65 lines
2.7 KiB
JavaScript
65 lines
2.7 KiB
JavaScript
import { streamCollector } from "@smithy/fetch-http-handler";
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import { toBase64 } from "@smithy/util-base64";
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import { toHex } from "@smithy/util-hex-encoding";
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import { toUtf8 } from "@smithy/util-utf8";
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import { isReadableStream } from "./stream-type-check";
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const ERR_MSG_STREAM_HAS_BEEN_TRANSFORMED = "The stream has already been transformed.";
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export const sdkStreamMixin = (stream) => {
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if (!isBlobInstance(stream) && !isReadableStream(stream)) {
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const name = stream?.__proto__?.constructor?.name || stream;
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throw new Error(`Unexpected stream implementation, expect Blob or ReadableStream, got ${name}`);
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}
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let transformed = false;
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const transformToByteArray = async () => {
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if (transformed) {
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throw new Error(ERR_MSG_STREAM_HAS_BEEN_TRANSFORMED);
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}
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transformed = true;
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return await streamCollector(stream);
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};
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const blobToWebStream = (blob) => {
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if (typeof blob.stream !== "function") {
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throw new Error("Cannot transform payload Blob to web stream. Please make sure the Blob.stream() is polyfilled.\n" +
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"If you are using React Native, this API is not yet supported, see: https://react-native.canny.io/feature-requests/p/fetch-streaming-body");
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}
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return blob.stream();
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};
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return Object.assign(stream, {
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transformToByteArray: transformToByteArray,
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transformToString: async (encoding) => {
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const buf = await transformToByteArray();
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if (encoding === "base64") {
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return toBase64(buf);
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}
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else if (encoding === "hex") {
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return toHex(buf);
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}
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else if (encoding === undefined || encoding === "utf8" || encoding === "utf-8") {
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return toUtf8(buf);
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}
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else if (typeof TextDecoder === "function") {
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return new TextDecoder(encoding).decode(buf);
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}
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else {
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throw new Error("TextDecoder is not available, please make sure polyfill is provided.");
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}
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},
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transformToWebStream: () => {
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if (transformed) {
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throw new Error(ERR_MSG_STREAM_HAS_BEEN_TRANSFORMED);
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}
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transformed = true;
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if (isBlobInstance(stream)) {
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return blobToWebStream(stream);
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}
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else if (isReadableStream(stream)) {
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return stream;
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}
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else {
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throw new Error(`Cannot transform payload to web stream, got ${stream}`);
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}
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},
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});
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};
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const isBlobInstance = (stream) => typeof Blob === "function" && stream instanceof Blob;
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