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crystal-langkemal

Starting crystal in production mode

I've been running my Crystal webapp by building it, and then running the executable. However, it always listens on port 3000.

How do I build/run Crystal webapps listening on 80 and 443?

I'm using Kemal as well. Here is my sample app.

require "kemal"

get "/" do
  "Hello World!"
end

Kemal.run

Building:

crystal build src/myapp.cr

Running:

./myapp
Solution

  • Simply pass a port to Kemal.run:

    require "kemal"

get "/" do
  "Hello World!"
end

port = ARGV[0]?.try &.to_i?
Kemal.run port

    Build:

    crystal build src/myapp.cr

    Run:

    ./myapp # default port 3000
./myapp 80
./myapp 443