serverless-spy
Version:
CDK-based library for writing elegant integration tests on AWS serverless architecture and an additional web console to monitor events in real time.
63 lines (62 loc) • 2.13 kB
JavaScript
import { Crc32 } from "@aws-crypto/crc32";
import { HeaderMarshaller } from "./HeaderMarshaller";
import { splitMessage } from "./splitMessage";
export class EventStreamCodec {
constructor(toUtf8, fromUtf8) {
this.headerMarshaller = new HeaderMarshaller(toUtf8, fromUtf8);
this.messageBuffer = [];
this.isEndOfStream = false;
}
feed(message) {
this.messageBuffer.push(this.decode(message));
}
endOfStream() {
this.isEndOfStream = true;
}
getMessage() {
const message = this.messageBuffer.pop();
const isEndOfStream = this.isEndOfStream;
return {
getMessage() {
return message;
},
isEndOfStream() {
return isEndOfStream;
},
};
}
getAvailableMessages() {
const messages = this.messageBuffer;
this.messageBuffer = [];
const isEndOfStream = this.isEndOfStream;
return {
getMessages() {
return messages;
},
isEndOfStream() {
return isEndOfStream;
},
};
}
encode({ headers: rawHeaders, body }) {
const headers = this.headerMarshaller.format(rawHeaders);
const length = headers.byteLength + body.byteLength + 16;
const out = new Uint8Array(length);
const view = new DataView(out.buffer, out.byteOffset, out.byteLength);
const checksum = new Crc32();
view.setUint32(0, length, false);
view.setUint32(4, headers.byteLength, false);
view.setUint32(8, checksum.update(out.subarray(0, 8)).digest(), false);
out.set(headers, 12);
out.set(body, headers.byteLength + 12);
view.setUint32(length - 4, checksum.update(out.subarray(8, length - 4)).digest(), false);
return out;
}
decode(message) {
const { headers, body } = splitMessage(message);
return { headers: this.headerMarshaller.parse(headers), body };
}
formatHeaders(rawHeaders) {
return this.headerMarshaller.format(rawHeaders);
}
}