download <title> of a url with minimal data usage - node.js

Question

For the purpose of generating links to another websites I need to download content of tag.
But I would like to use as minimal bandwidth as possible.
In some hardcore variant, to process input stream and close the connection when reached.
Or to e.g. fetch first 1024 chars on first attempt and when it did not contain the whole title as a fallback fetch the whole thing.
What could I use in nodejs to achieve this?

Answer 1

In case someone else is interested, here is what I end up with (very initial version, use just for notion what to use).
A few notes thought:
the core of this solution is to read as few chunks of http response as possible, till the is reached.
not sure, how friendly is by convention to interrupt the connection with response.destroy() (which probably closes the underlying socket).
import {get as httpGet, IncomingMessage} from 'http';
import {get as httpsGet} from 'https';
import {titleParser} from '../ParseTitleFromHtml';
async function parseFromStream(response: IncomingMessage): Promise<string|null> {
let body = '';
for await (const chunk of response) {
const text = chunk.toString();
body += text;
const title = titleParser.parse(body);
if (title !== null) {
response.destroy();
return title;
}
}
response.destroy();
return null;
}
export enum TitleDownloaderRejectionCodesEnum
{
INVALID_STATUS_CODE = 'INVALID_STATUS_CODE',
TIMEOUT = 'TIMEOUT',
NOT_FOUND = 'NOT_FOUND',
FAILED = 'FAILED', // all other errors
}
export class TitleDownloader
{
public async downloadTitle (url: string): Promise<string|null>
{
const isHttps = url.search(/https/i) === 0;
const method = isHttps ? httpsGet : httpGet;
return new Promise((resolve, reject) => {
const clientRequest = method(
url,
async (response) => {
if (!(response.statusCode >= 200 && response.statusCode < 300)) {
clientRequest.abort();
reject(response.statusCode === 404
? TitleDownloaderRejectionCodesEnum.NOT_FOUND
: TitleDownloaderRejectionCodesEnum.INVALID_STATUS_CODE
);
return;
}
const title = await parseFromStream(response);
resolve (title);
}
);
clientRequest.setTimeout(2000, () => {
clientRequest.abort();
reject(TitleDownloaderRejectionCodesEnum.TIMEOUT);
})
.on('error', (err: any) => {
// clear timeout
if (err && err.message && err.message.indexOf('ENOTFOUND') !== -1) {
reject(TitleDownloaderRejectionCodesEnum.NOT_FOUND);
}
reject(TitleDownloaderRejectionCodesEnum.FAILED);
});
});
}
}
export const titleDownloader = new TitleDownloader();