Merge branch 'api-subscribe-issue-mr' into 'master'

API: Subscribe and unsubscribe from issues and merge requests

* Closes #6024 

This MR is based on !3611, which must be merged first.


See merge request !3615

7 files changed, 415 insertions, 0 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 41b6e2c67fd..6d19887e442 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -12,6 +12,7 @@ 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 issues and merge requests (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)
diff --git a/doc/api/issues.md b/doc/api/issues.md
index f09847aef95..42024becc36 100644
--- a/doc/api/issues.md
+++ b/doc/api/issues.md
@@ -406,6 +406,115 @@ Example response:
 }
 ```
 
+## Subscribe to an issue
+
+Subscribes the authenticated user 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/subscription
+```
+
+| 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/subscription
+```
+
+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 the authenticated user from the issue to not receive notifications
+from it. If the operation is successful, status code `200` 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.
+
+```
+DELETE /projects/:id/issues/:issue_id/subscription
+```
+
+| 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 DELETE -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/projects/5/issues/93/subscription
+```
+
+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.
diff --git a/doc/api/merge_requests.md b/doc/api/merge_requests.md
index 20db73ea6c0..2057f9d77aa 100644
--- a/doc/api/merge_requests.md
+++ b/doc/api/merge_requests.md
@@ -606,3 +606,151 @@ Example response:
    },
 ]
 ```
+
+## Subscribe to a merge request
+
+Subscribes the authenticated user to a merge request to receive notification. If
+the operation is successful, status code `201` together with the updated merge
+request is returned. If the user is already subscribed to the merge request, the
+status code `304` is returned. If the project or merge request is not found,
+status code `404` is returned.
+
+```
+POST /projects/:id/merge_requests/:merge_request_id/subscription
+```
+
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `id` | integer | yes | The ID of a project |
+| `merge_request_id` | integer | yes   | The ID of the merge request |
+
+```bash
+curl -X POST -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/projects/5/merge_requests/17/subscription
+```
+
+Example response:
+
+```json
+{
+  "id": 17,
+  "iid": 1,
+  "project_id": 5,
+  "title": "Et et sequi est impedit nulla ut rem et voluptatem.",
+  "description": "Consequatur velit eos rerum optio autem. Quia id officia quaerat dolorum optio. Illo laudantium aut ipsum dolorem.",
+  "state": "opened",
+  "created_at": "2016-04-05T21:42:23.233Z",
+  "updated_at": "2016-04-05T22:11:52.900Z",
+  "target_branch": "ui-dev-kit",
+  "source_branch": "version-1-9",
+  "upvotes": 0,
+  "downvotes": 0,
+  "author": {
+    "name": "Eileen Skiles",
+    "username": "leila",
+    "id": 19,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/39ce4a2822cc896933ffbd68c1470e55?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/u/leila"
+  },
+  "assignee": {
+    "name": "Celine Wehner",
+    "username": "carli",
+    "id": 16,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/f4cd5605b769dd2ce405a27c6e6f2684?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/u/carli"
+  },
+  "source_project_id": 5,
+  "target_project_id": 5,
+  "labels": [],
+  "work_in_progress": false,
+  "milestone": {
+    "id": 7,
+    "iid": 1,
+    "project_id": 5,
+    "title": "v2.0",
+    "description": "Corrupti eveniet et velit occaecati dolorem est rerum aut.",
+    "state": "closed",
+    "created_at": "2016-04-05T21:41:40.905Z",
+    "updated_at": "2016-04-05T21:41:40.905Z",
+    "due_date": null
+  },
+  "merge_when_build_succeeds": false,
+  "merge_status": "cannot_be_merged",
+  "subscribed": true
+}
+```
+
+## Unsubscribe from a merge request
+
+Unsubscribes the authenticated user from a merge request to not receive
+notifications from that merge request. If the operation is successful, status
+code `200` together with the updated merge request is returned. If the user is
+not subscribed to the merge request, the status code `304` is returned. If the
+project or merge request is not found, status code `404` is returned.
+
+```
+DELETE /projects/:id/merge_requests/:merge_request_id/subscription
+```
+
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `id` | integer | yes | The ID of a project |
+| `merge_request_id` | integer | yes   | The ID of the merge request |
+
+```bash
+curl -X DELETE -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/projects/5/merge_requests/17/subscription
+```
+
+Example response:
+
+```json
+{
+  "id": 17,
+  "iid": 1,
+  "project_id": 5,
+  "title": "Et et sequi est impedit nulla ut rem et voluptatem.",
+  "description": "Consequatur velit eos rerum optio autem. Quia id officia quaerat dolorum optio. Illo laudantium aut ipsum dolorem.",
+  "state": "opened",
+  "created_at": "2016-04-05T21:42:23.233Z",
+  "updated_at": "2016-04-05T22:11:52.900Z",
+  "target_branch": "ui-dev-kit",
+  "source_branch": "version-1-9",
+  "upvotes": 0,
+  "downvotes": 0,
+  "author": {
+    "name": "Eileen Skiles",
+    "username": "leila",
+    "id": 19,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/39ce4a2822cc896933ffbd68c1470e55?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/u/leila"
+  },
+  "assignee": {
+    "name": "Celine Wehner",
+    "username": "carli",
+    "id": 16,
+    "state": "active",
+    "avatar_url": "http://www.gravatar.com/avatar/f4cd5605b769dd2ce405a27c6e6f2684?s=80&d=identicon",
+    "web_url": "https://gitlab.example.com/u/carli"
+  },
+  "source_project_id": 5,
+  "target_project_id": 5,
+  "labels": [],
+  "work_in_progress": false,
+  "milestone": {
+    "id": 7,
+    "iid": 1,
+    "project_id": 5,
+    "title": "v2.0",
+    "description": "Corrupti eveniet et velit occaecati dolorem est rerum aut.",
+    "state": "closed",
+    "created_at": "2016-04-05T21:41:40.905Z",
+    "updated_at": "2016-04-05T21:41:40.905Z",
+    "due_date": null
+  },
+  "merge_when_build_succeeds": false,
+  "merge_status": "cannot_be_merged",
+  "subscribed": false
+}
+```
diff --git a/lib/api/issues.rb b/lib/api/issues.rb
index 850e99981ff..4cdecadfe0f 100644
--- a/lib/api/issues.rb
+++ b/lib/api/issues.rb
@@ -231,6 +231,42 @@ 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/subscription
+      post ':id/issues/:issue_id/subscription' do
+        issue = user_project.issues.find(params[:issue_id])
+
+        if issue.subscribed?(current_user)
+          not_modified!
+        else
+          issue.toggle_subscription(current_user)
+          present issue, with: Entities::Issue, current_user: current_user
+        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:
+      #   DELETE /projects/:id/issues/:issue_id/subscription
+      delete ':id/issues/:issue_id/subscription' do
+        issue = user_project.issues.find(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
diff --git a/lib/api/merge_requests.rb b/lib/api/merge_requests.rb
index 4e7de8867b4..7e78609ecb9 100644
--- a/lib/api/merge_requests.rb
+++ b/lib/api/merge_requests.rb
@@ -327,6 +327,42 @@ module API
           issues = ::Kaminari.paginate_array(merge_request.closes_issues(current_user))
           present paginate(issues), with: Entities::Issue, current_user: current_user
         end
+
+        # Subscribes to a merge request
+        #
+        # Parameters:
+        #  id (required)               - The ID of a project
+        #  merge_request_id (required) - The ID of a merge request
+        # Example Request:
+        #   POST /projects/:id/issues/:merge_request_id/subscription
+        post "#{path}/subscription" do
+          merge_request = user_project.merge_requests.find(params[:merge_request_id])
+
+          if merge_request.subscribed?(current_user)
+            not_modified!
+          else
+            merge_request.toggle_subscription(current_user)
+            present merge_request, with: Entities::MergeRequest, current_user: current_user
+          end
+        end
+
+        # Unsubscribes from a merge request
+        #
+        # Parameters:
+        #  id (required)               - The ID of a project
+        #  merge_request_id (required) - The ID of a merge request
+        # Example Request:
+        #   DELETE /projects/:id/merge_requests/:merge_request_id/subscription
+        delete "#{path}/subscription" do
+          merge_request = user_project.merge_requests.find(params[:merge_request_id])
+
+          if merge_request.subscribed?(current_user)
+            merge_request.unsubscribe(current_user)
+            present merge_request, with: Entities::MergeRequest, current_user: current_user
+          else
+            not_modified!
+          end
+        end
       end
     end
   end
diff --git a/spec/requests/api/issues_spec.rb b/spec/requests/api/issues_spec.rb
index 3d7a31cbb6a..86ea223f206 100644
--- a/spec/requests/api/issues_spec.rb
+++ b/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 +570,46 @@ describe API::API, api: true  do
       end
     end
   end
+
+  describe 'POST :id/issues/:issue_id/subscription' do
+    it 'subscribes to an issue' do
+      post api("/projects/#{project.id}/issues/#{issue.id}/subscription", 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}/subscription", user)
+
+      expect(response.status).to eq(304)
+    end
+
+    it 'returns 404 if the issue is not found' do
+      post api("/projects/#{project.id}/issues/123/subscription", user)
+
+      expect(response.status).to eq(404)
+    end
+  end
+
+  describe 'DELETE :id/issues/:issue_id/subscription' do
+    it 'unsubscribes from an issue' do
+      delete api("/projects/#{project.id}/issues/#{issue.id}/subscription", user)
+
+      expect(response.status).to eq(200)
+      expect(json_response['subscribed']).to eq(false)
+    end
+
+    it 'returns 304 if not subscribed' do
+      delete api("/projects/#{project.id}/issues/#{issue.id}/subscription", user2)
+
+      expect(response.status).to eq(304)
+    end
+
+    it 'returns 404 if the issue is not found' do
+      delete api("/projects/#{project.id}/issues/123/subscription", user)
+
+      expect(response.status).to eq(404)
+    end
+  end
 end
diff --git a/spec/requests/api/merge_requests_spec.rb b/spec/requests/api/merge_requests_spec.rb
index 25fa30b2f21..1fa7e76894f 100644
--- a/spec/requests/api/merge_requests_spec.rb
+++ b/spec/requests/api/merge_requests_spec.rb
@@ -516,6 +516,48 @@ describe API::API, api: true  do
     end
   end
 
+  describe 'POST :id/merge_requests/:merge_request_id/subscription' do
+    it 'subscribes to a merge request' do
+      post api("/projects/#{project.id}/merge_requests/#{merge_request.id}/subscription", admin)
+
+      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}/merge_requests/#{merge_request.id}/subscription", user)
+
+      expect(response.status).to eq(304)
+    end
+
+    it 'returns 404 if the merge request is not found' do
+      post api("/projects/#{project.id}/merge_requests/123/subscription", user)
+
+      expect(response.status).to eq(404)
+    end
+  end
+
+  describe 'DELETE :id/merge_requests/:merge_request_id/subscription' do
+    it 'unsubscribes from a merge request' do
+      delete api("/projects/#{project.id}/merge_requests/#{merge_request.id}/subscription", user)
+
+      expect(response.status).to eq(200)
+      expect(json_response['subscribed']).to eq(false)
+    end
+
+    it 'returns 304 if not subscribed' do
+      delete api("/projects/#{project.id}/merge_requests/#{merge_request.id}/subscription", admin)
+
+      expect(response.status).to eq(304)
+    end
+
+    it 'returns 404 if the merge request is not found' do
+      post api("/projects/#{project.id}/merge_requests/123/subscription", user)
+
+      expect(response.status).to eq(404)
+    end
+  end
+
   def mr_with_later_created_and_updated_at_time
     merge_request
     merge_request.created_at += 1.hour