diff --git a/src/launchpad.cpp b/src/launchpad.cpp
index 1eaaaa8..8b0ff4c 100644
--- a/src/launchpad.cpp
+++ b/src/launchpad.cpp
@@ -211,14 +211,14 @@ bool launchpad::is_authenticated() const {
 std::string launchpad::build_full_url(const std::string& endpoint) const {
     if (endpoint.rfind("http", 0) == 0) {
         return endpoint;
-    } else if (endpoint != "") {
+    } else if (!endpoint.empty()) {
         return service_root + "/" + api_version + "/" + endpoint;
     }
     std::cerr << "Internal error: endpoint is empty" << std::endl;
     return "";
 }
 
-std::optional<std::string> launchpad::api_get(const std::string& endpoint, const std::map<std::string, std::string>& params) const {
+std::optional<std::string> launchpad::api_get(const std::string endpoint, const std::map<std::string, std::string> params) const {
     std::string url = build_full_url(endpoint);
     if (url.empty()) {
         if (!params.empty()) {
@@ -296,10 +296,10 @@ std::optional<std::string> launchpad::api_get(const std::string& endpoint, const
 }
 
 std::optional<std::string> launchpad::api_post(
-    const std::string& endpoint,
-    const std::map<std::string, std::string>& params,
+    const std::string endpoint,
+    const std::map<std::string, std::string> params,
     bool build_endpoint,
-    const std::string& token_secret_override
+    const std::string token_secret_override
 ) {
     if (endpoint.empty()) {
         if (!params.empty()) {
diff --git a/src/launchpad.h b/src/launchpad.h
index 8791b6c..d842633 100644
--- a/src/launchpad.h
+++ b/src/launchpad.h
@@ -69,11 +69,11 @@ public:
     // API Methods
     std::optional<archive> get_archive(const std::string& distribution_name);
 
-    std::optional<std::string> api_get(const std::string& endpoint = "", const std::map<std::string, std::string>& params = {}) const;
-    std::optional<std::string> api_post(const std::string& endpoint = "",
-                                        const std::map<std::string, std::string>& params = {},
+    std::optional<std::string> api_get(const std::string endpoint = "", const std::map<std::string, std::string> params = {}) const;
+    std::optional<std::string> api_post(const std::string endpoint = "",
+                                        const std::map<std::string, std::string> params = {},
                                         bool build_endpoint = true,
-                                        const std::string& token_secret_override = "");
+                                        const std::string token_secret_override = "");
     std::optional<std::string> api_patch(const std::string& endpoint = "", const nlohmann::json& data = nlohmann::json{});
     std::optional<std::string> api_delete(const std::string& endpoint = "");
 
diff --git a/src/source_package_publishing_history.cpp b/src/source_package_publishing_history.cpp
index 3171e2a..5cc2023 100644
--- a/src/source_package_publishing_history.cpp
+++ b/src/source_package_publishing_history.cpp
@@ -82,6 +82,7 @@ void source_package_publishing_history::set_lp(launchpad* lp_ptr) {
 }
 
 const std::optional<class distro_series> source_package_publishing_history::getDistroSeries() {
+    if (distro_series_link.empty()) return std::nullopt;
     auto response = lp->api_get(distro_series_link);
     if (!response) return std::nullopt;
     auto data = nlohmann::json::parse(response.value());