Eelco Dolstra 90ad02bf62 Enable HTTP/2 support ... The binary cache store can now use HTTP/2 to do lookups. This is much more efficient than HTTP/1.1 due to multiplexing: we can issue many requests in parallel over a single TCP connection. Thus it's no longer necessary to use a bunch of concurrent TCP connections (25 by default). For example, downloading 802 .narinfo files from https://cache.nixos.org/, using a single TCP connection, takes 11.8s with HTTP/1.1, but only 0.61s with HTTP/2. This did require a fairly substantial rewrite of the Downloader class to use the curl multi interface, because otherwise curl wouldn't be able to do multiplexing for us. As a bonus, we get connection reuse even with HTTP/1.1. All downloads are now handled by a single worker thread. Clients call Downloader::enqueueDownload() to tell the worker thread to start the download, getting a std::future to the result.		2016-09-14 16:36:02 +02:00
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local.mk	nix-prefetch-url: Rewrite in C++	2015-10-01 16:47:43 +02:00
nix-prefetch-url.cc	Enable HTTP/2 support	2016-09-14 16:36:02 +02:00