POST方式上传文件

#import "NSMutableURLRequest+Multipart.h"

/**随便的字符串作为分隔符*/
static NSString *boundary = @"itcastupload";

@implementation NSMutableURLRequest (Multipart)

+ (instancetype)requestWithURL:(NSURL *)url andLoaclFilePath:(NSString *)loaclFilePath andFileName:(NSString *)fileName
{
// 2. post请求
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url cachePolicy:1 timeoutInterval:2.0f];
// 2.1 指定post方法
request.HTTPMethod = @"POST";

// 2.2 拼接数据体
NSMutableData *dataM = [NSMutableData data];

//   1. \r\n--(可以随便写, 但是不能有中文)\r\n
NSString *str = [NSString stringWithFormat:@"\r\n--%@\r\n", boundary];
[dataM appendData:[str dataUsingEncoding:NSUTF8StringEncoding]];

//   2. Content-Disposition: form-data; name="userfile(php脚本中用来读取文件的字段)"; filename="demo.json(要保存到服务器的文件名)"

str = [NSString stringWithFormat:@"Content-Disposition: form-data; name=\"userfile\"; filename=\"%@\" \r\n", fileName];

[dataM appendData:[str dataUsingEncoding:NSUTF8StringEncoding]];

//   3. Content-Type: application/octet-stream(上传文件的类型)\r\n\r\n
str = @"Content-Type: application/octet-stream\r\n\r\n";
[dataM appendData:[str dataUsingEncoding:NSUTF8StringEncoding]];

//   4. 要上传的文件的二进制流
// 要上传图片的二进制
[dataM appendData:[NSData dataWithContentsOfFile:loaclFilePath]];

//   5. \r\n--(可以随便写, 但是不能有中文)--\r\n
str = [NSString stringWithFormat:@"\r\n--%@--\r\n", boundary];
[dataM appendData:[str dataUsingEncoding:NSUTF8StringEncoding]];

// 2.4 设置请求体
request.HTTPBody = dataM;

// 设置请求头
//    Content-Length(文件的大小)	290
//    Content-Type	multipart/form-data; boundary(分隔符)=(可以随便写, 但是不能有中文)

NSString *headerStr = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", boundary];

[request setValue:headerStr forHTTPHeaderField:@"Content-Type"];

return request;
}

@end