[Docs] Add guide on howto develop API (#9587)

* draft 1

* add suggestions
thanks to @bagasme @techknowlogick @davidsvantesson

* http methods

* use permalinks

* Apply suggestions from code review

Co-Authored-By: John Olheiser <42128690+jolheiser@users.noreply.github.com>

* Apply suggestions from code review

Co-Authored-By: John Olheiser <42128690+jolheiser@users.noreply.github.com>

* code format + add to INDEX

Co-authored-by: John Olheiser <42128690+jolheiser@users.noreply.github.com>
Co-authored-by: Lauris BH <lauris@nix.lv>
This commit is contained in:
6543 2020-01-04 03:23:40 +01:00 committed by Lunny Xiao
parent bedd7b2833
commit ee9b9365be

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@ -12,6 +12,7 @@
- [Code review](#code-review)
- [Styleguide](#styleguide)
- [Design guideline](#design-guideline)
- [API v1](#api-v1)
- [Developer Certificate of Origin (DCO)](#developer-certificate-of-origin-dco)
- [Release Cycle](#release-cycle)
- [Maintainers](#maintainers)
@ -177,6 +178,43 @@ To maintain understandable code and avoid circular dependencies it is important
- **templates:** Golang templates for generating the html output.
- **vendor:** External code that Gitea depends on.
## API v1
The API is documented by [swagger](http://try.gitea.io/api/swagger) and is based on [GitHub API v3](https://developer.github.com/v3/).
Thus, Gitea´s API should use the same endpoints and fields as GitHub´s API as far as possible, unless there are good reasons to deviate.
If Gitea provides functionality that GitHub does not, a new endpoint can be created.
If information is provided by Gitea that is not provided by the GitHub API, a new field can be used that doesn't collide with any GitHub fields.
Updating an existing API should not remove existing fields unless there is a really good reason to do so.
The same applies to status responses. If you notice a problem, feel free to leave a comment in the code for future refactoring to APIv2 (which is currently not planned).
All expected results (errors, success, fail messages) should be documented
([example](https://github.com/go-gitea/gitea/blob/c620eb5b2d0d874da68ebd734d3864c5224f71f7/routers/api/v1/repo/issue.go#L319-L327)).
All JSON input types must be defined as a struct in `models/structs/`
([example](https://github.com/go-gitea/gitea/blob/c620eb5b2d0d874da68ebd734d3864c5224f71f7/modules/structs/issue.go#L76-L91))
and referenced in
[routers/api/v1/swagger/options.go](https://github.com/go-gitea/gitea/blob/c620eb5b2d0d874da68ebd734d3864c5224f71f7/routers/api/v1/swagger/options.go).
They can then be used like the following:
([example](https://github.com/go-gitea/gitea/blob/c620eb5b2d0d874da68ebd734d3864c5224f71f7/routers/api/v1/repo/issue.go#L318)).
All JSON responses must be defined as a struct in `models/structs/`
([example](https://github.com/go-gitea/gitea/blob/c620eb5b2d0d874da68ebd734d3864c5224f71f7/modules/structs/issue.go#L36-L68))
and referenced in its category in `routers/api/v1/swagger/`
([example](https://github.com/go-gitea/gitea/blob/c620eb5b2d0d874da68ebd734d3864c5224f71f7/routers/api/v1/swagger/issue.go#L11-L16))
They can be used like the following:
([example](https://github.com/go-gitea/gitea/blob/c620eb5b2d0d874da68ebd734d3864c5224f71f7/routers/api/v1/repo/issue.go#L277-L279))
In general, HTTP methods are chosen as follows:
* **GET** endpoints return requested object and status **OK (200)**
* **DELETE** endpoints return status **No Content (204)**
* **POST** endpoints return status **Created (201)**, used to **create** new objects (e.g. a User)
* **PUT** endpoints return status **No Content (204)**, used to **add/assign** existing Obejcts (e.g. User) to something (e.g. Org-Team)
* **PATCH** endpoints return changed object and status **OK (200)**, used to **edit/change** an existing object
An endpoint which changes/edits an object expects all fields to be optional (except ones to identify the object, which are required).
## Developer Certificate of Origin (DCO)