Add param to Wiki REST endpoint to retrieve different page versions

In this MR we're introducing the param `version` to thet GET
page REST endpoint, to allow retrieving different versions of the
page.

Changelog: added

app/helpers/markup_helper.rb

@@ -181,7 +181,8 @@ module MarkupHelper
       wiki: wiki,
       repository: wiki.repository,
       page_slug: wiki_page.slug,
-      issuable_reference_expansion_enabled: true
+      issuable_reference_expansion_enabled: true,
+      requested_path: wiki_page.path
     ).merge(render_wiki_content_context_container(wiki))
   end
 
@@ -263,7 +264,7 @@ module MarkupHelper
   end
 
   def asciidoc_unsafe(text, context = {})
-    context.merge!(
+    context.reverse_merge!(
       commit:         @commit,
       ref:            @ref,
       requested_path: @path

doc/api/group_wikis.md

@@ -10,6 +10,7 @@ type: reference, api
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/212199) in GitLab 13.5.
 > - The `encoding` field was [added](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/81150) in GitLab 14.9.
 > - The `render_html` attribute was [added](https://gitlab.com/gitlab-org/gitlab/-/issues/336792) in GitLab 14.9.
+> - The `version` attribute was [added](https://gitlab.com/gitlab-org/gitlab/-/issues/336792) in GitLab 14.9.
 
 The [group wikis](../user/project/wiki/group.md) API is available only in APIv4.
 An API for [project wikis](wikis.md) is also available.
@@ -71,6 +72,7 @@ GET /groups/:id/wikis/:slug
 | `id`      | integer/string | yes      | The ID or [URL-encoded path of the group](index.md#namespaced-path-encoding) |
 | `slug`    | string         | yes      | URL-encoded slug (a unique string) of the wiki page, such as `dir%2Fpage_name`      |
 | `render_html`      | boolean    | no      | Return the rendered HTML of the wiki page  |
+| `version`      | string    | no      | Wiki page version sha  |
 
 ```shell
 curl --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/groups/1/wikis/home"

doc/api/wikis.md

@@ -8,6 +8,7 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 
 > - The `encoding` field was [added](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/81150) in GitLab 14.9.
 > - The `render_html` attribute was [added](https://gitlab.com/gitlab-org/gitlab/-/issues/336792) in GitLab 14.9.
+> - The `version` attribute was [added](https://gitlab.com/gitlab-org/gitlab/-/issues/336792) in GitLab 14.9.
 
 The project [wikis](../user/project/wiki/index.md) API is available only in APIv4.
 An API for [group wikis](group_wikis.md) is also available.
@@ -69,6 +70,7 @@ GET /projects/:id/wikis/:slug
 | `id`      | integer/string    | yes      | The ID or [URL-encoded path of the project](index.md#namespaced-path-encoding) |
 | `slug` | string  | yes       | URLencoded slug (a unique string) of the wiki page, such as `dir%2Fpage_name`  |
 | `render_html`      | boolean    | no      | Return the rendered HTML of the wiki page  |
+| `version`      | string    | no      | Wiki page version sha  |
 
 ```shell
 curl --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/projects/1/wikis/home"

ee/spec/requests/api/wikis_spec.rb

@@ -179,8 +179,6 @@ RSpec.describe API::Wikis do
       context 'when user is developer' do
         before do
           group.add_developer(user)
-
-          get api(url, user), params: params
         end
 
         include_examples 'wikis API returns wiki page'
@@ -188,6 +186,10 @@ RSpec.describe API::Wikis do
         context 'when page does not exist' do
           let(:url) { "/groups/#{group.id}/wikis/unknown" }
 
+          before do
+            get api(url, user), params: params
+          end
+
           include_examples 'wiki API 404 Wiki Page Not Found'
         end
       end
@@ -195,8 +197,6 @@ RSpec.describe API::Wikis do
       context 'when user is maintainer' do
         before do
           group.add_maintainer(user)
-
-          get api(url, user), params: params
         end
 
         include_examples 'wikis API returns wiki page'
@@ -204,6 +204,10 @@ RSpec.describe API::Wikis do
         context 'when page does not exist' do
           let(:url) { "/groups/#{group.id}/wikis/unknown" }
 
+          before do
+            get api(url, user), params: params
+          end
+
           include_examples 'wiki API 404 Wiki Page Not Found'
         end
       end
@@ -221,8 +225,6 @@ RSpec.describe API::Wikis do
       context 'when user is developer' do
         before do
           group.add_developer(user)
-
-          get api(url, user), params: params
         end
 
         include_examples 'wikis API returns wiki page'
@@ -230,6 +232,10 @@ RSpec.describe API::Wikis do
         context 'when page does not exist' do
           let(:url) { "/groups/#{group.id}/wikis/unknown" }
 
+          before do
+            get api(url, user), params: params
+          end
+
           include_examples 'wiki API 404 Wiki Page Not Found'
         end
       end
@@ -237,8 +243,6 @@ RSpec.describe API::Wikis do
       context 'when user is maintainer' do
         before do
           group.add_maintainer(user)
-
-          get api(url, user), params: params
         end
 
         include_examples 'wikis API returns wiki page'
@@ -246,6 +250,10 @@ RSpec.describe API::Wikis do
         context 'when page does not exist' do
           let(:url) { "/groups/#{group.id}/wikis/unknown" }
 
+          before do
+            get api(url, user), params: params
+          end
+
           include_examples 'wiki API 404 Wiki Page Not Found'
         end
       end

lib/api/entities/wiki_page.rb

@@ -6,7 +6,7 @@ module API
       include ::MarkupHelper
 
       expose :content do |wiki_page, options|
-        options[:render_html] ? render_wiki_content(wiki_page) : wiki_page.content
+        options[:render_html] ? render_wiki_content(wiki_page, ref: wiki_page.version.id) : wiki_page.content
       end
 
       expose :encoding do |wiki_page|

lib/api/helpers/wikis_helpers.rb

@@ -13,8 +13,8 @@ module API
         raise "Unknown wiki container #{kind}"
       end
 
-      def wiki_page
-        Wiki.for_container(container, current_user).find_page(params[:slug]) || not_found!('Wiki Page')
+      def wiki_page(version = nil)
+        Wiki.for_container(container, current_user).find_page(params[:slug], version.presence) || not_found!('Wiki Page')
       end
 
       def commit_params(attrs)

lib/api/wikis.rb

@@ -45,12 +45,13 @@ module API
         end
         params do
           requires :slug, type: String, desc: 'The slug of a wiki page'
+          optional :version, type: String, desc: 'The version hash of a wiki page'
           optional :render_html, type: Boolean, default: false, desc: 'Render content to HTML'
         end
         get ':id/wikis/:slug' do
           authorize! :read_wiki, container
 
-          present wiki_page, with: Entities::WikiPage, render_html: params[:render_html]
+          present wiki_page(params[:version]), with: Entities::WikiPage, render_html: params[:render_html]
         end
 
         desc 'Create a wiki page' do

spec/helpers/markup_helper_spec.rb

@@ -318,13 +318,14 @@ RSpec.describe MarkupHelper do
     let(:wiki) { build(:wiki, container: project) }
     let(:content) { 'wiki content' }
     let(:slug) { 'nested/page' }
-    let(:wiki_page) { double('WikiPage', path: "file.#{extension}", content: content, slug: slug, wiki: wiki) }
+    let(:path) { "file.#{extension}" }
+    let(:wiki_page) { double('WikiPage', path: path, content: content, slug: slug, wiki: wiki) }
 
     let(:context) do
       {
         pipeline: :wiki, project: project, wiki: wiki,
         page_slug: slug, issuable_reference_expansion_enabled: true,
-        repository: wiki.repository
+        repository: wiki.repository, requested_path: path
       }
     end
 

spec/lib/api/entities/wiki_page_spec.rb

@@ -29,6 +29,20 @@ RSpec.describe API::Entities::WikiPage do
       it 'returns the wiki page content rendered' do
         expect(subject[:content]).to eq "<p data-sourcepos=\"1:1-1:#{wiki_page.content.size}\" dir=\"auto\">#{wiki_page.content}</p>"
       end
+
+      it 'includes the wiki page version in the render context' do
+        expect(entity).to receive(:render_wiki_content).with(anything, hash_including(ref: wiki_page.version.id)).and_call_original
+
+        subject[:content]
+      end
+
+      context 'when page is an Ascii document' do
+        let(:wiki_page) { create(:wiki_page, content: "*Test* _content_", format: :asciidoc) }
+
+        it 'renders the page without errors' do
+          expect(subject[:content]).to eq("<div>&#x000A;<p><strong>Test</strong> <em>content</em></p>&#x000A;</div>")
+        end
+      end
     end
 
     context 'when it is false' do

spec/requests/api/wikis_spec.rb

@@ -174,8 +174,6 @@ RSpec.describe API::Wikis do
       context 'when user is developer' do
         before do
           project.add_developer(user)
-
-          request
         end
 
         include_examples 'wikis API returns wiki page'
@@ -183,6 +181,10 @@ RSpec.describe API::Wikis do
         context 'when page is not existing' do
           let(:url) { "/projects/#{project.id}/wikis/unknown" }
 
+          before do
+            request
+          end
+
           include_examples 'wiki API 404 Wiki Page Not Found'
         end
       end
@@ -190,8 +192,6 @@ RSpec.describe API::Wikis do
       context 'when user is maintainer' do
         before do
           project.add_maintainer(user)
-
-          request
         end
 
         include_examples 'wikis API returns wiki page'
@@ -199,6 +199,10 @@ RSpec.describe API::Wikis do
         context 'when page is not existing' do
           let(:url) { "/projects/#{project.id}/wikis/unknown" }
 
+          before do
+            request
+          end
+
           include_examples 'wiki API 404 Wiki Page Not Found'
         end
       end
@@ -220,8 +224,6 @@ RSpec.describe API::Wikis do
       context 'when user is developer' do
         before do
           project.add_developer(user)
-
-          request
         end
 
         include_examples 'wikis API returns wiki page'
@@ -229,6 +231,10 @@ RSpec.describe API::Wikis do
         context 'when page is not existing' do
           let(:url) { "/projects/#{project.id}/wikis/unknown" }
 
+          before do
+            request
+          end
+
           include_examples 'wiki API 404 Wiki Page Not Found'
         end
       end
@@ -236,8 +242,6 @@ RSpec.describe API::Wikis do
       context 'when user is maintainer' do
         before do
           project.add_maintainer(user)
-
-          request
         end
 
         include_examples 'wikis API returns wiki page'
@@ -245,6 +249,10 @@ RSpec.describe API::Wikis do
         context 'when page is not existing' do
           let(:url) { "/projects/#{project.id}/wikis/unknown" }
 
+          before do
+            request
+          end
+
           include_examples 'wiki API 404 Wiki Page Not Found'
         end
       end

spec/support/shared_examples/lib/wikis_api_examples.rb

@@ -44,7 +44,13 @@ RSpec.shared_examples_for 'wikis API returns list of wiki pages' do
 end
 
 RSpec.shared_examples_for 'wikis API returns wiki page' do
+  subject(:request) { get api(url, user), params: params }
+
   shared_examples 'returns wiki page' do
+    before do
+      request
+    end
+
     specify do
       expect(response).to have_gitlab_http_status(:ok)
       expect(json_response.size).to eq(5)
@@ -71,6 +77,38 @@ RSpec.shared_examples_for 'wikis API returns wiki page' do
 
     it_behaves_like 'returns wiki page'
   end
+
+  context 'when wiki page has versions' do
+    let(:new_content) { 'New content' }
+
+    before do
+      wiki.update_page(page.page, content: new_content, message: 'updated page')
+
+      expect(page.count_versions).to eq(2)
+
+      request
+    end
+
+    context 'when version param is not present' do
+      it 'retrieves the last version' do
+        expect(json_response['content']).to eq(new_content)
+      end
+    end
+
+    context 'when version param is set' do
+      let(:params) { { version: page.version.id } }
+
+      it 'retrieves the specific page version' do
+        expect(json_response['content']).to eq(page.content)
+      end
+
+      context 'when version param is not valid or inexistent' do
+        let(:params) { { version: 'foobar' } }
+
+        it_behaves_like 'wiki API 404 Wiki Page Not Found'
+      end
+    end
+  end
 end
 
 RSpec.shared_examples_for 'wikis API creates wiki page' do