From 2e0b3826997221289ce64d826c7a921541d7732d Mon Sep 17 00:00:00 2001
From: cmrd Senya <senya@riseup.net>
Date: Mon, 11 Jun 2018 18:21:06 +0300
Subject: [PATCH 1/4] Use 'post' prefix for status message route helpers

This is required to make url_for(StatusMessage.new) work
---
 app/models/status_message.rb               | 4 ++++
 app/views/publisher/_publisher.html.haml   | 2 +-
 app/views/publisher/_publisher.mobile.haml | 3 ++-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/app/models/status_message.rb b/app/models/status_message.rb
index 17d267797..0c68286ae 100644
--- a/app/models/status_message.rb
+++ b/app/models/status_message.rb
@@ -37,6 +37,10 @@ class StatusMessage < Post
     owned_or_visible_by_user(person.owner).joins(:mentions).where(mentions: {person_id: person.id})
   }
 
+  def self.model_name
+    Post.model_name
+  end
+
   def self.guids_for_author(person)
     Post.connection.select_values(Post.where(:author_id => person.id).select('posts.guid').to_sql)
   end
diff --git a/app/views/publisher/_publisher.html.haml b/app/views/publisher/_publisher.html.haml
index 808a79060..3322d7619 100644
--- a/app/views/publisher/_publisher.html.haml
+++ b/app/views/publisher/_publisher.html.haml
@@ -1,6 +1,6 @@
 .row.publisher#publisher{class: ((aspect == :profile || publisher_open?) ? "mention_popup" : "closed")}
   .content_creation
-    = form_for(StatusMessage.new) do |status|
+    = form_for StatusMessage.new, url: status_messages_path, as: :status_message do |status|
       = status.error_messages
       %params
         .publisher-textarea-wrapper#publisher-textarea-wrapper
diff --git a/app/views/publisher/_publisher.mobile.haml b/app/views/publisher/_publisher.mobile.haml
index 68681213b..e031c1027 100644
--- a/app/views/publisher/_publisher.mobile.haml
+++ b/app/views/publisher/_publisher.mobile.haml
@@ -2,7 +2,8 @@
 -#   licensed under the Affero General Public License version 3 or later.  See
 -#   the COPYRIGHT file.
 
-= form_for StatusMessage.new, html: {class: "control-group", data: {ajax: false}} do |status|
+= form_for StatusMessage.new, url: status_messages_path, as: :status_message,
+    html: {class: "control-group", data: {ajax: false}} do |status|
   .form-group
     = status.hidden_field :provider_display_name, value: 'mobile'
     = status.text_area :text, placeholder: t('shared.publisher.whats_on_your_mind'), rows: 4, autofocus: "autofocus", class: "form-control"

From 6f812a5b8f20c04ba1a7aa01dcec13d2a07ac1af Mon Sep 17 00:00:00 2001
From: cmrd Senya <senya@riseup.net>
Date: Mon, 11 Jun 2018 04:23:18 +0300
Subject: [PATCH 2/4] Add LinksController

LinksController redirects requests for provided diaspora:// links to
respective entities urls.
---
 app/controllers/links_controller.rb         | 16 +++++
 app/models/reference.rb                     |  3 +-
 app/services/diaspora_link_service.rb       | 45 +++++++++++++
 config/routes.rb                            |  2 +
 lib/diaspora/entity_finder.rb               | 22 +++++++
 spec/controllers/links_controller_spec.rb   | 71 +++++++++++++++++++++
 spec/services/diaspora_link_service_spec.rb | 44 +++++++++++++
 7 files changed, 201 insertions(+), 2 deletions(-)
 create mode 100644 app/controllers/links_controller.rb
 create mode 100644 app/services/diaspora_link_service.rb
 create mode 100644 lib/diaspora/entity_finder.rb
 create mode 100644 spec/controllers/links_controller_spec.rb
 create mode 100644 spec/services/diaspora_link_service_spec.rb

diff --git a/app/controllers/links_controller.rb b/app/controllers/links_controller.rb
new file mode 100644
index 000000000..f28fbbc64
--- /dev/null
+++ b/app/controllers/links_controller.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class LinksController < ApplicationController
+  def resolve
+    entity = DiasporaLinkService.new(query).find_or_fetch_entity
+    raise ActiveRecord::RecordNotFound if entity.nil?
+
+    redirect_to url_for(entity)
+  end
+
+  private
+
+  def query
+    @query ||= params.fetch(:q)
+  end
+end
diff --git a/app/models/reference.rb b/app/models/reference.rb
index 3de1ff20a..45501edd4 100644
--- a/app/models/reference.rb
+++ b/app/models/reference.rb
@@ -22,8 +22,7 @@ class Reference < ApplicationRecord
     private
 
     def add_reference(author, type, guid)
-      class_name = DiasporaFederation::Entity.entity_class(type).to_s.rpartition("::").last
-      entity = Diaspora::Federation::Mappings.model_class_for(class_name).find_by(guid: guid)
+      entity = Diaspora::EntityFinder.new(type, guid).find
       references.find_or_create_by(target: entity) if entity&.diaspora_handle == author
     rescue => e # rubocop:disable Lint/RescueWithoutErrorClass
       logger.warn "ignoring invalid diaspora-url: diaspora://#{author}/#{type}/#{guid}: #{e.class}: #{e.message}"
diff --git a/app/services/diaspora_link_service.rb b/app/services/diaspora_link_service.rb
new file mode 100644
index 000000000..1923aa01d
--- /dev/null
+++ b/app/services/diaspora_link_service.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+# Encapsulates logic of processing diaspora:// links
+class DiasporaLinkService
+  attr_reader :type, :author, :guid
+
+  def initialize(link)
+    @link = link.dup
+    parse
+  end
+
+  def find_or_fetch_entity
+    entity_finder.find || fetch_entity
+  end
+
+  private
+
+  attr_accessor :link
+
+  def fetch_entity
+    DiasporaFederation::Federation::Fetcher.fetch_public(author, type, guid)
+    entity_finder.find
+  rescue DiasporaFederation::Federation::Fetcher::NotFetchable
+    nil
+  end
+
+  def entity_finder
+    @entity_finder ||= Diaspora::EntityFinder.new(type, guid)
+  end
+
+  def normalize
+    link.gsub!(%r{^web\+diaspora://}, "diaspora://") ||
+      link.gsub!(%r{^//}, "diaspora://") ||
+      %r{^diaspora://}.match(link) ||
+      self.link = "diaspora://#{link}"
+  end
+
+  def parse
+    normalize
+    match = DiasporaFederation::Federation::DiasporaUrlParser::DIASPORA_URL_REGEX.match(link)
+    @author = match[1]
+    @type = match[2]
+    @guid = match[3]
+  end
+end
diff --git a/config/routes.rb b/config/routes.rb
index 846921b8b..f7ad53bec 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -74,6 +74,8 @@ Rails.application.routes.draw do
 	#Search
 	get 'search' => "search#search"
 
+  get "link" => "links#resolve"
+
   resources :conversations, except: %i(edit update destroy)  do
     resources :messages, only: %i(create)
     delete 'visibility' => 'conversation_visibilities#destroy'
diff --git a/lib/diaspora/entity_finder.rb b/lib/diaspora/entity_finder.rb
new file mode 100644
index 000000000..0bf824382
--- /dev/null
+++ b/lib/diaspora/entity_finder.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module Diaspora
+  class EntityFinder
+    def initialize(type, guid)
+      @type = type
+      @guid = guid
+    end
+
+    def class_name
+      @class_name ||= DiasporaFederation::Entity.entity_class(type).to_s.rpartition("::").last
+    end
+
+    def find
+      Diaspora::Federation::Mappings.model_class_for(class_name).find_by(guid: guid)
+    end
+
+    private
+
+    attr_reader :type, :guid
+  end
+end
diff --git a/spec/controllers/links_controller_spec.rb b/spec/controllers/links_controller_spec.rb
new file mode 100644
index 000000000..841b77cd4
--- /dev/null
+++ b/spec/controllers/links_controller_spec.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+describe LinksController, type: :controller do
+  describe "#resolve" do
+    context "with post" do
+      let(:post) { FactoryGirl.create(:status_message) }
+      let(:link_text) { "#{post.author.diaspora_handle}/post/#{post.guid}" }
+      subject { get :resolve, params: {q: link_query} }
+
+      shared_examples "redirects to the post" do
+        it "redirects to the post" do
+          expect(subject).to redirect_to(post_url(post))
+        end
+      end
+
+      context "with stripped link text" do
+        let(:link_query) { link_text }
+        include_examples "redirects to the post"
+      end
+
+      context "with link text starting with //" do
+        let(:link_query) { "//#{link_text}" }
+        include_examples "redirects to the post"
+      end
+
+      context "with link text starting with diaspora://" do
+        let(:link_query) { "diaspora://#{link_text}" }
+        include_examples "redirects to the post"
+      end
+
+      context "with link text starting with web+diaspora://" do
+        let(:link_query) { "web+diaspora://#{link_text}" }
+        include_examples "redirects to the post"
+      end
+
+      context "when post is non-fetchable" do
+        let(:diaspora_id) { FactoryGirl.create(:person).diaspora_handle }
+        let(:guid) { "1234567890abcdef" }
+        let(:link_query) { "web+diaspora://#{diaspora_id}/post/#{guid}" }
+
+        before do
+          expect(DiasporaFederation::Federation::Fetcher)
+            .to receive(:fetch_public)
+            .with(diaspora_id, "post", guid)
+            .and_raise(DiasporaFederation::Federation::Fetcher::NotFetchable)
+        end
+
+        it "responds 404" do
+          expect { subject }.to raise_error(ActiveRecord::RecordNotFound)
+        end
+      end
+
+      context "when user is non-fetchable" do
+        let(:diaspora_id) { "unknown@pod.tld" }
+        let(:guid) { "1234567890abcdef" }
+        let(:link_query) { "web+diaspora://#{diaspora_id}/post/#{guid}" }
+
+        before do
+          expect(Person)
+            .to receive(:find_or_fetch_by_identifier)
+            .with(diaspora_id)
+            .and_return(nil)
+        end
+
+        it "responds 404" do
+          expect { subject }.to raise_error(ActiveRecord::RecordNotFound)
+        end
+      end
+    end
+  end
+end
diff --git a/spec/services/diaspora_link_service_spec.rb b/spec/services/diaspora_link_service_spec.rb
new file mode 100644
index 000000000..bde411a27
--- /dev/null
+++ b/spec/services/diaspora_link_service_spec.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+describe DiasporaLinkService do
+  let(:service) { described_class.new(link) }
+
+  describe "#find_or_fetch_entity" do
+    context "when entity is known" do
+      let(:post) { FactoryGirl.create(:status_message) }
+      let(:link) { "diaspora://#{post.author.diaspora_handle}/post/#{post.guid}" }
+
+      it "returns the entity" do
+        expect(service.find_or_fetch_entity).to eq(post)
+      end
+    end
+
+    context "when entity is unknown" do
+      let(:remote_person) { FactoryGirl.create(:person) }
+      let(:guid) { "1234567890abcdef" }
+      let(:link) { "diaspora://#{remote_person.diaspora_handle}/post/#{guid}" }
+
+      it "fetches entity" do
+        expect(DiasporaFederation::Federation::Fetcher)
+          .to receive(:fetch_public)
+            .with(remote_person.diaspora_handle, "post", guid) {
+              FactoryGirl.create(:status_message, author: remote_person, guid: guid)
+            }
+
+        entity = service.find_or_fetch_entity
+        expect(entity).to be_a(StatusMessage)
+        expect(entity.guid).to eq(guid)
+        expect(entity.author).to eq(remote_person)
+      end
+
+      it "returns nil when entity is non fetchable" do
+        expect(DiasporaFederation::Federation::Fetcher)
+          .to receive(:fetch_public)
+          .with(remote_person.diaspora_handle, "post", guid)
+          .and_raise(DiasporaFederation::Federation::Fetcher::NotFetchable)
+
+        expect(service.find_or_fetch_entity).to be_nil
+      end
+    end
+  end
+end

From 80dfdcd6afb600b400c7bccd427918658feebdf3 Mon Sep 17 00:00:00 2001
From: cmrd Senya <senya@riseup.net>
Date: Mon, 11 Jun 2018 18:21:57 +0300
Subject: [PATCH 3/4] Add web+diaspora:// links handler installation

---
 app/assets/javascripts/main.js             |  1 +
 app/assets/javascripts/protocol-handler.js | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 app/assets/javascripts/protocol-handler.js

diff --git a/app/assets/javascripts/main.js b/app/assets/javascripts/main.js
index 8c139dc40..563bbc315 100644
--- a/app/assets/javascripts/main.js
+++ b/app/assets/javascripts/main.js
@@ -46,3 +46,4 @@
 //= require bootstrap-markdown/bootstrap-markdown
 //= require helpers/markdown_editor
 //= require jquery.are-you-sure
+//= require protocol-handler
diff --git a/app/assets/javascripts/protocol-handler.js b/app/assets/javascripts/protocol-handler.js
new file mode 100644
index 000000000..6afedf409
--- /dev/null
+++ b/app/assets/javascripts/protocol-handler.js
@@ -0,0 +1,17 @@
+// @license magnet:?xt=urn:btih:0b31508aeb0634b347b8270c7bee4d411b5d4109&dn=agpl-3.0.txt AGPL-v3-or-Later
+
+function registerDiasporaLinksProtocol() {
+  var protocol = location.protocol;
+  var slashes = protocol.concat("//");
+  var host = slashes.concat(window.location.hostname);
+
+  if (location.port) {
+    host = host.concat(":" + location.port);
+  }
+
+  window.navigator.registerProtocolHandler("web+diaspora", host.concat("/link?q=%s"), document.title);
+}
+
+if (typeof (window.navigator.registerProtocolHandler) === "function") {
+  registerDiasporaLinksProtocol();
+}

From a7cc0645e08b18aed2af9b091387794637046613 Mon Sep 17 00:00:00 2001
From: cmrd Senya <senya@riseup.net>
Date: Tue, 26 Jun 2018 23:09:20 +0300
Subject: [PATCH 4/4] Cuke for web+diaspora:// link handler

closes #7826
---
 Changelog.md                                    |  1 +
 features/desktop/diaspora_links_resolve.feature | 15 +++++++++++++++
 features/step_definitions/link_steps.rb         |  7 +++++++
 3 files changed, 23 insertions(+)
 create mode 100644 features/desktop/diaspora_links_resolve.feature
 create mode 100644 features/step_definitions/link_steps.rb

diff --git a/Changelog.md b/Changelog.md
index 7160afc43..1f39b07af 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -6,6 +6,7 @@
 * Add compatibility with macOS to `script/configure_bundler` [#7830](https://github.com/diaspora/diaspora/pull/7830)
 
 ## Features
+* Add `web+diaspora://` link handler [#7826](https://github.com/diaspora/diaspora/pull/7826)
 
 # 0.7.6.0
 
diff --git a/features/desktop/diaspora_links_resolve.feature b/features/desktop/diaspora_links_resolve.feature
new file mode 100644
index 000000000..6c615d5d1
--- /dev/null
+++ b/features/desktop/diaspora_links_resolve.feature
@@ -0,0 +1,15 @@
+@javascript
+Feature: (web+)diaspora:// links resolve
+  In order to open diaspora posts on my pod from external websites
+  As a user
+  I want external links to be resolved to local pod paths
+
+  Background:
+    Given following user exists:
+      | username | email             |
+      | Alice    | alice@alice.alice |
+    And "alice@alice.alice" has a public post with text "This is a post accessed by an external link"
+
+  Scenario: Resolving web+diaspora:// link
+    When I open an external link to the first post of "alice@alice.alice"
+    Then I should see "This is a post accessed by an external link"
diff --git a/features/step_definitions/link_steps.rb b/features/step_definitions/link_steps.rb
new file mode 100644
index 000000000..122d20eb7
--- /dev/null
+++ b/features/step_definitions/link_steps.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+When /^I open an external link to the first post of "([^"]*)"$/ do |email|
+  user = User.find_by(email: email)
+  post = user.posts.first
+  visit(link_path(q: "web+diaspora://#{user.diaspora_handle}/post/#{post.guid}"))
+end