Multipart form/data uploading in ios - afnetworking

Question

<form method="post" action="upload.php?u=test&p=test" name="FrmUpload" autocomplete="off" enctype="multipart/form-data">
<input type="file" name="file" id="file" onchange="document.forms[0].submit();"/>
</form>
The above code is working in html. I am trying to do in AFnetworking multipart audio file uploading: This is my equivalent ios code:
NSDictionary *dic = #{#"id":#"file"};
[[RequestOperationManager sharedManager] POST:#"my url string" parameters:dic
constructingBodyWithBlock:^(id<AFMultipartFormData> formData){
NSError *error = nil;
[formData appendPartWithFileURL:[NSURL fileURLWithPath:#"my file path"] name:#"file" fileName:file mimeType:#"audio/aac" error:&error];
}success:^(AFHTTPRequestOperation *operation, id responseObject){
} failure:^(AFHTTPRequestOperation *operation, NSError *error){
NSLog(#"%d : %#", error.code, error.description);
}
}];
It returns the error:
Error Domain=NSCocoaErrorDomain Code=3840 "The operation couldn’t be completed. (Cocoa error 3840.)" (JSON text did not start with array or object and option to allow fragments not set.)

Answer 1

-(void)uploadAudio{
AFHTTPRequestOperationManager *manager = [[AFHTTPRequestOperationManager alloc] *
initWithBaseURL:[NSURL URLWithString:#"http://server.url"]];
NSData *imageData = UIImageJPEGRepresentation(self.avatarView.image, 0.5);
NSDictionary *parameters = #{#"username": self.username, #"password" : self.password};
AFHTTPRequestOperation *op = [manager POST:#"rest.of.url" parameters:parameters constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
//do not put image inside parameters dictionary as I did, but append it!
[formData appendPartWithFileData:imageData name:paramNameForImage fileName:#"photo.jpg" mimeType:#"image/jpeg"];
} success:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(#"Success: %# ***** %#", operation.responseString, responseObject);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"Error: %# ***** %#", operation.responseString, error);
}];
[op start];
}
i Think Some detail must be missing ... like ur url ......or key.....