API: Endpoint to expose personal snippets as /snippets

Adding the necessary API for the new /snippets Restful resource
added with this commit. Added a new Grape class `Snippets`, as
well as a `PersonalSnippet` entity.

Issue: #20042
Merge-Request: !6373
Signed-off-by: Guyzmo <guyzmo+gitlab+pub@m0g.net>

1 files changed, 232 insertions, 0 deletions

diff --git a/doc/api/snippets.md b/doc/api/snippets.md
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+# Snippets
+
+> [Introduced][ce-6373] in GitLab 8.15.
+
+### Snippet visibility level
+
+Snippets in GitLab can be either private, internal, or public.
+You can set it with the `visibility_level` field in the snippet.
+
+Constants for snippet visibility levels are:
+
+| Visibility | Visibility level | Description |
+| ---------- | ---------------- | ----------- |
+| Private    | `0`  | The snippet is visible only to the snippet creator |
+| Internal   | `10` | The snippet is visible for any logged in user |
+| Public     | `20` | The snippet can be accessed without any authentication |
+
+## List snippets
+
+Get a list of current user's snippets.
+
+```
+GET /snippets
+```
+
+## Single snippet
+
+Get a single snippet.
+
+```
+GET /snippets/:id
+```
+
+Parameters:
+
+| Attribute          | Type    | Required | Description                   |
+| ---------          | ----    | -------- | -----------                   |
+| `id`               | Integer | yes      | The ID of a snippet           |
+
+``` bash
+curl --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/snippets/1
+```
+
+Example response:
+
+``` json
+{
+  "id": 1,
+  "title": "test",
+  "file_name": "add.rb",
+  "author": {
+    "id": 1,
+    "username": "john_smith",
+    "email": "john@example.com",
+    "name": "John Smith",
+    "state": "active",
+    "created_at": "2012-05-23T08:00:58Z"
+  },
+  "expires_at": null,
+  "updated_at": "2012-06-28T10:52:04Z",
+  "created_at": "2012-06-28T10:52:04Z",
+  "web_url": "http://example.com/snippets/1",
+}
+```
+
+## Create new snippet
+
+Creates a new snippet. The user must have permission to create new snippets.
+
+```
+POST /snippets
+```
+
+Parameters:
+
+| Attribute          | Type    | Required | Description                |
+| ---------          | ----    | -------- | -----------                |
+| `title`            | String  | yes      | The title of a snippet     |
+| `file_name`        | String  | yes      | The name of a snippet file |
+| `content`          | String  | yes      | The content of a snippet   |
+| `visibility_level` | Integer | yes      | The snippet's visibility   |
+
+
+``` bash
+curl --request POST --data '{"title": "This is a snippet", "content": "Hello world", "file_name": "test.txt", "visibility_level": 10 }' --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/snippets
+```
+
+Example response:
+
+``` json
+{
+  "id": 1,
+  "title": "This is a snippet",
+  "file_name": "test.txt",
+  "author": {
+    "id": 1,
+    "username": "john_smith",
+    "email": "john@example.com",
+    "name": "John Smith",
+    "state": "active",
+    "created_at": "2012-05-23T08:00:58Z"
+  },
+  "expires_at": null,
+  "updated_at": "2012-06-28T10:52:04Z",
+  "created_at": "2012-06-28T10:52:04Z",
+  "web_url": "http://example.com/snippets/1",
+}
+```
+
+## Update snippet
+
+Updates an existing snippet. The user must have permission to change an existing snippet.
+
+```
+PUT /snippets/:id
+```
+
+Parameters:
+
+| Attribute          | Type    | Required | Description                |
+| ---------          | ----    | -------- | -----------                |
+| `id`               | Integer | yes      | The ID of a snippet        |
+| `title`            | String  | no       | The title of a snippet     |
+| `file_name`        | String  | no       | The name of a snippet file |
+| `content`          | String  | no       | The content of a snippet   |
+| `visibility_level` | Integer | no       | The snippet's visibility   |
+
+
+``` bash
+curl --request PUT --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" --data '{"title": "foo", "content": "bar"}' https://gitlab.example.com/api/v3/snippets/1
+```
+
+Example response:
+
+``` json
+{
+  "id": 1,
+  "title": "test",
+  "file_name": "add.rb",
+  "author": {
+    "id": 1,
+    "username": "john_smith",
+    "email": "john@example.com",
+    "name": "John Smith",
+    "state": "active",
+    "created_at": "2012-05-23T08:00:58Z"
+  },
+  "expires_at": null,
+  "updated_at": "2012-06-28T10:52:04Z",
+  "created_at": "2012-06-28T10:52:04Z",
+  "web_url": "http://example.com/snippets/1",
+}
+```
+
+## Delete snippet
+
+Deletes an existing snippet. 
+
+```
+DELETE /snippets/:id
+```
+
+Parameters:
+
+| Attribute          | Type    | Required | Description                   |
+| ---------          | ----    | -------- | -----------                   |
+| `id`               | Integer | yes      | The ID of a snippet           |
+
+
+```
+curl --request DELETE --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/snippets/1"
+```
+
+upon successful delete a `204 No content` HTTP code shall be expected, with no data,
+but if the snippet is non-existent, a `404 Not Found` will be returned.
+
+## Explore all public snippets
+
+```
+GET /snippets/public
+```
+
+| Attribute  | Type    | Required | Description                           |
+| ---------  | ----    | -------- | -----------                           |
+| `per_page` | Integer | no       | number of snippets to return per page |
+| `page`     | Integer | no       | the page to retrieve                  |
+
+``` bash
+curl --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/snippets/public?per_page=2&page=1
+```
+
+Example response:
+
+``` json
+[
+    {
+        "author": {
+            "avatar_url": "http://www.gravatar.com/avatar/edaf55a9e363ea263e3b981d09e0f7f7?s=80&d=identicon",
+            "id": 12,
+            "name": "Libby Rolfson",
+            "state": "active",
+            "username": "elton_wehner",
+            "web_url": "http://localhost:3000/elton_wehner"
+        },
+        "created_at": "2016-11-25T16:53:34.504Z",
+        "file_name": "oconnerrice.rb",
+        "id": 49,
+        "raw_url": "http://localhost:3000/snippets/49/raw",
+        "title": "Ratione cupiditate et laborum temporibus.",
+        "updated_at": "2016-11-25T16:53:34.504Z",
+        "web_url": "http://localhost:3000/snippets/49"
+    },
+    {
+        "author": {
+            "avatar_url": "http://www.gravatar.com/avatar/36583b28626de71061e6e5a77972c3bd?s=80&d=identicon",
+            "id": 16,
+            "name": "Llewellyn Flatley",
+            "state": "active",
+            "username": "adaline",
+            "web_url": "http://localhost:3000/adaline"
+        },
+        "created_at": "2016-11-25T16:53:34.479Z",
+        "file_name": "muellershields.rb",
+        "id": 48,
+        "raw_url": "http://localhost:3000/snippets/48/raw",
+        "title": "Minus similique nesciunt vel fugiat qui ullam sunt.",
+        "updated_at": "2016-11-25T16:53:34.479Z",
+        "web_url": "http://localhost:3000/snippets/48"
+    }
+]
+```
+