- fix for issue #3

client.go

@@ -101,6 +101,10 @@ func isSchemeValid(parsed *urllib.URL, config *Config, debugLogFunc func(string)
 
 func isHostValid(parsed *urllib.URL, config *Config, debugLogFunc func(string)) error {
 	host := parsed.Hostname()
+	if host == "" {
+		debugLogFunc("empty host received")
+		return &InvalidHostError{host: ""}
+	}
 
 	if config.AllowedHosts != nil && !isAllowedHost(host, config.AllowedHosts) {
 		debugLogFunc(fmt.Sprintf("disallowed host: %s", host))
@@ -254,6 +258,14 @@ func (e *AllowedSchemeError) Error() string {
 	return fmt.Sprintf("scheme: %v not found in allowlist", e.scheme)
 }
 
+type InvalidHostError struct {
+	host string
+}
+
+func (e *InvalidHostError) Error() string {
+	return fmt.Sprintf("host: %v is not valid", e.host)
+}
+
 type AllowedHostError struct {
 	host string
 }

client_test.go

@@ -437,3 +437,24 @@ func TestInternalIPAreAlwaysBlocked(t *testing.T) {
 	}
 
 }
+
+func TestInvalidHostValidation(t *testing.T) {
+	cfg := GetConfigBuilder().Build()
+	client := Client(cfg)
+
+	urls := []string{"http://[]", "http://[]:123", "http://:123"}
+
+	for _, url := range urls {
+		_, err := client.Get(url)
+		if err == nil {
+			t.Errorf("invalid host from url => %v was accepted. client didn't not return an error", err)
+		}
+
+		err = unwrap(err)
+		_, ok := err.(*InvalidHostError)
+		if !ok {
+			t.Errorf("client returned incorrect error: %v", err)
+		}
+	}
+
+}