json parsing

backend-assemblyscript/step-2-json-encoding/assembly/response.ts

@@ -0,0 +1,78 @@
+import {JSONEncoder} from "../node_modules/assemblyscript-json/assembly/encoder";
+
+export abstract class Response {
+    serialize(): string {
+        unreachable();
+        return "";
+    };
+}
+
+export class Twit {
+    msg: string;
+    handle: string;
+
+    constructor(msg: string, handle: string) {
+        this.msg = msg;
+        this.handle = handle;
+    }
+}
+
+export class UnknownResponse extends Response {
+    constructor() {
+        super();
+    }
+
+    serialize(): string {
+        let encoder = new JSONEncoder();
+        encoder.pushObject(null);
+        encoder.setString("action", "Unknown");
+        encoder.setString("msg", "cannot handle request");
+        encoder.popObject();
+
+        return encoder.toString();
+    }
+}
+
+export class PostResponse extends Response {
+    numberOfTwits: i32;
+    constructor(numberOfTwits: i32) {
+        super();
+        this.numberOfTwits = numberOfTwits;
+    }
+
+    serialize(): string {
+        let encoder = new JSONEncoder();
+        encoder.pushObject(null);
+        encoder.setString("action", "Post");
+        encoder.setInteger("number_of_twits", this.numberOfTwits);
+        encoder.popObject();
+
+        return encoder.toString();
+    }
+}
+
+export class FetchResponse extends Response {
+    messageList: Array<string>;
+
+    constructor(messageList: Array<string>) {
+        super();
+        this.messageList = messageList;
+    }
+
+    serialize(): string {
+        let encoder = new JSONEncoder();
+        encoder.pushObject(null);
+        encoder.setString("action", "Fetch");
+        encoder.pushArray("msg_list");
+        for (let i = 0; i < this.messageList.length; i++) {
+            let message = this.messageList[i];
+            encoder.pushObject(null);
+            encoder.setString("msg", message);
+            encoder.popObject();
+        }
+        encoder.popArray();
+        encoder.popObject();
+
+        return encoder.toString();
+    }
+}