ENH: Add Google Custom Search widget

Fixes #56

Author: kernc

doc/pdoc_template/config.mako

@@ -2,4 +2,9 @@
 
 git_link_template = 'https://github.com/pdoc3/pdoc/blob/{commit}/{path}#L{start_line}-L{end_line}'
 
+search_query = '''
+    site:pdoc3.github.io
+    inurl:github.com/pdoc3
+'''
+
 %>

pdoc/templates/config.mako

@@ -42,6 +42,12 @@
     # tracking id (UA-XXXXXX-Y).
     google_analytics = ''
 
+    # If set, insert Google Custom Search search bar widget above the sidebar index.
+    # The whitespace-separated tokens represent arbitrary extra queries (at least one
+    # must match) passed to regular Google search. Example:
+    #search_query = 'inurl:github.com/USER/PROJECT  site:PROJECT.github.io  site:PROJECT.website'
+    search_query = ''
+
     # If set, render LaTeX math syntax within \(...\) (inline equations),
     # or within \[...\] or $$...$$ or `.. math::` (block equations)
     # as nicely-formatted math formulas using MathJax.

pdoc/templates/html.mako

@@ -285,6 +285,13 @@
 
     <%include file="logo.mako"/>
 
+    % if search_query:
+        <div class="gcse-search" style="height: 70px"
+             data-as_oq="${' '.join(search_query.strip().split()) | h }"
+             data-gaCategoryParameter="${module.refname | h}">
+        </div>
+    % endif
+
     <h1>Index</h1>
     ${extract_toc(module.docstring) if extract_module_toc_into_sidebar else ''}
     <ul id="index">
@@ -384,6 +391,11 @@
     </script><script async src='https://www.google-analytics.com/analytics.js'></script>
   % endif
 
+  % if search_query:
+    <script async src="https://cse.google.com/cse.js?cx=017837193012385208679:pey8ky8gdqw"></script>
+    <style>.gsc-control-cse {padding:0 !important;margin-top:1em}</style>
+  % endif
+
   % if latex_math:
     <script async src='https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.5/latest.js?config=TeX-AMS_CHTML'></script>
   % endif