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Does anyone know how I can unzip a file with javascript?

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Brandon Stryker
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Hello, I have created an express server and a bundled react app for my brightsign player. In addition I have each of these running via my autorun.brs. I am making a request from react to the express server to download a zip file from an external endpoint and unzip it. I am able to successfully download the file, but then I am getting the following error:

[ 63.088] finished downloading 
[ 63.260] start unzip 
[ 63.573] internal/fs/utils.js:314 
[ 63.573] throw err; 
[ 63.573] ^ 
[ 63.573] 
[ 63.573] Error: EPERM: operation not permitted, chmod '/storage/sd/media/slides/133444725423.png' 
[ 63.573] at Object.chmodSync (fs.js:1320:3) 
[ 63.573] at Utils.writeFileTo (/storage/sd/node_modules/adm-zip/util/utils.js:89:13) 
[ 63.573] at /storage/sd/node_modules/adm-zip/adm-zip.js:616:27 
[ 63.573] at Array.forEach (<anonymous>) 
[ 63.573] at Object.extractAllTo (/storage/sd/node_modules/adm-zip/adm-zip.js:604:26) 
[ 63.573] at WriteStream.<anonymous> (/storage/sd/app.js:66:11) 
[ 63.573] at WriteStream.emit (events.js:400:28) 
[ 63.573] at finish (internal/streams/writable.js:657:10) 
[ 63.573] at finishMaybe (internal/streams/writable.js:644:9) 
[ 63.573] at internal/streams/writable.js:617:7 { 
[ 63.573] errno: -1, 
[ 63.573] syscall: 'chmod', 
[ 63.573] code: 'EPERM',

I do not believe this linux distribution has the chmod command. My main question is... does it have chmod and is there a way I can give this script permission to run it? or more likely, does anyone know of a js lib that can unzip archives without calling chmod?

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6 comments

  • 0
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    Mkramer

    You can try:

    https://www.digitalocean.com/community/tutorials/java-unzip-file-example

    Cheers.

    Mark

  • 0
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    Brandon Stryker

    @Mkramer thank you for trying to help, however, though they share the word java, java and javascript are completely languages and javascript cannot use java libraries as far as I know. I was able to use a library called decompress. This is still erroring on the attempt to call utime, but this is not integral to the functionality and seems to only affect the metadata for a file/directory (time created/edited). Here is the code:


    const decompress = require("decompress");

    const zipFile = path.join(storagePath, "media", "archive.zip");
    constoutputDir = path.join(storagePath, "media");

    console.log("$$$ Making download request $$$");
    let fileUrl = "some url";
    let headers = {"some key": "some value"};
    request
      .get({ headers: headers, url: fileUrl })
      .on("error", function (error) {
        console.log(error);
      })
      .pipe(fs.createWriteStream(zipFile))
      .on("finish", async () => {
        console.log("$$$ finished downloading $$$");
        console.log("$$$ start unzip $$$");
        awaitdecompress("/storage/sd/media/archive.zip", "/storage/sd/media")
          .then(() => console.log("$$$ finished unzipping $$$"))
          .catch((err) => console.log(err));
        console.log("!!! past decompress function !!!");
        while (true) {
          awaitnewPromise((res) =>setTimeout(res, 5000));
          console.log("...");
          if (fs.existsSync(path.join(storagePath, "media", "index.html"))) {
            console.log("$$$ it seems files were extracted successfully $$$");
            res.json({ successful:true });
            break;
          }
        }
    });
  • 0
    Avatar
    Mkramer

    Try StackOverFlow's site

    https://stackoverflow.com/questions/2095697/unzipping-files

  • 0
    Avatar
    Brandon Stryker

    Yes I did, that is where I found the decompress library. The code sample I included above works fine. I believe most of these unzipper libraries are going to try to call some system function to change file permissions or do something. Brightsign players have a very lightweight version of linux with no way (as far as I can tell) to install additional linux utilities or functions. I'm sure many of the libraries will error in some way at some point. The one I have chose unzips the archive before it errors, which is good enough for me. It unzips, I catch error and do nothing about it, code continues on its merry way

  • 0
    Avatar
    Mkramer

    You might submit a ticket asking BrightSign if you can load additional utilities or functions - just to see what the reply is.  :-)

  • 0
    Avatar
    Brandon Stryker

    yeahhhh I've considered it. I don't want to start messing around with the OS too much. Thank you for all your helpful suggestions though

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