Cleaned up InternalServer::handle_suggest()

As a result of this clean-up the /suggest endpoint too stopped
generating confusing 404 Not Found errors (which, like in /meta's case
is not that important). Another functional change is that the "term"
parameter became optional.

src/server/internalServer.cpp

@@ -440,38 +440,26 @@ std::unique_ptr<Response> InternalServer::handle_suggest(const RequestContext& r
     printf("** running handle_suggest\n");
   }
 
-  std::string content;
-  std::string mimeType;
-
   std::string bookName;
-  std::string bookId;
-  std::string queryString;
   std::shared_ptr<zim::Archive> archive;
   try {
     bookName = request.get_argument("content");
-    bookId = mp_nameMapper->getIdForName(bookName);
+    const std::string bookId = mp_nameMapper->getIdForName(bookName);
-    queryString = request.get_argument("term");
     archive = mp_library->getArchiveById(bookId);
   } catch (const std::out_of_range&) {
-    return Response::build_404(*this, "", bookName, "");
+    // error handled by the archive == nullptr check below
-  }
-
-  auto start = 0;
-  try {
-    start = request.get_argument<unsigned int>("start");
-  } catch (const std::exception&) {}
-
-  unsigned int count = 10;
-  try {
-    count = request.get_argument<unsigned int>("count");
-  } catch (const std::exception&) {}
-
-  if (count == 0) {
-    count = 10;
   }
 
   if (archive == nullptr) {
-    return Response::build_404(*this, "", bookName, "");
+    const std::string error_details = "No such book: " + bookName;
+    return Response::build_404(*this, "", bookName, "", error_details);
+  }
+
+  const auto queryString = request.get_optional_param("term", std::string());
+  const auto start = request.get_optional_param<unsigned int>("start", 0);
+  unsigned int count = request.get_optional_param<unsigned int>("count", 10);
+  if (count == 0) {
+    count = 10;
   }
 
   if (m_verbose.load()) {

test/server.cpp

@@ -179,6 +179,7 @@ const ResourceCollection resources200Compressible{
 
   { NO_ETAG,   "/search?content=zimfile&pattern=a" },
 
+  { NO_ETAG,   "/suggest?content=zimfile" },
   { NO_ETAG,   "/suggest?content=zimfile&term=ray" },
 
   { NO_ETAG,   "/catch/external?source=www.example.com" },
@@ -282,7 +283,6 @@ const char* urls404[] = {
   "/random?content=non-existent-book",
   "/search",
   "/suggest",
-  "/suggest?content=zimfile",
   "/suggest?content=non-existent-book&term=abcd",
   "/catch/external",
   "/zimfile/A/non-existent-article",