email: Basic app to manage an email server

- Install postfix and manage the service
- Import ugettext
- Dummy forms and views
- <module>.version (integer) is required

[sunil: Disable the app until remaining issues are worked out]
Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/modules/email_server/__init__.py

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+"""FreedomBox email server app"""
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+from django.urls import reverse_lazy
+from django.utils.translation import ugettext_lazy as _
+
+import plinth.app
+import plinth.daemon
+import plinth.frontpage
+import plinth.menu
+from plinth.modules.firewall.components import Firewall
+
+from . import manifest
+
+version = 1
+managed_packages = ['postfix', 'dovecot-pop3d', 'dovecot-imapd',
+                    'dovecot-lmtpd', 'dovecot-ldap', 'dovecot-managesieved']
+managed_services = ['postfix', 'dovecot']
+app = None
+
+
+class EmailServerApp(plinth.app.App):
+    """FreedomBox email server app"""
+    app_id = 'email_server'
+
+    def __init__(self):
+        """The app's constructor"""
+        super().__init__()
+
+        info = plinth.app.Info(
+            app_id=self.app_id,
+            version=version,
+            name=_('Email Server'),
+            short_description=_('An email server for FreedomBox'),
+            manual_page='EmailServer',
+            clients=manifest.clients,
+            donation_url='https://freedomboxfoundation.org/donate/'
+        )
+        self.add(info)
+
+        menu_item = plinth.menu.Menu(
+            'menu_' + self.app_id,  # unique id
+            info.name,  # app display name
+            info.short_description,  # app description
+            'roundcube',  # icon name in `static/theme/icons/`
+            'email_server:index',  # view name
+            parent_url_name='apps'
+        )
+        self.add(menu_item)
+
+        shortcut = plinth.frontpage.Shortcut(
+            'shortcut_' + self.app_id,
+            name=info.name,
+            short_description=info.short_description,
+            icon='roundcube',
+            configure_url=reverse_lazy('email_server'),
+            clients=manifest.clients,
+            login_required=True
+        )
+        self.add(shortcut)
+
+        postfix_ports = []
+        dovecot_ports = []
+        all_firewalld_ports = []
+        for port in (25, 465, 587):
+            postfix_ports.extend([(port, 'tcp4'), (port, 'tcp6')])
+        for port in (993, 995):
+            dovecot_ports.extend([(port, 'tcp4'), (port, 'tcp6')])
+        all_firewalld_ports.extend(['smtp', 'smtps', 'smtp-submission'])
+        all_firewalld_ports.extend(['pop3s', 'imaps'])
+
+        # Manage daemons
+        postfixd = plinth.daemon.Daemon('daemon-postfix', 'postfix',
+                                        listen_ports=postfix_ports)
+        dovecotd = plinth.daemon.Daemon('daemon-dovecot', 'dovecot',
+                                        listen_ports=dovecot_ports)
+        self.add(postfixd)
+        self.add(dovecotd)
+
+        # Ports
+        firewall = Firewall('firewall-email', info.name,
+                            ports=all_firewalld_ports, is_external=True)
+        self.add(firewall)
+
+
+def setup(helper, old_version=None):
+    """Installs and configures module"""
+    helper.install(managed_packages)

plinth/modules/email_server/data/etc/plinth/modules-enabled/email_server

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+#plinth.modules.email_server

plinth/modules/email_server/forms.py

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+# SPDX-License-Identifier: AGPL-3.0-or-later
+from django import forms
+
+
+class EmailServerForm(forms.Form):
+    pass

plinth/modules/email_server/manifest.py

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+# SPDX-License-Identifier: AGPL-3.0-or-later
+from django.utils.translation import ugettext_lazy as _
+from plinth.clients import store_url
+
+clients = [{
+    'name': _('Roundcube'),
+    'platforms': [{
+        'type': 'web',
+        'url': '/plinth/apps/roundcube'
+    }]
+}, {
+    'name': _('Thunderbird'),
+    'platforms': [{
+        'type': 'download',
+        'os': 'gnu-linux',
+        'url': 'https://www.thunderbird.net/en-US/'
+    }, {
+        'type': 'download',
+        'os': 'macos',
+        'url': 'https://www.thunderbird.net/en-US/'
+    }, {
+        'type': 'download',
+        'os': 'windows',
+        'url': 'https://www.thunderbird.net/en-US/'
+    }]
+}, {
+    'name': _('K-9 Mail'),
+    'platforms': [{
+        'type': 'store',
+        'os': 'android',
+        'store_name': 'f-droid',
+        'url': store_url('f-droid', 'com.fsck.k9')
+    }, {
+        'type': 'store',
+        'os': 'android',
+        'store_name': 'google-play',
+        'url': store_url('google-play', 'com.fsck.k9')
+    }]
+}, {
+    'name': _('FairEmail'),
+    'platforms': [{
+        'type': 'store',
+        'os': 'android',
+        'store_name': 'f-droid',
+        'url': store_url('f-droid', 'eu.faircode.email')
+    }, {
+        'type': 'store',
+        'os': 'android',
+        'store_name': 'google-play',
+        'url': store_url('google-play', 'eu.faircode.email')
+    }]
+}]

plinth/modules/email_server/urls.py

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+# SPDX-License-Identifier: AGPL-3.0-or-later
+from django.urls import path
+from . import views
+
+
+urlpatterns = [
+    path('apps/email_server/', views.EmailServerView.as_view(), name='index')
+]

plinth/modules/email_server/views.py

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+# SPDX-License-Identifier: AGPL-3.0-or-later
+import plinth
+from . import forms
+
+
+class EmailServerView(plinth.views.AppView):
+    """Server configuration page"""
+    app_id = 'email_server'
+    form_class = forms.EmailServerForm
+
+    def form_valid(self, form):
+        # old_settings = form.initial
+        # new_status = form.cleaned_data
+        # plinth.actions.superuser_run('email_server', ['--help'])
+        return super().form_valid(form)