Greetings! I am currently in the process of developing an Ionic app with Firebase. My main goal is to upload multiple files while resizing them.
I have encountered a strange issue where, when I call the resize method, the input image appears different. However, once the uploading process is completed, it ends up uploading duplicated images (the last image in the array).
To investigate further, I used console.log to check the dataURL each time it resizes and discovered that the DataURL remains the same throughout.
The following code snippet demonstrates how to upload multiple files:
multipleUpload: function(key, folder, files, targetWidth) {
var q = $q.defer();
var ct = Date.now();
var urls = [];
var recursive = function (n, args) {
var arg = args[n];
ImageService.resize(arg.file, targetWidth)
.then(function(file) {
upload(ct + '' + n + key, folder + '/' + key, file, CONFIG.MESSAGE.FILE_UPLOAD + (n + 1) + '번 파일')
.then(function(url) {
urls.push(url);
if (++n < args.length) {
recursive(n, args);
} else {
q.resolve(urls);
}
}), function(error) {
q.reject(error);
};
})
}
recursive(0, files);
return q.promise;
},
Here's the code for the resizing method:
resize: function(file, targetWidth) {
var q = $q.defer();
// Resizing Image
var img = new Image();
img.setAttribute('crossOrigin', 'anonymous');
img.onload = function(){
var canvas = document.createElement("canvas"),
ctx = canvas.getContext("2d");
canvas.width = targetWidth;
canvas.height = canvas.width * (img.height / img.width);
ctx.drawImage(this, 0, 0, canvas.width, canvas.height);
// Data URL to BLOB
var dataURL = canvas.toDataURL();
console.log(dataURL); // Returns same dataURL all the time.
dataURLtoBlob(dataURL, Date.now())
.then(function(blob) {
q.resolve(blob);
});
};
img.src = file;
return q.promise;
},