Rails and Stuff at Abel killed Cain

PHP 5.3 lambda use case

inbreed — Sat, 06 Mar 2010 18:21:23 +0000

i just thought about iterating objects in php.

Since 5.3 supports lambda, i found this quite usefull:

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class Test {
public $vals = array();

function __construct(){
$this->vals = range(1,10);
}

// the hooray goes here!
function each($function){
foreach($this->vals as $element){
$function($element);
}
}
}

$t = new Test;

//the real hooray-part:
$t->each( function( $e ) {
echo "Hi, i am element $e\n";
});

Works! :)

Ah and yes, for idiots not knowing what happens on execution:

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$ php test.php
Hi, i am element 1
Hi, i am element 2
Hi, i am element 3
Hi, i am element 4
Hi, i am element 5
Hi, i am element 6
Hi, i am element 7
Hi, i am element 8
Hi, i am element 9
Hi, i am element 10

Have fun with Internet Exploider 6.0

inbreed — Tue, 16 Feb 2010 17:38:56 +0000

Building Websites is fun!

Having IE6 Users sucks instead!

Get rid of them by pasting the following code into your document-head.

IE 6 will crash after asking the user not to use it!

changing behavior of on_error_message and field errors

inbreed — Thu, 04 Feb 2010 16:30:25 +0000

Ruby on Rails provides a nice way to display error_messages; just by adding form.error_messages you get a nice overview of all your errors.

But i prefer to have it in different ways, so i 1) dont want the on_error_message-output to be a div element, 2) further i want to give each input field having bad content to be marked – by adding an error-class to that specific element for example.

Since i had to figure it out, here are the results for changing both.

1) different element instead of a div at on_error_message?

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module SpanOnErrorMessages #rename it properly
# File actionpack/lib/action_view/helpers/active_record_helper.rb, line 109
def error_message_on(object, method, *args)
options = args.extract_options!
unless args.empty?
ActiveSupport::Deprecation.warn('error_message_on takes an option hash instead of separate ' +
'prepend_text, append_text, and css_class arguments', caller)

options[:prepend_text] = args[0] || ''
options[:append_text] = args[1] || ''
options[:css_class] = args[2] || 'formError'
end
options.reverse_merge!(:prepend_text => '', :append_text => '', :css_class => 'formError')

if (obj = (object.respond_to?(:errors) ? object : instance_variable_get("@#{object}"))) && (errors = obj.errors.on(method))
content_tag("span", #rewritten to span! hooray!
"#{options[:prepend_text]}#{ERB::Util.html_escape(errors.is_a?(Array) ? errors.first : errors)}#{options[:append_text]}",
:class => options[:css_class]
)
else
''
end
end
end

#now telling ActionView to use it!
ActionView::Base.send :include, SpanOnErrorMessages

there we go, thats it! have fun!

If you need, set the element as a hash-paramter to have this more dynamic.

Okay now thats pretty! how about having:
2) adding an error-class to the bad input elements:

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#environment.rb
ActionView::Base.field_error_proc = Proc.new do |html_tag, instace_tag|
error_class = "error"
if html_tag =~ /<(input|textarea|select)[^>]+class=/
style_attribute = html_tag =~ /class=['"]/ #'my wordpress colors wierd
html_tag.insert(style_attribute + 7, "#{error_class} ")
elsif html_tag =~ /<(input|textarea|select)/
first_whitespace = html_tag =~ /\s/
html_tag[first_whitespace] = " class=\"#{error_class}\" "
end
html_tag
end

Thats fine! now a wrong input should look like:
class=”error” id=”user_email” … type=”text” value=”just@wrong”>

Hope you can take use of that? tell me! :)

more detailed logging information in Rails

inbreed — Wed, 03 Feb 2010 11:22:29 +0000

Rails logging methods are wonderful for development.

Indeed, they often suck when you want to inspect objects or cascaded objects. So here is a codesnipped that helps you inspect any kind of any object in rails, deeply and detailed.

as a new lib-file or, just as i do, in application_controller.rb, add the follogwing code:

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require 'pp'
require 'stringio'

module Kernel
def pp_s
s = StringIO.new
PP.pp(self, s)
s.rewind
s.read
end
end

now anywhere in the code, lets say you want to inspect a model, or a hash, or a parameter of any unknown type:

1	logger.warn var_of_any_kind.pp_s #or use .info

here is an example from irb:

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>> User.last.pp_s
=> "#\"foo@baz.net\", crypted_password: \"e8878b6c722ec64b921be4c98765431263ebe813293a6c995fe88...\", password_salt: \"jfDuRTvSomfg
4Q6sCjhNm\", persistence_token: \"464af1170bf8b1302ea3f108e03ed5ff3a0568417b084af27ef...\", login_count: 2, created_at: \"2010-02-01 11:24:16\", updated_at: \"2010-02-01 11:40:40\", newsletter: \"0\">\n"
>> User.pp_s
=> "User(id: integer, email: string, crypted_password: string, password_salt: string, persistence_token: string, login_count: integer, created_at: datetime, updated_at: datetime, newsletter: integer)\n"
>>

7 Ruby Tips for using Rails

inbreed — Sat, 23 Jan 2010 21:30:08 +0000

Here is a small collection of Tips and Tricks for Ruby in association to Rails.

I will paste some irb-logs, displaying all results.
1. Format decimals or text quickly

In order to display amounts or leading zeros:

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>> "%.2f" % 49.4
=> "49.40"
>> "%03d" % 1
=> "001"

# even text:

>> msg = "Welcome, %s";
?> msg % "peter"
=> "Welcome, peter"

# even cooler

>> "<%s> %s s>" % %w{strong cool strong}
=> "<strong> cool strong>"

Just keep in mind that the result is a String!

2. Using Hash-Keys

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>> test = {true => "Yes", false =>"No"}
>> test[ 100 == "foo" ]
=> "No"

3. Mass Assignment

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>> a,b,c,d = 1,2,3,4
=> [1, 2, 3, 4]
>> a
=> 1
>> c
=> 3

# for methonds:

def giveme_five(*hand) #<-- note the *
#get fingers
f1,f2,f3,f4,f5 = hand
end

4.The Ternary Operator
Often its forgotten! Imagine you want to add classes in HAML e.g.

1	>> :class=> current_user ? "active" : nil

5. Use ranges!
Instead of if/else hell, you can use:

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>> case number
>> when 0..100: "small"
>> when 100..200: "medium"
>> when 200..300: "big"
>> else "unbeliveable"
>> end
=> "medium"

6. Array.join
* followed by a String can be a shorter way to get the result:

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>> [1,2,3] * 2
=> [1, 2, 3, 1, 2, 3]
# BUT:
>> %w{ruby really rocks} * " - "
=> "ruby - really - rocks"

OC it works with numbers as well.

7. Easy Iteration
Imagine a bad class, giving:

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result = Model.first

# but sometimes:

result = Model.several_rows

Iterating these models is just as easy as:

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[*result].each {|r|
...
}

Hope this helps someone out.

What are your favorite Tips and Hints?

Sortable Tables with Ruby on Rails and Ajax

inbreed — Mon, 14 Dec 2009 18:10:05 +0000

This is more like a rather small hint, describing how to make tables sortable in rails.

Just like ryan bates shows in his rails casts, there is a similar way to sort tables, instead of lists.

Here the example-code how to make the tables sortable:

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- # this is haml-code! can be done in erb as well..
%table
%tbody{:id=>"products"}
-for product in @products
%tr{:id=>"product_#{product.id}"}
%td=product.name
-#.. more hamlcode
-# i want a drag-handler, optional
%td.drag_handle
=image_tag "move.gif"

Note: NOT the table has the id, the tbody has, its the actualy tr-s parentnode, ever!
This code actually only builds the table – important is the id setting of each tr and tbody.

after the table, just add this simple piece:

1	= sortable_element('products', :url => {:action => 'update_order'}, :handle => :drag_handle, :tag => :tr)

Note: the :tag symbol now points to the tr, default is li.

So far, saving the sorted rows is just like railscasts shows:

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# routes.rb
# currently in admin-namespace..
admin.resources :products, :collection=>{:update_order => :post}

# product_controller
def update_order
params[:products].each_with_index { |id,index|
Product.update_all(['position=?', index], ['id=?', id])
}
render :nothing=>true
end

Dont forget to include scriptacolous in your layouts.
Hope this helps anyone!

Original Podcast by Ryan Bates:
Sortable Lists

Rails Will_Paginate w/o next or previous buttons

inbreed — Thu, 03 Dec 2009 12:45:38 +0000

I wanted to have a rather simple pagination without next and previous buttons (yah, the post title told you, eh?).

However, did not find any option to deal with it. But Will_Paginate provides a nice way to overwrite the link renderer in order to have full customization.

So i created the following:

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class PaginationListLinkRenderer < WillPaginate::LinkRenderer

def to_html
links = @options[:page_links] ? windowed_links : []
links.unshift(page_link_or_span(@collection.previous_page, 'previous', @options[:previous_label])) if options[:do_prev]
links.push(page_link_or_span(@collection.next_page, 'next', @options[:next_label])) if options[:do_next]
html = links.join(@options[:separator])
@options[:container] ? @template.content_tag(:div, html, html_attributes) : html
end
end

So from now on, using the new class ans renderer, i can add :do_next=>true IF i want to have next/prev links. per default its disabled as you can see.
activate it via

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#environment.rb
WillPaginate::ViewHelpers.pagination_options[:renderer] = 'PaginationListLinkRenderer'
#or template:
will_paginate @foo, :renderer=>PaginationListLinkRenderer

hf!

Different route, same path/url calling in Rails

inbreed — Thu, 26 Nov 2009 13:35:36 +0000

I had the following problem to solve using rails:

Having 2 Subdomains, www and clients
a client always has a path-prefix to use google analytics for each of this subdirs. so i had the following urls:
www.domain.tld/foo.html and clients.domain.tld/3kunsdf7w/foo.html
I did not want to have a code on www.
i did not want to alter all tempaltes with new paramters and differen routes

Solving this, it was ok for me to duplicate all routes with a client_ prefix using textmate, so i took onl 4 seconds.. but what next, how to tell rails to use the clients_xy_path when i call xy_path?

To keep it short, i did not find a nice solution to let rails switch the routes. So i added a get_ to all of these path and urls via sed, also done fast. Now, instead of xy_path(:bar=>’foo’) the call was get_xy_path(:bar=>’foo’) – and yes, they really dont exist! :)

my goal:

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def method
client? ? clientspath : wwwpath
end

my solution:

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module PathHelper
def method_missing(method_id, *arguments)
if match = /^get_([_a-zA-Z]\w*)_(path|url)$/.match(method_id.to_s)
return (!session[:pid].nil? and session[:pid].to_i != 1) ?
eval("client_#{match[1]}_#{match[2]}(arguments.first)") :
eval("#{match[1]}_#{match[2]}(arguments.first)")
end
end
end

[ActionView::Base,ActionController::Base].each{|x|
x.send :include, PathHelper
}

hope this helps anybody!

Any suggestions for a better solution w/o changing railscode?

svn: Can’t convert string from ‘UTF-8′ to native encoding

inbreed — Tue, 24 Nov 2009 11:53:52 +0000

Today i was bored by svn. Filenames containing “special characters” can cause an annoying Subversion error message:

1	svn: Can't convert string from 'UTF-8' to native encoding:

From the subversion book:

Errors like this typically occur when the Subversion client has received a UTF-8 string from the repository, but not all of the characters in that string can be represented using the encoding of the current locale. For example, if your locale is en_US but a collaborator has committed a Japanese filename, you’re likely to see this error when you receive the file during an svn update.

To fix this error message you have to set your current locale appropriately:

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Pussybook Pro:~ inbreed$ export LC_CTYPE=en_US.UTF-8
Pussybook Pro:~ inbreed$ locale
LANG=
LC_COLLATE="C"
LC_CTYPE="en_US.UTF-8"
LC_MESSAGES="C"
LC_MONETARY="C"
LC_NUMERIC="C"
LC_TIME="C"
LC_ALL="C/en_US.UTF-8/C/C/C/C"
Pussybook Pro:~ inbreed$ svn update

Noticed: getting yourself confused with helper methods!

inbreed — Wed, 18 Nov 2009 22:40:40 +0000

Just a rather small hint for rails users.

Today i was getting angry about rails, since it told me that a specific method would not exist.. but i knew that i did exists, and both of us were wrong.

How come: i moved a method vom controller to helper, but forgott to remove it from helper_methods.

So Rails claims, that the gived method does not exists. Strange, but true, it complains when you call it in code or template, silence when you just add it as helper_method.

So be warned, be smarter than i was ;)