Backups: export and download archives in one step

Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

actions/backups

@@ -132,6 +132,9 @@ def subcommand_extract(arguments):
 
 def subcommand_export(arguments):
     """Export archive contents as tarball."""
+    # TODO: if this is only used for files in /tmp, add checks to verify that
+    # arguments.filename is within /tmp
+    # TODO: arguments.filename is not a filename but a path
     path = os.path.dirname(arguments.filename)
     if not os.path.exists(path):
         os.makedirs(path)

plinth/modules/backups/__init__.py

@@ -47,6 +47,8 @@ service = None
 MANIFESTS_FOLDER = '/var/lib/plinth/backups-manifests/'
 
 BACKUP_FOLDER_NAME = 'FreedomBox-backups'
+# default backup path for temporary actions like imports or download
+TMP_BACKUP_PATH = '/tmp/freedombox-backup.tar.gz'
 
 
 def init():
@@ -108,10 +110,14 @@ def delete_archive(name):
     actions.superuser_run('backups', ['delete', '--name', name])
 
 
-def export_archive(name, location):
-    location_path = get_location_path(location)
-    filepath = get_archive_path(location_path,
-                                get_valid_filename(name) + '.tar.gz')
+def export_archive(name, location, tmp_dir=False):
+    # TODO: find a better solution for distinguishing exports to /tmp
+    if tmp_dir:
+        filepath = TMP_BACKUP_PATH
+    else:
+        location_path = get_location_path(location)
+        filepath = get_archive_path(location_path,
+                                    get_valid_filename(name) + '.tar.gz')
     # TODO: that's a full path, not a filename; rename argument
     actions.superuser_run('backups',
                           ['export', '--name', name, '--filename', filepath])

plinth/modules/backups/templates/backups.html

@@ -86,6 +86,10 @@
                  href="{% url 'backups:export' archive.name %}">
                 {% trans "Export" %}
               </a>
+              <a class="archive-export btn btn-sm btn-default" target="_blank"
+                 href="{% url 'backups:export-and-download' archive.name %}">
+                {% trans "Download" %}
+              </a>
               <a class="archive-delete btn btn-sm btn-default"
                  href="{% url 'backups:delete' archive.name %}">
                 <span class="glyphicon glyphicon-trash" aria-hidden="true">

plinth/modules/backups/urls.py

@@ -21,7 +21,8 @@ URLs for the backups module.
 from django.conf.urls import url
 
 from .views import IndexView, CreateArchiveView, DownloadArchiveView, \
-    DeleteArchiveView, ExportArchiveView, RestoreView, UploadArchiveView
+    DeleteArchiveView, ExportArchiveView, RestoreView, UploadArchiveView, \
+    ExportAndDownloadView
 
 urlpatterns = [
     url(r'^sys/backups/$', IndexView.as_view(), name='index'),
@@ -30,6 +31,8 @@ urlpatterns = [
         ExportArchiveView.as_view(), name='export'),
     url(r'^sys/backups/download/(?P<device>[^/]+)/(?P<name>[^/]+)/$',
         DownloadArchiveView.as_view(), name='download'),
+    url(r'^sys/backups/export-and-download/(?P<name>[^/]+)/$',
+        ExportAndDownloadView.as_view(), name='export-and-download'),
     url(r'^sys/backups/delete/(?P<name>[^/]+)/$',
         DeleteArchiveView.as_view(), name='delete'),
     url(r'^sys/backups/upload/$', UploadArchiveView.as_view(), name='upload'),

plinth/modules/backups/views.py

@@ -19,6 +19,7 @@ Views for the backups app.
 """
 
 import mimetypes
+import os
 from datetime import datetime
 from urllib.parse import unquote
 
@@ -33,7 +34,7 @@ from django.views.generic import View, FormView, TemplateView
 
 from plinth.modules import backups
 
-from . import api, find_exported_archive, forms
+from . import api, find_exported_archive, TMP_BACKUP_PATH, forms
 
 
 subsubmenu = [{
@@ -131,6 +132,39 @@ def _get_file_response(path, filename):
     return response
 
 
+class ExportAndDownloadView(View):
+    """View to export and download an archive."""
+    def get(self, request, name):
+        name = unquote(name)
+        with create_temporary_backup_file(name) as filename, \
+                open(filename, 'rb') as file_handle:
+            (content_type, encoding) = mimetypes.guess_type(filename)
+            response = HttpResponse(File(file_handle),
+                content_type=content_type)
+            content_disposition = 'attachment; filename="%s"' % filename
+            response['Content-Disposition'] = content_disposition
+            if encoding:
+                response['Content-Encoding'] = encoding
+
+            return response
+
+
+class create_temporary_backup_file:
+    """Create a temporary backup file that gets deleted after using it"""
+
+    def __init__(self, name):
+        self.name = name
+        self.path = TMP_BACKUP_PATH
+
+    def __enter__(self):
+        backups.export_archive(self.name, self.path, tmp_dir=True)
+        return self.path
+
+    def __exit__(self, type, value, traceback):
+        if os.path.isfile(self.path):
+            os.remove(self.path)
+
+
 class UploadArchiveView(SuccessMessageMixin, FormView):
     form_class = forms.UploadForm
     prefix = 'backups'