Category: Web Development

Breaking the Internet

Validation Error Messages not Displaying – Ruby on Rails

Just another quick problem I ran into, the validation was indicating that an error had occurred however it did not show what the error was:

1 error prohibited this message from being saved:

— Usually an error would appear here —

Turns out the problem was pretty straight forward – it’s always the little things! I’d simply missed the each when displaying the error messages:


  
    

       
 prohibited this message from being saved:

       
    
         
         
         
  • 
           
         
    •

Simply adding the correct code fixed the problem straight away.

1 error prohibited this message from being saved:

Country can’t be blank

Good Luck!

No HTTP_REFERER was set in the request to this action, so redirect_to :back could not be called successfully

Well, I’ve managed to break my app again today – getting the following error message:

ActionController::RedirectBackError in OrdersController#new

No HTTP_REFERER was set in the request to this action, so redirect_to :back could not be called successfully. If this is a test, make sure to specify request.env[“HTTP_REFERER”].

 

Thankfully this is another one that’s fairly easy to fix. Simply create the following method – I’ve added mine to the application controller:

  #Redirect_to_back
  def go_back

    #Attempt to redirect
    redirect_to :back

    #Catch exception and redirect to root
    rescue ActionController::RedirectBackError
      redirect_to root_path
   end

 

You can then call this method from any of you controllers using the following code:

     #Redirect user to previous page
      go_back

 

You may get the following error depending on how the rest of your controller action is setup:

Render and/or redirect were called multiple times in this action. Please note that you may only call render OR redirect, and at most once per action. Also note that neither redirect nor render terminate execution of the action, so if you want to exit an action after redirecting, you need to do something like “redirect_to(…) and return”.

 

This message is pretty self explanatory – simply add return immediately after your call to go_back in order to prevent any additional redirects being called:

#Redirect user to previous page
      go_back

      #Return to prevent multiple redirects
      return

 

Hopefully that’ll help someone out there, Good Luck!

 

Placing Multiple Button_To on the Same Line – Ruby on Rails

This is a problem that had me confused for an embarrassingly long time. Rails wraps button_to elements within a form and a div. Unfortunately this will take up 100% of the available width. Thankfully the solution is pretty straight forward – simply wrap buttons in a div and float them left like so:

    

       'button'%>
    

    

       'button' %>

A wrapper div isn’t strictly necessary however I usually add one just to be safe. While this will probably give a bunch of designers another reason to hate developers, I find that wrapping floated elements seems to save a lot of headaches when making changes down the track.

Using the code above you may also find that the divs aren’t filling as expected, simply add a div with a ‘clear:both’ style to the bottom of the wrapper: 


    

       'button'%>
    

    

       'button' %>

Hopefully that doesn’t take anywhere near as long for you guys to figure out as it did me, time for a coffee break I think. Good luck!

Routing Error – No Route Matches [Post] “orders/new”

I ran into a fairly common routing error this morning, thankfully these are fairly easy to fix – usually!

Routing Error
No route matches [POST] “/orders/new”

Simply add the following the route to your routes.rb file:

siteconfigroutes.rb

#Orders
controller :orders do
post ‘orders/new’ => ‘orders#new’
end

You may also have to restart WEBrick for this new route to take affect. Good Luck!

How to View a Table’s Structure – Sqlite3

Just a quick post on how to view a table’s structure in SQLite3. Again, not something I’ve broken yet – more something I seem to keep forgetting. Simply start Sqlite:
chris@chris-VirtualBox:~/site$ sqlite3 -line db/development.sqlite3
SQLite version 3.7.4
Enter “.help” for instructions
Enter SQL statements terminated with a “;”

Then enter the following: – substituting orders for whatever your table name happens to be:
sqlite> pragma table_info(orders);
cid = 0
name = id
type = INTEGER
notnull = 1
dflt_value =
pk = 1

cid = 1
name = user_id
type = integer
notnull = 0
dflt_value =
pk = 0

cid = 3
name = created_at
type = datetime
notnull = 0
dflt_value =
pk = 0

Good Luck!

View All Tables – Sqlite3

Not really something that I’ve broken (yet), but definitely something I found useful when starting out with rails – how to view all tables:

Start Sqlite3 i.e.
chris@chris-VirtualBox:~/site$ sqlite3 -line db/development.sqlite3
SQLite version 3.7.4
Enter “.help” for instructions
Enter SQL statements terminated with a “;”

Then simply enter the following:
sqlite> .tables
carts message_recipients products taggings
categories message_statuses schema_migrations tags
comments messages store_pages user_settings
images order_items store_settings users
line_items orders stores
locations product_images sub_orders
sqlite>

Good Luck!

Rails Server – Address Already in Use

Well, looks like the first thing I’ve managed to break today is WEBrick – a web server for ruby on rails. The general idea behind the error message appears to be that the address it’s trying to start is already in use:

[2011-12-02 19:01:34] INFO  WEBrick 1.3.1
[2011-12-02 19:01:34] INFO  ruby 1.8.7 (2010-08-16) [i686-linux]
[2011-12-02 19:01:39] WARN  TCPServer Error: Address already in use – bind(2)
Exiting
/usr/lib/ruby/1.8/webrick/utils.rb:73:in `initialize’: Address already in use – bind(2) (Errno::EADDRINUSE)
from /usr/lib/ruby/1.8/webrick/utils.rb:73:in `new’
from /usr/lib/ruby/1.8/webrick/utils.rb:73:in `create_listeners’
from /usr/lib/ruby/1.8/webrick/utils.rb:70:in `each’
from /usr/lib/ruby/1.8/webrick/utils.rb:70:in `create_listeners’
from /usr/lib/ruby/1.8/webrick/server.rb:75:in `listen’
from /usr/lib/ruby/1.8/webrick/server.rb:63:in `initialize’
from /usr/lib/ruby/1.8/webrick/httpserver.rb:24:in `initialize’
from /usr/lib/ruby/gems/1.8/gems/rack-1.3.4/lib/rack/handler/webrick.rb:10:in `new’
from /usr/lib/ruby/gems/1.8/gems/rack-1.3.4/lib/rack/handler/webrick.rb:10:in `run’
from /usr/lib/ruby/gems/1.8/gems/rack-1.3.4/lib/rack/server.rb:265:in `start’
from /usr/lib/ruby/gems/1.8/gems/railties-3.1.1/lib/rails/commands/server.rb:70:in `start’
from /usr/lib/ruby/gems/1.8/gems/railties-3.1.1/lib/rails/commands.rb:54
from /usr/lib/ruby/gems/1.8/gems/railties-3.1.1/lib/rails/commands.rb:49:in `tap’
from /usr/lib/ruby/gems/1.8/gems/railties-3.1.1/lib/rails/commands.rb:49
from script/rails:6:in `require’
from script/rails:6

 

Sure enough, it turns out that one of my previous WEBrick processes had not closed properly. I was able to view the existing processes using the following:
chris@chris-VirtualBox:~/site$ pgrep ruby
1601

 

In order to close them simply kill the process:
chris@chris-VirtualBox:~/site$ kill 1601

 

Ensure that the process is gone:
chris@chris-VirtualBox:~/site$ pgrep ruby

 

And finally, start WEBrick again.
chris@chris-VirtualBox:~/site$ rails server
=> Booting WEBrick
=> Rails 3.1.1 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2011-12-02 19:13:21] INFO  WEBrick 1.3.1
[2011-12-02 19:13:21] INFO  ruby 1.8.7 (2010-08-16) [i686-linux]
[2011-12-02 19:13:26] INFO  WEBrick::HTTPServer#start: pid=1814 port=3000

 

Good luck!