Fix image webhook rewriting for uploads

This rewrote URLs to be absolute URLs. However, for uploads (the most
common case), we actually need them to point to not just the GitLab
instance, but the project they're from. Thankfully, we can normally get
that information from the object we're building the hook for.

changelogs/unreleased/test-usage-ping-in-timeout-case.yml

+---
+title: Fix auto-corrected upload URLs in webhooks
+merge_request: 22361
+author:
+type: fixed

doc/user/project/integrations/webhooks.md

@@ -73,8 +73,8 @@ Below are described the supported events.
 
 Triggered when you push to the repository except when pushing tags.
 
-> **Note:** When more than 20 commits are pushed at once, the `commits` web hook 
-  attribute will only contain the first 20 for performance reasons. Loading 
+> **Note:** When more than 20 commits are pushed at once, the `commits` web hook
+  attribute will only contain the first 20 for performance reasons. Loading
   detailed commit data is expensive. Note that despite only 20 commits being
   present in the `commits` attribute, the `total_commits_count` attribute will
   contain the actual total.
@@ -1157,10 +1157,11 @@ its description:
 ```
 
 It will appear in the webhook body as the below (assuming that GitLab is
-installed at gitlab.example.com):
+installed at gitlab.example.com, and the project is at
+example-group/example-project):
 
 ```markdown
-![image](https://gitlab.example.com/uploads/$sha/image.png)
+![image](https://gitlab.example.com/example-group/example-project/uploads/$sha/image.png)
 ```
 
 This will not rewrite URLs that already are pointing to HTTP, HTTPS, or

lib/gitlab/hook_data/base_builder.rb

@@ -25,6 +25,7 @@ module Gitlab
         markdown_text.gsub(MARKDOWN_SIMPLE_IMAGE) do
           if $~[:image]
             url = $~[:url]
+            url = "#{uploads_prefix}#{url}" if url.start_with?('/uploads')
             url = "/#{url}" unless url.start_with?('/')
 
             "![#{$~[:title]}](#{Gitlab.config.gitlab.url}#{url})"
@@ -33,6 +34,16 @@ module Gitlab
           end
         end
       end
+
+      def uploads_prefix
+        project&.full_path || ''
+      end
+
+      def project
+        return unless object.respond_to?(:project)
+
+        object.project
+      end
     end
   end
 end

spec/lib/gitlab/hook_data/base_builder_spec.rb

@@ -8,57 +8,94 @@ describe Gitlab::HookData::BaseBuilder do
       end
     end
 
-    subject { subclass.new(nil) }
-
     using RSpec::Parameterized::TableSyntax
 
-    where do
-      {
-        'relative image URL' => {
-          input: '![an image](foo.png)',
-          output: "![an image](#{Gitlab.config.gitlab.url}/foo.png)"
-        },
-        'HTTP URL' => {
-          input: '![an image](http://example.com/foo.png)',
-          output: '![an image](http://example.com/foo.png)'
-        },
-        'HTTPS URL' => {
-          input: '![an image](https://example.com/foo.png)',
-          output: '![an image](https://example.com/foo.png)'
-        },
-        'protocol-relative URL' => {
-          input: '![an image](//example.com/foo.png)',
-          output: '![an image](//example.com/foo.png)'
-        },
-        'URL reference by title' => {
-          input: "![foo]\n\n[foo]: foo.png",
-          output: "![foo]\n\n[foo]: foo.png"
-        },
-        'URL reference by label' => {
-          input: "![][foo]\n\n[foo]: foo.png",
-          output: "![][foo]\n\n[foo]: foo.png"
-        },
-        'in Markdown inline code block' => {
-          input: '`![an image](foo.png)`',
-          output: "`![an image](#{Gitlab.config.gitlab.url}/foo.png)`"
-        },
-        'in HTML tag on the same line' => {
-          input: '<p>![an image](foo.png)</p>',
-          output: "<p>![an image](#{Gitlab.config.gitlab.url}/foo.png)</p>"
-        },
-        'in Markdown multi-line code block' => {
-          input: "```\n![an image](foo.png)\n```",
-          output: "```\n![an image](foo.png)\n```"
-        },
-        'in HTML tag on different lines' => {
-          input: "<p>\n![an image](foo.png)\n</p>",
-          output: "<p>\n![an image](foo.png)\n</p>"
+    context 'with an upload prefix specified' do
+      let(:project_with_path) { double(full_path: 'baz/bar') }
+      let(:object_with_project) { double(project: project_with_path) }
+      subject { subclass.new(object_with_project) }
+
+      where do
+        {
+          'relative image URL' => {
+            input: '![an image](foo.png)',
+            output: "![an image](#{Gitlab.config.gitlab.url}/foo.png)"
+          },
+          'absolute upload URL' => {
+            input: '![an image](/uploads/foo.png)',
+            output: "![an image](#{Gitlab.config.gitlab.url}/baz/bar/uploads/foo.png)"
+          },
+          'absolute non-upload URL' => {
+            input: '![an image](/downloads/foo.png)',
+            output: "![an image](#{Gitlab.config.gitlab.url}/downloads/foo.png)"
+          }
         }
-      }
+      end
+
+      with_them do
+        it { expect(subject.absolute_image_urls(input)).to eq(output) }
+      end
     end
 
-    with_them do
-      it { expect(subject.absolute_image_urls(input)).to eq(output) }
+    context 'without an upload prefix specified' do
+      subject { subclass.new(nil) }
+
+      where do
+        {
+          'relative image URL' => {
+            input: '![an image](foo.png)',
+            output: "![an image](#{Gitlab.config.gitlab.url}/foo.png)"
+          },
+          'absolute upload URL' => {
+            input: '![an image](/uploads/foo.png)',
+            output: "![an image](#{Gitlab.config.gitlab.url}/uploads/foo.png)"
+          },
+          'absolute non-upload URL' => {
+            input: '![an image](/downloads/foo.png)',
+            output: "![an image](#{Gitlab.config.gitlab.url}/downloads/foo.png)"
+          },
+          'HTTP URL' => {
+            input: '![an image](http://example.com/foo.png)',
+            output: '![an image](http://example.com/foo.png)'
+          },
+          'HTTPS URL' => {
+            input: '![an image](https://example.com/foo.png)',
+            output: '![an image](https://example.com/foo.png)'
+          },
+          'protocol-relative URL' => {
+            input: '![an image](//example.com/foo.png)',
+            output: '![an image](//example.com/foo.png)'
+          },
+          'URL reference by title' => {
+            input: "![foo]\n\n[foo]: foo.png",
+            output: "![foo]\n\n[foo]: foo.png"
+          },
+          'URL reference by label' => {
+            input: "![][foo]\n\n[foo]: foo.png",
+            output: "![][foo]\n\n[foo]: foo.png"
+          },
+          'in Markdown inline code block' => {
+            input: '`![an image](foo.png)`',
+            output: "`![an image](#{Gitlab.config.gitlab.url}/foo.png)`"
+          },
+          'in HTML tag on the same line' => {
+            input: '<p>![an image](foo.png)</p>',
+            output: "<p>![an image](#{Gitlab.config.gitlab.url}/foo.png)</p>"
+          },
+          'in Markdown multi-line code block' => {
+            input: "```\n![an image](foo.png)\n```",
+            output: "```\n![an image](foo.png)\n```"
+          },
+          'in HTML tag on different lines' => {
+            input: "<p>\n![an image](foo.png)\n</p>",
+            output: "<p>\n![an image](foo.png)\n</p>"
+          }
+        }
+      end
+
+      with_them do
+        it { expect(subject.absolute_image_urls(input)).to eq(output) }
+      end
     end
   end
 end

spec/lib/gitlab/hook_data/issue_builder_spec.rb

@@ -46,7 +46,10 @@ describe Gitlab::HookData::IssueBuilder do
       let(:builder) { described_class.new(issue_with_description) }
 
       it 'sets the image to use an absolute URL' do
-        expect(data[:description]).to eq("test![Issue_Image](#{Settings.gitlab.url}/uploads/abc/Issue_Image.png)")
+        expected_path = "#{issue_with_description.project.path_with_namespace}/uploads/abc/Issue_Image.png"
+
+        expect(data[:description])
+          .to eq("test![Issue_Image](#{Settings.gitlab.url}/#{expected_path})")
       end
     end
   end

spec/lib/gitlab/hook_data/merge_request_builder_spec.rb

@@ -58,11 +58,14 @@ describe Gitlab::HookData::MergeRequestBuilder do
     end
 
     context 'when the MR has an image in the description' do
-      let(:mr_with_description) { create(:merge_request, description: 'test![Issue_Image](/uploads/abc/Issue_Image.png)') }
+      let(:mr_with_description) { create(:merge_request, description: 'test![MR_Image](/uploads/abc/MR_Image.png)') }
       let(:builder) { described_class.new(mr_with_description) }
 
       it 'sets the image to use an absolute URL' do
-        expect(data[:description]).to eq("test![Issue_Image](#{Settings.gitlab.url}/uploads/abc/Issue_Image.png)")
+        expected_path = "#{mr_with_description.project.path_with_namespace}/uploads/abc/MR_Image.png"
+
+        expect(data[:description])
+          .to eq("test![MR_Image](#{Settings.gitlab.url}/#{expected_path})")
       end
     end
   end