TosClient 在向服务端发起请求时，默认会在请求 Header 里包含签名。SDK 也支持构造带签名的 URL，可直接用该 URL 发起 HTTP 请求，也可以将该 URL 共享给第三方实现访问授权。
如下代码展示如何生成带签名的 URL。
TOSCredential *credential = [[TOSCredential alloc] initWithAccessKey:@"accesskey" secretKey:@"secretkey"]; TOSEndpoint *tosEndpoint = [[TOSEndpoint alloc] initWithURLString:@"endpoint" withRegion:@"region"]; TOSClientConfiguration *config = [[TOSClientConfiguration alloc] initWithEndpoint:tosEndpoint credential:credential]; TOSClient *client = [[TOSClient alloc] initWithConfiguration:config]; TOSPreSignedURLInput *input = [TOSPreSignedURLInput new]; input.tosBucket = @"bucket-name"; input.tosKey = @"object-name"; input.tosHttpMethod = TOSHTTPMethodTypeGet; TOSTask *task = [client preSignedURL:input]; [task continueWithBlock:^id _Nullable(TOSTask * _Nonnull task) { if (!task.error) { NSLog(@"Presigned success."); TOSPreSignedURLOutput *output = task.result; NSString *url = output.tosSignedUrl; } else { NSLog(@"Presigned failed, error: %@.", task.error); } return nil; }];