iOS，使用多部分表单数据上传文件

Question

我想上传文件到 HTTP 服务器。我现在就是这样做的:

NSString *boundary = @"*****";

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];

[request setURL:[NSURL URLWithString:@"http://someUploadScript.php"]];
[request setHTTPMethod:@"POST"];

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

[request setValue:@"Keep-Alive" forHTTPHeaderField: @"Connection"];

dispatch_async(queue, ^{
    NSMutableData *postbody = [NSMutableData data];

    [postbody appendData:[[NSString stringWithFormat:@"--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
    [postbody appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile\"; filename=\"video.mp4\"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
    [postbody appendData:[@"Content-Type: application/octet-stream\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];

    NSString* outputPath = @"somePathToFile";
    NSData *data = [NSData dataWithContentsOfFile:outputPath];

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

    [request setHTTPBody:postbody];
    previousBytesWritten = 0;
    connection = [[NSURLConnection alloc]initWithRequest:request delegate:self];
});

我想发送一些额外的数据，例如。使用“userId”值提交“user”。我想发送某种数组，例如:

video[user] = "userId"
video[file] = //file bytes

我知道我可以使用 HTTP multipartform-data 来做到这一点，但我真的不知道怎么做，也不明白它是如何工作的。谁能解释一下我该怎么做以及它是如何工作的？

Answer 1

尝试这样的事情:

NSMutableData *postbody = [NSMutableData data];

[postbody appendData:[[NSString stringWithFormat:@"--%@\r\n",boundary] dataUsingEncoding:NSUTF8StringEncoding]];
[postbody appendData:[[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile\"; filename=\"video.mp4\"\r\n"] dataUsingEncoding:NSUTF8StringEncoding]];
[postbody appendData:[@"Content-Type: application/octet-stream\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];

NSString* outputPath = @"somePathToFile";
NSData *data = [NSData dataWithContentsOfFile:outputPath];

[postbody appendData:data];
[postbody appendData:[@"\r\n" dataUsingEncoding:NSUTF8StringEncoding]];

// Adding one more field:
// append boundary
[postbody appendData:[[NSString stringWithFormat:@"--%@\r\n", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
// setting up form-data header, if it is text no 'filename' needed
[postbody appendData:[@"Content-Disposition: form-data; name=\"userId\"\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
// appending userId value
[postbody appendData:[_userId dataUsingEncoding:NSUTF8StringEncoding]];

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

[request setHTTPBody:postbody];

另外不要忘记在您的请求中添加“Content-Length”http header 字段。