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/*
* The content of this file is licensed. You may obtain a copy of
* the license at https://github.com/thsmi/sieve/ or request it via
* email from the author.
*
* Do not remove or change this comment.
*
* The initial author of the code is:
* Thomas Schmid <schmid-thomas@gmx.net>
*/
import logger from 'gulplog';
import https from 'https';
import fs from 'fs';
const HTTP_SUCCESS_MIN = 200;
const HTTP_SUCCESS_MAX = 299;
const HTTP_REDIRECT_MIN = 300;
const HTTP_REDIRECT_MAX = 399;
/**
* Checks if the http status code indicates a redirection.
*
* @param {int} status
* the status to be checked,
*
* @returns {boolean}
* the true in case the server requested a redirection otherwise false.
*/
function isRedirection(status) {
return (status >= HTTP_REDIRECT_MIN) && (status <= HTTP_REDIRECT_MAX);
}
/**
* Checks if the http status code indicates a success.
*
* @param {int} status
* the status to be checked,
*
* @returns {boolean}
* the true in case the server signaled a success otherwise false.
*/
function isSuccess(status) {
return (status >= HTTP_SUCCESS_MIN) && (status <= HTTP_SUCCESS_MAX);
}
/**
* Fetches a json file from a https url.
* E.g. used to download github releases via the api.
*
* @param {string} url
* the json file to be loaded.
* @returns {string}
* the bytes received.
*/
async function fetch(url) {
logger.debug(`Fetching ${url}`);
return await new Promise((resolve, reject) => {
// Github requires to have a user agents set.
// It should be the username plus the application name.
//
// https://developer.github.com/v3/#user-agent-required
const options = {headers: { 'User-Agent': 'thsmi-sieve' }};
https.get(url, options, async function (response) {
try {
if (isRedirection(response.statusCode)) {
logger.debug(`Following redirect to ${response.headers.location}`);
resolve(await fetch(response.headers.location));
return;
}
if (!isSuccess(response.statusCode))
throw new Error(`Fetching ${url} failed with status code ${response.statusCode}.`);
let data = "";
response.on("data", (bytes) => {
data += bytes;
});
response.on('end', () => {
resolve(JSON.parse(data));
});
} catch (ex) {
reject(new Error(ex));
}
});
});
}
/**
* Downloads a file from an https url and stores the data into the given file.
* It follows redirects. Upon a non 200 status code an error is thrown.
*
* @param {string} url
* the download url.
* @param {string} destination
* the file into which the downloaded data should be stored.
* In case the file exists it will be silently overwritten.
* @returns {undefined}
*/
async function download(url, destination) {
logger.debug(`Downloading ${url} to ${destination}`);
return await new Promise((resolve, reject) => {
// Github requires to have a user agents set.
// It should be the username plus the application name.
//
// https://developer.github.com/v3/#user-agent-required
const options = {headers: { 'User-Agent': 'thsmi-sieve' }};
https.get(url, options, async function (response) {
try {
if (isRedirection(response.statusCode)) {
logger.debug(`Following redirect to ${response.headers.location}`);
await download(response.headers.location, destination);
resolve();
return;
}
if (!isSuccess(response.statusCode))
throw new Error(`Downloading ${url} failed with status code ${response.statusCode}.`);
const file = fs.createWriteStream(destination);
response.pipe(file);
file.on('finish', function () {
file.close(function () {
resolve();
});
});
} catch (ex) {
reject(new Error(ex));
}
});
});
}
export default {
download,
fetch
};
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