Saving binary data as file using JavaScript from a browser

Question

I am working on a business application using angularJS. One of my service method returning me a byte[] (inclding PDF file content) now i need to download this file as PDF to client machine using JavaScript.

How is that possible using HTML5 Apis or any JavaScript API?

I have used window.atob(base64String)

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

but getting this following error Failed to execute 'atob' on 'Window': The string to be decoded is not correctly encoded.

Zinfandel

Possible duplicate of Using HTML5/Javascript to generate and save a file – Twowheeler

Answer 1

This is possible if the browser supports the download property in anchor elements.

var sampleBytes = new Int8Array(4096);

var saveByteArray = (function () {
    var a = document.createElement("a");
    document.body.appendChild(a);
    a.style = "display: none";
    return function (data, name) {
        var blob = new Blob(data, {type: "octet/stream"}),
            url = window.URL.createObjectURL(blob);
        a.href = url;
        a.download = name;
        a.click();
        window.URL.revokeObjectURL(url);
    };
}());

saveByteArray([sampleBytes], 'example.txt');

JSFiddle: http://jsfiddle.net/VB59f/2

Polonium

Getting this error og Chrome : TypeError: Failed to construct 'Blob': The 1st argument is neither an array, nor does it have indexed properties. – Zinfandel

@RaviMittal -- What are you feeding the data parameter? – Polonium

service is return byte[] but i think its converted to base64 string – Zinfandel

@Polonium How do we convert base64 string to array for blob – Zinfandel

@RaviMittal -- you want a typed array, check this out: developer.mozilla.org/en-US/docs/Web/JavaScript/… – Polonium

@Polonium How to convert base64 to array. – Zinfandel

@Polonium Getting this Error : Failed to execute 'atob' on 'Window': The string to be decoded is not correctly encoded. – Zinfandel

Works on Chrome, Edge and Firefox over Windows 10. Sadly, doesn't works on Safari.I wasn't able to find a solution that works on all major browsers. – Stevestevedore

If you are using GWT don't attach the anchor to the body element, otherwise your click event gets sunk. – Celin

GWT also transcompiles Java byte[] as JS Array, so you need to wrap it in the Int8Array, otherwise your byte[] will be interpreted as text, despite of the MIME type. – Celin

Doesn't work in Microsoft Edge 41.16299.248.0, but works in Chrome – Uterine

For IE11, use msSaveOrOpenBlob(blob, fileName): https://mcmap.net/q/75490/-quot-access-is-denied-quot-when-attempting-to-open-a-url-generated-for-a-procedurally-generated-pdf-in-ie11 – Riddell

I am using iOS 12. anchor tag doesnot have a download attribute. What can I do? – Kimberelykimberlee

Answer 2

Use FileSaver.js. It supports Chrome, Edge, Firefox, and IE 10+ (and probably IE < 10 with a few "polyfills" - see Note 4). FileSaver.js implements the saveAs() FileSaver interface in browsers that do not natively support it:
     https://github.com/eligrey/FileSaver.js

Minified version is really small at < 2.5KB, gzipped < 1.2KB.

Usage:

/* TODO: replace the blob content with your byte[] */
var blob = new Blob([yourBinaryDataAsAnArrayOrAsAString], {type: "application/octet-stream"});
var fileName = "myFileName.myExtension";
saveAs(blob, fileName);

You might need Blob.js in some browsers (see Note 3). Blob.js implements the W3C Blob interface in browsers that do not natively support it. It is a cross-browser implementation:
     https://github.com/eligrey/Blob.js

Consider StreamSaver.js if you have files larger than blob's size limitations.

Complete example:

/* Two options
 * 1. Get FileSaver.js from here
 *     https://github.com/eligrey/FileSaver.js/blob/master/FileSaver.min.js -->
 *     <script src="FileSaver.min.js" />
 *
 * Or
 *
 * 2. If you want to support only modern browsers like Chrome, Edge, Firefox, etc., 
 *    then a simple implementation of saveAs function can be:
 */
function saveAs(blob, fileName) {
    var url = window.URL.createObjectURL(blob);

    var anchorElem = document.createElement("a");
    anchorElem.style = "display: none";
    anchorElem.href = url;
    anchorElem.download = fileName;

    document.body.appendChild(anchorElem);
    anchorElem.click();

    document.body.removeChild(anchorElem);

    // On Edge, revokeObjectURL should be called only after
    // a.click() has completed, atleast on EdgeHTML 15.15048
    setTimeout(function() {
        window.URL.revokeObjectURL(url);
    }, 1000);
}

(function() {
    // convert base64 string to byte array
    var byteCharacters = atob("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");
    var byteNumbers = new Array(byteCharacters.length);
    for (var i = 0; i < byteCharacters.length; i++) {
        byteNumbers[i] = byteCharacters.charCodeAt(i);
    }
    var byteArray = new Uint8Array(byteNumbers);
    
    // now that we have the byte array, construct the blob from it
    var blob1 = new Blob([byteArray], {type: "application/octet-stream"});

    var fileName1 = "cool.gif";
    saveAs(blob1, fileName1);

    // saving text file
    var blob2 = new Blob(["cool"], {type: "text/plain"});
    var fileName2 = "cool.txt";
    saveAs(blob2, fileName2);
})();

JSFiddle here: should download two small files when the page loads - a binary file (GIF) and a text file. Update: StackOverflow's Run code snippet doesn't support downloading files anymore as sandboxes by default don't allow downloading files in newer browser versions.)

Tested on Chrome, Edge, Firefox, and IE 11 (use FileSaver.js for supporting IE 11).
You can also save from a canvas element. See https://github.com/eligrey/FileSaver.js#saving-a-canvas.

Demos: https://eligrey.com/demos/FileSaver.js/

Blog post by author of FileSaver.js: http://eligrey.com/blog/post/saving-generated-files-on-the-client-side

Note 1: Browser support: https://github.com/eligrey/FileSaver.js#supported-browsers

Note 2: Failed to execute 'atob' on 'Window'

Note 3: Polyfill for browsers not supporting Blob: https://github.com/eligrey/Blob.js
                See http://caniuse.com/#search=blob

Note 4: IE < 10 support (I've not tested this part):
                https://github.com/eligrey/FileSaver.js#ie--10
                https://github.com/eligrey/FileSaver.js/issues/56#issuecomment-30917476

Downloadify is a Flash-based polyfill for supporting IE6-9: https://github.com/dcneiner/downloadify (I don't recommend Flash-based solutions in general, though.)
Demo using Downloadify and FileSaver.js for supporting IE6-9 also: http://sheetjs.com/demos/table.html

Note 5: Creating a BLOB from a Base64 string in JavaScript

Note 6: FileSaver.js examples: https://github.com/eligrey/FileSaver.js#examples

Lisettelisha

Can you help me how to read it back to origin string? @sachin-joseph – Intramural

Note that Safari has very poor support for this function. Just try the FileSaver.js demo in Safari, it often creates a new tab instead of saving the file! eligrey.com/demos/FileSaver.js – Painty

@ColinD: Agreed. Supporting Safari doesn't seem to be easy: #36445007 – Lisettelisha

@ColinD: One workaround for Safari would be: 1) Create an anchor element with the file content in href attribute using createObjectURL. 2) Now ask the user to right-click and save the file. – Lisettelisha

@Sachin Joseph - Can this be used to convert a binary value into it's original excel format? I save an excel file that is uploaded by the user to the database (I'm using sheetjs to convert excel into json, then use btoa to convert to base64). I need to retrieve the saved binary object, convert it back into excel, and then display to user - all using javascript. – Ventura

@RogerDodger There is a demo on SheetJs's website which uses FileSaver.js and SheetJs to export data in Excel formats: sheetjs.com/demos/table.html – Lisettelisha

Yes I saw that - but that is exporting from html; that link just has the demo, but not the code; also I need to convert a base64 into xlsx. Will look around some more, thx. – Ventura

Answer 3

Try

let bytes = [65,108,105,99,101,39,115,32,65,100,118,101,110,116,117,114,101];

let base64data = btoa(String.fromCharCode.apply(null, bytes));

let a = document.createElement('a');
a.href = 'data:;base64,' + base64data;
a.download = 'binFile.txt'; 
a.click();

I convert here binary data to base64 (for bigger data conversion use this) - during downloading browser decode it automatically and save raw data in file. 2020.06.14 I upgrade Chrome to 83.0 and above SO snippet stop working (probably due to sandbox security restrictions) - but JSFiddle version works - here

Filmy

Answer 4

To do this task download.js library can be used. Here is an example from library docs:

download("data:image/gif;base64,R0lGODlhRgAVAIcAAOfn5+/v7/f39////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////yH5BAAAAP8ALAAAAABGABUAAAj/AAEIHAgggMGDCAkSRMgwgEKBDRM+LBjRoEKDAjJq1GhxIMaNGzt6DAAypMORJTmeLKhxgMuXKiGSzPgSZsaVMwXUdBmTYsudKjHuBCoAIc2hMBnqRMqz6MGjTJ0KZcrz5EyqA276xJrVKlSkWqdGLQpxKVWyW8+iJcl1LVu1XttafTs2Lla3ZqNavAo37dm9X4eGFQtWKt+6T+8aDkxUqWKjeQUvfvw0MtHJcCtTJiwZsmLMiD9uplvY82jLNW9qzsy58WrWpDu/Lp0YNmPXrVMvRm3T6GneSX3bBt5VeOjDemfLFv1XOW7kncvKdZi7t/S7e2M3LkscLcvH3LF7HwSuVeZtjuPPe2d+GefPrD1RpnS6MGdJkebn4/+oMSAAOw==", "dlDataUrlBin.gif", "image/gif");

Telencephalon