Hello Server!

After learning the very basics of how to write, compile and run a Crystal program. It’s time to crank it up a notch by writing our own HTTP server. So create a file named server.cr and start typing!

To create a server, we first need to require the http/server class. This allows us to use the HTTP module along with the Server implementation. For more information about requiring files, read here.

require "http/server"

Then we assign a new instance of the class HTTP::Server to the local variable server. Read more about local variables and methods.

server = HTTP::Server.new(3000) ...

server = HTTP::Server.new(3000) do |context|
  context.response.content_type = "text/plain"
  context.response.print "Hello world, got #{context.request.path}!"
end

puts "Listening on http://127.0.0.1:3000"
server.listen

Note: If you run Crystal from a Vagrant box you need to use a non-localhost bind address.

require "http/server"

server = HTTP::Server.new("0.0.0.0", 3000) do |context|
  context.response.content_type = "text/plain"
  context.response.print "Hello world, got #{context.request.path}!"
end

puts "Listening on http://0.0.0.0:3000"
server.listen