Facebook Javascript表单数据照片上传:需要上传文件错误

Facebook Javascript Form Data Photo Upload: requires upload file error

本文关键字：文件 错误 Javascript 数据 照片 Facebook 表单      更新时间：2023-09-26

我几乎搜索了每个帖子15-几个小时，还没有找到我问题的答案。我使用严格的Javascript上传照片到Facebook使用表单数据。我解码了JPEG图像(最初是svg -> canvas元素)中的base64数据，使用此解码方法(https://github.com/danguer/blog-examples/blob/master/js/base64-binary.js)，然后将其转换为表单数据格式的字符串，如https://gist.github.com/andyburke/1498758(不使用XMLHttpRequest)。然后，我将该字符串作为post中的"source"参数。我一直得到一个"(#324)需要上传文件"。如果我为图片输入一个url，效果就很好了。有人能帮忙吗?谢谢!

// The function to post the image:
FB.api("/me/photos", 
          "POST",
          {
              "source": window.image_source,
              "message": "...",
              "fileName": "..."
          },
          function(response) {
            console.log(response.error);
            }
      });
// How I got the image_source:
var img = canvas.toDataURL("image/jpeg");
var encoded = img.substring(img.indexOf(',')+1,img.length);
var decoded = decode(encoded);
convertToFormData(decoded);
function convertToFormData(imageData) {
    var boundary = 'myboundary';
    var formData = "Content-Type: multipart/form-data; boundary=" + boundary + ''r'n'r'n';
    formData += '--' + boundary + ''r'n';
    formData += 'Content-Disposition: form-data; name="source"; filename="' + "myfile" + '"'r'n';
    for ( var i = 0; i < imageData.length; ++i )
        formData += String.fromCharCode(imageData[i] & 0xff);
    formData += ''r'n';
    formData += '--' + boundary + ''r'n'+ 'Content-Disposition: form-data; name="message"'r'n'r'n';
    formData += "Description" + ''r'n';
    formData += '--' + boundary + '--'r'n';
    window.image_source = formData;
  }
function decode(input) {
    var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
    var lkey1 = keyStr.indexOf(input.charAt(input.length-1));    
    var lkey2 = keyStr.indexOf(input.charAt(input.length-2));    
    var bytes = (input.length/4) * 3;
    if (lkey1 == 64) bytes--; 
    if (lkey2 == 64) bytes--; 
    var chr1, chr2, chr3; var enc1, enc2, enc3, enc4;
    var i = 0;var j = 0;
    var uarray = new Uint8Array(bytes);
    input = input.replace(/[^A-Za-z0-9'+'/'=]/g, "");
    for (i=0; i<bytes; i+=3) {  
      enc1 = keyStr.indexOf(input.charAt(j++));
      enc2 = keyStr.indexOf(input.charAt(j++));
      enc3 = keyStr.indexOf(input.charAt(j++));
      enc4 = keyStr.indexOf(input.charAt(j++));
      chr1 = (enc1 << 2) | (enc2 >> 4);
      chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
      chr3 = ((enc3 & 3) << 6) | enc4;
      uarray[i] = chr1;     
      if (enc3 != 64) uarray[i+1] = chr2;
      if (enc4 != 64) uarray[i+2] = chr3;
    }
    return uarray;  
  }

你必须把画布图像变成一个Blob上传到Facebook:

const dataURItoBlob = (dataURI) => {
    let byteString = atob(dataURI.split(',')[1]);
    let ab = new ArrayBuffer(byteString.length);
    let ia = new Uint8Array(ab);
    for (let i = 0; i < byteString.length; i++) {
        ia[i] = byteString.charCodeAt(i);
    }
    return new Blob([ia], {
        type: 'image/jpeg'
    });
}

之后，您可以使用博客与FormData:

formData.append('source', blob);

来源:http://www.devils-heaven.com/facebook-javascript-sdk-photo-upload-from-canvas/

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