53 lines
1.6 KiB
TypeScript
53 lines
1.6 KiB
TypeScript
import * as fs from 'fs';
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import * as http from 'http';
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export default function saveResponse(
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filePath: string,
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resolve: (fileName: string) => void,
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reject: (reason: string) => void,
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response: http.IncomingMessage,
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) {
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//Check that file exists (200 HTTP status code)
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if (response.statusCode !== 200) {
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return reject(`Expected status code 200 but received ${response.statusCode}.`);
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}
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//Remember file size
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const headerLength = Number(response.headers['content-length']);
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const writeStream = fs.createWriteStream(filePath);
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//If we receive a part of the response, write it to disk
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let totalLength = 0;
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const chunkPromises: Array<Promise<void>> = [];
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response.on('data', (chunk: Buffer) => {
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totalLength += chunk.length;
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//Exit early if we received too much data
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if (totalLength > headerLength) {
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return reject(`Expected length ${headerLength} but received at least ${totalLength}.`);
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}
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//Write chunk to disk
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chunkPromises.push(new Promise((writeResolve) => {
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writeStream.write(chunk, () => {
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writeResolve();
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});
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}));
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});
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//If we finished reading response, check for correctness, then return it
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response.on('end', () => {
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//Check that length is correct
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if (totalLength !== headerLength) {
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return reject(`Expected length ${headerLength} but received ${totalLength}.`);
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}
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//wait until everything is written to disk, then return file name
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//TODO: need to automatically delete file once it is no longer used
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//TODO: need to provide methods to seek through file
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Promise.all(chunkPromises).then(() => {
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resolve(filePath);
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});
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});
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}
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