Support extracting content based on tags as well as line numbers.

Author: robertwb

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    jekyll_github_sample (0.2.0)
+    jekyll_github_sample (0.3.0)
       activesupport (~> 4.0)
       jekyll (~> 3.0)
 
@@ -76,4 +76,4 @@ DEPENDENCIES
   rspec
 
 BUNDLED WITH
-   1.13.6
+   1.13.7

README.md

@@ -5,7 +5,7 @@ Two Jekyll Liquid tags to display a code sample from a file in a public Github r
 
 # Install
 
-- First add the gem to your `Gemfile` 
+- First add the gem to your `Gemfile`
 ```
 gem 'jekyll_github_sample'
 ```
@@ -30,6 +30,16 @@ A [write up](https://bwillis.github.io/2014/05/28/include-github-repo-code-in-je
  * START_LINE_NUMBER - (optional) number that is the first line to include (0 based)
  * END_LINE_NUMBER - (optional) number that is the last line to include, if excluded will read to end of file
 
+One can also specify the lines to include based on markings in the file itself.
+This is done by invoking
+
+```
+{% github_sample URL_WITH_USERNAME_REPO_AND_FILE tag:TAG_NAME %}
+```
+
+and placing the strings `[START TAG_NAME]` and `[END TAG_NAME]` anywhere in the lines immediately before and after the content you wish to include.
+
+
 # github_sample_ref Usage
 ```
 {% github_sample_ref URL_WITH_USERNAME_REPO_AND_FILE %}

lib/jekyll_github_sample/code_tag.rb

@@ -11,15 +11,19 @@ class CodeTag < ::Liquid::Tag
     def initialize(tag_name, params, tokens)
       github_file_path, @line_start, @line_end = params.split
       @github_file                             = FileHelper.new(github_file_path)
-      @line_start, @line_end                   = determine_line_numbers(@line_start, @line_end)
       super
     end
 
     def render(context)
       all_lines = cache.fetch(@github_file.raw_uri) do
         open(@github_file.raw_uri).readlines
       end
-      lines     = all_lines[@line_start..@line_end]
+      if @line_start.respond_to?(:match) and tag_match = @line_start.match(/^tag:(.*)/)
+        lines     = extract_tagged_lines(all_lines, tag_match[1])
+      else
+        @line_start, @line_ends     = determine_line_numbers(@line_start, @line_end)
+        lines     = all_lines[@line_start..@line_end]
+      end
       lines     = remove_common_indentation(lines)
       lines.join
     end

lib/jekyll_github_sample/text_utils.rb

@@ -18,5 +18,24 @@ def remove_common_indentation(lines)
         line.length == 1 ? line : line[leading_spaces.min..-1]
       end
     end
+
+    def extract_tagged_lines(lines, tag)
+      start_tag = "[START #{tag}]"
+      end_tag = "[END #{tag}]"
+      tagged_lines = []
+      in_tagged_content = false
+      lines.each do |line|
+        if in_tagged_content
+          if line.include? end_tag
+            in_tagged_content = false
+          else
+            tagged_lines << line
+          end
+        else
+          in_tagged_content = line.include? start_tag
+        end
+      end
+      tagged_lines
+    end
   end
 end

lib/jekyll_github_sample/version.rb

@@ -1,3 +1,3 @@
 module JekyllGithubSample
-  VERSION = '0.2.0'
+  VERSION = '0.3.0'
 end

spec/lib/jekyll_github_sample/text_utils_spec.rb

@@ -33,4 +33,24 @@
     end
   end
 
-end
+  context '#extract_tagged_lines' do
+    let(:lines) { [
+        'header',
+        '[START tag]',
+        'content 1',
+        'content 2',
+        '[END tag]',
+        'footer 1',
+        'footer 2'
+    ] }
+    subject { text_utils.extract_tagged_lines(lines, 'tag') }
+
+    it 'extracts content' do
+      should =~ [
+        'content 1',
+        'content 2'
+      ]
+    end
+  end
+
+end