How to print the alphabet in Rails very easily.
("A".."Z").each {|letter| link_to letter, "/#{letter"}
"A".upto("Z") {|letter| link_to letter, "/#letter"}
Archive for October, 2009
A Through Z
Posted 30 Oct 2009 — by admin
Category Ruby on Rails
Category Ruby on Rails
Fun with Apache2 – httpd not running, trying to start (98)Address already in use: make_sock: could not bind to address 0.0.0.0:80 no listening sockets available, shutting down
Have you ever gotten this error message when trying to (re)start Apache
httpd not running, trying to start (98)Address already in use: make_sock: could not bind to address 0.0.0.0:80 no listening sockets available, shutting down
If you are running with an SSL certificate on your box, Apache cannot start up without the correct passphrase. I’ve run into this problem a couple times. Once when I rebuilt my virtual server from Mosso and the reboot process (obviously) required Apache to be started up when the machine came back up. Not being there when the start up phase required the correct passphrase Apache was up but not handling requests. The other time my server crashed when it ran out of memory. It was a 256 meg O’RAM box running a Rails app. Go figure!
Fortunately, there is an easy solution. Kill Apache and start it up again. If you’re in the console you’ll be prompted for the passphrase. Enter it correctly and everything will be fine. Here’s how I did it.
ps aux | grep apache root 3948 0.0 0.2 4028 668 ? S 17:48 0:00 /bin/sh -e /etc/rc2.d/S91apache2 start root 3959 0.0 0.2 4028 616 ? S 17:48 0:00 /bin/sh /usr/sbin/apache2ctl start root 3964 0.0 2.4 133564 6472 ? S 17:48 0:00 /usr/sbin/apache2 -k start root 4069 0.0 0.2 6268 660 pts/0 R+ 17:49 0:00 grep apache
I took at a look at the running processes and grep for apache. The one I wanted was the 2nd to last.
Look for the process id and kill it with the -9 option. The process id will be in the second column to the left
kill -9 3964
After it’s dead you can restart Apache like so
apache2ctl start
You’ll get the prompt for the passphrase. Enter it and everything should be fine.
Rails Paperclip Plugin Options for Attaching Files
Posted 15 Oct 2009 — by admin
Category Ruby on Rails
Category Ruby on Rails
I usually change some of the default settings when I use the Paperclip plugin. For most of my projects I don’t like having separate directories for each image that is uploaded. I prefer, in this instance, to put avatars of different sizes together under one directory and differentiated based on the style size of the image. To do this just set the path and url options like so…
has_attached_file :avatar,
:styles => {:thumb => "75x75", :medium => "150x150", :large => "500x500"},
:default_url => "/images/default_avatar.png",
:url => "/system/avatars/:id/:style_:basename.:extension",
:path => ":rails_root/public/system/avatars/:id/:style_:basename.:extension"
Also, when you set up the database your model will need to have the following columns for Paperclip to work properly
t.column :avatar_file_name, :string
t.column :avatar_content_type, :string
t.column :avatar_file_size, :integer
Don’t forget that to handle file uploads in Rails you need to set the form with
form_for current_user, :html =>{:multipart => true} do |f|
Otherwise, your upload won’t work 
link_to_function Rails Ajax Reference
Posted 14 Oct 2009 — by admin
Category Ruby on Rails
Category Ruby on Rails
Link_to_function syntax for Haml template. Notice the “|” pipe which will allow for new lines in your code.
= link_to_function( "Add Line Item") |
{|page| page.insert_html :bottom, :invoice_line_items, |
:partial => "line_item", :locals=>{:line_item=>LineItem.new}} |
SHA1 or MD5 Hashing in Python
Posted 10 Oct 2009 — by admin
Category Python
Category Python
import hashlib
print hashlib.sha1("My wonderful string").hexdigest()
print hashlib.md5("My other wonderful string").hexdigest()
Dynamic Attributes in Python Model Class
Posted 10 Oct 2009 — by admin
Category Python
Category Python
class Bar():
def __init__(self, **args):
for key in args:
self.__dict__[key] = args[key]
b = Bar(fullname="Monty Python", email="me@monthpython.org")
b.fullname #=> Monty Python
b.email #=>me@montypython.org
Python Zlib Compress DeCompress
Posted 09 Oct 2009 — by admin
Category Python
Category Python
import zlib regular_string = 'this is my string' compressed_string = zlib.compress(regular_string) decompressed_string = zlib.decompress(compressed_string) print compressed_string print decompressed_string
Pickle Python Objects
Posted 09 Oct 2009 — by admin
Category Python
Category Python
import pickle
entity = {
"user_id": "1",
"title": "Natural Dog Training",
"link": "http://naturaldogtraining.com",
}
pickled_entity = pickle.dumps(entity)
unpickled_entity = pickle.loads(pickled_entity)
Build Your Own Calendar in Rails without any Plugins in less than 10 lines of Ruby Code
Posted 07 Oct 2009 — by admin
Category Ruby on Rails
Category Ruby on Rails
There are a number of terrific calendar plugins for Rails. But it’s almost as easy, if not easier, to implement your own calendar.
The steps are pretty simple. First get the @beginning_of_month and @end_of_month and iterate over the days in between. In the loop we check if the day matches the @beginning_of_month and if it does we get the offset ( 0 – 6 ) because if the month doesn’t start on a Sunday all our days won’t match up correctly. We print out the offset number as table cells <td class=’offset’></td>. We then need to consider that weeks ‘restart’ and restart our row if we’re at the beginning of the week… this is accomplished with </tr><tr>. Then we just output the date contained in table cells <td>#{d.day}</td>. The code is below and it’s pretty simple.
In this example I use haml, but you could just as easily use ERB (at the bottom). If you’re not familiar with haml, check it out at http://haml-lang.com/ Haml automatically handles wrapping your html so you don’t have to! The end result is that it cuts your html in half and makes it look pretty, which in turns makes it a lot more manageable long term.
#app/views/calendars/show.html.haml
%table#calendar
%tr
%th
Sunday
%th
Monday
%th
Tuesday
%th
Wednesday
%th
Thursday
%th
Friday
%th
Saturday
%tr
- @beginning_of_month = Date.civil(2009,12,1)
- @end_of_month = Date.civil(2009, 12, -1)
- (@beginning_of_month..@end_of_month).each do |d|
- if d == @beginning_of_month
- (d.wday).times do # offset beginning of calendar
< td class='offset'> </td>
-if d.wday == 0 #restart the week
</tr><tr>
== <td class='#{d}'> #{d.day} </td>
Here it is in ERB
<table id='calendar'> <tr> <th>Sunday</th><th>Monday</th> <th>Tuesday</th><th>Wednesday</th> <th>Thursday</th><th>Friday</th> <th>Saturday</th> </tr> <tr> <% @beginning_of_month = Date.civil(2009, 12, 1) %> <% @end_of_month = Date.civil(2009, 12, -1) %> <% (@beginning_of_month..@end_of_month).each do |d| %> <% if d == @beginning_of_month %> <% d.wday.times do %> <td class='offset'></td> <% end %> <% end %> <% if d.wday == 0 %> </tr><tr> <% end %> <td> <%= d.day %> </td> <% end %> </tr> </table>
Override to_param method in model to get pseudo permalinks without any work
Posted 03 Oct 2009 — by admin
Category Ruby on Rails
Category Ruby on Rails
There are a number of permalink plugins for Rails, http://www.seoonrails.com/even-better-looking-urls-with-permalink_fu, is a good one that I’ve used before. However, this involves informing the model class (has_permalink :title), adding a route, using the route in your views and controllers and of course running some migrations. If you’re willing to get 99% of the functionality for 0% of the work, just override the to_param method in your model.
This assumes you have an attribute for your model that you’d like to use for your permalink, but that’s it.
#app/models/post.rb
class Post < ActiveRecord::Base
def to_param
"#{id}-#{title.gsub(/[^a-z0-9]+/i, '-').downcase}"
end
end
That's it. You don't have to change your controllers, routes or views. Your URL will look something like
/posts/45-pseudo-permalinks-with-rails
Active record will strip all alpha characters from the params[:id] variable leaving you with just the integer value of your model.
So long as you don't mind that integer in the url, it's an easy solution that you can bake in at any point w/out having to touch the rest of your application code.
