将blob附加到表单中类型file的输入 [英] Attach a blob to an input of type file in a form

问题描述

如何将blob附加到类型文件的输入

How to append blob to input of type file

// Input of type file
<input type="file" name="uploadedFile" id="uploadedFile" accept="image/*"><br>

// I am getting image from webcam and converting it to a blob
function takepicture() {
    canvas.width = width;
    canvas.height = height;
    canvas.getContext('2d').drawImage(video, 0, 1, width, height);
    var data = canvas.toDataURL('image/png');
    var dataURL = canvas.toDataURL();
    var blob = dataURItoBlob(dataURL);
    photo.setAttribute('src', data);
}

function dataURItoBlob(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/jpeg'});
    }

    // How can I append this var blob to "uploadedFile". I want to add this on form submit

推荐答案

我有一个类似的问题与角度应用程序中相当复杂的形式，所以而不是形式我只是使用 XMLHttpRequest（）单独发送blob。这个特殊的blob是在 WebAudioAPI 上下文中创建的，在用户的浏览器中创建了一个音轨。

I had a similar problem with a fairly complex form in an angular app, so instead of the form I just sent the blob individually using XMLHttpRequest(). This particular "blob" was created in a WebAudioAPI context, creating an audio track in the user's browser.

var xhr = new XMLHttpRequest();
xhr.open('POST', 'someURLForTheUpload', true); //my url had the ID of the item that the blob corresponded to
xhr.responseType = 'Blob';
xhr.setRequestHeader("x-csrf-token",csrf); //if you are doing CSRF stuff
xhr.onload = function(e) { /*irrelevant code*/ };
xhr.send(blob);

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