[cpp-rest-sdk] support serializing std::maps

Author: aminya

modules/openapi-generator/src/main/resources/cpp-rest-sdk-client/apiclient-header.mustache

@@ -59,6 +59,8 @@ public:
     {{/hasModelImport}}
     template<class T>
     static utility::string_t parameterToString(const std::vector<T>& value);
+    template<class T, class U>
+    static utility::string_t parameterToString(const std::map<T, U>& value);
     template<class T>
     static utility::string_t parameterToString(const std::shared_ptr<T>& value);
 
@@ -93,6 +95,19 @@ utility::string_t ApiClient::parameterToString(const std::vector<T>& value)
     return ss.str();
 }
 
+template<class T, class U>
+utility::string_t ApiClient::parameterToString(const std::map<T, U>& value)
+{
+    utility::stringstream_t ss;
+    ss << "{";
+    for(const auto& pair : value)
+    {
+        ss << ApiClient::parameterToString(pair.first) << ": " << ApiClient::parameterToString(pair.second) << ", ";
+    }
+    ss << "}";
+    return ss.str();
+}
+
 template<class T>
 utility::string_t ApiClient::parameterToString(const std::shared_ptr<T>& value)
 {