Lua HTTP Request TCP messages

Question

I am sending HTTP requests using socket.http to a Shelly 2.5 relay IOT device that contains a Mongoose/6.18 server running on an ESP8266, but am having problems.

HTTP requests to this device work as expected when initiated from postman or browser: the device's server responds as expected.

However if I send requests using Lua 5.3 socket.http module, the server does NOT respond. I've used tcpdump to see what's going on and from what I see, unlike browsers or postman which send the HTTP request in one TCP message containing both the HTTP startline and headers, Lua seems to send two separate TCP messages, first for the startline only, then a second for the headers. Mongoose responds with an ack when the startline is sent, then Lua sends the headers and Mongoose does not respond. Lua then tries 5 times to resend the headers before giving up.

I don't normally have problems using socket.http when sending HTTP requests to other servers.

I'm not sure if the 2-part HTTP message is what is causing the issue with this particular device, or if I'm perhaps misinterpreting the tcpdump output:

18:24:23.823886 IP 192.168.1.140.41894 > 192.168.1.136.http: Flags [P.], seq 1:151, ack 1, win 65392, length 150: HTTP: GET /settings/actions?index=0&name=out_on_url&enabled=true&urls[]=http://192.168.1.107:6667/b6cb7ffc-7919-41e6-ab80-6bed8b117753/relay/0/on HTTP/1.1
E.....@[email protected] /settings/actions?index=0&name=out_on_url&enabled=true&urls[]=http://192.168.1.107:6667/b6cb7ffc-7919-41e6-ab80-6bed8b117753/relay/0/on HTTP/1.1

18:24:23.898872 IP 192.168.1.136.http > 192.168.1.140.41894: Flags [.], ack 151, win 2770, length 0
E..([email protected]:P.
.......5...
18:24:23.898946 IP 192.168.1.140.41894 > 192.168.1.136.http: Flags [P.], seq 151:447, ack 1, win 65392, length 296: HTTP
E..P..@[email protected]{...........Pj.o:....P..p....Cache-Control: max-age=0
Host: 192.168.1.136
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Connection: keep-alive
User-Agent: LuaSocket 3.0-rc1
TE: trailers
Accept-Language: en-US,en;q=0.9


18:24:24.125746 IP 192.168.1.140.41894 > 192.168.1.136.http: Flags [P.], seq 151:447, ack 1, win 65392, length 296: HTTP
E..P..@[email protected]:....P..p....Cache-Control: max-age=0
Host: 192.168.1.136
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Connection: keep-alive
User-Agent: LuaSocket 3.0-rc1
TE: trailers
Accept-Language: en-US,en;q=0.9


18:24:24.575743 IP 192.168.1.140.41894 > 192.168.1.136.http: Flags [P.], seq 151:447, ack 1, win 65392, length 296: HTTP
E..P..@[email protected]:....P..p....Cache-Control: max-age=0
Host: 192.168.1.136
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Connection: keep-alive
User-Agent: LuaSocket 3.0-rc1
TE: trailers
Accept-Language: en-US,en;q=0.9


18:24:25.495791 IP 192.168.1.140.41894 > 192.168.1.136.http: Flags [P.], seq 151:447, ack 1, win 65392, length 296: HTTP
E..P..@[email protected]:....P..p....Cache-Control: max-age=0
Host: 192.168.1.136
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Connection: keep-alive
User-Agent: LuaSocket 3.0-rc1
TE: trailers
Accept-Language: en-US,en;q=0.9


18:24:27.328180 ARP, Request who-has 192.168.1.136 tell 192.168.1.1, length 46
........`.'.................>.[p.....!.....
>.
18:24:27.335732 IP 192.168.1.140.41894 > 192.168.1.136.http: Flags [P.], seq 151:447, ack 1, win 65392, length 296: HTTP
E..P..@[email protected]:....P..p....Cache-Control: max-age=0
Host: 192.168.1.136
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Connection: keep-alive
User-Agent: LuaSocket 3.0-rc1
TE: trailers
Accept-Language: en-US,en;q=0.9