https://github.com/nearprotocol/assemblyscript-bson

BSON encoder / decoder for AssemblyScript
https://github.com/nearprotocol/assemblyscript-bson

assemblyscript bson webassembly

Last synced: 3 months ago
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BSON encoder / decoder for AssemblyScript

• Host: GitHub
• URL: https://github.com/nearprotocol/assemblyscript-bson
• Owner: nearprotocol
• License: mit
• Created: 2018-12-01T01:44:45.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2021-02-11T16:28:27.000Z (over 3 years ago)
• Last Synced: 2024-01-18T07:19:43.251Z (6 months ago)
• Topics: assemblyscript, bson, webassembly
• Language: TypeScript
• Homepage: https://nearprotocol.com
• Size: 77.1 KB
• Stars: 33
• Watchers: 4
• Forks: 0
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Lists

• awesome-assemblyscript - nearprotocol/assemblyscript-bson - BSON implementation (unmaintained) (Packages)

README

        
# assemblyscript-bson

BSON encoder / decoder for AssemblyScript somewhat based on https://github.com/mpaland/bsonfy.

Special thanks to https://github.com/MaxGraey/bignum.wasm for basic unit testing infra for AssemblyScript.

# Limitations

This is developed for use in smart contracts written in AssemblyScript for https://github.com/nearprotocol/nearcore.

This imposes such limitations:

- Only limited data types are supported:

    - arrays

    - objects

    - 32-bit integers

    - strings

    - booleans

    - null

    - `Uint8Array`

- We assume that memory never needs to be deallocated (cause these contracts are short-lived).

Note that this mostly just defines the way it's currently implemented. Contributors are welcome to fix limitations.

# Usage

## Encoding BSON

```ts

// Make sure memory allocator is available

import "allocator/arena";

// Import encoder

import { BSONEncoder } from "path/to/module";

// Create encoder

let encoder = new BSONEncoder();

// Construct necessary object

encoder.pushObject("obj");

encoder.setInteger("int", 10);

encoder.setString("str", "");

encoder.popObject();

// Get serialized data

let bson: Uint8Array = encoder.serialize();

```

## Parsing BSON

```ts

// Make sure memory allocator is available

import "allocator/arena";

// Import decoder

import { BSONDecoder, BSONHandler } from "path/to/module";

// Events need to be received by custom object extending BSONHandler.

// NOTE: All methods are optional to implement.

class MyBSONEventsHandler extends BSONHandler {

    setString(name: string, value: string): void {

        // Handle field

    }

    setBoolean(name: string, value: bool): void {

        // Handle field

    }

    setNull(name: string): void {

        // Handle field

    }

    setInteger(name: string, value: i32): void {

        // Handle field

    }

    setUint8Array(name: string, value: Uint8Array): void {

        // Handle field

    }

    pushArray(name: string): bool {

        // Handle array start

        return true; // true means that nested object needs to be traversed, false otherwise

    }

    popArray(): void {

        // Handle array end

    }

    pushObject(name: string): bool {

        // Handle object start

        return true; // true means that nested object needs to be traversed, false otherwise

    }

    popObject(): void {

        // Handle object end

    }

}

// Create decoder

let decoder = new BSONDecoder(new MyBSONEventsHandler());

// Let's assume BSON data is available in this variable

let bson: Uint8Array = ...;

// Parse BSON

decoder.deserialize(bson); // This will send events to MyBSONEventsHandler

```