File download.file() does not follow 302 redirects in Node.js [PATCH] #585
Description
It looks like download.file() does not follow redirected URLs.
Example
$ node webR-download.file.bug.js
Node.js v v20.19.5
webR v0.5.7
download.file(<redirecting URL>):
Error fetching https://cran.r-universe.dev/bin/emscripten/contrib/4.5/listenv_0.10.0.tgz - Found. Redirecting to https://cdn.r-universe.dev/d9f4c99b3ea4a96ae2b5782941df7524a288a7bb26efb4c95caaca25e09bf6ac
trying URL 'https://cran.r-universe.dev/bin/emscripten/contrib/4.5/listenv_0.10.0.tgz'
Warning in download.file("https://cran.r-universe.dev/bin/emscripten/contrib/4.5/listenv_0.10.0.tgz", :
URL https://cran.r-universe.dev/bin/emscripten/contrib/4.5/listenv_0.10.0.tgz: Download failed. See the Javascript console for further information
Error: download from 'https://cran.r-universe.dev/bin/emscripten/contrib/4.5/listenv_0.10.0.tgz' failed
download.file(<directing URL>):
trying URL 'https://cdn.r-universe.dev/d9f4c99b3ea4a96ae2b5782941df7524a288a7bb26efb4c95caaca25e09bf6ac'
Success: TRUEwhere webR-download.file.bug.js:
import { WebR } from "webr";
import WebSocket from "ws";
async function webr_eval_code(code) {
let shelter = await new webR.Shelter()
let result = await shelter.captureR(code, {
withAutoprint: true,
captureStreams: true,
captureConditions: false
})
for (const { type, data } of result.output) {
if (type === "stdout") {
console.log(data);
} else if (type === "stderr") {
console.error(data);
}
}
shelter.purge();
return result;
}
console.log('Node.js v', process.version);
// Launch webR instance
const webR = new WebR();
await webR.init();
console.log("webR v" + webR.version);
console.log("\n\ndownload.file(<redirecting URL>):");
await webr_eval_code([
'download.file("https://cran.r-universe.dev/bin/emscripten/contrib/4.5/listenv_0.10.0.tgz", "foo.tgz", mode = "wb")',
'message("Success: ", file.exists("foo.tgz"))'
]);
console.log("\n\ndownload.file(<directing URL>):");
await webr_eval_code([
'download.file("https://cdn.r-universe.dev/d9f4c99b3ea4a96ae2b5782941df7524a288a7bb26efb4c95caaca25e09bf6ac", "foo.tgz", mode = "wb")',
'message("Success: ", file.exists("foo.tgz"))'
]);
process.exit(0);$ curl --head https://cran.r-universe.dev/bin/emscripten/contrib/4.5/listenv_0.10.0.tgz
HTTP/2 302
date: Tue, 16 Dec 2025 04:17:33 GMT
content-type: text/plain; charset=utf-8
content-length: 113
location: https://cdn.r-universe.dev/d9f4c99b3ea4a96ae2b5782941df7524a288a7bb26efb4c95caaca25e09bf6ac
server: cloudflare
x-powered-by: Express
access-control-allow-origin: *
cache-control: public, max-age=600
etag: W/"69194daf7b41ac9b6d02461c32"
last-modified: Tue, 16 Dec 2025 04:08:13 GMT
vary: Accept, accept-encoding
x-runiverse-cache: EXPIRED
age: 585
cf-cache-status: HIT
report-to: {"group":"cf-nel","max_age":604800,"endpoints":[{"url":"https://a.nel.cloudflare.com/report/v4?s=kaEAPaGvD6zXJVNeTbIMmd3Fai3K66JatcYEANCek4Au05l0stmkqFnIuhkfzRlqDNkWPhkE%2BlOlQgOtN32dKlIAMFDxhgnruSQPIT%2BKDiCI"}]}
nel: {"report_to":"cf-nel","success_fraction":0.0,"max_age":604800}
cf-ray: 9aeb5f2a880aa43c-SJC
alt-svc: h3=":443"; ma=86400PS. I think the culprit is in downloadFileContent(). I might have a patch, but need to test it a bit more. Stay tuned.