Add a button to download custom recipes to the dialog used for creating recipes. Fixes #1868209 [[Enhancement] Add a Download news button](https://bugs.launchpad.net/calibre/+bug/1868209)

src/calibre/db/adding.py

@@ -281,9 +281,9 @@ def add_news(cache, path, arg, dbapi=None):
         if mi.series_index is None:
             mi.series_index = cache._get_next_series_num_for(mi.series)
         mi.tags = [_('News')]
-        if arg['add_title_tag']:
+        if arg.get('add_title_tag'):
             mi.tags += [arg['title']]
-        if arg['custom_tags']:
+        if arg.get('custom_tags'):
             mi.tags += arg['custom_tags']
         if mi.pubdate is None:
             mi.pubdate = utcnow()

src/calibre/gui2/actions/fetch_news.py

@@ -48,6 +48,21 @@ class FetchNewsAction(InterfaceAction):
                 self.gui.library_view.model().delete_books_by_id,
                 type=Qt.QueuedConnection)
 
+    def download_custom_recipe(self, title, urn):
+        arg = {'title': title, 'urn': urn, 'username': None, 'password': None}
+        func, args, desc, fmt, temp_files = fetch_scheduled_recipe(arg)
+        job = self.gui.job_manager.run_job(
+                Dispatcher(self.custom_recipe_fetched), func, args=args, description=desc)
+        self.conversion_jobs[job] = (temp_files, fmt, arg)
+        self.gui.status_bar.show_message(_('Fetching news from ')+arg['title'], 2000)
+
+    def custom_recipe_fetched(self, job):
+        temp_files, fmt, arg = self.conversion_jobs.pop(job)
+        fname = temp_files[0].name
+        if job.failed:
+            return self.gui.job_exception(job)
+        self.gui.library_view.model().add_news(fname, arg)
+
     def download_scheduled_recipe(self, arg):
         func, args, desc, fmt, temp_files = \
                 fetch_scheduled_recipe(arg)

src/calibre/gui2/dialogs/custom_recipes.py

@@ -38,6 +38,11 @@ class CustomRecipeModel(QAbstractListModel):  # {{{
         if row > -1 and row < self.rowCount():
             return self.recipe_model.custom_recipe_collection[row].get('title', '')
 
+    def urn(self, index):
+        row = index.row()
+        if row > -1 and row < self.rowCount():
+            return self.recipe_model.custom_recipe_collection[row].get('id')
+
     def has_title(self, title):
         for x in self.recipe_model.custom_recipe_collection:
             if x.get('title', False) == title:
@@ -194,6 +199,10 @@ class RecipeList(QWidget):  # {{{
         b.clicked.connect(self.remove)
         b.setSizePolicy(QSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed))
         l.addWidget(b)
+        self.download_button = b = QPushButton(QIcon(I('download-metadata.png')), _('&Download this recipe'), w)
+        b.clicked.connect(self.download)
+        b.setSizePolicy(QSizePolicy(QSizePolicy.Fixed, QSizePolicy.Fixed))
+        l.addWidget(b)
 
         self.select_row()
         v.selectionModel().currentRowChanged.connect(self.recipe_selected)
@@ -247,6 +256,15 @@ class RecipeList(QWidget):  # {{{
             if self.model.rowCount() == 0:
                 self.stacks.setCurrentIndex(0)
 
+    def download(self):
+        idx = self.view.currentIndex()
+        if idx.isValid():
+            urn = self.model.urn(idx)
+            title = self.model.title(idx)
+            from calibre.gui2.ui import get_gui
+            gui = get_gui()
+            gui.iactions['Fetch News'].download_custom_recipe(title, urn)
+
     def has_title(self, title):
         return self.model.has_title(title)