

@@ -0,0 +1,47 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+[Unit]
+Description=Kiwix Content Server
+Documentation=man:kiwix-serve(1)
+After=network.target
+ConditionPathExists=/usr/bin/kiwix-serve
+
+[Service]
+CapabilityBoundingSet=~CAP_SYS_ADMIN CAP_SYS_PTRACE CAP_SETUID CAP_SETGID CAP_SETPCAP CAP_CHOWN CAP_FSETID CAP_SETFCAP CAP_DAC_OVERRIDE CAP_DAC_READ_SEARCH CAP_FOWNER CAP_IPC_OWNER CAP_NET_ADMIN CAP_AUDIT_CONTROL CAP_AUDIT_READ CAP_AUDIT_WRITE CAP_KILL CAP_NET_BIND_SERVICE CAP_NET_RAW CAP_LINUX_IMMUTABLE CAP_IPC_LOCK CAP_SYS_CHROOT CAP_BLOCK_SUSPEND CAP_LEASE CAP_SYS_PACCT CAP_SYS_TTY_CONFIG CAP_SYS_BOOT CAP_MAC_ADMIN CAP_MAC_OVERRIDE CAP_SYS_NICE CAP_SYS_RESOURCE
+DevicePolicy=closed
+Environment=HOME="/var/lib/kiwix-server-freedombox"
+Environment=LIBRARY_PATH="/var/lib/kiwix-server-freedombox/library_zim.xml"
+Environment=ARGS="--library --port=4201 --urlRootLocation=kiwix"
+ExecStartPre=sh -e -c "mkdir -p $HOME/content; library=$$(ls ${LIBRARY_PATH} 2>/dev/null || true); [ \"x$${library}\" = \"x\" ] && (mkdir -p \"${HOME}\" && echo '<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n<library version=\"20110515\">\n</library>' > \"${LIBRARY_PATH}\") || true"
+ExecStart=sh -e -c "exec /usr/bin/kiwix-serve $ARGS $LIBRARY_PATH"
+Restart=on-failure
+ExecReload=/bin/kill -HUP $MAINPID
+DynamicUser=yes
+LockPersonality=yes
+NoNewPrivileges=yes
+PrivateDevices=yes
+PrivateMounts=yes
+PrivateTmp=yes
+PrivateUsers=yes
+ProtectControlGroups=yes
+ProtectClock=yes
+ProtectHome=yes
+ProtectHostname=yes
+ProtectKernelLogs=yes
+ProtectKernelModules=yes
+ProtectKernelTunables=yes
+ProtectSystem=strict
+RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6 AF_NETLINK
+RestrictNamespaces=yes
+RestrictRealtime=yes
+RestrictSUIDSGID=yes
+StateDirectory=kiwix-server-freedombox
+SystemCallArchitectures=native
+SystemCallFilter=@system-service
+SystemCallFilter=~@resources
+SystemCallFilter=~@privileged
+SystemCallErrorNumber=EPERM
+Type=simple
+
+[Install]
+WantedBy=multi-user.target

plinth/modules/kiwix/data/usr/share/freedombox/etc/apache2/conf-available/kiwix-freedombox.conf

@@ -0,0 +1,6 @@
+##
+## On all sites, provide kiwix web interface on a path: /kiwix
+##
+<Location /kiwix>
+    ProxyPass http://localhost:4201/kiwix
+</Location>

plinth/modules/kiwix/data/usr/share/freedombox/modules-enabled/kiwix

@@ -0,0 +1 @@
+plinth.modules.kiwix

plinth/modules/kiwix/forms.py

@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+Forms for the Kiwix module.
+"""
+
+from django import forms
+from django.core import validators
+from django.utils.translation import gettext_lazy as _
+
+from plinth import cfg
+
+from .privileged import KIWIX_HOME
+
+
+class AddContentForm(forms.Form):
+    """Form to create an empty library."""
+
+    # Would be nice to have a progress bar when uploading large files.
+    file = forms.FileField(
+        label=_('Upload File'), required=True, validators=[
+            validators.FileExtensionValidator(
+                ['zim'], _('Content packages have to be in .zim format'))
+        ], help_text=_(f'''Uploaded ZIM files will be stored under
+        {KIWIX_HOME}/content on your {cfg.box_name}. If Kiwix fails to add the file,
+        it will be deleted immediately to save disk space.'''))

plinth/modules/kiwix/manifest.py

@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+from django.utils.translation import gettext_lazy as _
+
+from plinth.clients import validate
+
+clients = validate([{
+    'name': _('kiwix'),
+    'platforms': [{
+        'type': 'web',
+        'url': '/kiwix'
+    }]
+}])
+
+backup = {
+    'data': {
+        'directories': ['/var/lib/private/kiwix-server-freedombox/']
+    },
+    'services': ['kiwix-server-freedombox']
+}

plinth/modules/kiwix/privileged.py

@@ -0,0 +1,87 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+Privileged actions for Kiwix content server.
+"""
+
+import subprocess
+import pathlib
+import shutil
+import xml.etree.ElementTree as ET
+
+from plinth import action_utils
+from plinth.actions import privileged
+from plinth.modules import kiwix
+
+# Only one central library is supported.
+KIWIX_HOME = pathlib.Path('/var/lib/kiwix-server-freedombox')
+LIBRARY_FILE = KIWIX_HOME / 'library_zim.xml'
+CONTENT_DIR = KIWIX_HOME / 'content'
+
+
+@privileged
+def add_content(file_name: str):
+    """Adds a content package to Kiwix.
+
+    Adding packages is idempotent.
+
+     Users can add content to Kiwix in multiple ways:
+     - Upload a ZIM file
+     - Provide a link to the ZIM file
+     - Provide a magnet link to the ZIM file
+
+     The commandline download manager aria2c is a dependency of kiwix-tools.
+     aria2c is used for both HTTP and Magnet downloads.
+     """
+    kiwix.validate_file_name(file_name)
+
+    # Moving files to the Kiwix library path ensures that
+    # they can't be removed by other apps or users.
+    zim_file_name = pathlib.Path(file_name).name
+    CONTENT_DIR.mkdir(exist_ok=True)
+    zim_file_dest = str(CONTENT_DIR / zim_file_name)
+    shutil.move(file_name, zim_file_dest)
+
+    _kiwix_manage_add(zim_file_dest)
+
+
+def _kiwix_manage_add(zim_file: str):
+    subprocess.check_call(['kiwix-manage', LIBRARY_FILE, 'add', zim_file])
+
+    # kiwix-serve doesn't read the library file unless it is restarted.
+    action_utils.service_restart('kiwix-server-freedombox')
+
+
+@privileged
+def uninstall():
+    """Remove all content during uninstall."""
+    shutil.rmtree(str(CONTENT_DIR))
+    LIBRARY_FILE.unlink()
+
+
+@privileged
+def list_content_packages() -> dict[str, dict]:
+    library = ET.parse(LIBRARY_FILE).getroot()
+
+    # Relying on the fact that Python dictionaries maintain order of insertion.
+    return {
+        book.attrib['id']: {
+            'title': book.attrib['title'],
+            'description': book.attrib['description'],
+            # strip '.zim' from the path
+            'path': book.attrib['path'].split('/')[-1][:-4].lower()
+        }
+        for book in library
+    }
+
+
+@privileged
+def delete_content_package(zim_id: str):
+    library = ET.parse(LIBRARY_FILE).getroot()
+
+    for book in library:
+        if book.attrib['id'] == zim_id:
+            subprocess.check_call(
+                ['kiwix-manage', LIBRARY_FILE, 'remove', zim_id])
+            (KIWIX_HOME / book.attrib['path']).unlink()
+            action_utils.service_restart('kiwix-server-freedombox')
+            return

plinth/modules/kiwix/static/icons/kiwix.svg

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Generator: Adobe Illustrator 24.1.2, SVG Export Plug-In . SVG Version: 6.00 Build 0)  -->
+<svg version="1.1"
+	 id="Layer_1" xmlns:cc="http://creativecommons.org/ns#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:svg="http://www.w3.org/2000/svg"
+	 xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" viewBox="0 0 1256 1256"
+	 style="enable-background:new 0 0 1256 1256;" xml:space="preserve">
+<style type="text/css">
+	.st0{fill:#010101;}
+</style>
+<path class="st0" d="M1165,764.1c-8.3-36.4-68.5-141.3-191.6-234.4c-22.5-17.1-42.8-31.3-59.7-42.6
+	c24.6-105.3-103.3-232.3-228.1-172.5C596,230.3,496.1,195.9,404.2,197.3c-243.3,3.4-431,256.9-229.1,498.8c0.1,0.1,0.2,0.2,0.4,0.4
+	c3.1,3.7,6.3,7.4,9.5,11.1c13.1,15.7,21.8,29.6,29.2,54.1L274.4,959h-21.3c-19.6,0-35.6,15.9-35.6,35.6h80.8l135.8,64.2
+	c8.4-17.8,0.8-39-16.9-47.3l-35.6-16.8H484c0-19.6-15.9-35.6-35.6-35.6h-92.8c-16.2,0-30.6-10.6-35.3-26.1l-47.7-156.7
+	c-11.9-41.2,15.4-68.1,41.1-71.3c23.4-2.9,35.2,12.2,46.2,48.8l42.4,139h-21.3c-19.6,0-35.6,15.9-35.6,35.6h80.8l135.8,64.2
+	c8.4-17.8,0.8-39-16.9-47.3l-35.6-16.8h75.1c7.6,12.9,16.9,25.1,28,36.1c70,70,183.7,70,253.7,0s70-183.7,0-253.7s-183.7-70-253.7,0
+	c-49.2,49.2-63.9,120-43.9,182h-85c-16.2,0-30.6-10.6-35.3-26.1L378,635.4l12-6.4c167.1-70.1,345.8,55.1,470.2-65.2
+	c0.3-0.3,0.6-0.6,0.8-0.8c15.4-14,30.8-28.3,76.3,0.2c49,30.7,157.1,110.8,206.1,247.8C1143.5,811,1173.2,800.4,1165,764.1z
+	 M821.2,460.6c-0.4-18.7-15.6-33.7-34.5-33.7c-19,0-34.5,15.4-34.5,34.5c0,10.4,4.6,19.6,11.8,25.9c-25-4.8-43.8-26.6-43.8-52.9
+	c0-29.8,24.1-53.9,53.9-53.9c29.8,0,53.9,24.1,53.9,53.9C828,443.9,825.5,452.8,821.2,460.6z"/>
+</svg>

plinth/modules/kiwix/templates/add-content-package.html

@@ -0,0 +1,58 @@
+{% extends "base.html" %}
+{% comment %}
+# SPDX-License-Identifier: AGPL-3.0-or-later
+{% endcomment %}
+
+{% load bootstrap %}
+{% load i18n %}
+
+{% block content %}
+
+  <h3>{{ title }}</h3>
+
+  <p>
+    {% blocktrans %}
+      You can <a href="https://library.kiwix.org"
+                 target="_blank" rel="noopener noreferrer">download</a>
+      content packages from the Kiwix project or
+      <a href="https://openzim.org/wiki/Build_your_ZIM_file"
+         target="_blank" rel="noopener noreferrer">create</a> your own.
+    {% endblocktrans %}
+  </p>
+
+  <p>
+    {% blocktrans %}
+      Content packages can be added in the following ways:
+      <ul>
+        <li>upload a ZIM file</li>
+        <!-- <li>upload a BitTorrent file to download a ZIM file</li> -->
+        <!-- <li>provide a download link to a ZIM file</li> -->
+        <!-- <li>provide a magnet link to download a ZIM file</li> -->
+        <!-- <li>provide a file path to a ZIM file</li> -->
+      </ul>
+
+      <!-- TODO Add this somewhere -->
+      <!-- The Kiwix project recommends using BitTorrent for downloads. -->
+    {% endblocktrans %}
+  </p>
+
+  {% if max_filesize %}
+    <div class="alert alert-warning" role="alert">
+      <!-- <span class="fa fa-exclamation-triangle" aria-hidden="true"></span> -->
+      <!-- <span class="sr-only">{% trans "Caution:" %}</span> -->
+      {% blocktrans trimmed %}
+        You have {{ max_filesize }} of free disk space available.
+      {% endblocktrans %}
+    </div>
+  {% endif %}
+
+  <form class="form form-kiwix" enctype="multipart/form-data" method="post">
+    {% csrf_token %}
+
+    {{ form|bootstrap }}
+
+    <input type="submit" class="btn btn-primary"
+           value="{% trans "Upload file" %}"/>
+  </form>
+
+{% endblock %}

plinth/modules/kiwix/templates/delete-content-package.html

@@ -0,0 +1,29 @@
+{% extends "base.html" %}
+{% comment %}
+# SPDX-License-Identifier: AGPL-3.0-or-later
+{% endcomment %}
+
+{% load i18n %}
+
+{% block content %}
+
+  <h3>
+    {% blocktrans trimmed %}
+      Delete content package <em>{{ name }}</em>
+    {% endblocktrans %}
+  </h3>
+
+  <p>
+    {% blocktrans trimmed %}
+      Delete this package permanently? You may add it back later if you have a copy of the ZIM file.
+    {% endblocktrans %}
+  </p>
+
+  <form class="form form-delete" method="post">
+    {% csrf_token %}
+
+    <input type="submit" class="btn btn-md btn-danger"
+           value="{% blocktrans %}Delete {{ name }}{% endblocktrans %}"/>
+  </form>
+
+{% endblock %}

plinth/modules/kiwix/templates/kiwix.html

@@ -0,0 +1,48 @@
+{% extends "app.html" %}
+{% comment %}
+# SPDX-License-Identifier: AGPL-3.0-or-later
+{% endcomment %}
+
+{% load i18n %}
+
+{% block configuration %}
+  {{ block.super }}
+
+  <h3>{% trans "Manage Content" %}</h3>
+
+  <div class="btn-toolbar">
+    <a href="{% url 'kiwix:add-content' %}" class="btn btn-default"
+       role="button" title="{% trans 'Add a content package' %}">
+      <span class="fa fa-plus" aria-hidden="true"></span>
+      {% trans 'Add' %}
+    </a>
+  </div>
+
+  <div class="row">
+    <div class="col-md-6">
+      {% if not packages %}
+        <p>{% trans 'No content available.' %}</p>
+      {% else %}
+        <div id="kiwix-packages" class="list-group list-group-two-column">
+          {% for id, package in packages.items %}
+            <div class="list-group-item">
+              <a id="{{ id }}"
+                 class="primary"
+                 href="/kiwix/viewer#{{ package.path }}"
+                 title="{{ package.description  }}">
+                {{ package.title }}
+              </a>
+
+              <a href="{% url 'kiwix:delete-content' id %}"
+                 class="btn btn-default btn-sm secondary" role="button"
+                 title="{% blocktrans with title=package.title %}Delete package {{ title }}{% endblocktrans %}">
+                <span class="fa fa-trash-o" aria-hidden="true"></span>
+              </a>
+            </div>
+          {% endfor %}
+        </div>
+      {% endif %}
+    </div>
+  </div>
+
+{% endblock %}

plinth/modules/kiwix/tests/data/invalid.zim

@@ -0,0 +1 @@
+Nothing to see here.

plinth/modules/kiwix/tests/data/sample_library_zim.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<library version="20110515">
+  <book id="bc4f8cdf-5626-2b13-3860-0033deddfbea" path="content/FreedomBox.zim" title="FreedomBox" description="A sample content archive" language="eng" creator="FreedomBox" publisher="FreedomBox" tags="_ftindex:yes;_ftindex:yes;_pictures:yes;_videos:yes;_details:yes" date="2022-11-29" articleCount="1" mediaCount="1" size="88" />
+</library>

plinth/modules/kiwix/tests/test_functional.py

@@ -0,0 +1,98 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+Functional, browser based tests for Kiwix app.
+"""
+
+import pkg_resources
+import pytest
+
+from time import sleep
+from plinth.modules.kiwix.tests.test_privileged import ZIM_ID
+
+from plinth.tests import functional
+
+pytestmark = [pytest.mark.apps, pytest.mark.sso, pytest.mark.kiwix]
+
+_default_url = functional.config['DEFAULT']['url']
+
+ZIM_ID = 'bc4f8cdf-5626-2b13-3860-0033deddfbea'
+
+
+class TestKiwixApp(functional.BaseAppTests):
+    app_name = 'kiwix'
+    has_service = True
+    has_web = True
+
+    def test_add_delete_content_package(self, session_browser):
+        """Test adding/deleting content package to the library."""
+        functional.app_enable(session_browser, 'kiwix')
+
+        zim_file = pkg_resources.resource_filename(
+            'plinth.modules.kiwix.tests', 'data/FreedomBox.zim')
+        _add_content_package(session_browser, zim_file)
+        assert _is_content_package_listed(session_browser, 'freedombox')
+        assert _is_content_package_available(session_browser, 'FreedomBox')
+
+        _delete_content_package(session_browser, ZIM_ID)
+        assert not _is_content_package_listed(session_browser, 'freedombox')
+        assert not _is_content_package_available(session_browser, 'FreedomBox')
+
+    @pytest.mark.backups
+    def test_backup_restore(self, session_browser):
+        """Test backing up and restoring."""
+        functional.app_enable(session_browser, 'kiwix')
+
+        zim_file = pkg_resources.resource_filename(
+            'plinth.modules.kiwix.tests', 'data/FreedomBox.zim')
+        _add_content_package(session_browser, zim_file)
+        functional.backup_create(session_browser, 'kiwix', 'test_kiwix')
+
+        _delete_content_package(session_browser, ZIM_ID)
+        functional.backup_restore(session_browser, 'kiwix', 'test_kiwix')
+
+        assert _is_content_package_listed(session_browser, 'freedombox')
+        assert _is_content_package_available(session_browser, 'FreedomBox')
+
+    def test_add_invalid_zim_file(self, session_browser):
+        """Test handling of invalid zim files."""
+        functional.app_enable(session_browser, 'kiwix')
+
+        zim_file = pkg_resources.resource_filename(
+            'plinth.modules.kiwix.tests', 'data/invalid.zim')
+        _add_content_package(session_browser, zim_file)
+
+        assert not _is_content_package_listed(session_browser, 'invalid')
+
+
+def _add_content_package(browser, file_name):
+    browser.links.find_by_href('/plinth/apps/kiwix/content/add/').first.click()
+    browser.attach_file('kiwix-file', file_name)
+    functional.submit(browser, form_class='form-kiwix')
+
+
+def _is_content_package_available(browser, title) -> bool:
+    browser.visit(f'{_default_url}/kiwix')
+    sleep(1)  # Allow time for the books to appear
+    titles = browser.find_by_id('book__title')
+    print(len(titles))
+    print([title.value for title in titles])
+    return any(map(lambda e: e.value == title, titles))
+
+
+def _is_content_package_listed(browser, name) -> bool:
+    functional.nav_to_module(browser, 'kiwix')
+    links_found = browser.links.find_by_partial_href(f'/kiwix/viewer#{name}')
+    return len(links_found) == 1
+
+
+def _delete_content_package(browser, zim_id):
+    functional.nav_to_module(browser, 'kiwix')
+    link = browser.links.find_by_href(
+        f'/plinth/apps/kiwix/content/{zim_id}/delete/')
+    if not link:
+        raise ValueError('ZIM file missing!')
+    link.first.click()
+    functional.submit(browser, form_class='form-delete')
+
+
+# TODO Add test to check that Kiwix can be viewed without logging in.

plinth/modules/kiwix/tests/test_privileged.py

@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+Test module for Kiwix actions.
+"""
+
+import pathlib
+import pkg_resources
+from unittest.mock import patch
+
+import pytest
+
+from plinth.modules.kiwix import privileged
+
+pytestmark = pytest.mark.usefixtures('mock_privileged')
+privileged_modules_to_mock = ['plinth.modules.kiwix.privileged']
+
+EMPTY_LIBRARY_CONTENTS = '''<?xml version="1.0" encoding="UTF-8"?>
+<library version="20110515">
+</library>'''
+
+ZIM_ID = 'bc4f8cdf-5626-2b13-3860-0033deddfbea'
+
+
+@pytest.fixture(autouse=True)
+def fixture_kiwix_home(tmpdir):
+    """Set Kiwix home to a new temporary directory
+    initialized with an empty library file."""
+    privileged.KIWIX_HOME = pathlib.Path(str(tmpdir / 'kiwix'))
+    privileged.KIWIX_HOME.mkdir()
+    privileged.CONTENT_DIR = privileged.KIWIX_HOME / 'content'
+    privileged.CONTENT_DIR.mkdir()
+    privileged.LIBRARY_FILE = privileged.KIWIX_HOME / 'library_zim.xml'
+    with open(privileged.LIBRARY_FILE, 'w', encoding='utf_8') as library_file:
+        library_file.write(EMPTY_LIBRARY_CONTENTS)
+
+
+@pytest.fixture(autouse=True)
+def fixture_patch():
+    """Patch some underlying methods."""
+    with patch('subprocess.check_call'), patch('subprocess.run'):
+        yield
+
+
+def test_add_content(tmpdir):
+    """Test adding a content package to Kiwix."""
+    some_dir = tmpdir / 'some' / 'dir'
+    pathlib.Path(some_dir).mkdir(parents=True, exist_ok=True)
+    zim_file_name = 'wikipedia_en_all_maxi_2022-05.zim'
+    orig_file = some_dir / zim_file_name
+    pathlib.Path(orig_file).touch()
+
+    privileged.add_content(str(orig_file))
+    assert (privileged.KIWIX_HOME / 'content' / zim_file_name).exists()
+    assert not orig_file.exists()
+
+
+def test_list_content_packages():
+    """Test listing the content packages from a library file."""
+    privileged.LIBRARY_FILE = pkg_resources.resource_filename(
+        'plinth.modules.kiwix.tests', 'data/sample_library_zim.xml')
+    content_packages = privileged.list_content_packages()
+    assert content_packages[ZIM_ID] == {
+        'title': 'FreedomBox',
+        'description': 'A sample content archive',
+        'path': 'freedombox'
+    }
+
+
+def test_delete_content_package():
+    """Test deleting one content package."""
+    sample_library_file = pkg_resources.resource_filename(
+        'plinth.modules.kiwix.tests', 'data/sample_library_zim.xml')
+
+    with open(sample_library_file, 'r',
+              encoding='utf_8') as sample_library_file:
+        with open(privileged.LIBRARY_FILE, 'w',
+                  encoding='utf_8') as library_file:
+            library_file.write(sample_library_file.read())
+
+    zim_file = privileged.CONTENT_DIR / 'FreedomBox.zim'
+    zim_file.touch()
+
+    privileged.delete_content_package(ZIM_ID)
+
+    assert not zim_file.exists()
+    # Cannot check that the book is removed from library_zim.xml

plinth/modules/kiwix/tests/test_validations.py

@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+Test module for Kiwix validations.
+"""
+
+import unittest
+from plinth.modules import kiwix
+
+
+class TestValidations(unittest.TestCase):
+
+    def test_add_file_with_invalid_extension(self):
+        self.assertRaises(ValueError,
+                          lambda: kiwix.validate_file_name('wikipedia.zip'))
+
+        # We don't support the legacy format of split zim files.
+        self.assertRaises(
+            ValueError, lambda: kiwix.validate_file_name(
+                'wikipedia_en_all_maxi_2022-05.zima'))
+
+        kiwix.validate_file_name('wikipedia_en_all_maxi_2022-05.zim')

plinth/modules/kiwix/tests/test_views.py

@@ -0,0 +1,147 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+Test module for Kiwix views.
+"""
+
+from plinth import module_loader
+from django import urls
+from unittest.mock import call, patch
+from django.contrib.messages.storage.fallback import FallbackStorage
+from django.http.response import Http404
+from django.test.client import encode_multipart, RequestFactory
+
+import pytest
+
+from plinth.modules.kiwix import views
+
+# For all tests, use plinth.urls instead of urls configured for testing
+pytestmark = pytest.mark.urls('plinth.urls')
+
+ZIM_ID = 'bc4f8cdf-5626-2b13-3860-0033deddfbea'
+
+
+@pytest.fixture(autouse=True, scope='module')
+def fixture_kiwix_urls():
+    """Make sure kiwix app's URLs are part of plinth.urls."""
+    with patch('plinth.module_loader._modules_to_load', new=[]) as modules, \
+            patch('plinth.urls.urlpatterns', new=[]):
+        modules.append('plinth.modules.kiwix')
+        module_loader.include_urls()
+        yield
+
+
+def make_request(request, view, **kwargs):
+    """Make request with a message storage."""
+    setattr(request, 'session', 'session')
+    messages = FallbackStorage(request)
+    setattr(request, '_messages', messages)
+    response = view(request, **kwargs)
+
+    return response, messages
+
+
+@pytest.fixture(autouse=True)
+def kiwix_patch():
+    """Patch kiwix methods."""
+    with patch('plinth.modules.kiwix.privileged.list_content_packages'
+               ) as list_libraries:
+        list_libraries.return_value = {
+            ZIM_ID: {
+                'title': 'TestExistingContentPackage',
+                'description': 'A sample content package',
+                'path': 'test_existing_content_package'
+            }
+        }
+        yield
+
+
+@pytest.fixture()
+def storage_info_patch():
+    """Patch storage info method."""
+    with patch('plinth.modules.storage.get_mount_info') as get_mount_info:
+        get_mount_info.return_value = {'free_bytes': 1000000000000}
+        yield
+
+
+@patch('plinth.modules.kiwix.privileged.add_content')
+def test_add_content_package(add_content, rf):
+    """Test that adding content view works."""
+    with open('plinth/modules/kiwix/tests/data/FreedomBox.zim',
+              'rb') as zim_file:
+        post_data = {
+            'kiwix-file': zim_file,
+        }
+        post_data = encode_multipart('BoUnDaRyStRiNg', post_data)
+        request = rf.post(
+            '', data=post_data, content_type='multipart/form-data; '
+            'boundary=BoUnDaRyStRiNg')
+        response, messages = make_request(request,
+                                          views.AddContentView.as_view())
+        assert response.status_code == 302
+        assert response.url == urls.reverse('kiwix:index')
+        assert list(messages)[0].message == 'Content package added.'
+        add_content.assert_has_calls([call('/tmp/FreedomBox.zim')])
+
+
+@patch('plinth.modules.kiwix.privileged.add_content')
+def test_add_content_package_failed(add_content, rf):
+    """Test that adding content package fails in case of an error."""
+    add_content.side_effect = RuntimeError('TestError')
+    with open('plinth/modules/kiwix/tests/data/FreedomBox.zim',
+              'rb') as zim_file:
+        post_data = {
+            'kiwix-file': zim_file,
+        }
+        post_data = encode_multipart('BoUnDaRyStRiNg', post_data)
+        request = rf.post(
+            '', data=post_data, content_type='multipart/form-data; '
+            'boundary=BoUnDaRyStRiNg')
+        response, messages = make_request(request,
+                                          views.AddContentView.as_view())
+        assert response.status_code == 302
+        assert response.url == urls.reverse('kiwix:index')
+        assert list(messages)[0].message == \
+            'Failed to add content package.'
+
+
+@patch('plinth.app.App.get')
+def test_delete_package_confirmation_view(_app, rf):
+    """Test that deleting package confirmation shows correct title."""
+    response, _ = make_request(rf.get(''), views.delete_content, zim_id=ZIM_ID)
+    assert response.status_code == 200
+    assert response.context_data['name'] == 'TestExistingContentPackage'
+
+
+@patch('plinth.modules.kiwix.privileged.delete_content_package')
+@patch('plinth.app.App.get')
+def test_delete_content_package(_app, delete_content_package, rf):
+    """Test that deleting a content package works."""
+    response, messages = make_request(rf.post(''), views.delete_content,
+                                      zim_id=ZIM_ID)
+    assert response.status_code == 302
+    assert response.url == urls.reverse('kiwix:index')
+    assert list(messages)[0].message == 'TestExistingContentPackage deleted.'
+    delete_content_package.assert_has_calls([call(ZIM_ID)])
+
+
+@patch('plinth.modules.kiwix.privileged.delete_content_package')
+def test_delete_content_package_error(delete_content_package, rf):
+    """Test that deleting a content package shows an error when operation fails."""
+    delete_content_package.side_effect = ValueError('TestError')
+    response, messages = make_request(rf.post(''), views.delete_content,
+                                      zim_id=ZIM_ID)
+    assert response.status_code == 302
+    assert response.url == urls.reverse('kiwix:index')
+    assert list(messages)[0].message == \
+        'Could not delete TestExistingContentPackage: TestError'
+
+
+def test_delete_content_package_non_existing(rf):
+    """Test that deleting a content package shows error when operation fails."""
+    with pytest.raises(Http404):
+        make_request(rf.post(''), views.delete_content,
+                     zim_id='NonExistentZimId')
+
+    with pytest.raises(Http404):
+        make_request(rf.get(''), views.delete_content,
+                     zim_id='NonExistentZimId')

plinth/modules/kiwix/urls.py

@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+URLs for the Kiwix module.
+"""
+
+from django.urls import re_path
+
+from . import views
+
+urlpatterns = [
+    re_path(r'^apps/kiwix/$', views.KiwixAppView.as_view(), name='index'),
+    re_path(r'^apps/kiwix/content/add/$', views.AddContentView.as_view(),
+            name='add-content'),
+    re_path(r'^apps/kiwix/content/(?P<zim_id>[a-zA-Z0-9-]+)/delete/$',
+            views.delete_content, name='delete-content'),
+]

plinth/modules/kiwix/views.py

@@ -0,0 +1,105 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""
+Views for the Kiwix module.
+"""
+
+import logging
+
+from django.contrib import messages
+from django.contrib.messages.views import SuccessMessageMixin
+from django.http import Http404
+from django.shortcuts import redirect
+from django.template.response import TemplateResponse
+from django.urls import reverse_lazy
+from django.utils.translation import gettext as _
+from django.views.generic.edit import FormView
+
+from plinth import app as app_module
+from plinth import views
+from plinth.errors import PlinthError
+from plinth.modules import storage
+from plinth.modules.kiwix import privileged
+
+from . import forms
+
+logger = logging.getLogger(__name__)
+
+
+class KiwixAppView(views.AppView):
+    """Serve configuration form."""
+    app_id = 'kiwix'
+    template_name = 'kiwix.html'
+
+    def get_context_data(self, **kwargs):
+        """Return additional context for rendering the template."""
+        context = super().get_context_data(**kwargs)
+        context['packages'] = privileged.list_content_packages()
+        return context
+
+
+class AddContentView(SuccessMessageMixin, FormView):
+    """View to add content in the form of ZIM files."""
+    form_class = forms.AddContentForm
+    prefix = 'kiwix'
+    template_name = 'add-content-package.html'
+    success_url = reverse_lazy('kiwix:index')
+    success_message = _('Content package added.')
+
+    def get_context_data(self, **kwargs):
+        """Return additional context for rendering the template."""
+        context = super().get_context_data(**kwargs)
+        context['title'] = _('Add a new content package')
+
+        # TODO The following is almost duplicated in backups/views.py
+        try:
+            mount_info = storage.get_mount_info('/')
+        except PlinthError as exception:
+            logger.exception(
+                'Error getting information about root partition: %s',
+                exception)
+        else:
+            context['max_filesize'] = storage.format_bytes(
+                mount_info['free_bytes'])
+
+        return context
+
+    def form_valid(self, form):
+        """Store the uploaded file."""
+        multipart_file = self.request.FILES['kiwix-file']
+        zim_file_name = '/tmp/' + multipart_file.name
+        with open(zim_file_name, 'wb+') as zim_file:
+            for chunk in multipart_file.chunks():
+                zim_file.write(chunk)
+
+        try:
+            privileged.add_content(zim_file_name)
+        except Exception:
+            messages.error(self.request, _('Failed to add content package.'))
+            return redirect(reverse_lazy('kiwix:index'))
+
+        return super().form_valid(form)
+
+
+def delete_content(request, zim_id):
+    """View to delete a library."""
+    packages = privileged.list_content_packages()
+    if zim_id not in packages:
+        raise Http404
+
+    name = packages[zim_id]['title']
+
+    if request.method == 'POST':
+        try:
+            privileged.delete_content_package(zim_id)
+            messages.success(request, _(f'{name} deleted.'))
+        except Exception as error:
+            messages.error(
+                request,
+                _('Could not delete {name}: {error}').format(
+                    name=name, error=error))
+        return redirect(reverse_lazy('kiwix:index'))
+
+    return TemplateResponse(request, 'delete-content-package.html', {
+        'title': app_module.App.get('kiwix').info.name,
+        'name': name
+    })