schlib.cr 0.4.1

schlib.cr is a library with selected useful classes.

Installation

Add to your shard.yml

dependencies:
  schlib.cr:
    github: tpei/schlib.cr
    branch: master

and then install the library into your project with

$ crystal deps

Usage

This shard consists of several helper classes. Require them and use them.

Cache

Cache helps to cache long running computations or I/O. It acts similar to Rails' cache and persists to a file. It is only possible to cache simple data structures like Array, String, Integer, etc... All cached data must work with JSON::Type

require "schlib/cache"

def super_long_running_method
  sleep 10
  "wow, so long!"
end

def complicated_stuff
  c = Schlib::Cache.new("/tmp/my_cache_file.tmp")
  c.cache(:precise_pi) do
    super_long_running_method
  end
end

puts complicated_stuff # first call takes long time
puts complicated_stuff # successive calls are fast

Command

Command is a wrapper around crystal's backticks and enables logging and raising exceptions on bad exitcodes.

require "logger"
require "schlib/command"

Schlib::Command.new.run("wtf", raise_errors: true)
# COMMAND FAILED! (ScriptError)
# 0x101806195: *CallStack::unwind:Array(Pointer(Void)) at ??
# 0x101806131: *CallStack#initialize:Array(Pointer(Void)) at ??
# 0x101806108: *CallStack:🆕CallStack at ??
# 0x101805211: *raise<ScriptError>:NoReturn at ??
# 0x101872b06: *Schlib::Command#run<String, Bool>:String at ??
# 0x1017f2c72: __crystal_main at ??
# 0x101802b58: main at ??

logger = Logger.new(STDOUT)
Schlib::Command.new(logger).run "wtf????"
# --: wtf????: command not found

Spinner

Have a long running command? Use spinner to entertain.

require "schlib/spinner"

Schlib::Spinner.wait_for do
  sleep 2
  "well-rested"
end
# Loading ▇ ... done
#
# => "well-rested"

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/tpei/schlib.cr. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.