API: Ability to subscribe and unsubscribe from an issue

CHANGELOG

@@ -11,6 +11,7 @@ v 8.7.0 (unreleased)
   - Fix `signed_in_ip` being set to 127.0.0.1 when using a reverse proxy !3524
   - Improved Markdown rendering performance !3389 (Yorick Peterse)
   - Don't attempt to look up an avatar in repo if repo directory does not exist (Stan Hu)
+  - API: Ability to subscribe and unsubscribe from an issue (Robert Schilling)
   - Expose project badges in project settings
   - Preserve time notes/comments have been updated at when moving issue
   - Make HTTP(s) label consistent on clone bar (Stan Hu)

doc/api/issues.md

@@ -406,6 +406,114 @@ Example response:
 }
 ```
 
+## Subscribe to an issue
+
+Subscribes to an issue to receive notifications. If the operation is successful,
+status code `201` together with the updated issue is returned. If the user is
+already subscribed to the issue, the status code `304` is returned. If the
+project or issue is not found, status code `404` is returned.
+
+```
+POST /projects/:id/issues/:issue_id/subscribe
+```
+
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `id` | integer | yes | The ID of a project |
+| `issue_id` | integer | yes | The ID of a project's issue |
+
+```bash
+curl -X POST -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/projects/5/issues/93/subscribe
+```
+
+Example response:
+
+```json
+{
+  "id": 92,
+  "iid": 11,
+  "project_id": 5,
+  "title": "Sit voluptas tempora quisquam aut doloribus et.",
+  "description": "Repellat voluptas quibusdam voluptatem exercitationem.",
+  "state": "opened",
+  "created_at": "2016-04-05T21:41:45.652Z",
+  "updated_at": "2016-04-07T12:20:17.596Z",
+  "labels": [],
+  "milestone": null,
+  "assignee": {
+    "name": "Miss Monserrate Beier",
+    "username": "axel.block",
+    "id": 12,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/46f6f7dc858ada7be1853f7fb96e81da?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/u/axel.block"
+  },
+  "author": {
+    "name": "Kris Steuber",
+    "username": "solon.cremin",
+    "id": 10,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/7a190fecbaa68212a4b68aeb6e3acd10?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/u/solon.cremin"
+  }
+}
+```
+
+## Unsubscribe from an issue
+
+Unsubscribes from an issue to not receive notifications from that issue. If the
+operation is successful, status code `201` together with the updated issue is
+returned. If the user is not subscribed to the issue, the status code `304`
+is returned. If the project or issue is not found, status code `404` is
+returned.
+
+```
+POST /projects/:id/issues/:issue_id/unsubscribe
+```
+
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `id` | integer | yes | The ID of a project |
+| `issue_id` | integer | yes | The ID of a project's issue |
+
+```bash
+curl -X POST -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/projects/5/issues/93/unsubscribe
+```
+
+Example response:
+
+```json
+{
+  "id": 93,
+  "iid": 12,
+  "project_id": 5,
+  "title": "Incidunt et rerum ea expedita iure quibusdam.",
+  "description": "Et cumque architecto sed aut ipsam.",
+  "state": "opened",
+  "created_at": "2016-04-05T21:41:45.217Z",
+  "updated_at": "2016-04-07T13:02:37.905Z",
+  "labels": [],
+  "milestone": null,
+  "assignee": {
+    "name": "Edwardo Grady",
+    "username": "keyon",
+    "id": 21,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/3e6f06a86cf27fa8b56f3f74f7615987?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/u/keyon"
+  },
+  "author": {
+    "name": "Vivian Hermann",
+    "username": "orville",
+    "id": 11,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/5224fd70153710e92fb8bcf79ac29d67?s=80&d=identicon",
+    "web_url": "http://lgitlab.example.com/u/orville"
+  },
+  "subscribed": false
+}
+```
+
 ## Comments on issues
 
 Comments are done via the [notes](notes.md) resource.

lib/api/helpers.rb

@@ -241,6 +241,10 @@ module API
       render_api_error!('413 Request Entity Too Large', 413)
     end
 
+    def not_modified!
+      render_api_error!('304 Not modified', 304)
+    end
+
     def render_validation_error!(model)
       if model.errors.any?
         render_api_error!(model.errors.messages || '400 Bad Request', 400)

lib/api/issues.rb

@@ -231,6 +231,59 @@ module API
         authorize!(:destroy_issue, issue)
         issue.destroy
       end
+
+      # Subscribes to a project issue
+      #
+      # Parameters:
+      #  id (required) - The ID of a project
+      #  issue_id (required) - The ID of a project issue
+      # Example Request:
+      #   POST /projects/:id/issues/:issue_id
+      post ":id/issues/:issue_idsubscribe" do
+        issue = user_project.issues.find_by(id: params[:issue_id])
+
+        if !issue.subscribed?(current_user)
+          present issue, with: Entities::Issue, current_user: current_user
+        else
+          not_modified!
+        end
+      end
+
+      # Subscribes to a project issue
+      #
+      # Parameters:
+      #  id (required) - The ID of a project
+      #  issue_id (required) - The ID of a project issue
+      # Example Request:
+      #   POST /projects/:id/issues/:issue_id/subscribe
+      post ":id/issues/:issue_id/subscribe" do
+        issue = user_project.issues.find_by(id: params[:issue_id])
+
+        if !issue.subscribed?(current_user)
+          issue.toggle_subscription(current_user)
+          present issue, with: Entities::Issue, current_user: current_user
+        else
+          not_modified!
+        end
+      end
+
+      # Unsubscribes from a project issue
+      #
+      # Parameters:
+      #  id (required) - The ID of a project
+      #  issue_id (required) - The ID of a project issue
+      # Example Request:
+      #   POST /projects/:id/issues/:issue_id/unsubscribe
+      post ":id/issues/:issue_id/unsubscribe" do
+        issue = user_project.issues.find_by(id: params[:issue_id])
+
+        if issue.subscribed?(current_user)
+          issue.unsubscribe(current_user)
+          present issue, with: Entities::Issue, current_user: current_user
+        else
+          not_modified!
+        end
+      end
     end
   end
 end

spec/requests/api/issues_spec.rb

@@ -3,6 +3,7 @@ require 'spec_helper'
 describe API::API, api: true  do
   include ApiHelpers
   let(:user)        { create(:user) }
+  let(:user2)       { create(:user) }
   let(:non_member)  { create(:user) }
   let(:author)      { create(:author) }
   let(:assignee)    { create(:assignee) }
@@ -569,4 +570,34 @@ describe API::API, api: true  do
       end
     end
   end
+
+  describe 'POST :id/issues/:issue_id/subscribe' do
+    it 'subscribes to an issue' do
+      post api("/projects/#{project.id}/issues/#{issue.id}/subscribe", user2)
+
+      expect(response.status).to eq(201)
+      expect(json_response['subscribed']).to eq(true)
+    end
+
+    it 'returns 304 if already subscribed' do
+      post api("/projects/#{project.id}/issues/#{issue.id}/subscribe", user)
+
+      expect(response.status).to eq(304)
+    end
+  end
+
+  describe 'POST :id/issues/:issue_id/unsubscribe' do
+    it 'unsubscribes from an issue' do
+      post api("/projects/#{project.id}/issues/#{issue.id}/unsubscribe", user)
+
+      expect(response.status).to eq(201)
+      expect(json_response['subscribed']).to eq(false)
+    end
+
+    it 'returns 304 if not subscribed' do
+      post api("/projects/#{project.id}/issues/#{issue.id}/unsubscribe", user2)
+
+      expect(response.status).to eq(304)
+    end
+  end
 end