invite email translation now happens on the fly

.gitignore

@@ -17,4 +17,4 @@ ihatemoney/budget.db
 .idea
 .python-version
 .coverage*
-prof
+prof

ihatemoney/templates/translation_template.j2

@@ -0,0 +1,3 @@
+{% trans %}
+{{ untranslated_text }}
+{% endtrans %}

ihatemoney/utils.py

@@ -430,6 +430,10 @@ def render_localized_template(template_name_prefix, **context):
     # render_template() supports a list of templates to try in order
     return render_template(templates, **context)
 
+def translate_template_text(text, **context):
+    """Passes `text` to a basic Jinja translation template. A generalizable solution for translating outgoing emails."""
+
+    return render_template("translation_template.j2", untranslated_text=text, **context)
 
 def format_form_errors(form, prefix):
     """Format all form errors into a single string, with a string prefix in

ihatemoney/web.py

@@ -68,6 +68,7 @@
     list_of_dicts2csv,
     list_of_dicts2json,
     render_localized_template,
+    translate_template_text,
     send_email,
 )
 
@@ -601,7 +602,8 @@ def invite():
     if request.method == "POST":
         if form.validate():
             # send the email
-            message_body = render_localized_template("invitation_mail")
+            untranslated_body = render_template("invitation_mail.j2")
+            message_body = translate_template_text(untranslated_body)
             message_title = _(
                 "You have been invited to share your expenses for %(project)s",
                 project=g.project.name,