Download data URL file
JavascriptData UriJavascript Problem Overview
I'm playing with the idea of making a completely JavaScript-based zip/unzip utility that anyone can access from a browser. They can just drag their zip directly into the browser and it'll let them download all the files within. They can also create new zip files by dragging individual files in.
I know it'd be better to do it serverside, but this project is just for a bit of fun.
Dragging files into the browser should be easy enough if I take advantage of the various methods available. (Gmail style)
Encoding/decoding should hopefully be fine. I've seen some as3 zip libraries so I'm sure I should be fine with that.
My issue is downloading the files at the end.
window.location = 'data:jpg/image;base64,/9j/4AAQSkZJR....'
this works fine in Firefox but not in Chrome.
I can embed the files as images just fine in chrome using <img src="data:jpg/image;ba.." />
, but the files won't necessarily be images. They could be any format.
Can anyone think of another solution or some kind of workaround?
Javascript Solutions
Solution 1 - Javascript
If you also want to give a suggested name to the file (instead of the default 'download') you can use the following in Chrome, Firefox and some IE versions:
function downloadURI(uri, name) {
var link = document.createElement("a");
link.download = name;
link.href = uri;
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
delete link;
}
And the following example shows it's use:
downloadURI("data:text/html,HelloWorld!", "helloWorld.txt");
Solution 2 - Javascript
function download(dataurl, filename) {
const link = document.createElement("a");
link.href = dataurl;
link.download = filename;
link.click();
}
download("data:text/html,HelloWorld!", "helloWorld.txt");
or:
function download(url, filename) {
fetch(url)
.then(response => response.blob())
.then(blob => {
const link = document.createElement("a");
link.href = URL.createObjectURL(blob);
link.download = filename;
link.click();
})
.catch(console.error);
}
download("https://get.geojs.io/v1/ip/geo.json","geoip.json")
download("data:text/html,HelloWorld!", "helloWorld.txt");
Solution 3 - Javascript
Ideas:
-
Try a
<a href="data:...." target="_blank">
(Untested) -
Use downloadify instead of data URLs (would work for IE as well)
Solution 4 - Javascript
Want to share my experience and help someone stuck on the downloads not working in Firefox and updated answer to 2014. The below snippet will work in both firefox and chrome and it will accept a filename:
// Construct the <a> element
var link = document.createElement("a");
link.download = thefilename;
// Construct the uri
var uri = 'data:text/csv;charset=utf-8;base64,' + someb64data
link.href = uri;
document.body.appendChild(link);
link.click();
// Cleanup the DOM
document.body.removeChild(link);
Solution 5 - Javascript
Here is a pure JavaScript solution I tested working in Firefox and Chrome but not in Internet Explorer:
function downloadDataUrlFromJavascript(filename, dataUrl) {
// Construct the 'a' element
var link = document.createElement("a");
link.download = filename;
link.target = "_blank";
// Construct the URI
link.href = dataUrl;
document.body.appendChild(link);
link.click();
// Cleanup the DOM
document.body.removeChild(link);
delete link;
}
Cross-browser solutions found up until now:
downloadify -> Requires Flash
databounce -> Tested in IE 10 and 11, and doesn't work for me. Requires a servlet and some customization. (Incorrectly detects navigator. I had to set IE in compatibility mode to test, default charset in servlet, JavaScript options object with correct servlet path for absolute paths...) For non-IE browsers, it opens the file in the same window.
download.js -> http://danml.com/download.html Another library similar but not tested. Claims to be pure JavaScript, not requiring servlet nor Flash, but doesn't work on IE <= 9.
Solution 6 - Javascript
There are several solutions but they depend on HTML5 and haven't been implemented completely in some browsers yet. Examples below were tested in Chrome and Firefox (partly works).
- Canvas example with save to file support. Just set your
document.location.href
to the data URI. - Anchor download example. It uses
<a href="your-data-uri" download="filename.txt">
to specify file name.
Solution 7 - Javascript
Combining answers from @owencm and @Chazt3n, this function will allow download of text from IE11, Firefox, and Chrome. (Sorry, I don't have access to Safari or Opera, but please add a comment if you try and it works.)
initiate_user_download = function(file_name, mime_type, text) {
// Anything but IE works here
if (undefined === window.navigator.msSaveOrOpenBlob) {
var e = document.createElement('a');
var href = 'data:' + mime_type + ';charset=utf-8,' + encodeURIComponent(text);
e.setAttribute('href', href);
e.setAttribute('download', file_name);
document.body.appendChild(e);
e.click();
document.body.removeChild(e);
}
// IE-specific code
else {
var charCodeArr = new Array(text.length);
for (var i = 0; i < text.length; ++i) {
var charCode = text.charCodeAt(i);
charCodeArr[i] = charCode;
}
var blob = new Blob([new Uint8Array(charCodeArr)], {type: mime_type});
window.navigator.msSaveOrOpenBlob(blob, file_name);
}
}
// Example:
initiate_user_download('data.csv', 'text/csv', 'Sample,Data,Here\n1,2,3\n');
Solution 8 - Javascript
This can be solved 100% entirely with HTML alone. Just set the href
attribute to "data:(mimetypeheader),(url)"
. For instance...
<a
href="data:video/mp4,http://www.example.com/video.mp4"
target="_blank"
download="video.mp4"
>Download Video</a>
Working example: JSFiddle Demo.
Because we use a Data URL, we are allowed to set the mimetype which indicates the type of data to download. Documentation:
>Data URLs are composed of four parts: a prefix (data:), a MIME type indicating the type of data, an optional base64 token if non-textual, and the data itself. (Source: MDN Web Docs: Data URLs.)
Components:
-
<a ...>
: The link tag. -
href="data:video/mp4,http://www.example.com/video.mp4"
: Here we are setting the link to the adata:
with a header preconfigured tovideo/mp4
. This is followed by the header mimetype. I.E., for a.txt
file, it would would betext/plain
. And then a comma separates it from the link we want to download. -
target="_blank"
: This indicates a new tab should be opened, it's not essential, but it helps guide the browser to the desired behavior. -
download
: This is the name of the file you're downloading.
Solution 9 - Javascript
If you only need to actually have a download action, like if you bind it to some button that will generate the URL on the fly when clicked (in Vue or React for example), you can do something as easy as this:
const link = document.createElement('a')
link.href = url
link.click()
In my case, the file is already properly named but you can set it thanks to filename
if needed.
Solution 10 - Javascript
For anyone having issues in IE:
Please upvote the answer here by Yetti: https://stackoverflow.com/questions/15931341/saving-canvas-locally-in-ie
dataURItoBlob = function(dataURI) {
var binary = atob(dataURI.split(',')[1]);
var array = [];
for(var i = 0; i < binary.length; i++) {
array.push(binary.charCodeAt(i));
}
return new Blob([new Uint8Array(array)], {type: 'image/png'});
}
var blob = dataURItoBlob(uri);
window.navigator.msSaveOrOpenBlob(blob, "my-image.png");
Solution 11 - Javascript
Your problem essentially boils down to "not all browsers will support this".
You could try a workaround and serve the unzipped files from a Flash object, but then you'd lose the JS-only purity (anyway, I'm not sure whether you currently can "drag files into browser" without some sort of Flash workaround - is that a HTML5 feature maybe?)
Solution 12 - Javascript
export const downloadAs = async (url: string, name: string) => {
const blob = await axios.get(url, {
headers: {
'Content-Type': 'application/octet-stream',
},
responseType: 'blob',
});
const a = document.createElement('a');
const href = window.URL.createObjectURL(blob.data);
a.href = href;
a.download = name;
a.click();
};