Download and save PDF using Deno - deno

Question

Hello I want to download pdf files using deno.
I'm using
export default async function downloadPDF(uid: string): Promise<void> {
const res = await fetch(`${Deno.env.get('MY_PDF_URL')}/${uid}`);
const file = await Deno.open(`./pdfs/${uid}.pdf`, { create: true, write: true })
if (res?.body) {
for await(const chunk of res.body) {
await Deno.writeAll(file, chunk);
}
}
file.close();
}
The command I am using is deno run --allow-net --allow-read --allow-write --allow-env --allow-run main.ts. So I don't think I havent put the right permissions here.
However I get the error
error: Uncaught (in promise) PermissionDenied: Permission denied (os error 13)
api_1 | const file = await Deno.open(`./pdfs/${uid}.pdf`, { create: true, write: true })
api_1 | ^
api_1 | at unwrapOpResult (deno:core/core.js:100:13)
api_1 | at async Object.open (deno:runtime/js/40_files.js:46:17)
api_1 | at async downloadPDF (file:///app/downloadPDF.ts:3:17)
What might be the issue here? I am using the Dockerfile
FROM hayd/alpine-deno:1.9.0
EXPOSE 1993
WORKDIR /app
USER deno
COPY deps.ts .
RUN deno cache deps.ts
COPY . .
RUN deno cache main.ts
CMD [run --allow-net --allow-read --allow-write --allow-env --allow-run main.ts]
to run this application.

Answer 1

import { readerFromStreamReader } from "https://deno.land/std#0.93.0/io/mod.ts";
export default async function downloadPDF(uid: string): Promise<void> {
const res = await fetch(`https://example.com/pdfs/${uid}`);
if (res.status !== 200) {
console.error(`response status was ${res.status}, this is not handled.`);
return;
}
// we don't want to download existing files
if (await fileExists(`/html/${uid}.html`)) {
console.info(`${uid}.html already exists, skipping...`);
return;
}
const file = await Deno.open(`/pdfs/${uid}.pdf`, { create: true, write: true, read: true })
if (res?.body) {
const reader = readerFromStreamReader(res.body.getReader());
await Deno.copy(reader, file);
}
file.close();
}
The error I posted in the question happens because of file permissions of the deno user in my Dockerfile. Simply removing the user solves the problem. However setting permissions correctly would be better if this is used for production.