HTTP Error handling policy across Gutenberg

[adamziel]

Right now, there is no standardized way of handling HTTP errors in Gutenberg.

Any request may fail for a number of reasons, and different errors require different handling. Sometimes, the error is up to a specific API consumer to handle, for example:

• When a resolver re-requests an entity record that is now missing, it would make sense to remove it from the state and ensure it is somehow communicated to the user.
• When the validation failed, it would be great to tell the user why.

But there is also a class of global errors that could be consistently handled whenever they occur in random actions or resolvers, for example:

• When the user is no longer authenticated, it would be great to display a login form.
• When the user is unauthorized to do something, it would be great to tell them, and perhaps refresh the page if their permissions changed while the editor was open.
• When the server had a temporary hiccup, it would be great to retry the request before failing.
• Ditto for temporary network connection issues.

These are merely examples to illustrate the problem. There are many, many more scenarios and the list of HTTP response error codes would be a good place to start mapping out different cases so that we could discuss the most appropriate behaviors.

Related reads:

• Post Editor always assumes a logged in user with valid session #37682
• Core Data: Resolve getCurrentUser on API error #38989
• Handle resolution errors in @wordpress/data #38669

cc @youknowriad @jsnajdr @Mamaduka @dmsnell @gwwar @ntsekouras @jorgefilipecosta @ellatrix @gziolo @draganescu @scruffian @getdave @paaljoachim @spacedmonkey @TimothyBJacobs @talldan @noisysocks @kevin940726

[noisysocks]

When the user is no longer authenticated, it would be great to display a login form.

I think the block editor uses the same "heartbeat" mechanism as the rest of WP Admin and should show a login form if the session has expired. Perhaps could look at extending that if it's not enough.

When the user is unauthorized to do something, it would be great to tell them, and perhaps refresh the page if their permissions changed while the editor was open.

Let's just be careful about not losing any of the user's unsaved content during this.

When the server had a temporary hiccup, it would be great to retry the request before failing.
Ditto for temporary network connection issues.

I'm not sure about retrying automatically. Usually when I encounter network connection issues it's because I'm passing through a tunnel on my phone or not connected to WiFi. In these cases I want to retry the operation after I fix the issue. Could we show a Retry button on a Connection issue toast notification?

[getdave]

I wonder what we could learn from https://react-query.tanstack.com/guides/query-retries