#Problem
This repo is an attempt to demonstrate some odd behaviour I'm seeing in node-proxy.
Try this.
Run npm i
Run node proxy.js, this will start a server on port 8000 that proxies requests to port 3000.
In another console, start up a server of any kind on port 3000. I'm using a small rails app, though I've also confirmed the issue with sinatra and python's flask. There's a server.py checked in if you want to try it with flask on your own.
In a third console, try curl http://localhost:8000/, also try curl -d foo=bar http://localhost:8000/post_something
(Also, confirm that your requests work without a proxy by trying the same commands on port 3000).
Note that the HTTP GET succeeds, but the POST times out.
If I run lsof while the timeout is occurring I see this:
~ $ sudo lsof -nNPi @127.0.0.1
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
launchd 1 root 28u IPv4 0x55d89a057bc8f601 0t0 TCP 127.0.0.1:631 (LISTEN)
ntpd 87 root 23u IPv4 0x55d89a057ac88929 0t0 UDP 127.0.0.1:123
ruby 1519 kbaribeau 9u IPv4 0x55d89a058835e059 0t0 TCP 127.0.0.1:3000->127.0.0.1:51898 (ESTABLISHED)
Skype 1765 kbaribeau 10u IPv4 0x55d89a057c365569 0t0 UDP 127.0.0.1:62076
node 2183 kbaribeau 9u IPv4 0x55d89a058099f379 0t0 TCP 127.0.0.1:8000->127.0.0.1:51897 (ESTABLISHED)
node 2183 kbaribeau 12u IPv4 0x55d89a05888a7dd1 0t0 TCP 127.0.0.1:51898->127.0.0.1:3000 (ESTABLISHED)
curl 2184 kbaribeau 5u IPv4 0x55d89a057bf851e9 0t0 TCP 127.0.0.1:51897->127.0.0.1:8000 (ESTABLISHED)
It appears that node has successfully connected to ruby, but ruby isn't responding. However, these requests seem to work without a proxy. What's the missing secret sauce here?
#Solution
I found the issue (sort of). The bodyParser middleware does three things, it's equivalent to this:
app.use(express.json());
app.use(express.urlencoded());
app.use(express.multipart());
The urlencoded() middleware breaks POSTS. Removing it solves the issue.