2023-09-06 08:01:41 -07:00

90 lines
3.0 KiB
TypeScript

import * as fs from 'fs'
import * as zlib from 'zlib'
import {promisify} from 'util'
const stat = promisify(fs.stat)
/**
* GZipping certain files that are already compressed will likely not yield further size reductions. Creating large temporary gzip
* files then will just waste a lot of time before ultimately being discarded (especially for very large files).
* If any of these types of files are encountered then on-disk gzip creation will be skipped and the original file will be uploaded as-is
*/
const gzipExemptFileExtensions = [
'.gz', // GZIP
'.gzip', // GZIP
'.tgz', // GZIP
'.taz', // GZIP
'.Z', // COMPRESS
'.taZ', // COMPRESS
'.bz2', // BZIP2
'.tbz', // BZIP2
'.tbz2', // BZIP2
'.tz2', // BZIP2
'.lz', // LZIP
'.lzma', // LZMA
'.tlz', // LZMA
'.lzo', // LZOP
'.xz', // XZ
'.txz', // XZ
'.zst', // ZSTD
'.zstd', // ZSTD
'.tzst', // ZSTD
'.zip', // ZIP
'.7z' // 7ZIP
]
/**
* Creates a Gzip compressed file of an original file at the provided temporary filepath location
* @param {string} originalFilePath filepath of whatever will be compressed. The original file will be unmodified
* @param {string} tempFilePath the location of where the Gzip file will be created
* @returns the size of gzip file that gets created
*/
export async function createGZipFileOnDisk(
originalFilePath: string,
tempFilePath: string
): Promise<number> {
for (const gzipExemptExtension of gzipExemptFileExtensions) {
if (originalFilePath.endsWith(gzipExemptExtension)) {
// return a really large number so that the original file gets uploaded
return Number.MAX_SAFE_INTEGER
}
}
return new Promise((resolve, reject) => {
const inputStream = fs.createReadStream(originalFilePath)
const gzip = zlib.createGzip()
const outputStream = fs.createWriteStream(tempFilePath)
inputStream.pipe(gzip).pipe(outputStream)
outputStream.on('finish', async () => {
// wait for stream to finish before calculating the size which is needed as part of the Content-Length header when starting an upload
const size = (await stat(tempFilePath)).size
resolve(size)
})
outputStream.on('error', error => {
// eslint-disable-next-line no-console
console.log(error)
reject(error)
})
})
}
/**
* Creates a GZip file in memory using a buffer. Should be used for smaller files to reduce disk I/O
* @param originalFilePath the path to the original file that is being GZipped
* @returns a buffer with the GZip file
*/
export async function createGZipFileInBuffer(
originalFilePath: string
): Promise<Buffer> {
return new Promise(async resolve => {
const inputStream = fs.createReadStream(originalFilePath)
const gzip = zlib.createGzip()
inputStream.pipe(gzip)
// read stream into buffer, using experimental async iterators see https://github.com/nodejs/readable-stream/issues/403#issuecomment-479069043
const chunks: Uint8Array[] = []
for await (const chunk of gzip) {
chunks.push(chunk)
}
resolve(Buffer.concat(chunks))
})
}