Docusaurus-ify (#26051)

This PR cleans up the docs in a way to make them simpler to ingest by
our [docs repo](https://gitea.com/gitea/gitea-docusaurus).

1. It includes all of the sed invocations our ingestion did, removing
the need to do it at build time.
2. It replaces the shortcode variable replacement method with
`@variable@` style, simply for easier sed invocations when required.
3. It removes unused files and moves the docs up a level as cleanup.

---------

Signed-off-by: jolheiser <john.olheiser@gmail.com>

1 files changed, 202 insertions, 0 deletions

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+---
+date: "2023-06-01T08:40:00+08:00"
+title: "OAuth2 provider"
+slug: "oauth2-provider"
+sidebar_position: 41
+toc: false
+draft: false
+aliases:
+  - /en-us/oauth2-provider
+menu:
+  sidebar:
+    parent: "development"
+    name: "OAuth2 Provider"
+    sidebar_position: 41
+    identifier: "oauth2-provider"
+---
+
+# OAuth2 provider
+
+Gitea supports acting as an OAuth2 provider to allow third party applications to access its resources with the user's consent. This feature is available since release 1.8.0.
+
+## Endpoints
+
+| Endpoint                 | URL                                 |
+| ------------------------ | ----------------------------------- |
+| OpenID Connect Discovery | `/.well-known/openid-configuration` |
+| Authorization Endpoint   | `/login/oauth/authorize`            |
+| Access Token Endpoint    | `/login/oauth/access_token`         |
+| OpenID Connect UserInfo  | `/login/oauth/userinfo`             |
+| JSON Web Key Set         | `/login/oauth/keys`                 |
+
+## Supported OAuth2 Grants
+
+At the moment Gitea only supports the [**Authorization Code Grant**](https://tools.ietf.org/html/rfc6749#section-1.3.1) standard with additional support of the following extensions:
+
+- [Proof Key for Code Exchange (PKCE)](https://tools.ietf.org/html/rfc7636)
+- [OpenID Connect (OIDC)](https://openid.net/specs/openid-connect-core-1_0.html#CodeFlowAuth)
+
+To use the Authorization Code Grant as a third party application it is required to register a new application via the "Settings" (`/user/settings/applications`) section of the settings. To test or debug you can use the web-tool https://oauthdebugger.com/.
+
+## Scopes
+
+Gitea supports scoped access tokens, which allow users the ability to restrict tokens to operate only on selected url routes. Scopes are grouped by high-level API routes, and further refined to the following:
+
+- `read`: `GET` routes
+- `write`: `POST`, `PUT`, `PATCH`, and `DELETE` routes (in addition to `GET`)
+
+Gitea token scopes are as follows:
+
+| Name | Description                                                                                                                                          |
+| ---- |------------------------------------------------------------------------------------------------------------------------------------------------------|
+| **(no scope)** | Not supported. A scope is required even for public repositories.                                                                                     |
+| **activitypub** | `activitypub` API routes: ActivityPub related operations.                                                                                            |
+|     **read:activitypub** | Grants read access for ActivityPub operations.                                                                                                       |
+|     **write:activitypub** | Grants read/write/delete access for ActivityPub operations.                                                                                          |
+| **admin** | `/admin/*` API routes: Site-wide administrative operations (hidden for non-admin accounts).                                                          |
+|     **read:admin** | Grants read access for admin operations, such as getting cron jobs or registered user emails.                                                        |
+|     **write:admin** | Grants read/write/delete access for admin operations, such as running cron jobs or updating user accounts.                                           |
+| **issue** | `issues/*`, `labels/*`, `milestones/*` API routes: Issue-related operations.                                                                         |
+|     **read:issue** | Grants read access for issues operations, such as getting issue comments, issue attachments, and milestones.                                         |
+|     **write:issue** | Grants read/write/delete access for issues operations, such as posting or editing an issue comment or attachment, and updating milestones.           |
+| **misc** | Reserved for future usage.                                                                                                                           |
+|     **read:misc** | Reserved for future usage.                                                                                                                           |
+|     **write:misc** | Reserved for future usage.                                                                                                                           |
+| **notification** | `notification/*` API routes: user notification operations.                                                                                           |
+|     **read:notification** | Grants read access to user notifications, such as which notifications users are subscribed to and read new notifications.                            |
+|     **write:notification** | Grants read/write/delete access to user notifications, such as marking notifications as read.                                                        |
+| **organization** | `orgs/*` and `teams/*` API routes: Organization and team management operations.                                                                      |
+|     **read:organization** | Grants read access to org and team status, such as listing all orgs a user has visibility to, teams, and team members.                               |
+|     **write:organization** | Grants read/write/delete access to org and team status, such as creating and updating teams and updating org settings.                               |
+| **package** | `/packages/*` API routes: Packages operations                                                                                                        |
+|     **read:package** | Grants read access to package operations, such as reading and downloading available packages.                                                        |
+|     **write:package** | Grants read/write/delete access to package operations. Currently the same as `read:package`.                                                         |
+| **repository** | `/repos/*` API routes except `/repos/issues/*`: Repository file, pull-request, and release operations.                                               |
+|     **read:repository** | Grants read access to repository operations, such as getting repository files, releases, collaborators.                                              |
+|     **write:repository** | Grants read/write/delete access to repository operations, such as getting updating repository files, creating pull requests, updating collaborators. |
+| **user** | `/user/*` and `/users/*` API routes: User-related operations.                                                                                        |
+|     **read:user** | Grants read access to user operations, such as getting user repo subscriptions and user settings.                                                    |
+|     **write:user** | Grants read/write/delete access to user operations, such as updating user repo subscriptions, followed users, and user settings.                     |
+
+## Client types
+
+Gitea supports both confidential and public client types, [as defined by RFC 6749](https://datatracker.ietf.org/doc/html/rfc6749#section-2.1).
+
+For public clients, a redirect URI of a loopback IP address such as `http://127.0.0.1/` allows any port. Avoid using `localhost`, [as recommended by RFC 8252](https://datatracker.ietf.org/doc/html/rfc8252#section-8.3).
+
+## Examples
+
+### Confidential client
+
+**Note:** This example does not use PKCE.
+
+1. Redirect the user to the authorization endpoint in order to get their consent for accessing the resources:
+
+   ```curl
+   https://[YOUR-GITEA-URL]/login/oauth/authorize?client_id=CLIENT_ID&redirect_uri=REDIRECT_URI&response_type=code&state=STATE
+   ```
+
+   The `CLIENT_ID` can be obtained by registering an application in the settings. The `STATE` is a random string that will be sent back to your application after the user authorizes. The `state` parameter is optional, but should be used to prevent CSRF attacks.
+
+   ![Authorization Page](/authorize.png)
+
+   The user will now be asked to authorize your application. If they authorize it, the user will be redirected to the `REDIRECT_URL`, for example:
+
+   ```curl
+   https://[REDIRECT_URI]?code=RETURNED_CODE&state=STATE
+   ```
+
+2. Using the provided `code` from the redirect, you can request a new application and refresh token. The access token endpoint accepts POST requests with `application/json` and `application/x-www-form-urlencoded` body, for example:
+
+   ```curl
+   POST https://[YOUR-GITEA-URL]/login/oauth/access_token
+   ```
+
+   ```json
+   {
+     "client_id": "YOUR_CLIENT_ID",
+     "client_secret": "YOUR_CLIENT_SECRET",
+     "code": "RETURNED_CODE",
+     "grant_type": "authorization_code",
+     "redirect_uri": "REDIRECT_URI"
+   }
+   ```
+
+   Response:
+
+   ```json
+   {
+     "access_token": "eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.eyJnbnQiOjIsInR0IjowLCJleHAiOjE1NTUxNzk5MTIsImlhdCI6MTU1NTE3NjMxMn0.0-iFsAwBtxuckA0sNZ6QpBQmywVPz129u75vOM7wPJecw5wqGyBkmstfJHAjEOqrAf_V5Z-1QYeCh_Cz4RiKug",
+     "token_type": "bearer",
+     "expires_in": 3600,
+     "refresh_token": "eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.eyJnbnQiOjIsInR0IjoxLCJjbnQiOjEsImV4cCI6MTU1NzgwNDMxMiwiaWF0IjoxNTU1MTc2MzEyfQ.S_HZQBy4q9r5SEzNGNIoFClT43HPNDbUdHH-GYNYYdkRfft6XptJBkUQscZsGxOW975Yk6RbgtGvq1nkEcklOw"
+   }
+   ```
+
+   The `CLIENT_SECRET` is the unique secret code generated for this application. Please note that the secret will only be visible after you created/registered the application with Gitea and cannot be recovered. If you lose the secret, you must regenerate the secret via the application's settings.
+
+   The `REDIRECT_URI` in the `access_token` request must match the `REDIRECT_URI` in the `authorize` request.
+
+3. Use the `access_token` to make [API requests](https://docs.gitea.io/en-us/api-usage#oauth2) to access the user's resources.
+
+### Public client (PKCE)
+
+PKCE (Proof Key for Code Exchange) is an extension to the OAuth flow which allows for a secure credential exchange without the requirement to provide a client secret.
+
+**Note**: Please ensure you have registered your OAuth application as a public client.
+
+To achieve this, you have to provide a `code_verifier` for every authorization request. A `code_verifier` has to be a random string with a minimum length of 43 characters and a maximum length of 128 characters. It can contain alphanumeric characters as well as the characters `-`, `.`, `_`  and `~`.
+
+Using this `code_verifier` string, a new one called `code_challenge` is created by using one of two methods:
+
+- If you have the required functionality on your client, set `code_challenge` to be a URL-safe base64-encoded string of the SHA256 hash of `code_verifier`. In that case, your `code_challenge_method` becomes `S256`.
+- If you are unable to do so, you can provide your `code_verifier` as a plain string to `code_challenge`. Then you have to set your `code_challenge_method` as `plain`.
+
+After you have generated this values, you can continue with your request.
+
+1. Redirect the user to the authorization endpoint in order to get their consent for accessing the resources:
+
+   ```curl
+   https://[YOUR-GITEA-URL]/login/oauth/authorize?client_id=CLIENT_ID&redirect_uri=REDIRECT_URI&response_type=code&code_challenge_method=CODE_CHALLENGE_METHOD&code_challenge=CODE_CHALLENGE&state=STATE
+   ```
+
+   The `CLIENT_ID` can be obtained by registering an application in the settings. The `STATE` is a random string that will be sent back to your application after the user authorizes. The `state` parameter is optional, but should be used to prevent CSRF attacks.
+
+   ![Authorization Page](/authorize.png)
+
+   The user will now be asked to authorize your application. If they authorize it, the user will be redirected to the `REDIRECT_URL`, for example:
+
+   ```curl
+   https://[REDIRECT_URI]?code=RETURNED_CODE&state=STATE
+   ```
+
+2. Using the provided `code` from the redirect, you can request a new application and refresh token. The access token endpoint accepts POST requests with `application/json` and `application/x-www-form-urlencoded` body, for example:
+
+   ```curl
+   POST https://[YOUR-GITEA-URL]/login/oauth/access_token
+   ```
+
+   ```json
+   {
+     "client_id": "YOUR_CLIENT_ID",
+     "code": "RETURNED_CODE",
+     "grant_type": "authorization_code",
+     "redirect_uri": "REDIRECT_URI",
+     "code_verifier": "CODE_VERIFIER",
+   }
+   ```
+
+   Response:
+
+   ```json
+   {
+     "access_token": "eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.eyJnbnQiOjIsInR0IjowLCJleHAiOjE1NTUxNzk5MTIsImlhdCI6MTU1NTE3NjMxMn0.0-iFsAwBtxuckA0sNZ6QpBQmywVPz129u75vOM7wPJecw5wqGyBkmstfJHAjEOqrAf_V5Z-1QYeCh_Cz4RiKug",
+     "token_type": "bearer",
+     "expires_in": 3600,
+     "refresh_token": "eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.eyJnbnQiOjIsInR0IjoxLCJjbnQiOjEsImV4cCI6MTU1NzgwNDMxMiwiaWF0IjoxNTU1MTc2MzEyfQ.S_HZQBy4q9r5SEzNGNIoFClT43HPNDbUdHH-GYNYYdkRfft6XptJBkUQscZsGxOW975Yk6RbgtGvq1nkEcklOw"
+   }
+   ```
+
+   The `REDIRECT_URI` in the `access_token` request must match the `REDIRECT_URI` in the `authorize` request.
+
+3. Use the `access_token` to make [API requests](https://docs.gitea.io/en-us/api-usage#oauth2) to access the user's resources.