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;
}