Implement parsing browser requests and sending errors (#9)

errors/errors.go

@@ -0,0 +1,26 @@
+package errors
+
+import (
+	"os"
+)
+
+// Code exit code
+type Code int
+
+// Error codes that are sent to the browser extension and used as exit codes in the app.
+// DO NOT MODIFY THE VALUES, always append new error codes to the bottom.
+const (
+	// CodeParseRequestLength error parsing request length
+	CodeParseRequestLength Code = 10
+
+	// CodeParseRequest error parsing request
+	CodeParseRequest Code = 11
+
+	// CodeInvalidRequestAction error parsing request action
+	CodeInvalidRequestAction = 12
+)
+
+// ExitWithCode exit with error code
+func ExitWithCode(code Code) {
+	os.Exit(int(code))
+}