Wow, this is an odd one. I’m making an http request (post) to a server. Work fine from curl Works fine from iex Bombs out when I run from within app! I have literally never had this happen before, when the EXACT same function behaves differently live vs. iex. Just wondering if anyone has insigh…

When you make it from the application & from iex, I’d suggest using wireshark to look into the headers/body of outgoing request & look again byte-by-byte how are they different.

Cool, thanks for the suggestion. Installed wireshark, but unfortunately all TLS1.2, so all encrypted packets! Unable to read headers, etc. I guess I’d need to be able to run Mint in debug-mode to have it print out header, etc, like when you run curl -v.

It should be possible to decrypt TLS1.2, see “TLS Decryption” in TLS - Wireshark Wiki . It will require some manual setup steps though. Alternatively, if you control the other end, e.g. https://qa.xyz.com/ws/eca/create , then turning off HTTPS for the purpose of debugging may save you some time.

Decrypting TLS would be possible in two scenarios: You have access to the server’s private key and you constrain the negotiated cipher suites to ensure the key exchange does not use (EC)DHE, or You write the master secret for the session you want to decode to a file This last option can work both…

Awesome! So cool to know about this! Yet the insanity continues: When run from the app: error (returns status: 500) (<0.935.0>) call 'Elixir.Mint.Core.Transport.SSL':send({sslsocket,{gen_tcp,#Port<0.55584>,tls_connection,undefined},<0.941.0>}, [[<<"POST">>,32,<<"/ws/eca/create">>,<<" HTTP/1.1\r\n…

Crazy right?!?! Yes, I’m actually connecting to the live app and running it from there! E.g. iex \ --name $name \ --cookie $cookie \ --remsh $remote

Something very odd is going on. I ran curl as a System.cmd and am having the same issue! E.g. function calling curl run as a System.cmd works fine from iex, but not when run programmatically from app! Seems like maybe some weird permission thing, as it is being called from a phoenix channel, then …

At the end of the day, I think it’s just a super flaky endpoint, and it was more coincidence that some requests were working and other were not! I just tried 4 request in a row–first 3 bombed, last one went through. Again, thanks for all ideas! Rock on,

Elixir Programming Language Forum

Super weird http issue

Questions & Help Questions

gmile February 11, 2020, 3:44pm 7

Are you running the requests from the same IP? I am just thinking what else can be different…