Add opds image download

lib/OpdsParser/OpdsParser.cpp

@@ -197,6 +197,10 @@ void XMLCALL OpdsParser::startElement(void* userData, const XML_Char* name, cons
             }
             self->currentEntry.acquisitionLinks.push_back(acquisition);
           }
+        } else if (rel && type && strstr(rel, "opds-spec.org/image") != nullptr &&
+                   strstr(rel, "thumbnail") == nullptr && strstr(type, "image/jpeg") != nullptr &&
+                   self->currentEntry.imageHref.empty()) {
+          self->currentEntry.imageHref = href;
         } else if (type && strstr(type, "application/atom+xml") != nullptr) {
           if (self->currentEntry.type != OpdsEntryType::BOOK) {
             self->currentEntry.type = OpdsEntryType::NAVIGATION;

lib/OpdsParser/OpdsParser.h

@@ -31,6 +31,7 @@ struct OpdsEntry {
   std::string href;    // Navigation URL or epub download URL
   std::string id;
   std::vector<OpdsAcquisitionLink> acquisitionLinks;
+  std::string imageHref;  // Cover image URL (rel="http://opds-spec.org/image"), books only
 };
 
 // Legacy alias for backward compatibility