Zidan•12mo ago

Closing a file

How do I close a file after opening and streaming it? My handler function code is as follows:

return new Promise(
  (grant) => {
    Deno.open(
      asset.path
    ).then(
      (file) => {
        grant(
          new Response(
            file.readable,
            {
              status: 200,
              headers: {
                "content-type": asset.type,
                "content-length": file.stat.size.toString()
              }
            }
          )
        )
      }
    )
  }
);

return new Promise(
  (grant) => {
    Deno.open(
      asset.path
    ).then(
      (file) => {
        grant(
          new Response(
            file.readable,
            {
              status: 200,
              headers: {
                "content-type": asset.type,
                "content-length": file.stat.size.toString()
              }
            }
          )
        )
      }
    )
  }
);

Is there a good way of closing the "file" after returning the "Response" object?

6 Replies

ioB•12mo ago

If you use .readable, it's closed after the whole body is read automatically no need to manually close it

Zidan•12mo ago

oh, that's convenient got it, thanks 👍 file.stat appears to be a function that returns a promise now.. is there a way to get the file size in the same .then() or do i have to chain another .then?

ioB•12mo ago

I would have personally written this like

return new Promise(
  async (grant) => {
    const file = await Deno.open(
      asset.path
    );
    const stat = await file.stat();

    grant(
      new Response(
        file.readable,
        {
          status: 200,
          headers: {
            "content-type": asset.type,
            "content-length": file.stat.size.toString()
          }
        }
      )
    )
  }
);

return new Promise(
  async (grant) => {
    const file = await Deno.open(
      asset.path
    );
    const stat = await file.stat();

    grant(
      new Response(
        file.readable,
        {
          status: 200,
          headers: {
            "content-type": asset.type,
            "content-length": file.stat.size.toString()
          }
        }
      )
    )
  }
);

async/await syntax is your friend!

Zidan•12mo ago

and then check only the file open for erros i think?

ioB•12mo ago

if you want to throw a better error, yes

Zidan•12mo ago

got it, thanks a lot