Add page_id concept

CHANGELOG.md

@@ -1,6 +1,7 @@
 master
 ===
 
+* Add `page_id` concept. Using the `id` key in frontmatter, proxy or page will set an ID on a resource which can be referenced by `url_for` and `link_to`.
 * Allow looking for `Gemfile` when setting up a project to fail gracefully.
 
 # 4.1.1

middleman-core/features/page-id.feature

@@ -0,0 +1,26 @@
+Feature: Page IDs
+
+  Scenario: link_to works with blocks (erb)
+    Given the Server is running at "page-id-app"
+    When I go to "/index.html"
+    Then I should see "I am: index.html"
+    And I should see "URL1: /fm.html"
+    And I should see "URL2: /2.html"
+    And I should see 'URL3: <a href="/3.html">Hi</a>'
+    And I should see 'URL4: <a href="/overwrites/from-default.html">Sym</a>'
+
+    When I go to "/fm.html"
+    Then I should see "I am: frontmatter"
+
+    When I go to "/1.html"
+    Then I should see "I am: page1"
+    When I go to "/2.html"
+    Then I should see "I am: page2"
+    When I go to "/3.html"
+    Then I should see "I am: page3"
+
+    When I go to "/overwrites/from-default.html"
+    Then I should see "I am: something-else"
+
+    When I go to "/overwrites/from-frontmatter.html"
+    Then I should see "I am: from_frontmatter"

middleman-core/fixtures/page-id-app/config.rb

@@ -0,0 +1,5 @@
+%w(1 2 3).each do |n|
+  proxy "/#{n}.html", "/index.html", id: "page#{n}"
+end
+
+page "/overwrites/*", id: :"something-else"

middleman-core/fixtures/page-id-app/source/fm.html.erb

@@ -0,0 +1,5 @@
+---
+id: frontmatter
+---
+
+I am: <%= current_resource.page_id %>

middleman-core/fixtures/page-id-app/source/index.html.erb

@@ -0,0 +1,6 @@
+I am: <%= current_resource.page_id %>
+
+URL1: <%= url_for "frontmatter" %>
+URL2: <%= url_for "page2" %>
+URL3: <%= link_to "Hi", "page3" %>
+URL4: <%= link_to "Sym", :"something-else" %>

middleman-core/fixtures/page-id-app/source/overwrites/from-default.html.erb

@@ -0,0 +1 @@
+I am: <%= current_resource.page_id %>

middleman-core/fixtures/page-id-app/source/overwrites/from-frontmatter.html.erb

@@ -0,0 +1,5 @@
+---
+id: from_frontmatter
+---
+
+I am: <%= current_resource.page_id %>

middleman-core/lib/middleman-core/core_extensions/routing.rb

@@ -52,10 +52,13 @@ module Middleman
       def page(path, opts={})
         options = opts.dup
 
+        page_data = options.delete(:data) || {}
+        page_data[:id] = options.delete(:id) if options.key?(:id)
+
         # Default layout
         metadata = {
           locals: options.delete(:locals) || {},
-          page: options.delete(:data) || {},
+          page: page_data,
           options: options
         }
 

middleman-core/lib/middleman-core/sitemap/extensions/proxies.rb

@@ -36,10 +36,13 @@ module Middleman
           md = metadata.dup
           should_ignore = md.delete(:ignore)
 
+          page_data = md.delete(:data) || {}
+          page_data[:id] = md.delete(:id) if md.key?(:id)
+
           r = ProxyResource.new(app.sitemap, path, target)
           r.add_metadata(
             locals: md.delete(:locals) || {},
-            page: md.delete(:data) || {},
+            page: page_data || {},
             options: md
           )
 

middleman-core/lib/middleman-core/sitemap/resource.rb

@@ -85,6 +85,11 @@ module Middleman
         file_descriptor && file_descriptor[:full_path].to_s
       end
 
+      Contract Or[Symbol, String]
+      def page_id
+        metadata[:page][:id] || destination_path
+      end
+
       # Merge in new metadata specific to this resource.
       # @param [Hash] meta A metadata block with keys :options, :locals, :page.
       #   Options are generally rendering/sitemap options

middleman-core/lib/middleman-core/sitemap/store.rb

@@ -149,6 +149,17 @@ module Middleman
         end
       end
 
+      # Find a resource given its page id
+      # @param [String] page_id The page id.
+      # @return [Middleman::Sitemap::Resource]
+      Contract Or[String, Symbol] => Maybe[IsA['Middleman::Sitemap::Resource']]
+      def find_resource_by_page_id(page_id)
+        @lock.synchronize do
+          ensure_resource_list_updated!
+          @_lookup_by_page_id[page_id.to_sym]
+        end
+      end
+
       # Get the array of all resources
       # @param [Boolean] include_ignored Whether to include ignored resources
       # @return [Array<Middleman::Sitemap::Resource>]
@@ -220,6 +231,7 @@ module Middleman
                 @resources.each do |resource|
                   @_lookup_by_path[resource.path] = resource
                   @_lookup_by_destination_path[resource.destination_path] = resource
+                  @_lookup_by_page_id[resource.page_id.to_sym] = resource
                 end
 
                 invalidate_resources_not_ignored_cache!
@@ -239,6 +251,7 @@ module Middleman
         @lock.synchronize do
           @_lookup_by_path = {}
           @_lookup_by_destination_path = {}
+          @_lookup_by_page_id = {}
         end
       end
 

middleman-core/lib/middleman-core/util/paths.rb

@@ -99,8 +99,13 @@ module Middleman
     # Given a source path (referenced either absolutely or relatively)
     # or a Resource, this will produce the nice URL configured for that
     # path, respecting :relative_links, directory indexes, etc.
-    Contract ::Middleman::Application, Or[String, ::Middleman::Sitemap::Resource], Hash => String
+    Contract ::Middleman::Application, Or[String, Symbol, ::Middleman::Sitemap::Resource], Hash => String
     def url_for(app, path_or_resource, options={})
+      if path_or_resource.is_a?(String) || path_or_resource.is_a?(Symbol)
+        r = app.sitemap.find_resource_by_page_id(path_or_resource)
+        path_or_resource = r if r
+      end
+
       # Handle Resources and other things which define their own url method
       url = if path_or_resource.respond_to?(:url)
         path_or_resource.url