[RFC] API Routes in Expo Router (#24429)

# Why

Servers are an important part of developing many different types of
apps, but they're much harder to configure than they need to be.

API Routes

[RFC] API Routes in Expo Router (#24429)

# Why

Servers are an important part of developing many different types of
apps, but they're much harder to configure than they need to be.

API Routes will enable users to express some abstract JavaScript code
that runs in a server by simply creating a file in the app directory,
and adding the `+api.js` suffix. For example, to securely interact with
OpenAI, simply:

```ts
// app/generate+api.ts
import { ExpoRequest, ExpoResponse } from 'expo-router/server';

export async function POST(req: ExpoRequest): Promise<ExpoResponse> {
const { prompt } = await req.json();

const json = await fetch('https://api.openai.com/v1/engines/text-davinci-003/completions', {
headers: {
'Content-Type': 'application/json',
// `OPENAI_API_KEY` is pulled from the .env file when running in Expo CLI.
Authorization: `Bearer ${process.env.OPENAI_API_KEY ?? ''}`,
},
method: 'POST',
body: JSON.stringify({
prompt,
max_tokens: 100,
}),
}).then(res => res.json());

// Return as JSON
return ExpoResponse.json(json);
}
```

This will be served at `http://localhost:8081/generate` with `npx expo`
and can be used by making a request:

```sh
$ curl -X POST -H "Content-Type: application/json" -d \'{"prompt":"Hello, my name is"}\' http://localhost:8081/generate
```

Expo Router polyfills the URL and `window.location` object on native to
allow for universally requesting with a relative URL:

```js
// Expo prepends the host and port to the URL automatically in development.
const json = await fetch('/generate').then(res => res.json());
```

# How

- API Routes are bundled with Metro, leveraging all the same
functionality as the rest of the app and website.
- The project babel config is used to transpile the API routes.
Indication is passed to the Babel caller via the `isServer` boolean.
This can be used to change the preset based on the environment.
- Each API route is bundled into a standalone file in the `dist/_expo`
directory. This is akin to ncc, the tool we use to make Create Expo App
download in ~1 second.
- Create a new package `@expo/server` which includes the requisite
middleware and runtime polyfills for the Expo server environment.
- Add a new routes manifest which will be used by `@expo/server` to
serve up the three types of routes: HTML routes, API routes, and not
found routes (404s).
- Add a new export `expo-router/server` (potentially will be moved to
`expo/server`) which contains the `ExpoRequest` and `ExpoResponse`
objects. These are all based on the WinterCG specification, and include
some additional properties for interop with the Expo Router filesystem
convention. These are inspired by Remix, SvelteKit, and Next.js for
simplicity.
- Add a new export mode `web.output: "server"` which can be used to
export a dynamic server. Note: I may drop this for now and make server
the default since there's no expo-specific hosting code that must be
exported.
- This PR adds the ability to host the app with an express server,
different production adapters to follow.

# Test Plan

In addition to all the E2E Metro tests, I've added a new E2E runner
which starts a server and pings different requests to ensure expected
behavior. These run in the CLI as opposed to the `@expo/server` package.

- resolve ENG-10057 ENG-8243 ENG-8082 ENG-8079 ENG-8242 ENG-8081
ENG-8080 ENG-9625

---------

Co-authored-by: Expo Bot <[email protected]>
Co-authored-by: Cedric van Putten <[email protected]>

show more ...

feat(cli,router): support src/app directory in Expo Router (#22748)

# Why

- related https://github.com/expo/router/pull/629

<!--
Please describe the motivation for this PR, and link to releva

feat(cli,router): support src/app directory in Expo Router (#22748)

# Why

- related https://github.com/expo/router/pull/629

<!--
Please describe the motivation for this PR, and link to relevant GitHub
issues, forums posts, or feature requests.
-->

# How

<!--
How did you build this feature or fix this bug and why?
-->

# Test Plan

<!--
Please describe how you tested this change and how a reviewer could
reproduce your test, especially if this PR does not include automated
tests! If possible, please also provide terminal output and/or
screenshots demonstrating your test/reproduction.
-->

# Checklist

<!--
Please check the appropriate items below if they apply to your diff.
This is required for changes to Expo modules.
-->

- [ ] Documentation is up to date to reflect these changes (eg:
https://docs.expo.dev and README.md).
- [ ] Conforms with the [Documentation Writing Style
Guide](https://github.com/expo/expo/blob/main/guides/Expo%20Documentation%20Writing%20Style%20Guide.md)
- [ ] This diff will work correctly for `npx expo prebuild` & EAS Build
(eg: updated a module plugin).

---------

Co-authored-by: Expo Bot <[email protected]>

show more ...

feat: typed route generation for expo router (#21651)

> Draft PR - just seeking feedback on the implementation.

# Why

WIP implementation of route generation for Expo Router.

# How

## Typ

feat: typed route generation for expo router (#21651)

> Draft PR - just seeking feedback on the implementation.

# Why

WIP implementation of route generation for Expo Router.

# How

## Typescript bootstrapping

This is expands the Typescript bootstrapping to also accommodate for
long-lived typescript watchers.
- Changes `waitForMetroToObserveTypeScriptFile` to
`metroWatchTypeScriptFiles`
- Processes are now responsible to disabling their watcher
- tsconfig can optionally be watched

## Type generation

`typedRouteGenerator` is invokes after the CLI has bootstrapped
TypeScript.
- Generates types only for absolute paths
- Supports static and dynamic routes
- Supports URL normalisation (TODO: Need unit tests for these!)
- Supports dynamic route parameter typing

# Test Plan

`EXPO_ROUTER_TYPED_ROUTES=true nexpo start`

// Todo

# Checklist

- [x] Documentation is up to date to reflect these changes (eg:
https://docs.expo.dev and README.md).
- [x] Conforms with the [Documentation Writing Style
Guide](https://github.com/expo/expo/blob/main/guides/Expo%20Documentation%20Writing%20Style%20Guide.md)
- [x] This diff will work correctly for `expo prebuild` & EAS Build (eg:
updated a module plugin).

---------

Co-authored-by: Evan Bacon <[email protected]>

show more ...

feat(cli): add touch middleware and app entry (#19231)

* add middleware for creating files

* fix touch request

* added support for auto entry

* added tests for touch middleware

* added r

feat(cli): add touch middleware and app entry (#19231)

* add middleware for creating files

* fix touch request

* added support for auto entry

* added tests for touch middleware

* added router tests

* Update CHANGELOG.md

* Update packages/@expo/cli/CHANGELOG.md

Co-authored-by: Expo Bot <[email protected]>

* Update instantiateMetro.ts

Co-authored-by: Expo Bot <[email protected]>

show more ...