Build custom signup behavior with blocking serverless functions

Blocking functions give you more control over the entire authentication process allowing you to reject users if they don’t match a specific criteria. In this video, David explains what blocking serverless functions are.

Chapters:
0:00 - Why block a function?
0:41 - A traditional serverless function set up
1:26 - Blocking before a user is created
1:52 - Rejecting users with HttpsError
2:31 - Blocking before a user signs in
3:14 - Accepting a valid user
4:04 - Custom claims are amazing and you should use them
4:16 - Deploying
4:31- Registering blocking functions in the console
4:53 - Seeing it in action
5:00 - What else do you want to see?!

Resources:

#FirebaseFundamentals

[ArchitecturalAesthetics]

keep these videos coming dave. loved your firebase course on frontendmasters

[muncho]

Firebase casually spoiling devs🥰 Awesome feature🔥

[amitasayag]

That's a great feature, thanks.

Cloud functions might have a cold start that sometimes causing a timeout (hard timeout of 7 seconds) at the javascript SDK once a user sign-in.
I wish we could have increase this time or instead of a cloud function supply a url for a web hook to some service which is typically warm.

[robinyoulton]

Superb feature, I'm definitely going to use that :)😊

[picoroDaimaku]

Is this useful if we need to create a user document in Firestore at the same time user is created in Auth db?

[rubenheymans]

the annoying thing is once you create a new user from the frontend, that user automatically logs in and this automatically triggers the beforelogin which isn't always optimal

[hobbyturystaSEO]

Are those blocking functions are similar to session where users get hit by unauthorized request from unwanted source that last for a loop?

[boardtale]

Why you deployed the function via CLI? :( How to use such function if such is defined in GCP already?

[corchoneitor_ok]

Cold start in these functions with a 7 seconds timeout is a real pain.

[BRICKSINSILK]

why would u wanna block the authentication ur asking that....uve got a way to go

[ezzabuzaid]

does it work for anonymous users as well?

[seanaguinaga]

don't forget you can set the blocking functions in the config object!

Otherwise every time you update/deploy the function, you have to re-configure it!