# Wiki

Each repository has a wiki of Markdown pages, stored as files in a bare git repository at
`<git.repos_root>/<owner>/<repo>.wiki.git`. It is created by the first page save, on a `main` branch, and moves with the
repository when it is deleted, restored, purged or transferred. Pages are not cloneable over HTTP or SSH: the web editor
and `CodeService` are the only writers.

## Pages

- A page is `<slug>.md` at the root of the wiki tree. A slug matches `^[A-Za-z0-9_-]{1,100}$` (`validWikiSlug`);
  anything else is 400.
- `/{owner}/{repo}/wiki` redirects to the `Home` page.
- The sidebar lists pages in the order of the `.order` file (one slug per line), then any page it does not name
  alphabetically. A page's title is its first heading.
- Every save, rename, delete and reorder is one commit authored by the signed-in user (`UserService.CommitAuthor`).
- Renaming a page (`new_slug` on save) rewrites `.order` in the same commit, so its sidebar position survives. A
  `new_slug` that already exists is 409.

## Access

| Action                        | Needs     | Refusal                                |
| ----------------------------- | --------- | -------------------------------------- |
| View a page                   | CanRead   | 404, so a private wiki is not revealed |
| Create, edit, rename, reorder | CanWrite  | 403                                    |
| Delete a page                 | CanManage | 403                                    |

The wiki can be turned off per repository with the **Wiki** feature toggle in repository settings
(`repositories.allow_wiki`, migration 058). A disabled wiki answers 404 on every route above. It also answers 404 when a
repository named `<repo>.wiki`, created before that suffix was reserved, holds the directory.

## Storage and conflicts

The wiki's disk use counts toward the owner's storage [quota](./configuration.md#quotas); a save at or over it returns
`403` (the same message as a web commit), and a successful save, delete or reorder re-measures the repository. A change
commits against the branch tip it read; if a push moved the branch meanwhile, the request returns `409` and the client
reloads and retries (`service.ErrRefMoved`, as for [pr-merge](./pr-merge.md#merge-flow)).

## Routes

| Method | Path                                    | Auth                | Description                                                         |
| ------ | --------------------------------------- | ------------------- | ------------------------------------------------------------------- |
| GET    | `/{owner}/{repo}/wiki`                  | Optional            | Redirect to `Home`                                                  |
| GET    | `/{owner}/{repo}/wiki/new`              | Required, CanWrite  | New page form                                                       |
| GET    | `/{owner}/{repo}/wiki/{slug}`           | Optional            | A page                                                              |
| GET    | `/{owner}/{repo}/wiki/{slug}/edit`      | Required, CanWrite  | Edit form                                                           |
| POST   | `/api/repos/{owner}/{repo}/wiki/{slug}` | Required, CanWrite  | Create or update: `content`, `message`, `new_slug`; 303 to the page |
| POST   | `/api/repos/{owner}/{repo}/wiki/order`  | Required, CanWrite  | `order`: comma-separated slugs; 200                                 |
| DELETE | `/api/repos/{owner}/{repo}/wiki/{slug}` | Required, CanManage | Delete a page; HTMX gets 200, otherwise 303 to the wiki             |

The `order` route sits before `{slug}`, so a page cannot be named `order` through the API.