Chapter 6: Asynchronous emails (6b)

hello.py

@@ -1,4 +1,5 @@
 import os
+from threading import Thread
 from flask import Flask, render_template, session, redirect, url_for
 from flask_bootstrap import Bootstrap
 from flask_moment import Moment
@@ -53,12 +54,19 @@ class User(db.Model):
         return '<User %r>' % self.username
 
 
+def send_async_email(app, msg):
+    with app.app_context():
+        mail.send(msg)
+
+
 def send_email(to, subject, template, **kwargs):
     msg = Message(app.config['FLASKY_MAIL_SUBJECT_PREFIX'] + subject,
                   sender=app.config['FLASKY_MAIL_SENDER'], recipients=[to])
     msg.body = render_template(template + '.txt', **kwargs)
     msg.html = render_template(template + '.html', **kwargs)
-    mail.send(msg)
+    thr = Thread(target=send_async_email, args=[app, msg])
+    thr.start()
+    return thr
 
 
 class NameForm(FlaskForm):