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.
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.
// 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();// 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<MyBSONEventsHandler>(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