createChecksumStream.browser.js•1.59 kB
import { toBase64 } from "@smithy/util-base64";
import { isReadableStream } from "../stream-type-check";
import { ChecksumStream } from "./ChecksumStream.browser";
export const createChecksumStream = ({ expectedChecksum, checksum, source, checksumSourceLocation, base64Encoder, }) => {
if (!isReadableStream(source)) {
throw new Error(`@smithy/util-stream: unsupported source type ${source?.constructor?.name ?? source} in ChecksumStream.`);
}
const encoder = base64Encoder ?? toBase64;
if (typeof TransformStream !== "function") {
throw new Error("@smithy/util-stream: unable to instantiate ChecksumStream because API unavailable: ReadableStream/TransformStream.");
}
const transform = new TransformStream({
start() { },
async transform(chunk, controller) {
checksum.update(chunk);
controller.enqueue(chunk);
},
async flush(controller) {
const digest = await checksum.digest();
const received = encoder(digest);
if (expectedChecksum !== received) {
const error = new Error(`Checksum mismatch: expected "${expectedChecksum}" but received "${received}"` +
` in response header "${checksumSourceLocation}".`);
controller.error(error);
}
else {
controller.terminate();
}
},
});
source.pipeThrough(transform);
const readable = transform.readable;
Object.setPrototypeOf(readable, ChecksumStream.prototype);
return readable;
};