Upgrades the stability of Server Actions from experimental to canary.
- Turns on enableAsyncActions and enableFormActions
- Removes "experimental_" prefix from useOptimistic, useFormStatus, and
useFormState
This automatically exposes `$$FORM_ACTIONS` on Server References coming
from Flight. So that when they're used in a form action, we can encode
the ID for the server reference as a hidden field or as part of the name
of a button.
If the Server Action is a bound function it can have complex data
associated with it. In this case this additional data is encoded as
additional form fields.
To process a POST on the server there's now a `decodeAction` helper that
can take one of these progressive posts from FormData and give you a
function that is prebound with the correct closure and FormData so that
you can just invoke it.
I updated the fixture which now has a "Server State" that gets
automatically refreshed. This also lets us visualize form fields.
There's no "Action State" here for showing error messages that are not
thrown, that's still up to user space.
This lets you pass a function to `<form action={...}>` or `<button
formAction={...}>` or `<input type="submit formAction={...}>`. This will
behave basically like a `javascript:` URL except not quite implemented
that way. This is a convenience for the `onSubmit={e => {
e.preventDefault(); const fromData = new FormData(e.target); ... }`
pattern.
You can still implement a custom `onSubmit` handler and if it calls
`preventDefault`, it won't invoke the action, just like it would if you
used a full page form navigation or javascript urls. It behaves just
like a navigation and we might implement it with the Navigation API in
the future.
Currently this is just a synchronous function but in a follow up this
will accept async functions, handle pending states and handle errors.
This is implemented by setting `javascript:` URLs, but these only exist
to trigger an error message if something goes wrong instead of
navigating away. Like if you called `stopPropagation` to prevent React
from handling it or if you called `form.submit()` instead of
`form.requestSubmit()` which by-passes the `submit` event. If CSP is
used to ban `javascript:` urls, those will trigger errors when these
URLs are invoked which would be a different error message but it's still
there to notify the user that something went wrong in the plumbing.
Next up is improving the SSR state with action replaying and progressive
enhancement.
Previously when a called server reference function was rejected, the
emitted error chunk was not flushed, and the request was not properly
closed.
Co-authored-by: Sebastian Markbage <sebastian@calyptus.eu>
This is the first of a series of PRs, that let you pass functions, by
reference, to the client and back. E.g. through Server Context. It's
like client references but they're opaque on the client and resolved on
the server.
To do this, for security, you must opt-in to exposing these functions to
the client using the `"use server"` directive. The `"use client"`
directive lets you enter the client from the server. The `"use server"`
directive lets you enter the server from the client.
This works by tagging those functions as Server References. We could
potentially expand this to other non-serializable or stateful objects
too like classes.
This only implements server->server CJS imports and server->server ESM
imports. We really should add a loader to the webpack plug-in for
client->server imports too. I'll leave closures as an exercise for
integrators.
You can't "call" a client reference on the server, however, you can
"call" a server reference on the client. This invokes a callback on the
Flight client options called `callServer`. This lets a router implement
calling back to the server. Effectively creating an RPC. This is using
JSON for serializing those arguments but more utils coming from
client->server serialization.
Andrew Clark
Sebastian Markbåge
Hendrik Liebau