通过 Node.js 从 iOS 应用程序将图像上传到服务器

我正在开发一个 iOS 应用程序并且正在使用node.js用于服务器端脚本编写。我在从 iOS 应用程序将图像上传到服务器时遇到问题。如果我从网页表单上传图像，它工作正常。但如果从应用程序端上传，则无法正常工作。

 //test file
 h3 Pic Upload
 form(action='/pic_upload', method='post',enctype='multipart/form-data') 
  | user_pic:
  input(type='file', name='user_pic')
  input(type='submit')

 //app.js
 var userlogin =require('./routes/userlogin');
 app.post('/pic_upload', userlogin.picUpload);

//userlogin.js
//picUpload function
exports.picUpload = function(req, res) {
console.log(req.files);  // showing undefined, when called from IOS app
// pic upload script...
});

我尝试从应用程序端发送图像作为数据或文件参数，但它不起作用。如何从应用程序端发送文件参数以便我可以轻松地将图像上传到服务器？请提出解决该问题的方法。

这段代码适用于我的应用程序。尝试这个。

NSData *imgData = UIImageJPEGRepresentation(newImg, 0.2);

NSString *str = @"displayImage";

    NSString *urlString = @"http://some.url.com/post";

    // create request
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
    [request setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];
    [request setHTTPShouldHandleCookies:NO];
    [request setTimeoutInterval:30];
    [request setURL:[NSURL URLWithString:urlString]];

    [request setHTTPMethod:@"POST"];

    NSString *boundary = [NSString stringWithFormat:@"---------------------------14737809831464368775746641449"];

    // set Content-Type in HTTP header
    NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary];
    [request setValue:contentType forHTTPHeaderField: @"Content-Type"];

    // post body
    NSMutableData *body = [NSMutableData data];

    // add params (all params are strings)
        [body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"currentEventID\"\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:[@"52344457901000006" dataUsingEncoding:NSUTF8StringEncoding]];


    // add image data
    if (imgData) {
        [body appendData:[[NSString stringWithFormat:@"\r\n--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
       // [body appendData:[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"displayImage\"; filename=\"image.jpg\"\r\n"]];
        [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"; filename=\"image.jpg\"\r\n", str] dataUsingEncoding:NSUTF8StringEncoding]];

        [body appendData:[@"Content-Type: image/jpeg\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
        [body appendData:imgData];
        [body appendData:[[NSString stringWithFormat:@"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    }

    [body appendData:[[NSString stringWithFormat:@"\r\n--%@--\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];

    // setting the body of the post to the reqeust
    [request setHTTPBody:body];

    // set URL
    [request setURL:[NSURL URLWithString:urlString]];

    NSString *bodyStr = [[NSString alloc]initWithData:body encoding:NSUTF8StringEncoding];
    NSLog(@" %@",bodyStr);

    NSURLConnection *lot_Connection=[[NSURLConnection alloc]initWithRequest:request delegate:self];

    if(lot_Connection)
    {
        webdata = [[NSMutableData alloc] init];

    }