ParamChecker
ParamChecker is a small Ruby library for validating and casting string parameters. It is for example a handy way to check GET/POST params
in Ruby On Rails.
Installation
gem install param_checker
or add ParamChecker to your Gemfile
gem 'param_checker'
and afterwards (when using the Gemfile) execute
bundle install
Usage
Include the ParamChecker module where ever you like. I usually put it into my Rails ApplicationController.rb
class ApplicationController < ActionController::Base
include ParamChecker
end
You can then simply call for example check_string(params[:name], "Mia", :allowed => ["foo", "bar"])
in every controller.
Instead of including the module you could also call all functions of the module directly, like
ParamChecker.check_string(params[:name], "Mia", ["foo", "bar"])
There are currently 5 supported functions:
check_integer(param, default, )
check_float(param, default, )
check_string(param, default, )
check_symbol(param, default, )
check_boolean(param, default, )
-
param
is the string parameter to check. -
default
is the value that will be returned whenparam
does not pass the check. -
options
are function specific options to checkparam
against:-
:min
,:max
incheck_integer
andcheck_float
are the minimum and maximum allowed values of param. (If not provided then no range is checked at all.) -
:allowed
incheck_string
andcheck_symbol
represent the allowed values ofparam
. It can be either a regular expression, a string (resp. a symbol forcheck_symbol
), or an array of strings (resp. an array of symbols forcheck_symbol
). -
:true
and:false
represent the allowed string values for the true and false booleans. By default is :true => [“1”, “true”] and :false => [“0”, “false”]
-
All functions return the casted value (check_integer returns an integer, check_symbol returns a symbol, and so on).
Examples
Below are some simple examples how to use those functions.
# Check if per_page parameter is a valid integer representation, ensure that it is bigger than 1 and smaller than 100 and return its integer value. Otherwise return 10.
page = check_integer(params[:per_page], 10, :min => 1, :max => 100)
# If field parameter is equal to "name" or "address" then return it, otherwise return "name".
field = check_string(params[:field], "name", :allowed => ["name", "address"])
# Return the boolean if params[:accepted] is a valid boolean representation and the default false otherwise.
accepted = check_boolean(params[:accepted], false)
# Have custom boolean string representation values.
accepted = check_boolean(params[:accepted], false, :true => ["yep", "yes"], :false => ["nope", "no"])
Alternative usage
Since version 0.3 you can also extend your Hash or HashWithIndifferentAccess with ParamChecker::HashExt. This will allow you to directly call the ParamChecker methods on the params
hash:
params.check(type, params_key, default, )
type
can be:
-
:i
or:integer
calls check_integer internally -
:f
or:float
calls check_float internally -
:s
or:string
calls check_string internally -
:sym
or:symbol
calls check_symbol internally -
:b
or:boolean
calls check boolean internally
params_key
can be either an array of keys or just one key to access the hash.
Examples
# Checks params[:page] and returns the integer representation if valid.
params.check(:i, :page, 5, :min => 1)
# Check params[:company][:name] and returns "Comparilla" if invalid.
params.check(:s, [:company, :name], "Comparilla")
# Does exactly the same (alternative type symbol for string type)
params.check(:string, [:company, :name], "Comparilla")
Testing
ParamChecker uses RSpec for testing and has a rake task for executing the provided specs
rake spec
Copyright © 2010-2011 Kai Schlamp (www.medihack.org), released under the MIT license