Archive for August 21st, 2007

Rails url_for and params missery

Posted August 21, 2007 * Comments(1)

Assume you have a params array with the following items:

params[:qry][:name] = ‘jo’
params[:qry][:city] = ”

You would like to build a new URL with the current params appended. Should be as simple as:

url_for( :action => ‘list’, :params => params.merge( { :sort => key, :page => nil } ) )

Well that’s not the case it results in the following URL:

http://localhost/controller/list?qry=namejocity&sort=created_at

Long live Rails! The frustrating part of it, is that it first converts inner Hashmaps to a string. I don’t have a clue why!

The solution, put the following code in your ApplicationHelper. (Is a nice method to have ;-)

#
# Converts the given HASH array like ‘params’ to a flat
# HASH array that’s compatible with url_for and link_to
#
def flatten_param_hash( params )
  found = true

  while found
    found = false
    new_hash = {}

    params.each do |key,value|
      if value.is_a?( Hash )
        found = true
        value.each do |key2,value2|
          new_hash[ key.to_s + ‘[' + key2.to_s + ']‘ ] = value2
        end
      else
        new_hash[ key.to_s ] = value
      end
    end
    params = new_hash
  end
  params
end

Adjust your code to the following

url_for( :action => ‘list’, :params => flatten_param_hash( params.merge( { :sort => key, :page => nil } ) ) )

And voila the result is now a little bit better:

http://localhost/controller/list?qry[name]=jo&qry[city]=&sort=created_at

Restart Webrick when mangling constants with Merge! (of course!)

Posted August 21, 2007 * Comments(0)

Yesterday I’ve encountered the irritating date problem in Rails. Please remember to restart Webrick when you change the date conversion constants or time conversion constants with the ‘merge!’ method:

ActiveSupport::CoreExtensions::Date::Conversions::DATE_FORMATS.merge!(
:default => “%d-%m-%Y”
)

On reload it merges the array again… You can never remove the ‘:default’ date with a merge…
*sigh*

This tip can save you a whole lot of time, because reloading doesn’t work