# Custom preprocessor plugin blocks upload

**URL:** <https://community.transloadit.com/t/custom-preprocessor-plugin-blocks-upload/15026>\
**Category:** Uppy\
**Created:** [August 20, 2019, 2:07pm UTC](https://community.transloadit.com/t/custom-preprocessor-plugin-blocks-upload/15026 "2019-08-20T14:07:58Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![adventmedia](https://yyz2.discourse-cdn.com/flex032/user_avatar/community.transloadit.com/adventmedia/32/147_2.png) [@adventmedia](https://community.transloadit.com/u/adventmedia)\
**Post date:** [August 20, 2019, 2:07pm UTC](https://community.transloadit.com/t/custom-preprocessor-plugin-blocks-upload/15026/1 "2019-08-20T14:07:58Z")

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I created a custom preprocessor (using Jimp to rotate images), using the example code for a compressor plugin in the docs.  
The preprocessing part of the code appears to work (if console logs are to believed), every step executes as expected except for the upload.

```
  if (rotation !== 0) {
    uppy.use(UppyRotatePlugin, { rotate: rotation });
    console.log('using rotate'); // -> 'using rotate'
  }
// console shows log statements for custom plugin's 'prepareUpload' steps
  console.log('ready to upload'); //-> 'ready to upload'
  await uppy.upload();
  console.log('and... uploaded'); // -> never happens

```

What am I missing?

---

<div class="post-metadata">

**Author:** ![ajkachnic](https://yyz2.discourse-cdn.com/flex032/user_avatar/community.transloadit.com/ajkachnic/32/260_2.png) [@ajkachnic](https://community.transloadit.com/u/ajkachnic)\
**Post date:** [July 9, 2020, 9:31pm UTC](https://community.transloadit.com/t/custom-preprocessor-plugin-blocks-upload/15026/2 "2020-07-09T21:31:38Z")

</div>

Hello! This is most likely an issue with the plugin and not Uppy itself. If you some of the code, that would definitely help resolving this issue.

Without being able to see the code, I have a few **guesses** as to the problem area:

1. A forgotten return value in part of the plugin
2. Maybe a function or method from `jimp` is acting unexpectedly or not returning the proper result (try debugging the output)

I’m sure that there are many possible reasons for this, and note that these are **just approximations** and I can’t say anything for sure until I see some of the code

I hope this helps. Let me know if you have any further questions or problems

- Andrew