sdk-stream-mixin.js•2.07 kB
import { streamCollector } from "@smithy/node-http-handler";
import { fromArrayBuffer } from "@smithy/util-buffer-from";
import { Readable } from "stream";
import { sdkStreamMixin as sdkStreamMixinReadableStream } from "./sdk-stream-mixin.browser";
const ERR_MSG_STREAM_HAS_BEEN_TRANSFORMED = "The stream has already been transformed.";
export const sdkStreamMixin = (stream) => {
if (!(stream instanceof Readable)) {
try {
return sdkStreamMixinReadableStream(stream);
}
catch (e) {
const name = stream?.__proto__?.constructor?.name || stream;
throw new Error(`Unexpected stream implementation, expect Stream.Readable instance, got ${name}`);
}
}
let transformed = false;
const transformToByteArray = async () => {
if (transformed) {
throw new Error(ERR_MSG_STREAM_HAS_BEEN_TRANSFORMED);
}
transformed = true;
return await streamCollector(stream);
};
return Object.assign(stream, {
transformToByteArray,
transformToString: async (encoding) => {
const buf = await transformToByteArray();
if (encoding === undefined || Buffer.isEncoding(encoding)) {
return fromArrayBuffer(buf.buffer, buf.byteOffset, buf.byteLength).toString(encoding);
}
else {
const decoder = new TextDecoder(encoding);
return decoder.decode(buf);
}
},
transformToWebStream: () => {
if (transformed) {
throw new Error(ERR_MSG_STREAM_HAS_BEEN_TRANSFORMED);
}
if (stream.readableFlowing !== null) {
throw new Error("The stream has been consumed by other callbacks.");
}
if (typeof Readable.toWeb !== "function") {
throw new Error("Readable.toWeb() is not supported. Please ensure a polyfill is available.");
}
transformed = true;
return Readable.toWeb(stream);
},
});
};