/// 文件上传

• (void)NSURLSessionUploadTaskTest {
  // 1.创建url 采用Apache本地服务器
  NSString *urlString = @"http://localhost/upload/upload.php";
  urlString = [urlString stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLFragmentAllowedCharacterSet]];
  NSURL *url = [NSURL URLWithString:urlString];

  // 2.创建请求
  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
  // 文件上传使用post
  request.HTTPMethod = @"POST";
  NSString contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",@"boundary"];
  [request setValue:contentType forHTTPHeaderField:@"Content-Type"];
  // 3.拼接表单，大小受MAX_FILE_SIZE限制(2MB) FilePath:要上传的本地文件路径 formName:表单控件名称，应于服务器一致
  NSData data = [self getHttpBodyWithFilePath:@"/Users/userName/Desktop/IMG_0359.jpg" formName:@"file" reName:@"newName.png"];
  request.HTTPBody = data;
  // 根据需要是否提供，非必须,如果不提供，session会自动计算
  [request setValue:[NSString stringWithFormat:@"%lu",data.length] forHTTPHeaderField:@"Content-Length"];

  // 4.1 使用dataTask
  [[[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
  if (error == nil) {
  NSLog(@"upload success：%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
  } else {
  NSLog(@"upload error:%@",error);
  }

  }] resume];

if 0

// 4.2 开始上传 使用uploadTask   fromData:可有可无，会被忽略
[[[NSURLSession sharedSession] uploadTaskWithRequest:request fromData:nil     completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
    if (error == nil) {
        NSLog(@"upload success：%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
    } else {
        NSLog(@"upload error:%@",error);
    }
}] resume];

endif

}

/// filePath:要上传的文件路径 formName：表单控件名称 reName：上传后文件名

• (NSData *)getHttpBodyWithFilePath:(NSString *)filePath formName:(NSString *)formName reName:(NSString *)reName
  {
  NSMutableData *data = [NSMutableData data];
  NSURLResponse *response = [self getLocalFileResponse:filePath];
  // 文件类型：MIMEType 文件的大小：expectedContentLength 文件名字：suggestedFilename
  NSString *fileType = response.MIMEType;

  // 如果没有传入上传后文件名称,采用本地文件名!
  if (reName == nil) {
  reName = response.suggestedFilename;
  }

  // 表单拼接
  NSMutableString *headerStrM =[NSMutableString string];
  [headerStrM appendFormat:@"--%@\r\n",@"boundary"];
  // name：表单控件名称 filename：上传文件名
  [headerStrM appendFormat:@"Content-Disposition: form-data; name=%@; filename=%@\r\n",formName,reName];
  [headerStrM appendFormat:@"Content-Type: %@\r\n\r\n",fileType];
  [data appendData:[headerStrM dataUsingEncoding:NSUTF8StringEncoding]];

  // 文件内容
  NSData *fileData = [NSData dataWithContentsOfFile:filePath];
  [data appendData:fileData];

  NSMutableString *footerStrM = [NSMutableString stringWithFormat:@"\r\n--%@--\r\n",@"boundary"];
  [data appendData:[footerStrM dataUsingEncoding:NSUTF8StringEncoding]];
  // NSLog(@"dataStr=%@",[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
  return data;
  }
  /// 获取响应，主要是文件类型和文件名

• (NSURLResponse *)getLocalFileResponse:(NSString *)urlString
  {
  urlString = [urlString stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLFragmentAllowedCharacterSet]];
  // 本地文件请求
  NSURL *url = [NSURL fileURLWithPath:urlString];
  NSURLRequest *request = [NSURLRequest requestWithURL:url];

  __block NSURLResponse *localResponse = nil;
  // 使用信号量实现NSURLSession同步请求
  dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
  [[[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
  localResponse = response;
  dispatch_semaphore_signal(semaphore);
  }] resume];
  dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
  return localResponse;
  }