Applied cache-id to search_results.css

The story of search_results.css

static/skin/search_results.css was extracted from
static/templates/no_search_result.html before the latter was dropped.

static/templates/no_search_result.html in turn seems to be a copied and
edited version of static/templates/search_result.html.

In the context of exploratory work on the internationalization of
kiwix-serve (PR #679) I noticed duplication of inline CSS across those
two templates and intended to eliminated it. That goal was not fully
accomplished (static/templates/search_result.html remained untouched)
because by that time PR #679 grew too big and the efforts were diverted
into splitting it into smaller ones. Thus search_results.css slipped
into one of those small PRs, without making much sense because nothing
really justifies preserving custom CSS in the "Fulltext search unavailable"
error page.

At the same time, it served as the only case where a link to a cacheable
resource is generated in C++ code (rather than found in a template).
This poses certain problems to the handling of cache-ids. A workaround
is to expel the URL into a template so that it is processed by
`kiwix-resources`. This commit merely demonstrates that solution. But
whether it should be preserved (or rather the "Fulltext search
unavailable" page should be deprived of CSS) is questionable.

scripts/kiwix-resources

@@ -43,7 +43,7 @@ def fill_resource_revisions(resource_file_path):
     for resource in read_resource_file(resource_file_path):
         resource_revisions[resource] = get_resource_revision(base_dir, resource)
 
-RESOURCE_WITH_CACHEID_URL_PATTERN=r'"([^"?]+)\?KIWIXCACHEID([^"]*)"'
+RESOURCE_WITH_CACHEID_URL_PATTERN=r'([^"?]+)\?KIWIXCACHEID([^"]*)'
 
 def set_cacheid(resource_matchobj):
     path = resource_matchobj.group(1)
@@ -53,7 +53,7 @@ def set_cacheid(resource_matchobj):
         resource = resource[len(root_prefix):]
     extra_query = resource_matchobj.group(2)
     cacheid = 'cacheid=' + resource_revisions[resource]
-    return f'"{path}?{cacheid}{extra_query}"'
+    return f'{path}?{cacheid}{extra_query}'
 
 def preprocess_line(line):
     if 'KIWIXCACHEID' in line:

src/server/internalServer.cpp

@@ -442,6 +442,16 @@ SuggestionsList_t getSuggestions(SuggestionSearcherCache& cache, const zim::Arch
 namespace
 {
 
+std::string renderUrl(const std::string& root, const std::string& urlTemplate)
+{
+  MustacheData data;
+  data.set("root", root);
+  auto url = kainjow::mustache::mustache(urlTemplate).render(data);
+  if ( url.back() == '\n' )
+    url.pop_back();
+  return url;
+}
+
 std::string makeFulltextSearchSuggestion(const std::string& lang, const std::string& queryString)
 {
   return i18n::expandParameterizedString(lang, "suggest-full-text-search",
@@ -622,10 +632,11 @@ std::unique_ptr<Response> InternalServer::handle_search(const RequestContext& re
     } catch(std::runtime_error& e) {
       // Searcher->search will throw a runtime error if there is no valid xapian database to do the search.
       // (in case of zim file not containing a index)
+      const auto cssUrl = renderUrl(m_root, RESOURCE::templates::url_of_search_results_css);
       return HTTPErrorHtmlResponse(*this, request, MHD_HTTP_NOT_FOUND,
                                    "fulltext-search-unavailable",
                                    "404-page-heading",
-                                   m_root + "/skin/search_results.css")
+                                   cssUrl)
            + nonParameterizedMessage("no-search-results")
            + TaskbarInfo(searchInfo.bookName, archive.get());
     }

static/resources_list.txt

@@ -47,5 +47,6 @@ templates/catalog_v2_entries.xml
 templates/catalog_v2_entry.xml
 templates/catalog_v2_categories.xml
 templates/catalog_v2_languages.xml
+templates/url_of_search_results_css
 opensearchdescription.xml
 catalog_v2_searchdescription.xml

static/templates/url_of_search_results_css

@@ -0,0 +1 @@
+{{root}}/skin/search_results.css?KIWIXCACHEID

test/server.cpp

@@ -345,7 +345,7 @@ R"EXPECTEDRESULT(<link type="root" href="/ROOT"><link type="text/css" href="/ROO
       // Searching in a ZIM file without a full-text index returns
       // a page rendered from static/templates/no_search_result_html
       /* url */ "/ROOT/search?content=poor&pattern=whatever",
-R"EXPECTEDRESULT(    <link type="text/css" href="/ROOT/skin/search_results.css" rel="Stylesheet" />
+R"EXPECTEDRESULT(    <link type="text/css" href="/ROOT/skin/search_results.css?cacheid=76d39c84" rel="Stylesheet" />
   <link type="root" href="/ROOT"><link type="text/css" href="/ROOT/skin/jquery-ui/jquery-ui.min.css?cacheid=e1de77b3" rel="Stylesheet" />
 <link type="text/css" href="/ROOT/skin/jquery-ui/jquery-ui.theme.min.css?cacheid=2a5841f9" rel="Stylesheet" />
 <link type="text/css" href="/ROOT/skin/taskbar.css?cacheid=49365e9c" rel="Stylesheet" />
@@ -847,7 +847,7 @@ TEST_F(ServerTest, 404WithBodyTesting)
 
     { /* url */ "/ROOT/search?content=poor&pattern=whatever",
       expected_page_title=="Fulltext search unavailable" &&
-      expected_css_url=="/ROOT/skin/search_results.css" &&
+      expected_css_url=="/ROOT/skin/search_results.css?cacheid=76d39c84" &&
       book_name=="poor" &&
       book_title=="poor" &&
       expected_body==R"(