How to read image files from url using only vanilla javascript?
Question
Is there a way to read image files from url using only vanilla javascript ? As context, I'm building a simple drag and drop image uploader and I think I've got the part where you read a literal file from a PC, but as for URLs how can I do it? Example: https://imgur.com/upload
I would like to be able to drag an image from google and have it read in the dropzone.
https://codepen.io/Ryenra/pen/JjoyPaq
function dropEv(e) { e.preventDefault(); e.stopPropagation(); } function dragOver(e) { document.getElementById('box').style = "opacity: 0.9;"; } function dragLeave(e) { document.getElementById('box').style.removeProperty('opacity'); } function receiveFile(e) { let temp = e.dataTransfer.files; if(temp.length && temp[0].type.match(/image.*/)){ document.getElementById('eText').textContent = temp[0].name; }else{ alert('nv'); } }
html,body{ height: 100% } #content { height: 100%; display: flex; justify-content: center; align-items: center; } #box{ width: 350px; height: 300px; background: repeating-linear-gradient( -55deg, #222, #222 10px, #333 10px, #333 20px ); display: flex; justify-content: center; align-items: center; } #opa{ width: 100%; height: 100%; border: 2px solid #000; display: flex; justify-content: center; align-items: center; } #inputFile{ display: none; }
<.DOCTYPE html> <html lang="en"> <head> <link rel="stylesheet" href="style.css"> <script src="script,js"></script> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width. initial-scale=1,0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> </head> <body> <div id="content"> <div id="box" ondrop="dropEv(event),dragLeave(event),receiveFile(event)" ondragover="dragOver(event),dropEv(event)" ondragleave="dragLeave(event)"> <div id= "opa"> <p id="eText">Choose an image or drag it here!</p> </div> </div> </div> </body> </html>
2 answers
solution1
0 2020-01-09 13:13:27
You can use the Fetch API like Nigel mentioned.
fetch('the image url', {mode: 'cors'})
.then(res => res.blob())
.then(blob => { /* use the blob */ })
fetch will return a response that you need to read as a Blob using res.blob()
Note: both fetch and res.blob return a promise which needs to be resolved using either .then() like in the example or async/await.
Blob and File are basically the same so you can probably use the Blob for whatever you need, but if you really need to, you can convert it into a File by using the File() constructor like this:
let file = new File([blob], "file name", {type: blob.type})
However because CORS exists, you might run into issues when trying to fetch images from arbitrary sites. Then you'll probably have to create a proxy server to fetch the images and add the 'Access-Control-Allow-Origin' header to the image with the value of either "*" (any domain) or "the domain your site is on".
Sorry for the plug, but I've recently wrote a guide on working with files on the client-side recently and it might prove useful for your project: Using Files in Client-Side JavaScript
solution2
0 2020-01-09 13:19:24
In general, you can't. The Same-origin policy prevents browsers from reading the data from a different origin (unless CORS is used to grant permission).
You gave https://imgur.com/upload as an example, but they don't read the image using client-side JavaScript. The URL itself is sent to the server, then the requested from there by server-side code.
solution3
-1 2019-12-27 06:56:18
Is there a way to read image files from url using only vanilla javascript ? As context, I'm building a simple drag and drop image uploader and I think I've got the part where you read a literal file from a PC, but as for URLs how can I do it? Example: https://imgur.com/upload
I would like to be able to drag an image from google and have it read in the dropzone.
https://codepen.io/Ryenra/pen/JjoyPaq
function dropEv(e) { e.preventDefault(); e.stopPropagation(); } function dragOver(e) { document.getElementById('box').style = "opacity: 0.9;"; } function dragLeave(e) { document.getElementById('box').style.removeProperty('opacity'); } function receiveFile(e) { let temp = e.dataTransfer.files; if(temp.length && temp[0].type.match(/image.*/)){ document.getElementById('eText').textContent = temp[0].name; }else{ alert('nv'); } }
html,body{ height: 100% } #content { height: 100%; display: flex; justify-content: center; align-items: center; } #box{ width: 350px; height: 300px; background: repeating-linear-gradient( -55deg, #222, #222 10px, #333 10px, #333 20px ); display: flex; justify-content: center; align-items: center; } #opa{ width: 100%; height: 100%; border: 2px solid #000; display: flex; justify-content: center; align-items: center; } #inputFile{ display: none; }
<!DOCTYPE html> <html lang="en"> <head> <link rel="stylesheet" href="style.css"> <script src="script.js"></script> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> </head> <body> <div id="content"> <div id="box" ondrop="dropEv(event),dragLeave(event),receiveFile(event)" ondragover="dragOver(event),dropEv(event)" ondragleave="dragLeave(event)"> <div id= "opa"> <p id="eText">Choose an image or drag it here!</p> </div> </div> </div> </body> </html>
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