Why is not gm's method 'toBuffer' promisified?

Asked Aug 26 '16 at 13:39

Active Aug 26 '16 at 13:39

Viewed 469 times

I tried to use gm to resize a big avatar image to 64 * 64.
The express function is an async function and I tried to promisify all methods by the following codes:

import gm_origin from 'gm'
import Promise from 'bluebird';
const gm = Promise.promisifyAll(gm_origin);

...
const processThumb = async (req, res) => {
  
  const thumbFile = gm(req.file.buffer).resize(config.thumbSize);
  const thumbBuffer = await thumbFile.toBufferAsync('JPG');
  ...
}

But the API does not respond at all.
So I set a breakpoint to the line and it is saying that thumbFile does not have 'goBufferAsync' method. Is anybody know how to promisify all methods of 'gm'?

asked Aug 26 '16 at 13:39

Colin Wang

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Apparently the prototoype of `thumbFile` is not accessible from `gm`, so it cannot promisify it. Use `Promise.promisifyAll(thumbFile)` instead. – Bergi Aug 26 '16 at 13:41
If there was an error like that, it should not "not respond at all", but rather call your error handler. You have one, right? – Bergi Aug 26 '16 at 13:42
Could you tell me how to promisify all methods of gm ? Or it doesn't support 'promise'? – Colin Wang Aug 26 '16 at 13:45
`toBuffer` appears not to be a `gm` method, it's a `thumbFile` method. – Bergi Aug 26 '16 at 13:46
Have you ever seen https://github.com/aheckmann/gm/issues/320 ? – Colin Wang Aug 26 '16 at 13:52
So have you tried `Promise.promisifyAll(gm_origin.prototype);` as it was used in the Bluebird issue referenced from there? – Bergi Aug 26 '16 at 14:00
I have also tried it but it was same. – Colin Wang Aug 26 '16 at 15:20
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/122005/discussion-between-colin-witkamp-and-bergi). – Colin Wang Aug 27 '16 at 15:19

Why is not gm's method 'toBuffer' promisified?

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