Newbie here. The problem is that I currently have written a method which checks uploaded file size and extension in order to validate it. However, checking extensions is not a solution as that kind of validation may cause a lot of problems. What I want to do is to check the actual file type and validate it without using extension method. I have tried to use jQuery file validator but to no avail... This is a snippet from my current code:
<input type='file' id='imageLoader' name='imageLoader' accept="image/*" data-type='image' />
Script:
App.Dispatcher.on("uploadpic", function() {
$(":file").change(function() {
if (this.files && this.files[0] && this.files[0].name.match(/\.(jpg|jpeg|png|gif)$/) ) {
if(this.files[0].size>1048576) {
alert('File size is larger than 1MB!');
}
else {
var reader = new FileReader();
reader.onload = imageIsLoaded;
reader.readAsDataURL(this.files[0]);
}
} else alert('This is not an image file!');
});
function imageIsLoaded(e) {
result = e.target.result;
$('#image').attr('src', result);
};
});
It is called once the upload input changes and after validation it uploads and displays the image. For now, I only care about validation and any help or ideas would be greatly appreciated!
Try something like this:
JavaScript
const file = this.files[0];
const fileType = file['type'];
const validImageTypes = ['image/gif', 'image/jpeg', 'image/png'];
if (!validImageTypes.includes(fileType)) {
// invalid file type code goes here.
}
jQuery
var file = this.files[0];
var fileType = file["type"];
var validImageTypes = ["image/gif", "image/jpeg", "image/png"];
if ($.inArray(fileType, validImageTypes) < 0) {
// invalid file type code goes here.
}
You don't need jquery here.
var mimeType=this.files[0]['type'];//mimeType=image/jpeg or application/pdf etc...
//ie image/jpeg will be ['image','jpeg'] and we keep the first value
if(mimeType.split('/')[0] === 'image'){
console.log('the file is image');
}
You can also create a function to check when a file is image.
function isImage(file){
return file['type'].split('/')[0]=='image');//returns true or false
}
isImage(this.file[0]);
Update (es6)
using es6 includes method, makes it even more simple.
const isImage = (file) => file['type'].includes('image');
Pls refer a related query here. The answer here suggests to load the image in an Image object and check for it's width and height properties to be non zero. I think the technique can be used to solve your problem too.
I also worked out a fiddle for you to refer. Pertinent code below:
var img = new Image();
img.addEventListener("load",function(){
alert('success');
});
img.addEventListener("error",function(){
alert('error');
});
img.src = picFile.result;