Synopsis

A realtime webserver allowing users to store and forward custom messages.

Protocol

Helpful commands

cabal sandbox init cabal install --only-dependencies --enable-tests

Variable naming conventions:

Trying to follow haskell conventions. Though, if a variable is needed in the method signature, I am using smalltalkish convention: for example

f :: T -> T f aT = aT

if the above function is written as below:

f = \aL -> aL

in the latter case the variable is curried, and aL(ocal). Though, we should probably use a sequence, which would then look as below

f =\a1 -> a1

Sub note:

If things are working, we dont need to go about changing conventions. Though each new refactoring, which is almost a daily activity, I try to fix these as I go.

Postgres commands

If you need to restart. sudo /etc/init.d/postgresql restart

How to run the app on localhost

sudo route add -net 224.0.0.0 netmask 240.0.0.0 dev lo sudo ifconfig lo multicast This worked for me. : Linux pop-os 4.13.0-16-generic #19-Ubuntu SMP Wed Oct 11 18:35:14 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

Curl commands for websockets

$ curl -i -N -H "Connection: Upgrade" -H "Upgrade: websocket" -H "Host: echo.websocket.org" -H "Origin: http://localhost:30001"

Some more setup commands

When we see postgresql errors, it is most likely on ubuntu due to missing libraries:

  sudo apt-get install liblz-dev
  sudo apt-get install c2hs cpphs hscolour hugs
  sudo apt-get install postgresql-server-dev-all

Heap profile analysis

Tool to print heap analysis is hp2pretty (not hp2ps). The output is in svg and you need inkscape or some of the popular tools for viewing svg files.

Use stack

Install stack and run the following

stack setup
stack build
stack-run <executable_name>

Install stack-run

stack install stack-run

The onboarding may be a bit more smoother.

dservgun / zya