ios http 上传图片

• (NSMutableURLRequest *)PostImageRequest:(NSString )URLString
  UIImage:(UIImage)image
  parameters:(NSDictionary *)parameters
  success:(void (^)(id))success
  failure:(void (^)(NSError *))failure
  {
  _success = [success copy];
  _failure = [failure copy];
  //分界线的标识符
  NSString *TWITTERFON_FORM_BOUNDARY = @"AaB03x";
  //根据url初始化request
  _request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:URLString]
  cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
  timeoutInterval:10];
  //分界线 --AaB03x
  NSString *MPboundary=[[NSString alloc]initWithFormat:@"--%@",TWITTERFON_FORM_BOUNDARY];
  //结束符 AaB03x--
  NSString endMPboundary=[[NSString alloc]initWithFormat:@"%@--",MPboundary];
  //得到图片的data
  NSData data = UIImageJPEGRepresentation(image, 1);
  //http body的字符串
  NSMutableString *body=[[NSMutableString alloc]init];
  //参数的集合的所有key的集合
  NSArray *keys= [parameters allKeys];

  //遍历keys
  for(int i=0;i<[keys count];i++)
  {
  //得到当前key
  NSString *key=[keys objectAtIndex:i];
  //如果key不是pic，说明value是字符类型，比如name：Boris
  if(![key isEqualToString:@"pic"])
  {
  //添加分界线，换行
  [body appendFormat:@"%@\r\n",MPboundary];
  //添加字段名称，换2行
  [body appendFormat:@"Content-Disposition: form-data; name="%@"\r\n\r\n",key];
  //添加字段的值
  [body appendFormat:@"%@\r\n",[parameters objectForKey:key]];
  }
  }

  ////添加分界线，换行
  [body appendFormat:@"%@\r\n",MPboundary];
  //声明pic字段，文件名为boris.png
  [body appendFormat:@"Content-Disposition: form-data; name="ImageField"; filename="x1234.png"\r\n"];
  //声明上传文件的格式
  [body appendFormat:@"Content-Type: image/jpeg\r\n\r\n"];

  //声明结束符：--AaB03x--
  NSString *end=[[NSString alloc]initWithFormat:@"\r\n%@",endMPboundary];
  //声明myRequestData，用来放入http body
  NSMutableData *myRequestData=[NSMutableData data];
  //将body字符串转化为UTF8格式的二进制
  [myRequestData appendData:[body dataUsingEncoding:NSUTF8StringEncoding]];
  //将image的data加入
  [myRequestData appendData:data];
  //加入结束符--AaB03x--
  [myRequestData appendData:[end dataUsingEncoding:NSUTF8StringEncoding]];

  //设置HTTPHeader中Content-Type的值
  NSString *content=[[NSString alloc] initWithFormat:@"multipart/form-data; boundary=%@",TWITTERFON_FORM_BOUNDARY];
  //设置HTTPHeader
  [_request setValue:content forHTTPHeaderField:@"Content-Type"];
  //设置Content-Length
  [_request setValue:[NSString stringWithFormat:@"%d", [myRequestData length]] forHTTPHeaderField:@"Content-Length"];
  //设置http body
  [_request setHTTPBody:myRequestData];
  //http method
  [_request setHTTPMethod:@"POST"];

  return _request;
  }