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I'm currently working on an application that allows the user to upload a file which gets sent to a express server that then converts that file into a bytearray that I can then store somewhere else.
However, I need to be able to convert this bytearray back into a file and send it back to the user. This is my current code in the express API:
app.post("/upload", async (req, res) => {
const file = req.files.file;
const filePath = "divali";
file.mv(filePath, async (err) => {
const nfile = fs.readFileSync(filePath);
let fileData = nfile.toString("hex");
let result = [];
for (var i = 0; i < fileData.length; i += 2)
result.push("0x" + fileData[i] + "" + fileData[i + 1]);
console.log(result);
var pfile = new Blob([result], { type: "application/pdf" });
// var fileURL = URL.createObjectURL(pfile);
console.log(pfile);
pfile.lastModifiedDate = new Date();
pfile.name = "some-name";
console.log(pfile);
});
});
I have Base64-encoded binary data in a string:
const contentType = 'image/png';
const b64Data = 'iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==';
I would like to create a blob: URL containing this data and display it to the user:
const blob = new Blob(????, {type: contentType});
const blobUrl = URL.createObjectURL(blob);
window.location = blobUrl;
I haven't been been able to figure out how to create the BLOB.
In some cases I am able to avoid this by using a data: URL instead:
const dataUrl = `data:${contentType};base64,${b64Data}`;
window.location = dataUrl;
However, in most cases the data: URLs are prohibitively large.
How can I decode a Base64 string to a BLOB object in JavaScript?
The atob function will decode a Base64-encoded string into a new string with a character for each byte of the binary data.
const byteCharacters = atob(b64Data);
Each character's code point (charCode) will be the value of the byte. We can create an array of byte values by applying this using the .charCodeAt method for each character in the string.
const byteNumbers = new Array(byteCharacters.length);
for (let i = 0; i < byteCharacters.length; i++) {
byteNumbers[i] = byteCharacters.charCodeAt(i);
}
You can convert this array of byte values into a real typed byte array by passing it to the Uint8Array constructor.
const byteArray = new Uint8Array(byteNumbers);
This in turn can be converted to a BLOB by wrapping it in an array and passing it to the Blob constructor.
const blob = new Blob([byteArray], {type: contentType});
The code above works. However the performance can be improved a little by processing the byteCharacters in smaller slices, rather than all at once. In my rough testing 512 bytes seems to be a good slice size. This gives us the following function.
const b64toBlob = (b64Data, contentType='', sliceSize=512) => {
const byteCharacters = atob(b64Data);
const byteArrays = [];
for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
const slice = byteCharacters.slice(offset, offset + sliceSize);
const byteNumbers = new Array(slice.length);
for (let i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
const byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
const blob = new Blob(byteArrays, {type: contentType});
return blob;
}
const blob = b64toBlob(b64Data, contentType);
const blobUrl = URL.createObjectURL(blob);
window.location = blobUrl;
Full Example:
const b64toBlob = (b64Data, contentType='', sliceSize=512) => {
const byteCharacters = atob(b64Data);
const byteArrays = [];
for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
const slice = byteCharacters.slice(offset, offset + sliceSize);
const byteNumbers = new Array(slice.length);
for (let i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
const byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
const blob = new Blob(byteArrays, {type: contentType});
return blob;
}
const contentType = 'image/png';
const b64Data = 'iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==';
const blob = b64toBlob(b64Data, contentType);
const blobUrl = URL.createObjectURL(blob);
const img = document.createElement('img');
img.src = blobUrl;
document.body.appendChild(img);
Here is a more minimal method without any dependencies or libraries.
It requires the new fetch API. (Can I use it?)
var url = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg=="
fetch(url)
.then(res => res.blob())
.then(console.log)
With this method you can also easily get a ReadableStream, ArrayBuffer, text, and JSON.
(fyi this also works with node-fetch in Node)
As a function:
const b64toBlob = (base64, type = 'application/octet-stream') =>
fetch(`data:${type};base64,${base64}`).then(res => res.blob())
But I would encourage you to don't use base64 in the first place. There are better ways to send and receive binary data. JSON isn't always the best option. it takes up more bandwidth and waste processing time (de)encodeing stuff. Us eg canvas.toBlob instead of canvas.toDataURL and use FormData to send binary files. you can also return back a multipart payload and decode it using await response.formData() that is coming from a server response. FormData can go both ways.
I did a simple performance test towards Jeremy's ES6 sync version.
The sync version will block UI for a while.
keeping the devtool open can slow the fetch performance
document.body.innerHTML += '<input autofocus placeholder="try writing">'
// get some dummy gradient image
var img=function(){var a=document.createElement("canvas"),b=a.getContext("2d"),c=b.createLinearGradient(0,0,1500,1500);a.width=a.height=3000;c.addColorStop(0,"red");c.addColorStop(1,"blue");b.fillStyle=c;b.fillRect(0,0,a.width,a.height);return a.toDataURL()}();
async function perf() {
const blob = await fetch(img).then(res => res.blob())
// turn it to a dataURI
const url = img
const b64Data = url.split(',')[1]
// Jeremy Banks solution
const b64toBlob = (b64Data, contentType = '', sliceSize=512) => {
const byteCharacters = atob(b64Data);
const byteArrays = [];
for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
const slice = byteCharacters.slice(offset, offset + sliceSize);
const byteNumbers = new Array(slice.length);
for (let i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
const byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
const blob = new Blob(byteArrays, {type: contentType});
return blob;
}
// bench blocking method
let i = 500
console.time('blocking b64')
while (i--) {
await b64toBlob(b64Data)
}
console.timeEnd('blocking b64')
// bench non blocking
i = 500
// so that the function is not reconstructed each time
const toBlob = res => res.blob()
console.time('fetch')
while (i--) {
await fetch(url).then(toBlob)
}
console.timeEnd('fetch')
console.log('done')
}
perf()
Optimized (but less readable) implementation:
function base64toBlob(base64Data, contentType) {
contentType = contentType || '';
var sliceSize = 1024;
var byteCharacters = atob(base64Data);
var bytesLength = byteCharacters.length;
var slicesCount = Math.ceil(bytesLength / sliceSize);
var byteArrays = new Array(slicesCount);
for (var sliceIndex = 0; sliceIndex < slicesCount; ++sliceIndex) {
var begin = sliceIndex * sliceSize;
var end = Math.min(begin + sliceSize, bytesLength);
var bytes = new Array(end - begin);
for (var offset = begin, i = 0; offset < end; ++i, ++offset) {
bytes[i] = byteCharacters[offset].charCodeAt(0);
}
byteArrays[sliceIndex] = new Uint8Array(bytes);
}
return new Blob(byteArrays, { type: contentType });
}
Following is my TypeScript code which can be converted easily into JavaScript and you can use
/**
* Convert BASE64 to BLOB
* #param base64Image Pass Base64 image data to convert into the BLOB
*/
private convertBase64ToBlob(base64Image: string) {
// Split into two parts
const parts = base64Image.split(';base64,');
// Hold the content type
const imageType = parts[0].split(':')[1];
// Decode Base64 string
const decodedData = window.atob(parts[1]);
// Create UNIT8ARRAY of size same as row data length
const uInt8Array = new Uint8Array(decodedData.length);
// Insert all character code into uInt8Array
for (let i = 0; i < decodedData.length; ++i) {
uInt8Array[i] = decodedData.charCodeAt(i);
}
// Return BLOB image after conversion
return new Blob([uInt8Array], { type: imageType });
}
See this example: https://jsfiddle.net/pqhdce2L/
function b64toBlob(b64Data, contentType, sliceSize) {
contentType = contentType || '';
sliceSize = sliceSize || 512;
var byteCharacters = atob(b64Data);
var byteArrays = [];
for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
var slice = byteCharacters.slice(offset, offset + sliceSize);
var byteNumbers = new Array(slice.length);
for (var i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
var byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
var blob = new Blob(byteArrays, {type: contentType});
return blob;
}
var contentType = 'image/png';
var b64Data = Your Base64 encode;
var blob = b64toBlob(b64Data, contentType);
var blobUrl = URL.createObjectURL(blob);
var img = document.createElement('img');
img.src = blobUrl;
document.body.appendChild(img);
For all browser support, especially on Android, perhaps you can add this:
try{
blob = new Blob(byteArrays, {type : contentType});
}
catch(e){
// TypeError old Google Chrome and Firefox
window.BlobBuilder = window.BlobBuilder ||
window.WebKitBlobBuilder ||
window.MozBlobBuilder ||
window.MSBlobBuilder;
if(e.name == 'TypeError' && window.BlobBuilder){
var bb = new BlobBuilder();
bb.append(byteArrays);
blob = bb.getBlob(contentType);
}
else if(e.name == "InvalidStateError"){
// InvalidStateError (tested on FF13 WinXP)
blob = new Blob(byteArrays, {type : contentType});
}
else{
// We're screwed, blob constructor unsupported entirely
}
}
For all copy-paste lovers out there like me, here is a cooked download function which works on Chrome, Firefox and Edge:
window.saveFile = function (bytesBase64, mimeType, fileName) {
var fileUrl = "data:" + mimeType + ";base64," + bytesBase64;
fetch(fileUrl)
.then(response => response.blob())
.then(blob => {
var link = window.document.createElement("a");
link.href = window.URL.createObjectURL(blob, { type: mimeType });
link.download = fileName;
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
});
}
I'm posting a more declarative way of sync Base64 converting. While async fetch().blob() is very neat and I like this solution a lot, it doesn't work on Internet Explorer 11 (and probably Edge - I haven't tested this one), even with the polyfill - take a look at my comment to Endless' post for more details.
const blobPdfFromBase64String = base64String => {
const byteArray = Uint8Array.from(
atob(base64String)
.split('')
.map(char => char.charCodeAt(0))
);
return new Blob([byteArray], { type: 'application/pdf' });
};
Bonus
If you want to print it you could do something like:
const isIE11 = !!(window.navigator && window.navigator.msSaveOrOpenBlob); // Or however you want to check it
const printPDF = blob => {
try {
isIE11
? window.navigator.msSaveOrOpenBlob(blob, 'documents.pdf')
: printJS(URL.createObjectURL(blob)); // http://printjs.crabbly.com/
} catch (e) {
throw PDFError;
}
};
Bonus x 2 - Opening a BLOB file in new tab for Internet Explorer 11
If you're able to do some preprocessing of the Base64 string on the server you could expose it under some URL and use the link in printJS :)
For image data, I find it simpler to use canvas.toBlob (asynchronous)
function b64toBlob(b64, onsuccess, onerror) {
var img = new Image();
img.onerror = onerror;
img.onload = function onload() {
var canvas = document.createElement('canvas');
canvas.width = img.width;
canvas.height = img.height;
var ctx = canvas.getContext('2d');
ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
canvas.toBlob(onsuccess);
};
img.src = b64;
}
var base64Data = 'data:image/jpg;base64,/9j/4AAQSkZJRgABAQA...';
b64toBlob(base64Data,
function(blob) {
var url = window.URL.createObjectURL(blob);
// do something with url
}, function(error) {
// handle error
});
If you can stand adding one dependency to your project there's the great blob-util npm package that provides a handy base64StringToBlob function. Once added to your package.json you can use it like this:
import { base64StringToBlob } from 'blob-util';
const contentType = 'image/png';
const b64Data = 'iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==';
const blob = base64StringToBlob(b64Data, contentType);
// Do whatever you need with your blob...
I noticed that Internet Explorer 11 gets incredibly slow when slicing the data like Jeremy suggested. This is true for Chrome, but Internet Explorer seems to have a problem when passing the sliced data to the Blob-Constructor. On my machine, passing 5 MB of data makes Internet Explorer crash and memory consumption is going through the roof. Chrome creates the blob in no time.
Run this code for a comparison:
var byteArrays = [],
megaBytes = 2,
byteArray = new Uint8Array(megaBytes*1024*1024),
block,
blobSlowOnIE, blobFastOnIE,
i;
for (i = 0; i < (megaBytes*1024); i++) {
block = new Uint8Array(1024);
byteArrays.push(block);
}
//debugger;
console.profile("No Slices");
blobSlowOnIE = new Blob(byteArrays, { type: 'text/plain'});
console.profileEnd();
console.profile("Slices");
blobFastOnIE = new Blob([byteArray], { type: 'text/plain'});
console.profileEnd();
So I decided to include both methods described by Jeremy in one function. Credits go to him for this.
function base64toBlob(base64Data, contentType, sliceSize) {
var byteCharacters,
byteArray,
byteNumbers,
blobData,
blob;
contentType = contentType || '';
byteCharacters = atob(base64Data);
// Get BLOB data sliced or not
blobData = sliceSize ? getBlobDataSliced() : getBlobDataAtOnce();
blob = new Blob(blobData, { type: contentType });
return blob;
/*
* Get BLOB data in one slice.
* => Fast in Internet Explorer on new Blob(...)
*/
function getBlobDataAtOnce() {
byteNumbers = new Array(byteCharacters.length);
for (var i = 0; i < byteCharacters.length; i++) {
byteNumbers[i] = byteCharacters.charCodeAt(i);
}
byteArray = new Uint8Array(byteNumbers);
return [byteArray];
}
/*
* Get BLOB data in multiple slices.
* => Slow in Internet Explorer on new Blob(...)
*/
function getBlobDataSliced() {
var slice,
byteArrays = [];
for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
slice = byteCharacters.slice(offset, offset + sliceSize);
byteNumbers = new Array(slice.length);
for (var i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
byteArray = new Uint8Array(byteNumbers);
// Add slice
byteArrays.push(byteArray);
}
return byteArrays;
}
}
The method with fetch is the best solution, but if anyone needs to use a method without fetch then here it is, as the ones mentioned previously didn't work for me:
function makeblob(dataURL) {
const BASE64_MARKER = ';base64,';
const parts = dataURL.split(BASE64_MARKER);
const contentType = parts[0].split(':')[1];
const raw = window.atob(parts[1]);
const rawLength = raw.length;
const uInt8Array = new Uint8Array(rawLength);
for (let i = 0; i < rawLength; ++i) {
uInt8Array[i] = raw.charCodeAt(i);
}
return new Blob([uInt8Array], { type: contentType });
}
In browser just
Uint8Array.from(atob(YOUR_BASE64_DATA), (c) => c.charCodeAt(0))
compare with fetch
!(async () => {
const start = performance.now();
let i = 0;
while (i++ < 1e3) {
const dataUrl =
"data:application/octet-stream;base64,H4sIAAAAAAAAA0vOzyvOz0nVy8lP10jISM3JyVdIr8osUFCpdkksSdXLyy/X0KxN0ORKHlU3qm5U3ai6UXWj6kauOgBVt1KRLwcAAA==";
body = await (await fetch(dataUrl)).blob();
}
console.log(performance.now() - start); // 508.19999999925494ms
})();
!(async () => {
const start = performance.now();
let i = 0;
while (i++ < 1e3) {
const base64Data =
"H4sIAAAAAAAAA0vOzyvOz0nVy8lP10jISM3JyVdIr8osUFCpdkksSdXLyy/X0KxN0ORKHlU3qm5U3ai6UXWj6kauOgBVt1KRLwcAAA==";
body = Uint8Array.from(atob(base64Data), (c) => c.charCodeAt(0));
}
console.log(performance.now() - start); // 7.899999998509884ms
})();
Depends on your data size, choose performance one.
Two different variations
function base64ToBlob(base64, contentType='image/png', chunkLength=512) {
const byteCharsArray = Array.from(atob(base64.substr(base64.indexOf(',') + 1)));
const chunksIterator = new Array(Math.ceil(byteCharsArray.length / chunkLength));
const bytesArrays = [];
for (let c = 0; c < chunksIterator.length; c++) {
bytesArrays.push(new Uint8Array(byteCharsArray.slice(c * chunkLength, chunkLength * (c + 1)).map(s => s.charCodeAt(0))));
}
const blob = new Blob(bytesArrays, {type: contentType});
return blob;
}
/* Not sure how it performs with big images */
async function base64ToBlobLight(base64) { return await fetch(base64).then(res => res.blob()); }
/* Test */
const base64Data = 'data:image/png;base64,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';
const blob = base64ToBlob(base64Data);
const blobUrl = URL.createObjectURL(blob);
const img = document.createElement('img');
img.src = blobUrl;
document.body.appendChild(img);
/**********************/
/* Test */
(async () => {
const blob = await base64ToBlobLight(base64Data);
const blobUrl = URL.createObjectURL(blob);
const img = document.createElement('img');
img.src = blobUrl;
document.body.appendChild(img);
})();
This would prove to be much short solution.
const byteArray = new Buffer(base64String.replace(/^[\w\d;:\/]+base64\,/g, ''), 'base64');
base64String is the string containing the base 64 string.
byteArray is the array you need.
The regex replacement is optional and is just there to deal with prefix as in the case of dataurl string.
Method: PUT
Endpoint :
/application1/file/{filetype}/transactionType {
"accountNumber":"344224433344333"
}
API will return file of type CSV/pdf/xls
Question:
How to open in new tab or download suing angularJs 1.5
I have tried few solution but it doesnot works in IE
https://codepen.io/waghanil87/pen/vZBozE
Thanks in advance!
you need to convert the base64 string to blob type and then donload/print it
function b64toBlob(b64Data,callback) {
var contentType = 'application/pdf'; // put your file type here
var sliceSize = 512;
b64Data = b64Data.replace(/^[^,]+,/, '');
b64Data = b64Data.replace(/\s/g, '');
var byteCharacters = window.atob(b64Data);
var byteArrays = [];
for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
var slice = byteCharacters.slice(offset, offset + sliceSize);
var byteNumbers = new Array(slice.length);
for (var i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
var byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
blob = new Blob(byteArrays, {
type: contentType
});
callback(blob)
}
function downloadData(fileName,blob) {
var a = document.createElement("a");
var url = window.URL.createObjectURL(blob);
document.body.appendChild(a);
a.style = "display: none";
a.href = url;
a.download = fileName;
a.click();
window.URL.revokeObjectURL(url);
}
// call it like this
b64toBlob(base64string,function(data){
function downloadData('sample.pdf',data)
})
My code is working fine when I zip 3 files around 300kb each and send it to client. Used following links for help:
Dynamically create and stream zip to client
how to convert multiple files to compressed zip file using node js
But as soon as I try to zip 4th file I get "download - Failed Network error" in chrome.
Following is my code:
var express = require('express');
var app = express();
var fileSystem = require('fs');
var Archiver = require('archiver');
var util = require('util');
var AdmZip = require('adm-zip');
var config = require('./config');
var log_file = fileSystem.createWriteStream(__dirname + '/debug.log', {flags : 'a'});
logError = function(d) { //
log_file.write('[' + new Date().toUTCString() + '] ' + util.format(d) + '\n');
};
app.get('/zip', function(req, res, next) {
try {
res = setHeaderOfRes(res);
sendZip(req, res);
}catch (err) {
logError(err.message);
next(err); // This will call the error middleware for 500 error
}
});
var setHeaderOfRes = function (res){
res.setHeader("Access-Control-Allow-Origin", "*"); //Remove this when this is on production
res.setHeader("Content-Type", "application/zip");
res.setHeader("Content-disposition", "attachment;");
return res;
};
var sendZip = function (req, res) {
var filesNotFound = [];
zip.pipe(res);
if (req.query.leapIds) {
var leapIdsArray = req.query.leapIds.split(',');
var i, lengthi;
for (i = 0, lengthi = leapIdsArray.length; i < lengthi; i++) {
try {
var t = config.web.sharedFilePath + leapIdsArray[i] + '.vsdx';
if (fileSystem.statSync(t).isFile()) {
zip.append(new fileSystem.createReadStream(t), {
name: leapIdsArray[i] + '.vsdx'
});
};
} catch (err) {
filesNotFound.push(leapIdsArray[i] + '.vsdx');
}
}
var k, lengthk;
var str = '';
for (k = 0, lengthk = filesNotFound.length; k < lengthk; k++) {
str += filesNotFound[k] +',';
}
if(filesNotFound.length > 0){
zip.append('These file/files does not exist on server - ' + str , { name: 'logFile.log' });
}
zip.finalize();
}
};
I tried zip.file instead of zip.append that didn't work.
I want to zip minimum 10 files of 300kb each and send it to the client. Can anyone please let me know the approach.
Thanks
/********************* Update ****************************************
I was only looking at server.js created in node. Actually the data is sent correctly to client. Angularjs client code seems to be not working for large files.
$http.get(env.nodeJsServerUrl + "zip?leapIds=" + nodeDetails, { responseType: "arraybuffer" }
).then(function (response) {
nodesDetails = response.data;
var base64String = _arrayBufferToBase64(nodesDetails);
function _arrayBufferToBase64(buffer) {
var binary = '';
var bytes = new Uint8Array(buffer);
var len = bytes.byteLength;
for (var i = 0; i < len; i++) {
binary += String.fromCharCode(bytes[i]);
}
return window.btoa(binary);
}
var anchor = angular.element('<a/>');
anchor.attr({
href: 'data:application/zip;base64,' + base64String,
target: '_blank',
download: $scope.main.routeParams.sectorId + "-ProcessFiles.zip"
})[0].click();
});
This part href: 'data:application/zip;base64,' + base64String, seems to be failing for large data received from server. For small files it is working. Large files it is failing.
Found out.
The problem was not in nodejs zipping logic. That worked perfect.
Issue was in the way I was handling the received response data.
If the data that is received is too large then following code fails
anchor.attr({
href: 'data:application/zip;base64,' + base64String,
target: '_blank',
download: $scope.main.routeParams.sectorId + "-ProcessFiles.zip"
})[0].click();
so the work around is to use blob:
function b64toBlob(b64Data, contentType, sliceSize) {
contentType = contentType || '';
sliceSize = sliceSize || 512;
var byteCharacters = atob(b64Data);
var byteArrays = [];
for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
var slice = byteCharacters.slice(offset, offset + sliceSize);
var byteNumbers = new Array(slice.length);
for (var i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}
var byteArray = new Uint8Array(byteNumbers);
byteArrays.push(byteArray);
}
var blob = new Blob(byteArrays, { type: contentType });
return blob;
}
var contentType = 'application/zip'
var blob = b64toBlob(base64String, contentType);
saveAs(blob, "hello world.zip");
This link helped me out: How to save binary data of zip file in Javascript?
already answered here: https://stackoverflow.com/a/62639710/8612027
Sending a zip file as binary data with expressjs and node-zip:
app.get("/multipleinzip", (req, res) => {
var zip = new require('node-zip')();
var csv1 = "a,b,c,d,e,f,g,h\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8";
zip.file('test1.file', csv1);
var csv2 = "z,w,x,d,e,f,g,h\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8";
zip.file('test2.file', csv2);
var csv3 = "q,w,e,d,e,f,g,h\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8";
zip.file('test3.file', csv3);
var csv4 = "t,y,u,d,e,f,g,h\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8\n1,2,3,4,5,6,7,8";
zip.file('test4.file', csv4);
var data = zip.generate({base64:false,compression:'DEFLATE'});
console.log(data); // ugly data
res.type("zip")
res.send(new Buffer(data, 'binary'));
})
Creating a download link for the zip file. Fetch data and convert the response to an arraybuffer with ->
//get the response from fetch as arrayBuffer...
var data = response.arrayBuffer();
const blob = new Blob([data]);
const fileName = `${filename}.${extension}`;
if (navigator.msSaveBlob) {
// IE 10+
navigator.msSaveBlob(blob, fileName);
} else {
const link = document.createElement('a');
// Browsers that support HTML5 download attribute
if (link.download !== undefined) {
const url = URL.createObjectURL(blob);
link.setAttribute('href', url);
link.setAttribute('download', fileName);
link.style.visibility = 'hidden';
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
}
}
I am using ngCropImage to crop an image and want to upload it following this link:
NgCropImage directive is returning me dataURI of the image and I am converting it to a blob (after converting it I get a blob object: which has size and type), Converted DataURI to blob using following code:
/*html*/
<img-crop image="myImage" result-image="myCroppedImage" result-image-size="250"></img-crop>
$scope.myImage='';
$scope.myCroppedImage = {image: ''}
var blob;
//called when user crops
var handleFileSelect=function(evt) {
var file=evt.currentTarget.files[0];
var reader = new FileReader();
reader.onload = function (evt) {
$scope.$apply(function($scope){
$scope.myImage=evt.target.result;
});
};
console.log($scope.myCroppedImage)
reader.readAsDataURL(file);
var link = document.createElement('link');
blob = dataURItoBlob($scope.myCroppedImage)
console.log(blob)
};
angular.element(document.querySelector('#fileInput')).on('change',handleFileSelect);
function dataURItoBlob(dataURI) {
// convert base64/URLEncoded data component to raw binary data held in a string
var binary = atob(dataURI.split(',')[1]);
var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];
var array = [];
for(var i = 0; i < binary.length; i++) {
array.push(binary.charCodeAt(i));
}
return new Blob([new Uint8Array(array)], {type: mimeString});
}
$scope.upload = function(file) {
//var file = new File(file, "filename");
// Configure The S3 Object
console.log($scope.creds)
AWS.config.update({ accessKeyId: $.trim($scope.creds.access_key), secretAccessKey: $.trim($scope.creds.secret_key) });
AWS.config.region = 'us-east-1';
var bucket = new AWS.S3({ params: { Bucket: $.trim($scope.creds.bucket) } });
if(file) {
//file.name = 'abc';
var uniqueFileName = $scope.uniqueString() + '-' + file.name;
var params = { Key: file.name , ContentType: file.type, Body: file, ServerSideEncryption: 'AES256' };
bucket.putObject(params, function(err, data) {
if(err) {
// There Was An Error With Your S3 Config
alert(err.message);
return false;
}
else {
// Success!
alert('Upload Done');
}
})
.on('httpUploadProgress',function(progress) {
// Log Progress Information
console.log(Math.round(progress.loaded / progress.total * 100) + '% done');
});
}
else {
// No File Selected
alert('No File Selected');
}
}
$scope.uniqueString = function() {
var text = "";
var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
for( var i=0; i < 8; i++ ) {
text += possible.charAt(Math.floor(Math.random() * possible.length));
}
return text;
}
//for uploading
$scope.handleSave = function(){
$scope.upload(blob);
}
Now, I want to upload this blob on S3 using this, but I am not able to figure out how to upload this blob file to s3 (as I am not getting 'name' in the blob file)
Any help would be really appreciated. Thanks
You can always create file from blob. You can pass file name also.
var file = new File([blob], "filename");
This same file object you can use to upload on s3.
Change your handleSave method to following. File name will be abc.png for now
//for uploading
$scope.handleSave = function(){
blob = dataURItoBlob($scope.myCroppedImage)
$scope.upload(new File([blob], "abc.png"));
}
It is not advisable that you do to put the key
secretAccessKey: $.trim($scope.creds.secret_key)
on the client side ... That is not done !, anyone can manipulate your bucket at will.