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MediaSource fetching/downloading

When I try to fetch MediaSource object via blob link or send GET XMLHttpRequest I'm getting the error net::ERR_FILE_NOT_FOUND.
This happened for youtube or instagram MediaSource links.
eg
var xhr = new XMLHttpRequest;
xhr.open('get', url);
xhr.responseType = 'arraybuffer';
xhr.onload = function () {
some_Further_CallBack(xhr.response);
};
xhr.send();
I'm completelly stuck, please say me what I'm doing wrong.

The blob: URL when created from a MediaSource can not be fetched from that URL. Note that even when it's created from a Blob, it's not the same Blob object that you fetch.
The best is to keep your MediaSource instance available in a variable, but in cases you can't (e.g because you're not the author of the page), you can add some hooks on the URL methods to save the original object and retrieve it later as exposed in this answer of mine. But note that you'd need this script to be ran BEFORE the page's use of URL.creatObjectURL(), which means that in your case you will probably need an user-script to inject it as soon as possible.

Try get error after send
https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/error_event
But i think is not possible get content from youtube by XMLHttpRequest

Javascript delete blobs from xmlhttprequest

I have a web app that pre-loads videos by requesting blobs and creating blob urls.
// Get video Blob URL
const url = 'https://www.some-video-url.com/video.mp4';
const xhr = new XMLHttpRequest();
xhr.open('GET', sourceUrl, true);
xhr.responseType = 'blob';
xhr.onprogress = () => {console.log('downloading')};
const blobUrl;
xhr.onload = () => {
blobUrl = URL.createObjectURL(req.response);
console.log('done');
};
xhr.send();
...
// After using video
URL.revokeObjectURL(blobUrl);
I would send such requests multiple times. It work fine in the beginning, however, when I send too many of these requests I get this error.
VM1853:10 GET https://www.some-video-url.com/video.mp4 net::ERR_FAILED 200
I am running this on Chrome and it here is my hypothesis.
According to this documentation it seems like Blob storage limit for chrome is 10% of total disk space. I confirmed this by sending xhr request to GET a 2 GB file until I hit the error. It got an error when I sent request for 20 of the 2GB files. It seems like the blobs are not garbage collected because it is not properly de-referenced. This mysterious reference seems to be related to the xhr.
In my application, I would like to
1. Start downloading videos in the background
2. Client watches a video
3. When the video playback is done, remove the video
Is there a reliable way to execute step 3? I would like the Blob to be deleted after its use.

Get image data from another domain with AJAX request

I am trying to get binary data of an image from another domain with an AJAX request. I tried various methods, but there was no working solution. I found some code on the internet that looked good, but even with this calls I get errors.
What do I wrong? Is there a standardized way to do this?
Here is what I tried until now:
var request = this.createCORSRequest('GET', 'http://url/to/image.png');
request.onload = function () {
var text = request.response;
};
request.onerror = function (error) {
alert('Woops, there was an error making the request.');
};
request.send();
private createCORSRequest(method, url) {
var xhr: XMLHttpRequest = new XMLHttpRequest();
if ("withCredentials" in xhr) {
// Check if the XMLHttpRequest object has a "withCredentials" property.
// "withCredentials" only exists on XMLHTTPRequest2 objects.
xhr.open(method, url, true);
} else if (typeof XDomainRequest != "undefined") {
// Otherwise, check if XDomainRequest.
// XDomainRequest only exists in IE, and is IE's way of making CORS requests.
var xdhr = new XDomainRequest();
xdhr.open(method, url);
} else {
// Otherwise, CORS is not supported by the browser.
xhr = null;
}
return xhr;
}
I even found this solution without ajax here on stackoverflow, but it does not work for me:
Asynchronously load images with jQuery
Here a screen of the properties the error event contains:
My goal is to get the binary of an image from a url which I get from an atom feed . I need the binaries to copy the picture to MS SharePoint.

You cannot get data from another domain unless :
the remote server allows it using CORS
you run your browser in an unsafe mode.
Reason : otherwise site A would be able to (maliciously) read the user data from site B

You must add headers to the method to allow cross domain request.
For example, if you are trying to get data from www.example.com/main.php , then you must add headers to allow those method to be called from different domain.

Javascript binary file download, and ajax file POST upload in Chrome Extension

I'm writing a chrome extension content script which will embed itself on some pages, and when there are certain file type links (.doc, .torrent, etc) it will download that file, and then do a file POST to a python web server which will save that file. The python server is working, and handles a normal multipart/form-data POST request, and successfully saves the file when I use the html interface I wrote for it.
I have javascript downloading the file properly:
var req = new XMLHttpRequest();
req.open('GET', 'http://foo.com/bar.torrent', false);
req.overrideMimeType('text/plain; charset=x-user-defined');
req.send(null);
if (req.status != 200) return '';
var response = req.responseText;
And then when I try to create a POST request and upload it
// Define a boundary, I stole this from IE but you can use any string AFAIK
var boundary = "---------------------------7da24f2e50046";
var xhr = new XMLHttpRequest();
var body = '--' + boundary + '\r\n'
// Parameter name is "file" and local filename is "temp.txt"
+ 'Content-Disposition: form-data; name="upfile";'
+ 'filename="temp.torrent"\r\n'
// Add the file's mime-type
+ 'Content-type: application/bittorrent\r\n\r\n'
+ response + '\r\n';
//+ boundary + '--';
xhr.open("POST", "http://python.server/", true);
xhr.setRequestHeader(
"Content-type", "multipart/form-data; boundary="+boundary
);
xhr.onreadystatechange = function ()
{
if (xhr.readyState == 4 && xhr.status == 200)
alert("File uploaded!");
}
xhr.send(body);
It thinks that it uploaded successfully, but when I try to open the file it says the data is corrupted. I think this is some kind of encoding issue, but I'm not 100% sure.
Any thoughts would be very helpful.

Your upload method does not work, because all binary characters are encoded as UTF-8. I posted the explanation and solution in an answer at this question.
In your case, you don't need to manually create the post data. Request the initial data in a smart way, and use the FormData object to post the binary data. For instance:
var x = new XMLHttpRequest();
x.onload = function() {
// Create a form
var fd = new FormData();
fd.append("upfile", x.response); // x.response is a Blob object
// Upload to your server
var y = new XMLHttpRequest();
y.onload = function() {
alert('File uploaded!');
};
y.open('POST', 'http://python/server/');
y.send(fd);
};
x.responseType = 'blob'; // <-- This is necessary!
x.open('GET', 'http://foo.com/bar.torrent', true);
x.send();
Note: I replaced false with true at the initial request. Avoid using synchronous XMLHttpRequest when it's also possible to asynchronously create the request.
If you don't understand the answer, here are more examples with thorough explanations:
XMLHttpRequest: Multipart/Related POST with XML and image as payload - FormData is not used, but the post data is manually created instead.
Upload a File in a Google Chrome Extension - A sample Chrome extension which uses Web Workers (with a FormData polyfill) to upload files
Google chrome rehost image extension - Scrapes an image from the page, and upload the image to imgur using a Chrome extension.

Canvas tainted by cross-origin data

I'm loading a motion jpeg from third-party site, which I can trust. I'm trying to getImageData() but the browser (Chrome 23.0) complains that:
Unable to get image data from canvas because the canvas has been tainted by
cross-origin data.
There are some similar questions on SO, but they are using local file and I'm using third party media. My script runs on a shared server and I don't own the remote server.
I tried img.crossOrigin = 'Anonymous' or img.crossOrigin = '' (see this post on the Chromium blog about CORS), but it didn't help. Any idea on how can I getImageData on a canvas with cross-origin data? Thanks!

You cannot reset the crossOrigin flag once it is tainted, but if you know before hand what the image is you can convert it to a data url, see Drawing an image from a data URL to a canvas
But no, you cannot and should not be using getImageData() from external sources that don't support CORS

While the question is very old the problem remains and there is little on the web to solve it. I came up with a solution I want to share:
You can use the image (or video) without the crossorigin attribute set first and test if you can get a HEAD request thru to the same resource via AJAX. If that fails, you cannot use the resource. if it succeeds you can add the attribute and re-set the source of the image/video with a timestamp attached which reloads it.
This workaround allows you to show your resource to the user and simply hide some functions if CORS is not supported.
HTML:
<img id="testImage" src="path/to/image.png?_t=1234">
JavaScript:
var target = $("#testImage")[0];
currentSrcUrl = target.src.split("_t=").join("_t=1"); // add a leading 1 to the ts
$.ajax({
url: currentSrcUrl,
type:'HEAD',
withCredentials: true
})
.done(function() {
// things worked out, we can add the CORS attribute and reset the source
target.crossOrigin = "anonymous";
target.src = currentSrcUrl;
console.warn("Download enabled - CORS Headers present or not required");
/* show make-image-out-of-canvas-functions here */
})
.fail(function() {
console.warn("Download disabled - CORS Headers missing");
/* ... or hide make-image-out-of-canvas-functions here */
});
Tested and working in IE10+11 and current Chrome 31, FF25, Safari 6 (Desktop).
In IE10 and FF you might encounter a problem if and only if you try to access http-files from a https-script. I don't know about a workaround for that yet.
UPDATE Jan 2014:
The required CORS headers for this should be as follows (Apache config syntax):
Header set Access-Control-Allow-Origin "*"
Header set Access-Control-Allow-Headers "referer, range, accept-encoding, x-requested-with"
the x-header is required for the ajax request only. It's not used by all but by most browsers as far as I can tell

Also worth noting that the CORS will apply if you are working locally regardless of if the resource is in the same directory as the index.html file you are working with. For me this mean the CORS problems disappeared when I uploaded it to my server, since that has a domain.

You can use base64 of the image on canvas,
While converting into base64 you can use a proxy URL (https://cors-anywhere.herokuapp.com/) before your image path to avoid cross-origin issue
check full details here
https://stackoverflow.com/a/44199382/5172571
var getDataUri = function (targetUrl, callback) {
var xhr = new XMLHttpRequest();
xhr.onload = function () {
var reader = new FileReader();
reader.onloadend = function () {
callback(reader.result);
};
reader.readAsDataURL(xhr.response);
};
var proxyUrl = 'https://cors-anywhere.herokuapp.com/';
xhr.open('GET', proxyUrl + targetUrl);
xhr.responseType = 'blob';
xhr.send();
};
getDataUri(path, function (base64) {
// base64 availlable here
})