nettop -m tcp -J rtt_min,rtt_var,bytes_in,bytes_out -p 40893 Make sure to scroll to the right to see the bytes-in/bytes-out/round-trip-time by website/socket for the webkit process. I just want to show how cool this command is using preformatted text. I don't remember the name of the tool, and have not been able to find it in macOS Catalina (10.15).ĭoes anyone remember the name of the MacOS CLI which shows the response-time by network destination?ĮDIT AFTER ANSWERED. I remember seeing a MacOS CLI which showed the recorded response times by destination. Some recent implementations also give a preference to IPv6 (I've heard of preferences from 25msec to 300msec). If it’s extremely popular, NodeJS can merge it in, and the code can be removed from here."Happy Eyeballs" is the IPv6 feature (RFC8305) where the OS tests response time on IPv4 and IPv6 per destination and tries to optimize performance by choosing the "fastest" protocol for hostnames which have both A-records and AAAA-records. Ultimately though, I think it would probably be better for the community to develop something like this and test it out before merging it into NodeJS anyway and see the response it gets. It would be great if node could implement this natively, but there are currently no plans to do that. So, if you’re on a IPv6-only network, you don’t have to try every single IPv4 address before you get to the IPv6 address. In curl’s implementation, which I prefer, its starts with the first address, then tries the next address of a different family. Still, this is better than dropping the request entirely. Implement Happy Eyeballs 1326 Draft jimmywarting Version 3.x.x milestone on jimmywarting added on hold and removed Hacktoberfest labels on Sign up for free to join this conversation on GitHub. It could be a good idea to log a warning for the user that the first address sent by getaddrinfo was not available, as the 300ms timeout adds latency to every connection. Ideally, fetch would send the first address first, wait 300ms, and if no connection was made, continue down the line of addresses returned by dns.lookup. This can cause extremely confusing errors for developers using dual stack networks where IPv4 support periodically drops, because it’s very hard to find what is causing the issue (I should know). Note, that verbatim=true will probably become the default. Currently, due to a poor design decision by NodeJS developers, IPv4 addresses are preferred, even when this contradicts RFC 6724. It will repeatedly attempt to load, via this browser instance, a randomly named dual stack javascript resource. The Happy Eyeballs algorithm of racing connections to resolved addresses has several stages to avoid delays to the user whenever possible, while preferring the use of IPv6. ![]() Btw, semi-related, the DNS lookup should be returning results with verbatim=true. Net.createConnection attempts to create a connection with the default dns.lookup server. Cette vidéo explique lutilisation de Happy Eyeballs dans un contexte Dual-Stack (ipv4 et ipv6)Le lien vers le site de Microsoft et qui va vous permettre da. ![]() I would propose node-fetch handle failover similarly to the browser. With IPv6-only network connectivity becoming increasingly common, misconfigurations in DNS servers can cause requests to fail, even when connectivity is available through alternative servers.īrowsers typically try to create a connection, wait 300ms, then try the next available server provided by getaddrinfo in the kernel.Ĭurrently, node-fetch implements no failover for support for timed-out connections. This functionality is also implemented in curl, iOS, Android, etc… In the browser, this is handled for you using the Happy Eyeballs algorithm. Is your feature request related to a problem? Please describe.ĭNS misconfigurations or server down time can cause fetch requests not to be fulfilled.
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