headplane/server/streams.mjs
2025-01-06 08:19:40 +05:30

124 lines
2.6 KiB
JavaScript

// https://github.com/remix-run/react-router/blob/main/packages/react-router-node/stream.ts#L4
export async function writeReadableStreamToWritable(stream, writable) {
let reader = stream.getReader();
let flushable = writable;
try {
while (true) {
let { done, value } = await reader.read();
if (done) {
writable.end();
break;
}
writable.write(value);
if (typeof flushable.flush === 'function') {
flushable.flush();
}
}
} catch (error) {
writable.destroy(error);
throw error;
}
}
// https://github.com/remix-run/react-router/blob/08e4f2fd399543cab776f4be8a29181093a3702c/packages/react-router-node/stream.ts#L66
export const createReadableStreamFromReadable = (source) => {
let pump = new StreamPump(source);
let stream = new ReadableStream(pump, pump);
return stream;
};
class StreamPump {
highWaterMark;
accumalatedSize;
stream;
controller;
constructor(stream) {
this.highWaterMark =
stream.readableHighWaterMark ||
new Stream.Readable().readableHighWaterMark;
this.accumalatedSize = 0;
this.stream = stream;
this.enqueue = this.enqueue.bind(this);
this.error = this.error.bind(this);
this.close = this.close.bind(this);
}
size(chunk) {
return chunk?.byteLength || 0;
}
start(controller) {
this.controller = controller;
this.stream.on('data', this.enqueue);
this.stream.once('error', this.error);
this.stream.once('end', this.close);
this.stream.once('close', this.close);
}
pull() {
this.resume();
}
cancel(reason) {
if (this.stream.destroy) {
this.stream.destroy(reason);
}
this.stream.off('data', this.enqueue);
this.stream.off('error', this.error);
this.stream.off('end', this.close);
this.stream.off('close', this.close);
}
enqueue(chunk) {
if (this.controller) {
try {
let bytes = chunk instanceof Uint8Array ? chunk : Buffer.from(chunk);
let available = (this.controller.desiredSize || 0) - bytes.byteLength;
this.controller.enqueue(bytes);
if (available <= 0) {
this.pause();
}
} catch (error) {
this.controller.error(
new Error(
'Could not create Buffer, chunk must be of type string or an instance of Buffer, ArrayBuffer, or Array or an Array-like Object',
),
);
this.cancel();
}
}
}
pause() {
if (this.stream.pause) {
this.stream.pause();
}
}
resume() {
if (this.stream.readable && this.stream.resume) {
this.stream.resume();
}
}
close() {
if (this.controller) {
this.controller.close();
delete this.controller;
}
}
error(error) {
if (this.controller) {
this.controller.error(error);
delete this.controller;
}
}
}