@zowe/imperative
Version:
framework for building configurable CLIs
125 lines • 5.11 kB
JavaScript
;
/*
* This program and the accompanying materials are made available under the terms of the
* Eclipse Public License v2.0 which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-v20.html
*
* SPDX-License-Identifier: EPL-2.0
*
* Copyright Contributors to the Zowe Project.
*
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.CompressionUtils = void 0;
const stream_1 = require("stream");
const zlib = require("zlib");
const error_1 = require("../../../error");
const io_1 = require("../../../io");
const Headers_1 = require("./Headers");
class CompressionUtils {
/**
* Decompress a buffer using the specified algorithm.
* @param data Compressed buffer
* @param encoding Value of Content-Encoding header
* @throws {ImperativeError}
*/
static decompressBuffer(data, encoding) {
if (!Headers_1.Headers.CONTENT_ENCODING_TYPES.includes(encoding)) {
throw new error_1.ImperativeError({ msg: `Unsupported content encoding type ${encoding}` });
}
try {
switch (encoding) {
case "br": return zlib.brotliDecompressSync(data);
case "deflate": return zlib.inflateSync(data);
case "gzip": return zlib.gunzipSync(data);
}
}
catch (err) {
throw this.decompressError(err, "buffer", encoding);
}
}
/**
* Add zlib decompression transform to a Writable stream. Any compressed
* data written to the returned stream will be decompressed using the
* specified algorithm.
*
* The returned stream should only be used internally by a REST client to
* write to. Use the original stream to read back the decompressed output
* and handle decompression errors.
* @param responseStream Writable stream that will receive compressed data
* @param encoding Value of Content-Encoding header
* @param normalizeNewLines Specifies if line endings should be converted
* @throws {ImperativeError}
*/
static decompressStream(responseStream, encoding, normalizeNewLines) {
if (!Headers_1.Headers.CONTENT_ENCODING_TYPES.includes(encoding)) {
throw new error_1.ImperativeError({ msg: `Unsupported content encoding type ${encoding}` });
}
try {
// First transform handles decompression
const transforms = [this.zlibTransform(encoding, !normalizeNewLines)];
// Second transform is optional and processes line endings
if (normalizeNewLines) {
transforms.push(this.newLinesTransform());
}
// Chain transforms and response stream together
for (const [i, stream] of transforms.entries()) {
const next = transforms[i + 1] || responseStream;
stream.pipe(next);
stream.on("error", (err) => {
responseStream.emit("error", this.decompressError(err, "stream", encoding));
});
}
// Return first stream in chain
return transforms[0];
}
catch (err) {
throw this.decompressError(err, "stream", encoding);
}
}
/**
* Return ImperativeError populated with details of decompression error
* @param err Thrown error object
* @param source Type of object being decompressed
* @param encoding Value of Content-Encoding header
*/
static decompressError(err, source, encoding) {
return new error_1.ImperativeError({
msg: `Failed to decompress response ${source} with content encoding type ${encoding}`,
additionalDetails: err.message,
causeErrors: err
});
}
/**
* Return a transform to normalize line endings in response text.
*/
static newLinesTransform() {
let lastByteReceived = 0;
return new stream_1.Transform({
transform(chunk, _, callback) {
this.push(io_1.IO.processNewlines(chunk, lastByteReceived));
lastByteReceived = chunk[chunk.byteLength - 1];
callback();
}
});
}
/**
* Return zlib transform for the specified decompression algorithm.
* @param encoding Value of Content-Encoding header
*/
static zlibTransform(encoding, binary) {
const opts = {};
if (binary) {
// Handle binary data that may be truncated or missing the GZIP end of file sequence.
// See https://nodejs.org/api/zlib.html#compressing-http-requests-and-responses
opts.finishFlush = encoding === "br" ? zlib.constants.BROTLI_OPERATION_FLUSH : zlib.constants.Z_SYNC_FLUSH;
}
switch (encoding) {
case "br": return zlib.createBrotliDecompress(opts);
case "deflate": return zlib.createInflate(opts);
case "gzip": return zlib.createGunzip(opts);
}
}
}
exports.CompressionUtils = CompressionUtils;
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