Uploads to wiki stored inside the wiki git repository

24 files changed, 906 insertions, 85 deletions

diff --git a/app/helpers/wiki_helper.rb b/app/helpers/wiki_helper.rb
index 41f9eedd4bd..17940aeb900 100644
--- a/app/helpers/wiki_helper.rb
+++ b/app/helpers/wiki_helper.rb
@@ -1,4 +1,6 @@
 module WikiHelper
+  include API::Helpers::RelatedResourcesHelpers
+
   # Produces a pure text breadcrumb for a given page.
   #
   # page_slug - The slug of a WikiPage object.
@@ -39,4 +41,8 @@ module WikiHelper
       end
     end
   end
+
+  def wiki_attachment_upload_url
+    expose_url(api_v4_projects_wikis_attachments_path(id: @project.id))
+  end
 end
diff --git a/app/services/files/base_service.rb b/app/services/files/base_service.rb
index 025f093a428..fc7b236f7da 100644
--- a/app/services/files/base_service.rb
+++ b/app/services/files/base_service.rb
@@ -7,8 +7,8 @@ module Files
     def initialize(*args)
       super
 
-      @author_email = params[:author_email]
-      @author_name = params[:author_name]
+      @author_email = params[:author_email] || current_user&.email
+      @author_name = params[:author_name] || current_user&.name
       @commit_message = params[:commit_message]
       @last_commit_sha = params[:last_commit_sha]
 
diff --git a/app/services/wikis/create_attachment_service.rb b/app/services/wikis/create_attachment_service.rb
new file mode 100644
index 00000000000..30fe0e371a6
--- /dev/null
+++ b/app/services/wikis/create_attachment_service.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+module Wikis
+  class CreateAttachmentService < Files::CreateService
+    ATTACHMENT_PATH = 'uploads'.freeze
+    MAX_FILENAME_LENGTH = 255
+
+    delegate :wiki, to: :project
+    delegate :repository, to: :wiki
+
+    def initialize(*args)
+      super
+
+      @file_name = truncate_file_name(params[:file_name])
+      @file_path = File.join(ATTACHMENT_PATH, SecureRandom.hex, @file_name) if @file_name
+      @commit_message ||= "Upload attachment #{@file_name}"
+      @branch_name ||= wiki.default_branch
+    end
+
+    def create_commit!
+      commit_result(create_transformed_commit(@file_content))
+    end
+
+    private
+
+    def truncate_file_name(file_name)
+      return unless file_name.present?
+      return file_name if file_name.length <= MAX_FILENAME_LENGTH
+
+      extension = File.extname(file_name)
+      truncate_at = MAX_FILENAME_LENGTH - extension.length - 1
+      base_name = File.basename(file_name, extension)[0..truncate_at]
+      base_name + extension
+    end
+
+    def validate!
+      validate_file_name!
+      validate_permissions!
+    end
+
+    def validate_file_name!
+      raise_error('The file name cannot be empty') unless @file_name
+    end
+
+    def validate_permissions!
+      unless can?(current_user, :create_wiki, project)
+        raise_error('You are not allowed to push to the wiki')
+      end
+    end
+
+    def create_transformed_commit(content)
+      repository.create_file(
+        current_user,
+        @file_path,
+        content,
+        message: @commit_message,
+        branch_name: @branch_name,
+        author_email: @author_email,
+        author_name: @author_name)
+    end
+
+    def commit_result(commit_id)
+      {
+        file_name: @file_name,
+        file_path: @file_path,
+        branch: @branch_name,
+        commit: commit_id
+      }
+    end
+  end
+end
diff --git a/app/uploaders/file_uploader.rb b/app/uploaders/file_uploader.rb
index b1365659834..ffc1e5f75ca 100644
--- a/app/uploaders/file_uploader.rb
+++ b/app/uploaders/file_uploader.rb
@@ -122,12 +122,6 @@ class FileUploader < GitlabUploader
     }
   end
 
-  def markdown_link
-    markdown = +"[#{markdown_name}](#{secure_url})"
-    markdown.prepend("!") if image_or_video? || dangerous?
-    markdown
-  end
-
   def to_h
     {
       alt:      markdown_name,
@@ -192,10 +186,6 @@ class FileUploader < GitlabUploader
     storage.delete_dir!(store_dir) # only remove when empty
   end
 
-  def markdown_name
-    (image_or_video? ? File.basename(filename, File.extname(filename)) : filename).gsub("]", "\\]")
-  end
-
   def identifier
     @identifier ||= filename
   end
diff --git a/app/uploaders/uploader_helper.rb b/app/uploaders/uploader_helper.rb
index 2a2b54a9270..e8a2dce7755 100644
--- a/app/uploaders/uploader_helper.rb
+++ b/app/uploaders/uploader_helper.rb
@@ -2,32 +2,7 @@
 
 # Extra methods for uploader
 module UploaderHelper
-  IMAGE_EXT = %w[png jpg jpeg gif bmp tiff ico].freeze
-  # We recommend using the .mp4 format over .mov. Videos in .mov format can
-  # still be used but you really need to make sure they are served with the
-  # proper MIME type video/mp4 and not video/quicktime or your videos won't play
-  # on IE >= 9.
-  # http://archive.sublimevideo.info/20150912/docs.sublimevideo.net/troubleshooting.html
-  VIDEO_EXT = %w[mp4 m4v mov webm ogv].freeze
-  # These extension types can contain dangerous code and should only be embedded inline with
-  # proper filtering. They should always be tagged as "Content-Disposition: attachment", not "inline".
-  DANGEROUS_EXT = %w[svg].freeze
-
-  def image?
-    extension_match?(IMAGE_EXT)
-  end
-
-  def video?
-    extension_match?(VIDEO_EXT)
-  end
-
-  def image_or_video?
-    image? || video?
-  end
-
-  def dangerous?
-    extension_match?(DANGEROUS_EXT)
-  end
+  include Gitlab::FileMarkdownLinkBuilder
 
   private
 
diff --git a/app/views/projects/wikis/edit.html.haml b/app/views/projects/wikis/edit.html.haml
index d80d2957466..71359708022 100644
--- a/app/views/projects/wikis/edit.html.haml
+++ b/app/views/projects/wikis/edit.html.haml
@@ -41,3 +41,8 @@
 = render 'sidebar'
 
 #delete-wiki-modal.modal.fade
+
+- content_for :scripts_body do
+  -# haml-lint:disable InlineJavaScript
+  :javascript
+    window.uploads_path = "#{wiki_attachment_upload_url}";
diff --git a/changelogs/unreleased/fj-33475-files-inside-wiki-repo.yml b/changelogs/unreleased/fj-33475-files-inside-wiki-repo.yml
new file mode 100644
index 00000000000..8c1f0e3dbf2
--- /dev/null
+++ b/changelogs/unreleased/fj-33475-files-inside-wiki-repo.yml
@@ -0,0 +1,5 @@
+---
+title: Store wiki uploads inside git repository
+merge_request: 21362
+author:
+type: added
diff --git a/doc/api/wikis.md b/doc/api/wikis.md
index 15ce5f96b60..fb0ec773da5 100644
--- a/doc/api/wikis.md
+++ b/doc/api/wikis.md
@@ -97,12 +97,12 @@ curl --data "format=rdoc&title=Hello&content=Hello world" --header "PRIVATE-TOKE
 Example response:
 
 ```json
-{ 
+{
   "content" : "Hello world",
   "format" : "markdown",
   "slug" : "Hello",
   "title" : "Hello"
-} 
+}
 ```
 
 ## Edit an existing wiki page
@@ -154,6 +154,44 @@ DELETE /projects/:id/wikis/:slug
 curl --request DELETE --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v4/projects/1/wikis/foo"
 ```
 
-On success the HTTP status code is `204` and no JSON response is expected. 
+On success the HTTP status code is `204` and no JSON response is expected.
 
 [ce-13372]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13372
+
+## Upload an attachment to the wiki repository
+
+Uploads a file to the attachment folder inside the wiki's repository. The
+ attachment folder is the `uploads` folder.
+
+```
+POST /projects/:id/wikis/attachments
+```
+
+| Attribute     | Type    | Required | Description                  |
+| ------------- | ------- | -------- | ---------------------------- |
+| `id`      | integer/string    | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) |
+| `file` | string | yes | The attachment to be uploaded |
+| `branch` | string | no | The name of the branch. Defaults to the wiki repository default branch |
+
+To upload a file from your filesystem, use the `--form` argument. This causes
+cURL to post data using the header `Content-Type: multipart/form-data`.
+The `file=` parameter must point to a file on your filesystem and be preceded
+by `@`. For example:
+
+```bash
+curl --request POST --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" --form "file=@dk.png" https://gitlab.example.com/api/v4/projects/1/wikis/attachments
+```
+
+Example response:
+
+```json
+{
+  "file_name" : "dk.png",
+  "file_path" : "uploads/6a061c4cf9f1c28cb22c384b4b8d4e3c/dk.png",
+  "branch" : "master",
+  "link" : {
+    "url" : "uploads/6a061c4cf9f1c28cb22c384b4b8d4e3c/dk.png",
+    "markdown" : "![dk](uploads/6a061c4cf9f1c28cb22c384b4b8d4e3c/dk.png)"
+  }
+}
+```
diff --git a/lib/api/entities.rb b/lib/api/entities.rb
index 59042d2b568..624eda3f5dd 100644
--- a/lib/api/entities.rb
+++ b/lib/api/entities.rb
@@ -10,6 +10,28 @@ module API
       expose :content
     end
 
+    class WikiAttachment < Grape::Entity
+      include Gitlab::FileMarkdownLinkBuilder
+
+      expose :file_name
+      expose :file_path
+      expose :branch
+      expose :link do
+        expose :file_path, as: :url
+        expose :markdown do |_entity|
+          self.markdown_link
+        end
+      end
+
+      def filename
+        object.file_name
+      end
+
+      def secure_url
+        object.file_path
+      end
+    end
+
     class UserSafe < Grape::Entity
       expose :id, :name, :username
     end
diff --git a/lib/api/wikis.rb b/lib/api/wikis.rb
index b3fc4e876ad..e86ebc573f2 100644
--- a/lib/api/wikis.rb
+++ b/lib/api/wikis.rb
@@ -1,6 +1,14 @@
 module API
   class Wikis < Grape::API
     helpers do
+      def commit_params(attrs)
+        {
+          file_name: attrs[:file][:filename],
+          file_content: File.read(attrs[:file][:tempfile]),
+          branch_name: attrs[:branch]
+        }
+      end
+
       params :wiki_page_params do
         requires :content, type: String, desc: 'Content of a wiki page'
         requires :title, type: String, desc: 'Title of a wiki page'
@@ -84,6 +92,29 @@ module API
         status 204
         WikiPages::DestroyService.new(user_project, current_user).execute(wiki_page)
       end
+
+      desc 'Upload an attachment to the wiki repository' do
+        detail 'This feature was introduced in GitLab 11.3.'
+        success Entities::WikiAttachment
+      end
+      params do
+        requires :file, type: File, desc: 'The attachment file to be uploaded'
+        optional :branch, type: String, desc: 'The name of the branch'
+      end
+      post ":id/wikis/attachments", requirements: API::PROJECT_ENDPOINT_REQUIREMENTS do
+        authorize! :create_wiki, user_project
+
+        result = ::Wikis::CreateAttachmentService.new(user_project,
+                                                      current_user,
+                                                      commit_params(declared_params(include_missing: false))).execute
+
+        if result[:status] == :success
+          status(201)
+          present OpenStruct.new(result[:result]), with: Entities::WikiAttachment
+        else
+          render_api_error!(result[:message], 400)
+        end
+      end
     end
   end
 end
diff --git a/lib/banzai/filter/wiki_link_filter.rb b/lib/banzai/filter/wiki_link_filter.rb
index 870721f895d..1728a442533 100644
--- a/lib/banzai/filter/wiki_link_filter.rb
+++ b/lib/banzai/filter/wiki_link_filter.rb
@@ -1,7 +1,5 @@
 # frozen_string_literal: true
 
-require 'uri'
-
 module Banzai
   module Filter
     # HTML filter that "fixes" links to pages/files in a wiki.
@@ -13,8 +11,12 @@ module Banzai
       def call
         return doc unless project_wiki?
 
-        doc.search('a:not(.gfm)').each do |el|
-          process_link_attr el.attribute('href')
+        doc.search('a:not(.gfm)').each { |el| process_link_attr(el.attribute('href')) }
+        doc.search('video').each { |el| process_link_attr(el.attribute('src')) }
+        doc.search('img').each do |el|
+          attr = el.attribute('data-src') || el.attribute('src')
+
+          process_link_attr(attr)
         end
 
         doc
diff --git a/lib/banzai/filter/wiki_link_filter/rewriter.rb b/lib/banzai/filter/wiki_link_filter/rewriter.rb
index 072d24e5a11..4bf80aff418 100644
--- a/lib/banzai/filter/wiki_link_filter/rewriter.rb
+++ b/lib/banzai/filter/wiki_link_filter/rewriter.rb
@@ -10,11 +10,16 @@ module Banzai
 
         def apply_rules
           # Special case: relative URLs beginning with `/uploads/` refer to
-          # user-uploaded files and will be handled elsewhere.
-          return @uri.to_s if @uri.relative? && @uri.path.starts_with?('/uploads/')
+          # user-uploaded files will be handled elsewhere.
+          return @uri.to_s if public_upload?
+
+          # Special case: relative URLs beginning with Wikis::CreateAttachmentService::ATTACHMENT_PATH
+          # refer to user-uploaded files to the wiki repository.
+          unless repository_upload?
+            apply_file_link_rules!
+            apply_hierarchical_link_rules!
+          end
 
-          apply_file_link_rules!
-          apply_hierarchical_link_rules!
           apply_relative_link_rules!
           @uri.to_s
         end
@@ -39,6 +44,14 @@ module Banzai
             @uri = Addressable::URI.parse(link)
           end
         end
+
+        def public_upload?
+          @uri.relative? && @uri.path.starts_with?('/uploads/')
+        end
+
+        def repository_upload?
+          @uri.relative? && @uri.path.starts_with?(Wikis::CreateAttachmentService::ATTACHMENT_PATH)
+        end
       end
     end
   end
diff --git a/lib/gitlab/file_markdown_link_builder.rb b/lib/gitlab/file_markdown_link_builder.rb
new file mode 100644
index 00000000000..5386656efe7
--- /dev/null
+++ b/lib/gitlab/file_markdown_link_builder.rb
@@ -0,0 +1,21 @@
+# Builds the markdown link of a file
+# It needs the methods filename and secure_url (final destination url) to be defined.
+module Gitlab
+  module FileMarkdownLinkBuilder
+    include FileTypeDetection
+
+    def markdown_link
+      return unless name = markdown_name
+
+      markdown = "[#{name.gsub(']', '\\]')}](#{secure_url})"
+      markdown.prepend("!") if image_or_video? || dangerous?
+      markdown
+    end
+
+    def markdown_name
+      return unless filename.present?
+
+      image_or_video? ? File.basename(filename, File.extname(filename)) : filename
+    end
+  end
+end
diff --git a/lib/gitlab/file_type_detection.rb b/lib/gitlab/file_type_detection.rb
new file mode 100644
index 00000000000..25ee07cf940
--- /dev/null
+++ b/lib/gitlab/file_type_detection.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+# File helpers methods.
+# It needs the method filename to be defined.
+module Gitlab
+  module FileTypeDetection
+    IMAGE_EXT = %w[png jpg jpeg gif bmp tiff ico].freeze
+    # We recommend using the .mp4 format over .mov. Videos in .mov format can
+    # still be used but you really need to make sure they are served with the
+    # proper MIME type video/mp4 and not video/quicktime or your videos won't play
+    # on IE >= 9.
+    # http://archive.sublimevideo.info/20150912/docs.sublimevideo.net/troubleshooting.html
+    VIDEO_EXT = %w[mp4 m4v mov webm ogv].freeze
+    # These extension types can contain dangerous code and should only be embedded inline with
+    # proper filtering. They should always be tagged as "Content-Disposition: attachment", not "inline".
+    DANGEROUS_EXT = %w[svg].freeze
+
+    def image?
+      extension_match?(IMAGE_EXT)
+    end
+
+    def video?
+      extension_match?(VIDEO_EXT)
+    end
+
+    def image_or_video?
+      image? || video?
+    end
+
+    def dangerous?
+      extension_match?(DANGEROUS_EXT)
+    end
+
+    private
+
+    def extension_match?(extensions)
+      return false unless filename
+
+      extension = File.extname(filename).delete('.')
+      extensions.include?(extension.downcase)
+    end
+  end
+end
diff --git a/spec/features/projects/wiki/user_creates_wiki_page_spec.rb b/spec/features/projects/wiki/user_creates_wiki_page_spec.rb
index 149eeb4f9ba..b30286e4446 100644
--- a/spec/features/projects/wiki/user_creates_wiki_page_spec.rb
+++ b/spec/features/projects/wiki/user_creates_wiki_page_spec.rb
@@ -146,6 +146,8 @@ describe "User creates wiki page" do
           expect(page).to have_selector(".katex", count: 3).and have_content("2+2 is 4")
         end
       end
+
+      it_behaves_like 'wiki file attachments'
     end
 
     context "in a group namespace", :js do
diff --git a/spec/features/projects/wiki/user_updates_wiki_page_spec.rb b/spec/features/projects/wiki/user_updates_wiki_page_spec.rb
index 2840d28cf30..2ce5ee0e87d 100644
--- a/spec/features/projects/wiki/user_updates_wiki_page_spec.rb
+++ b/spec/features/projects/wiki/user_updates_wiki_page_spec.rb
@@ -3,6 +3,7 @@ require 'spec_helper'
 describe 'User updates wiki page' do
   shared_examples 'wiki page user update' do
     let(:user) { create(:user) }
+
     before do
       project.add_maintainer(user)
       sign_in(user)
@@ -55,6 +56,8 @@ describe 'User updates wiki page' do
 
           expect(page).to have_content('Updated Wiki Content')
         end
+
+        it_behaves_like 'wiki file attachments'
       end
     end
 
@@ -64,14 +67,14 @@ describe 'User updates wiki page' do
 
       before do
         visit(project_wikis_path(project))
+
+        click_link('Edit')
       end
 
       context 'in a user namespace' do
         let(:project) { create(:project, :wiki_repo, namespace: user.namespace) }
 
         it 'updates a page' do
-          click_link('Edit')
-
           # Commit message field should have correct value.
           expect(page).to have_field('wiki[message]', with: 'Update home')
 
@@ -84,8 +87,6 @@ describe 'User updates wiki page' do
         end
 
         it 'shows a validation error message' do
-          click_link('Edit')
-
           fill_in(:wiki_content, with: '')
           click_button('Save changes')
 
@@ -97,8 +98,6 @@ describe 'User updates wiki page' do
         end
 
         it 'shows the emoji autocompletion dropdown', :js do
-          click_link('Edit')
-
           find('#wiki_content').native.send_keys('')
           fill_in(:wiki_content, with: ':')
 
@@ -106,8 +105,6 @@ describe 'User updates wiki page' do
         end
 
         it 'shows the error message' do
-          click_link('Edit')
-
           wiki_page.update(content: 'Update')
 
           click_button('Save changes')
@@ -116,30 +113,27 @@ describe 'User updates wiki page' do
         end
 
         it 'updates a page' do
-          click_on('Edit')
           fill_in('Content', with: 'Updated Wiki Content')
           click_on('Save changes')
 
           expect(page).to have_content('Updated Wiki Content')
         end
 
-        it 'cancels edititng of a page' do
-          click_on('Edit')
-
+        it 'cancels editing of a page' do
           page.within(:css, '.wiki-form .form-actions') do
             click_on('Cancel')
           end
 
           expect(current_path).to eq(project_wiki_path(project, wiki_page))
         end
+
+        it_behaves_like 'wiki file attachments'
       end
 
       context 'in a group namespace' do
         let(:project) { create(:project, :wiki_repo, namespace: create(:group, :public)) }
 
         it 'updates a page' do
-          click_link('Edit')
-
           # Commit message field should have correct value.
           expect(page).to have_field('wiki[message]', with: 'Update home')
 
@@ -151,6 +145,8 @@ describe 'User updates wiki page' do
           expect(page).to have_content("Last edited by #{user.name}")
           expect(page).to have_content('My awesome wiki!')
         end
+
+        it_behaves_like 'wiki file attachments'
       end
     end
 
@@ -222,6 +218,8 @@ describe 'User updates wiki page' do
 
         expect(current_path).to eq(project_wiki_path(project, "foo1/bar1/#{page_name}"))
       end
+
+      it_behaves_like 'wiki file attachments'
     end
   end
 
diff --git a/spec/features/projects/wiki/user_views_wiki_page_spec.rb b/spec/features/projects/wiki/user_views_wiki_page_spec.rb
index 760324adacc..747406efc8b 100644
--- a/spec/features/projects/wiki/user_views_wiki_page_spec.rb
+++ b/spec/features/projects/wiki/user_views_wiki_page_spec.rb
@@ -93,7 +93,7 @@ describe 'User views a wiki page' do
         allow(wiki_file).to receive(:mime_type).and_return('image/jpeg')
         allow_any_instance_of(ProjectWiki).to receive(:find_file).with('image.jpg', nil).and_return(wiki_file)
 
-        expect(page).to have_xpath('//img[@data-src="image.jpg"]')
+        expect(page).to have_xpath("//img[@data-src='#{project.wiki.wiki_base_path}/image.jpg']")
         expect(page).to have_link('image', href: "#{project.wiki.wiki_base_path}/image.jpg")
 
         click_on('image')
diff --git a/spec/lib/banzai/filter/wiki_link_filter_spec.rb b/spec/lib/banzai/filter/wiki_link_filter_spec.rb
index 50d053011b3..b9059b85fdc 100644
--- a/spec/lib/banzai/filter/wiki_link_filter_spec.rb
+++ b/spec/lib/banzai/filter/wiki_link_filter_spec.rb
@@ -7,6 +7,7 @@ describe Banzai::Filter::WikiLinkFilter do
   let(:project)   { build_stubbed(:project, :public, name: "wiki_link_project", namespace: namespace) }
   let(:user) { double }
   let(:wiki) { ProjectWiki.new(project, user) }
+  let(:repository_upload_folder) { Wikis::CreateAttachmentService::ATTACHMENT_PATH }
 
   it "doesn't rewrite absolute links" do
     filtered_link = filter("<a href='http://example.com:8000/'>Link</a>", project_wiki: wiki).children[0]
@@ -20,6 +21,45 @@ describe Banzai::Filter::WikiLinkFilter do
     expect(filtered_link.attribute('href').value).to eq('/uploads/a.test')
   end
 
+  describe "when links point to the #{Wikis::CreateAttachmentService::ATTACHMENT_PATH} folder" do
+    context 'with an "a" html tag' do
+      it 'rewrites links' do
+        filtered_link = filter("<a href='#{repository_upload_folder}/a.test'>Link</a>", project_wiki: wiki).children[0]
+
+        expect(filtered_link.attribute('href').value).to eq("#{wiki.wiki_base_path}/#{repository_upload_folder}/a.test")
+      end
+    end
+
+    context 'with "img" html tag' do
+      let(:path) { "#{wiki.wiki_base_path}/#{repository_upload_folder}/a.jpg" }
+
+      context 'inside an "a" html tag' do
+        it 'rewrites links' do
+          filtered_elements = filter("<a href='#{repository_upload_folder}/a.jpg'><img src='#{repository_upload_folder}/a.jpg'>example</img></a>", project_wiki: wiki)
+
+          expect(filtered_elements.search('img').first.attribute('src').value).to eq(path)
+          expect(filtered_elements.search('a').first.attribute('href').value).to eq(path)
+        end
+      end
+
+      context 'outside an "a" html tag' do
+        it 'rewrites links' do
+          filtered_link = filter("<img src='#{repository_upload_folder}/a.jpg'>example</img>", project_wiki: wiki).children[0]
+
+          expect(filtered_link.attribute('src').value).to eq(path)
+        end
+      end
+    end
+
+    context 'with "video" html tag' do
+      it 'rewrites links' do
+        filtered_link = filter("<video src='#{repository_upload_folder}/a.mp4'></video>", project_wiki: wiki).children[0]
+
+        expect(filtered_link.attribute('src').value).to eq("#{wiki.wiki_base_path}/#{repository_upload_folder}/a.mp4")
+      end
+    end
+  end
+
   describe "invalid links" do
     invalid_links = ["http://:8080", "http://", "http://:8080/path"]
 
diff --git a/spec/lib/gitlab/file_markdown_link_builder_spec.rb b/spec/lib/gitlab/file_markdown_link_builder_spec.rb
new file mode 100644
index 00000000000..feb2776c5d0
--- /dev/null
+++ b/spec/lib/gitlab/file_markdown_link_builder_spec.rb
@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+require 'rails_helper'
+
+describe Gitlab::FileMarkdownLinkBuilder do
+  let(:custom_class) do
+    Class.new do
+      include Gitlab::FileMarkdownLinkBuilder
+    end.new
+  end
+
+  before do
+    allow(custom_class).to receive(:filename).and_return(filename)
+  end
+
+  describe 'markdown_link' do
+    let(:url) { "/uploads/#{filename}"}
+
+    before do
+      allow(custom_class).to receive(:secure_url).and_return(url)
+    end
+
+    context 'when file name has the character ]' do
+      let(:filename) { 'd]k.png' }
+
+      it 'escapes the character' do
+        expect(custom_class.markdown_link).to eq '![d\\]k](/uploads/d]k.png)'
+      end
+    end
+
+    context 'when file is an image or video' do
+      let(:filename) { 'dk.png' }
+
+      it 'returns preview markdown link' do
+        expect(custom_class.markdown_link).to eq '![dk](/uploads/dk.png)'
+      end
+    end
+
+    context 'when file is not an image or video' do
+      let(:filename) { 'dk.zip' }
+
+      it 'returns markdown link' do
+        expect(custom_class.markdown_link).to eq '[dk.zip](/uploads/dk.zip)'
+      end
+    end
+
+    context 'when file name is blank' do
+      let(:filename) { nil }
+
+      it 'returns nil' do
+        expect(custom_class.markdown_link).to eq nil
+      end
+    end
+  end
+
+  describe 'mardown_name' do
+    context 'when file is an image or video' do
+      let(:filename) { 'dk.png' }
+
+      it 'retrieves the name without the extension' do
+        expect(custom_class.markdown_name).to eq 'dk'
+      end
+    end
+
+    context 'when file is not an image or video' do
+      let(:filename) { 'dk.zip' }
+
+      it 'retrieves the name with the extesion' do
+        expect(custom_class.markdown_name).to eq 'dk.zip'
+      end
+    end
+
+    context 'when file name is blank' do
+      let(:filename) { nil }
+
+      it 'returns nil' do
+        expect(custom_class.markdown_name).to eq nil
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/file_type_detection_spec.rb b/spec/lib/gitlab/file_type_detection_spec.rb
new file mode 100644
index 00000000000..5e9b8988cc8
--- /dev/null
+++ b/spec/lib/gitlab/file_type_detection_spec.rb
@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+require 'rails_helper'
+
+describe Gitlab::FileTypeDetection do
+  def upload_fixture(filename)
+    fixture_file_upload(File.join('spec', 'fixtures', filename))
+  end
+
+  describe '#image_or_video?' do
+    context 'when class is an uploader' do
+      let(:uploader) do
+        example_uploader = Class.new(CarrierWave::Uploader::Base) do
+          include Gitlab::FileTypeDetection
+
+          storage :file
+        end
+
+        example_uploader.new
+      end
+
+      it 'returns true for an image file' do
+        uploader.store!(upload_fixture('dk.png'))
+
+        expect(uploader).to be_image_or_video
+      end
+
+      it 'returns true for a video file' do
+        uploader.store!(upload_fixture('video_sample.mp4'))
+
+        expect(uploader).to be_image_or_video
+      end
+
+      it 'returns false for other extensions' do
+        uploader.store!(upload_fixture('doc_sample.txt'))
+
+        expect(uploader).not_to be_image_or_video
+      end
+
+      it 'returns false if filename is blank' do
+        uploader.store!(upload_fixture('dk.png'))
+
+        allow(uploader).to receive(:filename).and_return(nil)
+
+        expect(uploader).not_to be_image_or_video
+      end
+    end
+
+    context 'when class is a regular class' do
+      let(:custom_class) do
+        custom_class = Class.new do
+          include Gitlab::FileTypeDetection
+        end
+
+        custom_class.new
+      end
+
+      it 'returns true for an image file' do
+        allow(custom_class).to receive(:filename).and_return('dk.png')
+
+        expect(custom_class).to be_image_or_video
+      end
+
+      it 'returns true for a video file' do
+        allow(custom_class).to receive(:filename).and_return('video_sample.mp4')
+
+        expect(custom_class).to be_image_or_video
+      end
+
+      it 'returns false for other extensions' do
+        allow(custom_class).to receive(:filename).and_return('doc_sample.txt')
+
+        expect(custom_class).not_to be_image_or_video
+      end
+
+      it 'returns false if filename is blank' do
+        allow(custom_class).to receive(:filename).and_return(nil)
+
+        expect(custom_class).not_to be_image_or_video
+      end
+    end
+  end
+end
diff --git a/spec/requests/api/wikis_spec.rb b/spec/requests/api/wikis_spec.rb
index 489cb001b82..c40d01e1a14 100644
--- a/spec/requests/api/wikis_spec.rb
+++ b/spec/requests/api/wikis_spec.rb
@@ -139,6 +139,27 @@ describe API::Wikis do
     end
   end
 
+  shared_examples_for 'uploads wiki attachment' do
+    it 'pushes attachment to the wiki repository' do
+      allow(SecureRandom).to receive(:hex).and_return('fixed_hex')
+
+      post(api(url, user), payload)
+
+      expect(response).to have_gitlab_http_status(201)
+      expect(json_response).to eq result_hash.deep_stringify_keys
+    end
+
+    it 'responds with validation error on empty file' do
+      payload.delete(:file)
+
+      post(api(url, user), payload)
+
+      expect(response).to have_gitlab_http_status(400)
+      expect(json_response.size).to eq(1)
+      expect(json_response['error']).to eq('file is missing')
+    end
+  end
+
   describe 'GET /projects/:id/wikis' do
     let(:url) { "/projects/#{project.id}/wikis" }
 
@@ -698,4 +719,107 @@ describe API::Wikis do
       include_examples '204 No Content'
     end
   end
+
+  describe 'POST /projects/:id/wikis/attachments' do
+    let(:payload) { { file: fixture_file_upload('spec/fixtures/dk.png') } }
+    let(:url) { "/projects/#{project.id}/wikis/attachments" }
+    let(:file_path) { "#{Wikis::CreateAttachmentService::ATTACHMENT_PATH}/fixed_hex/dk.png" }
+    let(:result_hash) do
+      {
+        file_name: 'dk.png',
+        file_path: file_path,
+        branch: 'master',
+        link: {
+          url: file_path,
+          markdown: "![dk](#{file_path})"
+        }
+      }
+    end
+
+    context 'when wiki is disabled' do
+      let(:project) { create(:project, :wiki_disabled, :wiki_repo) }
+
+      context 'when user is guest' do
+        before do
+          post(api(url), payload)
+        end
+
+        include_examples '404 Project Not Found'
+      end
+
+      context 'when user is developer' do
+        before do
+          project.add_developer(user)
+          post(api(url, user), payload)
+        end
+
+        include_examples '403 Forbidden'
+      end
+
+      context 'when user is maintainer' do
+        before do
+          project.add_maintainer(user)
+          post(api(url, user), payload)
+        end
+
+        include_examples '403 Forbidden'
+      end
+    end
+
+    context 'when wiki is available only for team members' do
+      let(:project) { create(:project, :wiki_private, :wiki_repo) }
+
+      context 'when user is guest' do
+        before do
+          post(api(url), payload)
+        end
+
+        include_examples '404 Project Not Found'
+      end
+
+      context 'when user is developer' do
+        before do
+          project.add_developer(user)
+        end
+
+        include_examples 'uploads wiki attachment'
+      end
+
+      context 'when user is maintainer' do
+        before do
+          project.add_maintainer(user)
+        end
+
+        include_examples 'uploads wiki attachment'
+      end
+    end
+
+    context 'when wiki is available for everyone with access' do
+      let(:project) { create(:project, :wiki_repo) }
+
+      context 'when user is guest' do
+        before do
+          post(api(url), payload)
+        end
+
+        include_examples '404 Project Not Found'
+      end
+
+      context 'when user is developer' do
+        before do
+          project.add_developer(user)
+        end
+
+        include_examples 'uploads wiki attachment'
+      end
+
+      context 'when user is maintainer' do
+        before do
+          project.add_maintainer(user)
+        end
+
+        include_examples 'uploads wiki attachment'
+      end
+    end
+  end
 end
diff --git a/spec/services/wikis/create_attachment_service_spec.rb b/spec/services/wikis/create_attachment_service_spec.rb
new file mode 100644
index 00000000000..3f4da873ce4
--- /dev/null
+++ b/spec/services/wikis/create_attachment_service_spec.rb
@@ -0,0 +1,202 @@
+# frozen_string_literal: true
+require 'spec_helper'
+
+describe Wikis::CreateAttachmentService do
+  let(:project) { create(:project, :wiki_repo) }
+  let(:user) { create(:user) }
+  let(:file_name) { 'filename.txt' }
+  let(:file_path_regex) { %r{#{described_class::ATTACHMENT_PATH}/\h{32}/#{file_name}} }
+
+  let(:file_opts) do
+    {
+      file_name: file_name,
+      file_content: 'Content of attachment'
+    }
+  end
+  let(:opts) { file_opts }
+
+  subject(:service) { described_class.new(project, user, opts) }
+
+  before do
+    project.add_developer(user)
+  end
+
+  describe 'initialization' do
+    context 'author commit info' do
+      it 'does not raise error if user is nil' do
+        service = described_class.new(project, nil, opts)
+
+        expect(service.instance_variable_get(:@author_email)).to be_nil
+        expect(service.instance_variable_get(:@author_name)).to be_nil
+      end
+
+      it 'fills file_path from the repository uploads folder' do
+        expect(service.instance_variable_get(:@file_path)).to match(file_path_regex)
+      end
+
+      context 'when no author info provided' do
+        it 'fills author_email and author_name from current_user info' do
+          expect(service.instance_variable_get(:@author_email)).to eq user.email
+          expect(service.instance_variable_get(:@author_name)).to eq user.name
+        end
+      end
+
+      context 'when author info provided' do
+        let(:author_email) { 'author_email' }
+        let(:author_name) { 'author_name' }
+        let(:opts) { file_opts.merge(author_email: author_email, author_name: author_name) }
+
+        it 'fills author_email and author_name from params' do
+          expect(service.instance_variable_get(:@author_email)).to eq author_email
+          expect(service.instance_variable_get(:@author_name)).to eq author_name
+        end
+      end
+    end
+
+    context 'commit message' do
+      context 'when no commit message provided' do
+        it 'sets a default commit message' do
+          expect(service.instance_variable_get(:@commit_message)).to eq "Upload attachment #{opts[:file_name]}"
+        end
+      end
+
+      context 'when commit message provided' do
+        let(:commit_message) { 'whatever' }
+        let(:opts) { file_opts.merge(commit_message: commit_message) }
+
+        it 'use the commit message from params' do
+          expect(service.instance_variable_get(:@commit_message)).to eq commit_message
+        end
+      end
+    end
+
+    context 'branch name' do
+      context 'when no branch provided' do
+        it 'sets the branch from the wiki default_branch' do
+          expect(service.instance_variable_get(:@branch_name)).to eq project.wiki.default_branch
+        end
+      end
+
+      context 'when branch provided' do
+        let(:branch_name) { 'whatever' }
+        let(:opts) { file_opts.merge(branch_name: branch_name) }
+
+        it 'use the commit message from params' do
+          expect(service.instance_variable_get(:@branch_name)).to eq branch_name
+        end
+      end
+    end
+  end
+
+  describe 'validations' do
+    context 'when file_name' do
+      context 'is not present' do
+        let(:file_name) { nil }
+
+        it 'returns error' do
+          result = service.execute
+
+          expect(result[:status]).to eq :error
+          expect(result[:message]).to eq 'The file name cannot be empty'
+        end
+      end
+
+      context 'length' do
+        context 'is bigger than 255' do
+          let(:file_name) { "#{'0' * 256}.jpg" }
+
+          it 'truncates file name' do
+            result = service.execute
+
+            expect(result[:status]).to eq :success
+            expect(result[:result][:file_name].length).to eq 255
+            expect(result[:result][:file_name]).to match(/0{251}\.jpg/)
+          end
+        end
+
+        context 'is less or equal to 255 does not return error' do
+          let(:file_name) { '0' * 255 }
+
+          it 'does not return error' do
+            result = service.execute
+
+            expect(result[:status]).to eq :success
+          end
+        end
+      end
+    end
+
+    context 'when user' do
+      shared_examples 'wiki attachment user validations' do
+        it 'returns error' do
+          result = described_class.new(project, user2, opts).execute
+
+          expect(result[:status]).to eq :error
+          expect(result[:message]).to eq 'You are not allowed to push to the wiki'
+        end
+      end
+
+      context 'does not have permission' do
+        let(:user2) { create(:user) }
+
+        it_behaves_like 'wiki attachment user validations'
+      end
+
+      context 'is nil' do
+        let(:user2) { nil }
+
+        it_behaves_like 'wiki attachment user validations'
+      end
+    end
+  end
+
+  describe '#execute' do
+    let(:wiki) { project.wiki }
+    subject(:service_execute) { service.execute[:result] }
+
+    context 'creates branch if it does not exists' do
+      let(:branch_name) { 'new_branch' }
+      let(:opts) { file_opts.merge(branch_name: branch_name) }
+
+      it do
+        expect(wiki.repository.branches).to be_empty
+        expect { service.execute }.to change { wiki.repository.branches.count }.by(1)
+        expect(wiki.repository.branches.first.name).to eq branch_name
+      end
+    end
+
+    it 'adds file to the repository' do
+      expect(wiki.repository.ls_files('HEAD')).to be_empty
+
+      service.execute
+
+      files = wiki.repository.ls_files('HEAD')
+      expect(files.count).to eq 1
+      expect(files.first).to match(file_path_regex)
+    end
+
+    context 'returns' do
+      before do
+        allow(SecureRandom).to receive(:hex).and_return('fixed_hex')
+
+        service_execute
+      end
+
+      it 'returns the file name' do
+        expect(service_execute[:file_name]).to eq file_name
+      end
+
+      it 'returns the path where file was stored' do
+        expect(service_execute[:file_path]).to eq 'uploads/fixed_hex/filename.txt'
+      end
+
+      it 'returns the branch where the file was pushed' do
+        expect(service_execute[:branch]).to eq wiki.default_branch
+      end
+
+      it 'returns the commit id' do
+        expect(service_execute[:commit]).not_to be_empty
+      end
+    end
+  end
+end
diff --git a/spec/support/shared_examples/wiki_file_attachments_examples.rb b/spec/support/shared_examples/wiki_file_attachments_examples.rb
new file mode 100644
index 00000000000..b6fb2a66b0e
--- /dev/null
+++ b/spec/support/shared_examples/wiki_file_attachments_examples.rb
@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+# Requires a context containing:
+#   project
+
+shared_examples 'wiki file attachments' do
+  include DropzoneHelper
+
+  context 'uploading attachments', :js do
+    let(:wiki) { project.wiki }
+
+    def attach_with_dropzone(wait = false)
+      dropzone_file([Rails.root.join('spec', 'fixtures', 'dk.png')], 0, wait)
+    end
+
+    context 'before uploading' do
+      it 'shows "Attach a file" button' do
+        expect(page).to have_button('Attach a file')
+        expect(page).not_to have_selector('.uploading-progress-container', visible: true)
+      end
+    end
+
+    context 'uploading is in progress' do
+      it 'cancels uploading on clicking to "Cancel" button' do
+        slow_requests do
+          attach_with_dropzone
+
+          click_button 'Cancel'
+        end
+
+        expect(page).to have_button('Attach a file')
+        expect(page).not_to have_button('Cancel')
+        expect(page).not_to have_selector('.uploading-progress-container', visible: true)
+      end
+
+      it 'shows "Attaching a file" message on uploading 1 file' do
+        slow_requests do
+          attach_with_dropzone
+
+          expect(page).to have_selector('.attaching-file-message', visible: true, text: 'Attaching a file -')
+        end
+      end
+    end
+
+    context 'uploading is complete' do
+      it 'shows "Attach a file" button on uploading complete' do
+        attach_with_dropzone
+        wait_for_requests
+
+        expect(page).to have_button('Attach a file')
+        expect(page).not_to have_selector('.uploading-progress-container', visible: true)
+      end
+
+      it 'the markdown link is added to the page' do
+        fill_in(:wiki_content, with: '')
+        attach_with_dropzone(true)
+        wait_for_requests
+
+        expect(page.find('#wiki_content').value)
+          .to match(%r{\!\[dk\]\(uploads/\h{32}/dk\.png\)$})
+      end
+
+      it 'the links point to the wiki root url' do
+        attach_with_dropzone(true)
+        wait_for_requests
+
+        find('.js-md-preview-button').click
+        file_path = page.find('input[name="files[]"]', visible: :hidden).value
+        link = page.find('a.no-attachment-icon')['href']
+        img_link = page.find('a.no-attachment-icon img')['src']
+
+        expect(link).to eq img_link
+        expect(URI.parse(link).path).to eq File.join(wiki.wiki_base_path, file_path)
+      end
+
+      it 'the file has been added to the wiki repository' do
+        expect do
+          attach_with_dropzone(true)
+          wait_for_requests
+        end.to change { wiki.repository.ls_files('HEAD').count }.by(1)
+
+        file_path = page.find('input[name="files[]"]', visible: :hidden).value
+
+        expect(wiki.find_file(file_path, 'HEAD').path).not_to be_nil
+      end
+    end
+  end
+end
diff --git a/spec/uploaders/uploader_helper_spec.rb b/spec/uploaders/uploader_helper_spec.rb
index 33da93cc9d0..fd6712d4645 100644
--- a/spec/uploaders/uploader_helper_spec.rb
+++ b/spec/uploaders/uploader_helper_spec.rb
@@ -11,27 +11,10 @@ describe UploaderHelper do
     example_uploader.new
   end
 
-  def upload_fixture(filename)
-    fixture_file_upload(File.join('spec', 'fixtures', filename))
-  end
-
-  describe '#image_or_video?' do
-    it 'returns true for an image file' do
-      uploader.store!(upload_fixture('dk.png'))
-
-      expect(uploader).to be_image_or_video
-    end
-
-    it 'it returns true for a video file' do
-      uploader.store!(upload_fixture('video_sample.mp4'))
-
-      expect(uploader).to be_image_or_video
-    end
-
-    it 'returns false for other extensions' do
-      uploader.store!(upload_fixture('doc_sample.txt'))
-
-      expect(uploader).not_to be_image_or_video
+  describe '#extension_match?' do
+    it 'returns false if file does not exists' do
+      expect(uploader.file).to be_nil
+      expect(uploader.send(:extension_match?, 'jpg')).to eq false
     end
   end
 end