Use JSON over strings as payload format

backend/src/Model/Base64Message.ts

@@ -0,0 +1,27 @@
+import { Base64 } from 'js-base64'
+
+export class Base64Message {
+  private base64Message: string
+  public length: number
+
+  private constructor(base64Str: string) {
+    this.base64Message = base64Str
+    this.length = base64Str.length
+  }
+
+  public static toUnicodeString(message: Base64Message) {
+    return Base64.decode(message.base64Message)
+  }
+
+  public static fromBuffer(buffer: Buffer) {
+    return new Base64Message(buffer.toString('base64'))
+  }
+
+  public static fromString(str: string) {
+    return new Base64Message(Base64.encode(str))
+  }
+
+  public static toDataUri(message: Base64Message, mimeType: string) {
+    return `data:${mimeType};base64,${message.base64Message}`
+  }
+}