如何将图像从 URL 附加到 FormData - Javascript

Question

这是我的小javascript代码：

<script>

var formData = new FormData();

URL = "view.php?fetchImageById=1";

formData.append("imageFile", ....);

formData.append("author","user");
formData.append("description","image");

x=new XMLHttpRequest();
x.open("POST","upload.php",true);
x.setRequestHeader("Content-type", "multipart/form-data");
x.setRequestHeader("Content-Length",formData.length);
x.send(formData);
</script>

我不知道如何将 URL 附加到 formData。

Answer 1

你可以执行两个 XMLHttpRequest()；首先 GET 通过将 responseType 设置为 "blob" 来请求图像作为 Blob；然后在 POST

处将 Blob 回复附加到 FormData

var formData = new FormData();   
URL = "view.php?fetchImageById=1";    
var x;

var request = new XMLHttpRequest();
request.responseType = "blob";
request.onload = function() {
  formData.append("imageFile", request.response);
  formData.append("author","user");
  formData.append("description","image");
  x = new XMLHttpRequest();
  x.open("POST","upload.php",true);
  x.setRequestHeader("Content-type", "multipart/form-data");
  x.setRequestHeader("Content-Length", formData.length);
  x.send(formData);
}
request.open("GET", URL);
request.send();

如何将图像从 URL 附加到 FormData - Javascript

How to append an image from URL to a FormData - Javascript

javascript

form-data