Month: December 2011

Truncating a String within a View – Ruby on Rails

Another quick post, just on how to truncate a string within a view. I used the following in order to ensure that my order_item title is never longer than 100 characters:

Title:  100, :seperator => ' ...') %>

 

This will output the title, if it’s longer than 100 characters the string will be shortened to 100 characters (minus the separator’s length). The neat thing about truncate is all the separator functionality is built in – you don’t have to throw any if/else logic in to check whether it’s required or not.

Output:

#Less than 100 characters
Title: lentesque porttitor

#More than 100 characters
Title: lentesque porttitor, velit vel ullamcorper pharetra, augue erat pharetra risus, quis bibendum fel…

Good Luck!

Adding a Link Within a Flash Notice/Message – Ruby on Rails

I came across an instance where I needed to add a link to flash notice tonight. Manually creating a hyperlink seems to work fine, however I was chasing a rubyish way of doing things:

flash[:notice] = "Order created - Click here to pay for it!"

 

Luckily a quick Google revealed the answer:

flash[:notice] = "Order created - Click here to pay for it!".html_safe

 

If you’re using rails 3 make sure you throw in the .html_safe or your link will be appear as plain text. Just a quick screenshot of the end result below:

Anyway, that’s all. Good Luck!

Passing Variables to a Partial from a View – Ruby on Rails

Just another one of those things that I find myself needing to do from time to time. Luckily this is all pretty straight forward (thankyou Ruby on Rails!). Assuming your partial is a form in the locations folder and that the variable you’re expecting is location all that you have to do is following:

View: users/show.html.erb

 'locations/form', :locals => { :location => @user.location } %>

Partial: locations/_form.html.erb


Street:

Good luck!

Error 324 (net::ERR_EMPTY_RESPONSE) – Ruby on Rails

I managed to break my app again while playing around with the routes and a few redirects:

No data received
Unable to load the webpage because the server sent no data.
Here are some suggestions:
Reload this webpage later.
Error 324 (net::ERR_EMPTY_RESPONSE): The server closed the connection without sending any data.

 

This wasn’t one I had encountered before and unfortunately Google couldn’t give me anything to cheat off. Luckily, a quick review of the server log revealed the following message just before it closed the connection:

[2011-12-03 21:09:05] ERROR URI::InvalidURIError: the scheme http does not accept registry part: 192.168.1.3:3000locations (or bad hostname?)

 

From this error message it became clear that I needed to place a forward slash before my redirect path:

#Redirect to edit location path      
redirect_to '/locations/edit'

 

Hopefully this’ll be able to help someone else out there, Good Luck!

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!