msgpack

Introduction

MessagePack is a library that provides efficient object serialization. It is like JSON but offers higher efficiency and smaller data size. Currently, MessagePack 3.0 can be used to implement complex int64 encoding.

How to Install

ohpm install @ohos/msgpack

For details, see Installing an OpenHarmony HAR.

How to Use

Encoding and Decoding

import { encode,decode } from "@ohos/msgpack";

// Encode.
let encoded:Uint8Array = encode({ foo: "bar" });
// Decode.
let decodedObject = decode(encoded);

Using Encoder and Decoder

import { Encoder,Decoder } from "@ohos/msgpack";
// Reuse the encoder instance.
let encoder = new Encoder()
// Reuse the decoder instance.
let decoder = new Decoder()
// Encode.
let encoded:Uint8Array = encoder.encode({ foo: "bar" });
// Decode.
let decodedObject = decoder.decode(encoded);
// Decode a complex int64 object.
let data: ESObject =
   {
     ints: [0, Number.MAX_SAFE_INTEGER, Number.MIN_SAFE_INTEGER],
     nums: [Number.NaN, Math.PI, Math.E, Number.POSITIVE_INFINITY, Number.NEGATIVE_INFINITY],
     bigints: [BigInt(0), BigInt(Number.MAX_SAFE_INTEGER) + BigInt(1), BigInt(Number.MIN_SAFE_INTEGER) - BigInt(1)],
   };
// Encode the minimum int64 value.
return BigInt(Number.MIN_SAFE_INTEGER) - BigInt(1);
// Encode and decode a common int64 value.
return BigInt(0);
// Encode the maximum int64 value.
return BigInt(Number.MAX_SAFE_INTEGER) + BigInt(1);

Encoding and Decoding an Array Object

import { encode,decodeMulti } from "@ohos/msgpack";

let items = [
  "foo",
  10,
  {
    name: "bar",
  },
  [1, 2, 3],
];
// Encode the item array.
let encodedItems = items.map((item) => encode(item));
// Create a blank buffer for storing streams.
let encoded = new Uint8Array(encodedItems.reduce((p, c) => p + c.byteLength, 0));
let offset = 0;
// Store the encoded items in the buffer.
for (let encodedItem of encodedItems) {
  encoded.set(encodedItem, offset);
  offset += encodedItem.byteLength;
}
let result: Array<unknown> = [];
// Store the decoded items in the result array.
for (let item of decodeMulti(encoded)) {
  result.push(item);
}
// The value of result is the same as that of items.
expect(result).assertDeepEquals(items);

Directory Structure

|---- msgpackJavaScript  
|     |---- entry  # Sample code
|           |---- Index.ets  # External APIs
			|---- EncodeDecodePage.ets  # Common encoding and decoding
      |---- Encoding64DemoFour.ets # Decoding complex int64 objects
      |---- Encoding64DemoOne.ets # Encoding the minimum int64 value
      |---- Encoding64DemoThree.ets # Encoding and decoding the common int64 value
      |---- Encoding64DemoTwo.ets # Encoding the maximum int64 value
			|---- EncodeDecodeConstructorPage.ets # Using encoder and decoder
			|---- MultiDecodePage.ets # Decoding complex objects
|     |---- library # Library code
|     |---- README_EN.MD  # Brief introduction of the MessagePack library                   

About obfuscation

• Code obfuscation, please seeCode Obfuscation
• If you want the msgpack-javascript library not to be obfuscated during code obfuscation, you need to add corresponding exclusion rules in the obfuscation rule configuration file obfuscation-rules.txt：

-keep
./oh_modules/@ohos/msgpack

Constraints

MessagePack has been verified only in the following version:

• DevEco Studio: 5.0.3.132, SDK: API12 (5.0.0.19)

How to Contribute

If you find any problem during the use, submit an Issue or a PR to us.

License

This project is licensed under ISC License.