include canonical link in meta tags

build.py

@@ -52,11 +52,17 @@ for markdown_filename in glob.glob(os.path.join(input_directory, '*.md')):
   if markdown_filename == os.path.join(input_directory, 'index.md'):
     title = 'Colin McMillen'
 
+  out_filename = os.path.basename(markdown_filename).replace('.md', '.html')
+
   html = markdown.markdown(text, extensions=md_extensions, output_format='html5')
   output = template.replace('__TITLE_GOES_HERE__', title)
   output = output.replace('__CONTENT_GOES_HERE__', html)
 
-  out_filename = os.path.basename(markdown_filename).replace('.md', '.html')
+  page_url = out_filename
+  if page_url.endswith('index.html'):  # strip off index.html
+    page_url = page_url[:-len('index.html')]
+  output = output.replace('__PAGE_URL_GOES_HERE__', page_url)
+
   out_filenames.append(out_filename)
   out_fullpath = os.path.join(output_directory, out_filename)
   print_file(markdown_filename, out_fullpath)

template.html

@@ -13,6 +13,7 @@
 <link rel="stylesheet" href="/pygments.css">
 <link rel="stylesheet" href="/style.css">
 <link rel="icon" type="image/png" href="/favicon-32.png">
+<link rel="canonical" href="https://www.mcmillen.dev/__PAGE_URL_GOES_HERE__">
 <!-- TODO: add apple touch icon, maybe other favicon sizes -->
 </head>