如果在iOS& amp;上的网络应用中使用FormData发送文件，则文件转换为[Object object]字符串安卓 [英] File converted to [Object object] string if sent using FormData in web app on iOS & Android

问题描述

我正在构建基于Cordova/PhoneGap的Web应用程序，该应用程序使用多部分/表单数据POST请求将文件上传到服务器.

I am building a web app based on Cordova/PhoneGap which uploads files to a server using a multipart/form-data POST request.

以下代码可在BlackBerry 10上使用:

The following code works on BlackBerry 10:

var postRequest = new XMLHttpRequest();
if (postRequest.overrideMimeType) {
    postRequest.overrideMimeType('text/xml');
}
var fd = new FormData();
fd.append('param1', 'value1');
[...]
fd.append('file', file, fileName);
postRequest.open('POST', url, true);
postRequest.send(fd);

但是，在运行iOS6的iPhone上，当将 File 对象发送到服务器时，它会由 String [Object object]替换，类似于 Safari在以下情况下将文件转换为[object Object]插入FormData中.如何解决?.

However on an iPhone running iOS6 the File object is replaced by the String [Object object] when sent to the server, similar to the issue described in Safari converts File to [object Object] when inserted into FormData. How to fix?.

与该问题相反，我没有克隆File对象.通过在...中打开"菜单使用其他应用程序中的文档调用我的应用程序.我通过了一个本地文件系统URI，可以使用 window.resolveLocalFileSystemURI()进行解析.这可以完美地工作，我首先收到一个FileEntry，然后从该File对象收到一个.但是，似乎无法正确识别该对象，并且在将请求传输到服务器时调用了它的 toString()方法.

In contrast to that issue I am not cloning the File object. My app is invoked with documents from other apps via the "Open in..." menu. I am passed a local file system URI which I resolve using window.resolveLocalFileSystemURI(). This works perfectly and I receive first a FileEntry and from that a File object. However it appears this object is not recognized correctly and its toString() method is called instead when transmitting the request to the server.

这是iOS上的错误吗?还是在创建File对象时PhoneGap中的错误?最好的解决方法是什么?

Is this a bug on iOS? Or maybe a bug in PhoneGap when creating the File object? What is the best workaround?

更新:我只是在Android上遇到了相同的问题，因此该问题似乎并非特定于iOS.

UPDATE: I just ran into the same problem on Android, so this problem doesn't seem to be specific to iOS.

推荐答案

iOS可能的解决方法似乎是使用FileReader读取文件，从中构造一个新的Blob对象，然后将其传输到服务器:

A possible workaround for iOS seems to be to read the file using FileReader, construct a new Blob object from it and then transmit this to the server instead:

var reader = new FileReader();
reader.onloadend = function(evt) {
     var fileBlob = new Blob([evt.target.result], { 'type' : fileType });
};
reader.readAsArrayBuffer(file);

此处使用的Blob构造函数需要iOS 6.0或更高版本.这样，数据就可以按照预期的方式完全传输到服务器了.

The Blob constructor used here requires iOS 6.0 or higher. This way the data was completely transmitted to the server as intended.

也可以使用WebKitBlobBuilder在Android上创建Blob.不幸的是，在我进行测试时，这并不能解决Android上的问题.

A Blob can be created on Android, too, using WebKitBlobBuilder. Unfortunately this didn't fix the problem on Android during my tests.

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