Add support for anchor/context/context_uri

Author: jgarber623

lib/link_header_parser/parsed_header.rb

@@ -10,6 +10,15 @@ def initialize(header, base:)
       @base = base
     end
 
+    # https://tools.ietf.org/html/rfc8288#section-3.2
+    def context
+      @context ||= parameters.anchor || target
+    end
+
+    def context_uri
+      @context_uri ||= Absolutely.to_abs(base: target_uri, relative: context)
+    end
+
     def inspect
       format(%(#<#{self.class.name}:%#0x @header="#{header.gsub('"', '\"')}">), object_id)
     end
@@ -22,10 +31,12 @@ def relation_types
       @relation_types ||= relations&.split(' ') || nil
     end
 
+    # https://tools.ietf.org/html/rfc8288#section-3.3
     def relations
       @relations ||= parameters.rel || nil
     end
 
+    # https://tools.ietf.org/html/rfc8288#section-3.1
     def target
       @target ||= header_match_data[:target]
     end
@@ -40,6 +51,8 @@ def to_h
         target_uri: target_uri,
         relations: relations,
         relation_types: relation_types,
+        context: context,
+        context_uri: context_uri,
         parameters: parameters.to_h
       }
     end

spec/lib/link_header_parser/parsed_header_context_spec.rb

@@ -0,0 +1,11 @@
+describe LinkHeaderParser::ParsedHeader, '#context' do
+  ExampleLinkHeaders::EXAMPLE_LINK_HEADERS_WITH_ANCHORS.each do |header, result|
+    context "when header is #{header}" do
+      subject(:parsed_header) { described_class.new(header, base: 'https://example.com') }
+
+      it 'returns a Hash' do
+        expect(parsed_header.to_h).to include(result)
+      end
+    end
+  end
+end

spec/support/example_link_headers_with_anchors.rb

@@ -0,0 +1,178 @@
+module ExampleLinkHeaders
+  EXAMPLE_LINK_HEADERS_WITH_ANCHORS = [
+    [
+      '<https://example.com>; anchor=#foo',
+      {
+        context: '#foo',
+        context_uri: 'https://example.com/#foo',
+        parameters: {
+          anchor: '#foo'
+        }
+      }
+    ],
+    [
+      '<https://example.com>; anchor="#foo"',
+      {
+        context: '#foo',
+        context_uri: 'https://example.com/#foo',
+        parameters: {
+          anchor: '#foo'
+        }
+      }
+    ],
+    [
+      '</>; anchor=#foo',
+      {
+        context: '#foo',
+        context_uri: 'https://example.com/#foo',
+        parameters: {
+          anchor: '#foo'
+        }
+      }
+    ],
+    [
+      '</>; anchor="#foo"',
+      {
+        context: '#foo',
+        context_uri: 'https://example.com/#foo',
+        parameters: {
+          anchor: '#foo'
+        }
+      }
+    ],
+    [
+      '<https://example.com/foo>; anchor=bar',
+      {
+        context: 'bar',
+        context_uri: 'https://example.com/bar',
+        parameters: {
+          anchor: 'bar'
+        }
+      }
+    ],
+    [
+      '<https://example.com/foo>; anchor="bar"',
+      {
+        context: 'bar',
+        context_uri: 'https://example.com/bar',
+        parameters: {
+          anchor: 'bar'
+        }
+      }
+    ],
+    [
+      '<https://example.com/foo>; anchor=../bar',
+      {
+        context: '../bar',
+        context_uri: 'https://example.com/bar',
+        parameters: {
+          anchor: '../bar'
+        }
+      }
+    ],
+    [
+      '<https://example.com/foo>; anchor="../bar"',
+      {
+        context: '../bar',
+        context_uri: 'https://example.com/bar',
+        parameters: {
+          anchor: '../bar'
+        }
+      }
+    ],
+    [
+      '</>; anchor=bar',
+      {
+        context: 'bar',
+        context_uri: 'https://example.com/bar',
+        parameters: {
+          anchor: 'bar'
+        }
+      }
+    ],
+    [
+      '</>; anchor="bar"',
+      {
+        context: 'bar',
+        context_uri: 'https://example.com/bar',
+        parameters: {
+          anchor: 'bar'
+        }
+      }
+    ],
+    [
+      '</>; anchor=../bar',
+      {
+        context: '../bar',
+        context_uri: 'https://example.com/bar',
+        parameters: {
+          anchor: '../bar'
+        }
+      }
+    ],
+    [
+      '</>; anchor="../bar"',
+      {
+        context: '../bar',
+        context_uri: 'https://example.com/bar',
+        parameters: {
+          anchor: '../bar'
+        }
+      }
+    ],
+    [
+      '<https://example.com>; rel=home; anchor="#foo"',
+      {
+        context: '#foo',
+        context_uri: 'https://example.com/#foo',
+        parameters: {
+          anchor: '#foo',
+          rel: 'home'
+        }
+      }
+    ],
+    [
+      '<https://example.com>; rel="home previous"; anchor=#foo',
+      {
+        context: '#foo',
+        context_uri: 'https://example.com/#foo',
+        parameters: {
+          anchor: '#foo',
+          rel: 'home previous'
+        }
+      }
+    ],
+    [
+      '</foo>; rel=home; anchor="#bar"',
+      {
+        context: '#bar',
+        context_uri: 'https://example.com/foo#bar',
+        parameters: {
+          anchor: '#bar',
+          rel: 'home'
+        }
+      }
+    ],
+    [
+      '</foo>; rel="home previous"; anchor=#bar',
+      {
+        context: '#bar',
+        context_uri: 'https://example.com/foo#bar',
+        parameters: {
+          anchor: '#bar',
+          rel: 'home previous'
+        }
+      }
+    ],
+    [
+      '</>; anchor="https://context.example.com"',
+      {
+        context: 'https://context.example.com',
+        context_uri: 'https://context.example.com/',
+        parameters: {
+          anchor: 'https://context.example.com'
+        }
+      }
+    ]
+  ].freeze
+end