Serialization-deserialization with Apache Thrift in nodejs - node.js

Question

I am working on a Node.js application and I need to serialize and deserialize instances of the structs defined in an .thrift file, like the following:
struct Notification {
1: string subject,
2: string message
}
Now this is easy doable in Java, according to the tutorial at http://www.gettingcirrius.com/2011/03/rabbitmq-with-thrift-serialization.html :
Notification notification = new Notification();
TDeserializer deserializer = new TDeserializer();
deserializer.deserialize(notification, serializedNotification);
System.out.println("Received "+ notification.toString());
But I can't find how this is done using the nodejs library of Thrift. Can anyone help, please?

Answer 1

Ok, after wasting a lot of time on research and trying different solutions, I finally came to the answer to my own question:
//SERIALIZATION:
var buffer = new Buffer(notification);
var transport = new thrift.TFramedTransport(buffer);
var binaryProt = new thrift.TBinaryProtocol(transport);
notification.write(binaryProt);
where notification is the object I wish to serialize. At this point, the byte array can be found in the transport.outBuffers field:
var byteArray = transport.outBuffers;
For deserialization:
var tTransport = new thrift.TFramedTransport(byteArray);
var tProtocol = new thrift.TBinaryProtocol(tTransport);
var receivedNotif = new notification_type.Notification();
receivedNotif.read(tProtocol);
Assuming that the following lines have been added to the index.js file from the nodejs library for thrift:
exports.TFramedTransport = require('./transport').TFramedTransport;
exports.TBufferedTransport = require('./transport').TBufferedTransport;
exports.TBinaryProtocol = require('./protocol').TBinaryProtocol;

Answer 2

Here is my TypeScript version which runs in a browser. npm install buffer before use.
It should work on node if you remove import { Buffer }.
/*
Thrift serializer for browser and node.js
Author: Hirano Satoshi
Usage:
let byteArray = thriftSerialize(thriftObj);
let thriftObj2 = thriftDeserialize(byteArray, new ThriftClass())
let mayBeTrue = byteArrayCompare(byteArray, thriftSerialize(thriftObj2))
*/
import { TBufferedTransport, TFramedTransport, TJSONProtocol, TBinaryProtocol } from 'thrift';
import { Buffer } from 'buffer';
export function thriftSerialize(thriftObj: any): Buffer {
let transport = new TBufferedTransport(null);
let protocol = new TBinaryProtocol(transport);
thriftObj.write(protocol);
// copy array of array into byteArray
let source = transport.outBuffers;
var byteArrayLen = 0;
for (var i = 0, len = source.length; i < len; i++)
byteArrayLen += source[i].length;
let byteArray = new Buffer(byteArrayLen);
for (var i = 0, len = source.length, pos = 0; i < len; i++) {
let chunk = source[i];
chunk.copy(byteArray, pos);
pos += chunk.length;
}
return byteArray;
}
export function thriftDeserialize(byteArray: Buffer, thriftObj: any): any {
let transport = new TBufferedTransport(byteArray);
let callback = (transport_with_data) => {
var proto = new TBinaryProtocol(transport_with_data);
// var proto = new TJSONProtocol(transport);
thriftObj.read(proto);
}
// var buf = new Buffer(byteArray);
TBufferedTransport.receiver(callback)(byteArray);
return thriftObj;
}
export function byteArrayCompare(array1, array2): boolean {
if (!array1 || !array2)
return false;
let val = array1.length === array2.length && array1.every((value, index) => value === array2[index])
return val;
}

Answer 3

Somehow i did not find the the byte array at:
transport.outBuffers
i needed to do the following:
var transport = new Thrift.TFramedTransport(null, function(bytes){
dataWrapper.out = bytes;
cb(dataWrapper)
})
var binaryProt = new Thrift.TCompactProtocol(transport);
notification.write(binaryProt) ;
transport.flush() ; //important without the flush the transport callback will not be invoked