iOS-SDK之如何实现下载文件(二)?

流式下载


实际上，SDK没有提供stream类型的下载接口，但是提供了类似NSURLSession库的didRecieveData的分段回调功能，下载时，每次得到一段数据，会回调这个函数进行通知。注意，如果设置了这个回调，下载的结果将不再包含实际数据。

1. OSSGetObjectRequest * request = [OSSGetObjectRequest new];
2. // required
3. request.bucketName = @"<bucketName>";
4. request.objectKey = @"<objectKey>";
6. // 分段回调函数
7. request.onRecieveData = ^(NSData * data) {
8.     NSLog(@"Recieve data, length: %ld", [data length]);
9. };
11. OSSTask * getTask = [client getObject:request];
13. [getTask continueWithBlock:^id(OSSTask *task) {
14.     if (!task.error) {
15.         NSLog(@"download object success!");
16.     } else {
17.         NSLog(@"download object failed, error: %@" ,task.error);
18.     }
19.     return nil;
20. }];
22. // [getTask waitUntilFinished];
24. // [request cancel];

1. OSSGetObjectRequest * request = [OSSGetObjectRequest new];
2. request.bucketName = @"<bucketName>;
3. request.objectKey = @"<objectKey>";
4. request.range = [[OSSRange alloc] initWithStart:1 withEnd:99]; // bytes=1-99
5. // request.range = [[OSSRange alloc] initWithStart:-1 withEnd:99]; // bytes=-99
6. // request.range = [[OSSRange alloc] initWithStart:10 withEnd:-1]; // bytes=10-
8. request.downloadProgress = ^(int64_t bytesWritten, int64_t totalBytesWritten, int64_t totalBytesExpectedToWrite) {
9.     NSLog(@"%lld, %lld, %lld", bytesWritten, totalBytesWritten, totalBytesExpectedToWrite);
10. };
12. OSSTask * getTask = [client getObject:request];
14. [getTask continueWithBlock:^id(OSSTask *task) {
15.     if (!task.error) {
16.         NSLog(@"download object success!");
17.         OSSGetObjectResult * getResult = task.result;
18.         NSLog(@"download result: %@", getResult.dowloadedData);
19.     } else {
20.         NSLog(@"download object failed, error: %@" ,task.error);
21.     }
22.     return nil;
23. }];
25. // [getTask waitUntilFinished];
27. // [request cancel];

1. OSSHeadObjectRequest * request = [OSSHeadObjectRequest new];
2. request.bucketName = @"<bucketName>;
3. request.objectKey = @"<objectKey>";
5. OSSTask * headTask = [client headObject:request];
7. [headTask continueWithBlock:^id(OSSTask *task) {
8.     if (!task.error) {
9.         NSLog(@"head object success!");
10.         OSSHeadObjectResult * result = task.result;
11.         NSLog(@"header fields: %@", result.httpResponseHeaderFields);
12.         for (NSString * key in result.objectMeta) {
13.             NSLog(@"ObjectMeta: %@ - %@", key, [result.objectMeta objectForKey:key]);
14.         }
15.     } else {
16.         NSLog(@"head object failed, error: %@" ,task.error);
17.     }
18.     return nil;
19. }];