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S
satoris
Inspiring
July 18, 2023
Answered

How do you correctly load a JSON file from disk in a UXP script?

  • July 18, 2023
  • 3 replies
  • 2196 views

I'm not a JavaScript or UXP expert, most likely I'm doing something obvious wrong here. But I haven't been able to find an answer for this anywhere.

 

Here's how I attempt to load the JSON:

 

const fs = require('fs');
const data = JSON.parse(fs.readFile("path/to/file.json"));

 

However, the last line gives the error "Unexpected token o in position 1" and the script quits.

 

I have double-checked the file path and made sure it is correct. Also, if I copy/paste the JSON directly into the script everything works correctly, so I know the file is not corrupt.

 

What is wrong here?

    This topic has been closed for replies.
    Correct answer Manan Joshi

    What @Eugene Tyson suggested regarding using the sync variant of the method or parsing the content in the callback are valid suggestions. However, with this done I still get the error you say. Checking the content of the file read I see that all the double quotes are escaped.

    I suggest another way to read the json file. Just require it and you should be good.

     

    const data = require(path to the JSON file)

    P.S. :- Make sure the path is relative to your script file

     

    -Manan

    3 replies

    S
    sttk3
    Legend
    July 22, 2023

    It has already been solved, but I will explain.

     

    UXP plugins can use fs by giving permissions, but UXP scripts cannot for security reasons. Instead, call localFileSystem. In this case, the user must select the file through a dialog. So I am surprised that you can read JSON using require.

     

    const { localFileSystem } = require('uxp').storage ;

const targetEntry = await localFileSystem.getFileForOpening({types: ['json']}) ;
if(targetEntry == null) {return ;}

const data = JSON.parse(await targetEntry.read()) ;

     

    (Edit: UXP scripts could use the fs module without permissions.)

    M
    Community Expert
    Manan JoshiCommunity Expert
    Community Expert
    July 23, 2023

    Hi @sttk3,

    I have tested and the OP as well that the require is able to read the file. Secondly even fs is able to read the file, but as far as I remember it was escaping the double quotes. Lastly, thanks for sharing another way to do this but I would say this ain't a proper replacement of what the OP might be wanting to do, with scripts we many times have use case of silent execution in such cases making selection on a dialog would be disruptive.

    -Manan

    -Manan
    M
    Community Expert
    Manan JoshiCommunity Expert
    Community Expert
    July 23, 2023

    I don’t mean to deny what you said, just that I was pleasantly surprised you found a way to make it work with UXP’s limited file access.


    Oh I meant to further the discussion by affirming my findings. As if all the scenarios discussed here are true then surely something is broken in UXP implementation in this respect. If security was of consideration then require is bypassing it, and then again even the file is read albeit wrongly.

    -Manan

    -Manan
      M
      Community Expert
      Manan JoshiCommunity ExpertCorrect answer
      Community Expert
      July 19, 2023

      What @Eugene Tyson suggested regarding using the sync variant of the method or parsing the content in the callback are valid suggestions. However, with this done I still get the error you say. Checking the content of the file read I see that all the double quotes are escaped.

      I suggest another way to read the json file. Just require it and you should be good.

       

      const data = require(path to the JSON file)

      P.S. :- Make sure the path is relative to your script file

       

      -Manan

      -Manan
        S
        satorisAuthor
        Inspiring
        July 19, 2023

        Using require with the path to the json file gives the error "Module not found". I thought require was only for modules, or is there some sort of hack to get around that? From the sound of what you're saying, it appears that this is a bug. Does Adobe have a portal somewhere to report it, or do they look here?

         

        For now, I'll just continue pasting in the json into the script. It's not ideal, but at least I can get things done.

        M
        Community Expert
        Manan JoshiCommunity Expert
        Community Expert
        July 19, 2023

        It's not a bug reading file using require. I was able to read the file fine usin require. Did you use the path relative to the script?

        https://stackoverflow.com/questions/7163061/is-there-a-require-for-json-in-node-js

        The other use case that we were trying to solve using readFile is still not working but I am not sure if it's a bug or are we missing something typical to UXP

        -Manan

        -Manan
        E
        Community Expert
        Eugene TysonCommunity Expert
        Community Expert
        July 19, 2023

        Does this work?

        const fs = require('fs');
const data = JSON.parse(fs.readFileSync("path/to/file.json", 'utf8'));
        E
        Community Expert
        Eugene TysonCommunity Expert
        Community Expert
        July 19, 2023

        Or maybe this

         

        const fs = require('fs');
fs.readFile("path/to/file.json", 'utf8', (err, data) => {
  if (err) {
    console.error('Error reading the file:', err);
    return;
  }
  
  const jsonData = JSON.parse(data);
  // Now you can work with the jsonData object here.
});
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