HTTP/2 服务器推入 iOS 10

Question

我正在尝试让服务器推送在 iOS 10 上运行。我正在使用 Akamai HTTP/2 演示。

https://http2.akamai.com/demo

以下是我测试服务器推送的尝试。

@interface ViewController () <NSURLSessionTaskDelegate>

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration];
    NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: self delegateQueue: [NSOperationQueue mainQueue]];

    NSString *displayArtUrl;
    for(int i=0; i<378; i++) {
        displayArtUrl = [NSString stringWithFormat:@"https://http2.akamai.com/demo/tile-%ld.png", (long)i];
        NSURL *url = [NSURL URLWithString:displayArtUrl];
        NSURLSessionDataTask *downloadTask = [defaultSession
                                              dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
                                              }];
        [downloadTask resume];
    }

}

- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didFinishCollectingMetrics:(NSURLSessionTaskMetrics *)metrics {
    NSArray *fetchTypes = @[ @"Unknown", @"Network Load", @"Server Push", @"Local Cache" ];

    for(NSURLSessionTaskTransactionMetrics *transactionMetrics in [metrics transactionMetrics]) {

        NSLog(@"protocol[%@] reuse[%d] fetch:%@ - %@", [transactionMetrics networkProtocolName], [transactionMetrics isReusedConnection], fetchTypes[[transactionMetrics resourceFetchType]], [[transactionMetrics request] URL]);

        if([transactionMetrics resourceFetchType] == NSURLSessionTaskMetricsResourceFetchTypeServerPush) {
            NSLog(@"Asset was server pushed");
        }
    }
}

@end

不幸的是，日志显示获取类型始终是 NSURLSessionTaskMetricsResourceFetchTypeNetworkLoad，而我有时希望它是 NSURLSessionTaskMetricsResourceFetchTypeServerPush。服务器显然支持它，如网络演示所示。

...
2016-11-22 19:27:37.596205 HttpServerPush[2356:735927] protocol[h2] reuse[1] fetch:Network Load - https://http2.akamai.com/demo/tile-4.png
2016-11-22 19:27:37.596960 HttpServerPush[2356:735927] protocol[h2] reuse[1] fetch:Network Load - https://http2.akamai.com/demo/tile-5.png
2016-11-22 19:27:37.597877 HttpServerPush[2356:735927] protocol[h2] reuse[1] fetch:Network Load - https://http2.akamai.com/demo/tile-6.png
2016-11-22 19:27:37.603988 HttpServerPush[2356:735927] protocol[h2] reuse[1] fetch:Network Load - https://http2.akamai.com/demo/tile-1.png
2016-11-22 19:27:37.976911 HttpServerPush[2356:735927] protocol[h2] reuse[1] fetch:Network Load - https://http2.akamai.com/demo/tile-7.png
....

有人在 iOS 10 上 HTTP/2 服务器推送成功了吗？请求资产的方式是否遗漏了什么？

仅供参考，在这种情况下，Charles Proxy 似乎会妨碍您。启用它会导致 iOS 10 完全停止使用 HTTP/2。

...
2016-11-22 19:55:15.763 HttpServerPush[59822:1612935] protocol[http/1.1] reuse[1] fetch:Network Load - https://http2.akamai.com/demo/tile-8.png
2016-11-22 19:55:15.766 HttpServerPush[59822:1612935] protocol[http/1.1] reuse[1] fetch:Network Load - https://http2.akamai.com/demo/tile-11.png
2016-11-22 19:55:15.769 HttpServerPush[59822:1612935] protocol[http/1.1] reuse[1] fetch:Network Load - https://http2.akamai.com/demo/tile-9.png
2016-11-22 19:55:15.771 HttpServerPush[59822:1612935] protocol[http/1.1] reuse[1] fetch:Network Load - https://http2.akamai.com/demo/tile-12.png
...

Answer 1

据我所知，Akamai 演示页面目前没有推送任何资源。当服务器向客户端发送 PUSH_PROMISE 帧时发生推送。 nghttp（可通过 brew 在 Mac OS X: brew install nghttp2 上安装）可用于显示服务器发送的帧：

$ nghttp -nv 'https://http2.akamai.com/demo' | grep 'PUSH_PROMISE'
$

另一方面，H2O HTTP服务器首页https://h2o.examp1e.net/确实推送资源：

$ nghttp -nv 'https://h2o.examp1e.net' | grep 'PUSH_PROMISE'
[  0.587] recv PUSH_PROMISE frame <length=59, flags=0x04, stream_id=13>
[  0.587] recv PUSH_PROMISE frame <length=33, flags=0x04, stream_id=13>
[  0.588] recv PUSH_PROMISE frame <length=35, flags=0x04, stream_id=13>
[  0.588] recv PUSH_PROMISE frame <length=24, flags=0x04, stream_id=13>
[  0.588] recv PUSH_PROMISE frame <length=28, flags=0x04, stream_id=13>
$

Answer 2

HTTP/2 推送在 Safari 中被广泛认为是坏的。不要认为这些信息是最新的，但上次我检查浏览器会接受并有时使用推送的资源，而其他时候则不会。

原始答案：

我正要回答你 HTTP/2 iOS 不支持推送，但后来我快速浏览了我们的页面：

https://www.shimmercat.com

并等待连接统计信息出现在右上角。 HTTP/2 iOS 10 支持推送!!

HTTP/2 服务器推入 iOS 10

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