ios 使用 HTTP POST 上传图像和文本

谢谢阅读。

我是 iOS 新手，我正在尝试使用上传图像和文本multi-part form encoding在 iOS 中。

The curl等价的是这样的：curl -F "param1=value1" -F "[email protected] /cdn-cgi/l/email-protection" "http://some.ip.address:5000/upload http://some.ip.address:5000/upload"

The curl上面的命令返回预期的正确响应JSON.

Problem:我不断收到 HTTP 400 请求，这意味着我在编写 HTTP POST 正文时做错了什么。

我做了什么：作为一些参考，我尝试过Flickr API iOS 应用程序“POST 大小太大！” https://stackoverflow.com/questions/4683559/flickr-api-ios-app-post-size-too-large and Objective C：如何使用HTTP POST上传图像和文本？ https://stackoverflow.com/questions/5422028/objective-c-how-to-upload-image-and-text-using-http-post。但是，我不断收到 HTTP 400。

我尝试过ASIHttpRequest但那里有一个不同的问题（回调从未被调用）。但是，我没有对此进行进一步调查，因为我听说开发人员已停止支持该库：http://allseeing-i.com/[request_release] http://allseeing-i.com/%5Brequest_release%5D;

有人可以帮我吗？

以下是我的应用程序中用于将图像发布到我们的网络服务器的代码：

// Dictionary that holds post parameters. You can set your post parameters that your server accepts or programmed to accept.
NSMutableDictionary* _params = [[NSMutableDictionary alloc] init];
[_params setObject:[NSString stringWithString:@"1.0"] forKey:[NSString stringWithString:@"ver"]];
[_params setObject:[NSString stringWithString:@"en"] forKey:[NSString stringWithString:@"lan"]];
[_params setObject:[NSString stringWithFormat:@"%d", userId] forKey:[NSString stringWithString:@"userId"]];
[_params setObject:[NSString stringWithFormat:@"%@",title] forKey:[NSString stringWithString:@"title"]];

// the boundary string : a random string, that will not repeat in post data, to separate post data fields.
NSString *BoundaryConstant = [NSString stringWithString:@"----------V2ymHFg03ehbqgZCaKO6jy"];

// string constant for the post parameter 'file'. My server uses this name: `file`. Your's may differ 
NSString* FileParamConstant = [NSString stringWithString:@"file"];

// the server url to which the image (or the media) is uploaded. Use your server url here
NSURL* requestURL = [NSURL URLWithString:@""]; 

// create request
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];                                    
[request setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];
[request setHTTPShouldHandleCookies:NO];
[request setTimeoutInterval:30];
[request setHTTPMethod:@"POST"];

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

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

// add params (all params are strings)
for (NSString *param in _params) {
    [body appendData:[[NSString stringWithFormat:@"--%@\r\n", BoundaryConstant] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"\r\n\r\n", param] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"%@\r\n", [_params objectForKey:param]] dataUsingEncoding:NSUTF8StringEncoding]];
}

// add image data
NSData *imageData = UIImageJPEGRepresentation(imageToPost, 1.0);
if (imageData) {
    [body appendData:[[NSString stringWithFormat:@"--%@\r\n", BoundaryConstant] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"%@\"; filename=\"image.jpg\"\r\n", FileParamConstant] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:[[NSString stringWithString:@"Content-Type: image/jpeg\r\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [body appendData:imageData];
    [body appendData:[[NSString stringWithFormat:@"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
}

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

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

// set the content-length
NSString *postLength = [NSString stringWithFormat:@"%lu",(unsigned long) [body length]];
[request setValue:postLength forHTTPHeaderField:@"Content-Length"];

// set URL
[request setURL:requestURL];