Implement parsing browser requests and sending errors (#9)

response/response.go

@@ -0,0 +1,65 @@
+package response
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/json"
+	"os"
+
+	"github.com/browserpass/browserpass-native/errors"
+	"github.com/browserpass/browserpass-native/version"
+	log "github.com/sirupsen/logrus"
+)
+
+type okResponse struct {
+	Status  string      `json:"status"`
+	Version int         `json:"version"`
+	Data    interface{} `json:"data"`
+}
+
+type errorResponse struct {
+	Status  string      `json:"status"`
+	Code    errors.Code `json:"code"`
+	Version int         `json:"version"`
+	Params  interface{} `json:"params"`
+}
+
+// SendError sends an error response to the browser extension in the predefined json format
+func SendError(errorCode errors.Code, errorMsg string, extraParams *map[string]string) {
+	params := map[string]string{
+		"message": errorMsg,
+	}
+	if extraParams != nil {
+		for key, value := range *extraParams {
+			params[key] = value
+		}
+	}
+	send(&errorResponse{
+		Status:  "error",
+		Code:    errorCode,
+		Version: version.Code,
+		Params:  params,
+	})
+}
+
+func send(data interface{}) {
+	switch data.(type) {
+	case *okResponse:
+	case *errorResponse:
+		break
+	default:
+		log.Fatalf("Only data of type OkResponse and ErrorResponse is allowed to be sent to the browser extension, attempted to send: %+v", data)
+	}
+
+	var bytesBuffer bytes.Buffer
+	if err := json.NewEncoder(&bytesBuffer).Encode(data); err != nil {
+		log.Fatal("Unable to encode data for sending: ", err)
+	}
+
+	if err := binary.Write(os.Stdout, binary.LittleEndian, uint32(bytesBuffer.Len())); err != nil {
+		log.Fatal("Unable to send the length of the response data: ", err)
+	}
+	if _, err := bytesBuffer.WriteTo(os.Stdout); err != nil {
+		log.Fatal("Unable to send the response data: ", err)
+	}
+}