pwlmaciejewski/imghash

Broken image ignores promise's catch

Closed this issue · 2 comments

auszig commented

I was hashing some images in a loop using promises and a broken image caused the entire program to crash instead of being caught by the promise chain.

/node_modules/@cwasm/nsgif/index.js:38
    throw new Error('Failed to decode gif image')
    ^

Error: Failed to decode gif image
    at Object.exports.decode (/node_modules/@cwasm/nsgif/index.js:38:11)
    at decodeImage (/node_modules/@canvas/image/index.js:28:16)
    at imageFromBuffer (/node_modules/@canvas/image/index.js:185:29)
    at /node_modules/imghash/index.js:22:15
    at FSReqCallback.readFileAfterClose [as oncomplete] (internal/fs/read_file_context.js:61:3)

I managed to recreate the issue by making a test file with content GIF89a to simulate a malformed GIF and running the following code, which results in the same error. Instead of ignoring the error, it still crashes.

imghash.hash("test.txt")
  .then(hash => console.log)
  .catch(err => {})

I did a little digging, and it seems to be occuring because imageFromBuffer is not a true promise in that it returns the promise after doing some synchronous work (which returns the error above). I managed to get it to work properly by amending the code in index.js to this, but it's not really a nice fix (and probably needs to be added to the if statement above fs.readFile):

return new Promise((resolve, reject) => {
  if (Buffer.isBuffer(filepath)) {
    return resolve(imageFromBuffer(filepath));
  }

  fs.readFile(filepath, (err, content) => {
    if (err) return reject(err);
    try {
      imageFromBuffer(content).then(image => resolve(image));
    } catch (err) {
      reject(err);
    }
  });
})
LinusU commented

This is fixed with @canvas/image 1.0.1, you should be able to run npm update @canvas/image --depth=10 to pull in the fix in your project 👍