Code Iteratively » tip

Tip: Using vim with Rails Apps

Christopher Gooley — Sat, 04 Sep 2010 09:31:18 +0000

I’ve been trying a few different editors for working with Rails, including TextMate, Aptana and my trusty vim. I was leaning towards TextMate (bought a license too) but since I also develop on Ubuntu and would like to standardize tools to a certain extent, I decided to see if I could supercharge vim. The answer is a resounding YES.

This plugin is awesome. Because it is aware of the Rails app structure, you can do cool things like jumping between files using commands like :Rcontroller User which will load the UserController or :Rview places/new which loads /app/views/places/new.html.erb. And, when your cursor is over a reference like a has_many line in a model if you key in gf, it will jump to the file where that reference is defined.

Or, if you’re looking at specific action in a controller, the command :R will jump you to the view for that action (and vice versa). It even supports refactoring and neato stuff like that. These are just a few examples, try it out and read the documentation to see how powerful it is!

Aha! The trick to getting custom named routes!

Christopher Gooley — Fri, 03 Sep 2010 17:19:16 +0000

It was frustrating me that I had to hardcode strings like /activate/#{user.activation_token} when using link_to and other constructs with wacky custom routes (because they wouldn’t auto-generate a named route). The trick is to add :as => 'routename' to your routes.rb match statement. This will then expose routename_url to the rest of your app so you can do routename_url(user.activation_token) to get the proper url.

It’s easy when you know how… Also, $ rake routes is essential to understanding the magic under the hood. Use it!

Upgrading your Authlogic Gem for Rails3

Christopher Gooley — Fri, 03 Sep 2010 08:45:17 +0000

If you’re using Authlogic in Rails3 (or if you’re upgrading your existing app from 2.3.8 to Rails3) you really need to be using the rails3 branch of the Authlogic gem. If you’re using Bundler, this is super-easy because you just need to update your Gemfile.

In your Gemfile, update the authlogic line to be:

gem 'authlogic', :git => 'git://github.com/odorcicd/authlogic.git', :branch => 'rails3'

Now you should run $ bundle install to grab the new gem. Then, there are just a few more deprecated things in Rails3 that you’ll need to change in your upgraded app. I’ll try to enumerate here from memory, so please forgive me if I forget something.

First, you need to update your ApplicationController because #requesturi is outdated. Replace it with #fullpath:

def store_location
  session[:return_to] = request.fullpath
end

Second, you need to drop the filter_parameter_logging setting from your ApplicationController because it’s now handled in the new application.rb file. Just remember to add the :password_confirmation field to the default array like so:

# Configure sensitive parameters which will be filtered from the log file.
config.filter_parameters += [:password, :password_confirmation]

Third, if your migration script (or the steps you followed manually) didn’t get rid of the /config/initializers/cookie_verification_secret.rb file, delete it now. Cookie secrets are now handled in the /config/initializers/secret_token.rb file.

Fourth, the f.error_message construct isn’t available anymore in core rails, so you should take this opportunity to create your own better more customizable error messages. If you really really want to keep using f.error_message you can install the dynamic_form plugin, but don’t do that. Railscast.com did a very nice explanation of how to create your own shared _error_messages.html.erb view (along with some other validation-related stuff.)

Finally, you need to make sure your generated pages include the csrf_meta_tag. Check out my previous post if you’re getting an InvalidAuthenticityToken error when you hit the Logout link.

That should be all you need to do to have Authlogic working in Rails3 without deprecated warnings.

InvalidAuthenticityToken on Logout when using Authlogic

Christopher Gooley — Fri, 03 Sep 2010 08:07:46 +0000

This one took me a while to debug. When upgrading my existing application to Rails 3 almost everything was working fine except whenever I would click the Logout link I would get an error because Rails couldn’t verify that the UserSessionsController#destroy request was valid from my app.

This is the error message shown:
ActionController::InvalidAuthenticityToken in User sessionsController#destroy

actionpack (3.0.0) lib/action_controller/metal/ request_forgery_protection.rb:96:in `verify_authenticity_token'

And the solution is simple, you just need to add the new csrf_meta_tag helper to your generated page (probably in the /views/layouts/application.html.erb file).

...

  
  Some Title
  <%= stylesheet_link_tag :all %>
  <%= javascript_include_tag :defaults %>
  <%= csrf_meta_tag %>

...

Line 7 is the one you care about and need to have in your html.erb file.

This helper includes the appropriate meta tags which make the authenticity_token available to the handleMethod javascript function. In Rails3, links generated with the link_to helper which use a :method other than GET get passed through that handleMethod function in rails.js. That function creates a temporary form, sets some parameters and submits it. And if you’re using protect_from_forgery (you should be) all non-GET requests are checked to prevent Cross Site Request Forgery (CSRF). So, if those meta tags don’t exist on your page, the handleMethod function doesn’t know what your authenticity_token is, and the request will be rejected with the error above.

Line 5 below is an example of my main nav logout link that was causing the problem when clicked. No change was required to this code after doing the above fix.

<% if !current_user %>
  <%= link_to "Log In", new_user_session_path %> |
  <%= link_to "Register", new_account_path %> |
<% else %>
  <%= link_to "Logout", user_session_path, :method => :delete %> |
<% end %>

This isn’t specific to Authlogic’s logout click – any time you are using link_to now in Rails3 with non-GET methods, it uses unobtrusive javascript. And if you’re missing the csrf_meta_tag helper, any unobtrusive javascript posts will fail to validate.

PDFLib .NET Deploy Tip (specified module could not be found)

Christopher Gooley — Tue, 16 Dec 2008 20:24:01 +0000

We’re using the ASP.NET C# version of PDFLib at work to generate loads of reports and cool pdf files. Everything was peachy on our development systems until we deployed to staging servers and started getting a strange error.

All of the sudden we started getting the following exception on the site:
The specified module could not be found. (Exception from HRESULT: 0x8007007E)
Not one of Microsoft’s more useful error messages, to be true and googling for that error returns so many diverse topics that they were completely useless.

So after a bit of troubleshooting, we came to the following solution tips. These should work for both C# and VB and any other .NET language. Tested on Windows 2003 and Windows Server 2008.

Make sure your webserver is 32-bit

PDFLib for .NET does not support 64-bit servers. In theory you could run your IIS worker processes in 32-bit on a 64-bit OS, but I leave that as an exercise to the reader.

Make sure you have .NET 1.1 installed

Because pdflib_dotnet.dll is built on 1.1 and you will have this installed on your development box, you will never think about this for your prod/staging servers. If you already have IIS installed before you run the 1.1 installer, don’t forget to register it with IIS:
C:\Windows\Microsoft.NET\Framework\v1.1.xxxxx\aspnet_regiis.exe -ir

Put the MSVCR71.DLL into your web bin directory

On your development machine (or wherever you have PDFLib actually installed) the msvcr71.dll will be in C:\Program Files\PDFlib\PDFlib 32-bit 7.0.3\dotNET\bin or thereabouts. Drop that into your website bin directory on the server.

UPDATE: You may also need to place this dll into the C:\Windows\System32 folder on a dedicated server.

Reboot, then check it out.

Taste the sweet goodness of success.

PDFLib produces a great end product (and it should for that much caaaassssshh). But it has many weird cases. Probably because it seems that the .NET version is just a simple crappy wrapper on the C library. Oh well. It’s still the best thing on the market to separate your developers from your designers.

Build your own modded System.Web.Extensions.dll

Christopher Gooley — Wed, 31 Jan 2007 09:01:01 +0000

Earlier today Microsoft released the source code to the AJAX 1.0 release System.Web.Extensions library. I was in the apparently unique position of needing to modify parts of the code for a special case application, so I downloaded the source right away ready to modify, compile and deploy.

I guess I was pretty naive to think that it would be that easy. The distribution doesn’t include some pretty important parts. A .csproj file for one. The entire Resources class for another.

So I had to work my way through the process of getting a compile-able version of the library ready to replace the official System.Web.Extensions binary in my project. The server code Reference License prevents me from simply providing the project to you, but here are the high points if you need to do the same.

Be aware:
This is neither easy nor straightforward and I probably forgot a few steps when I was writing this. You’re gonna have to be diligent to get it to work, even with this howto.

Getting Started
1) Download and install the source
2) Create a new C# project in Visual Studio. You can call it whatever you want but I would suggest you avoid using the same namespace because the System.Web namespace is strongly named and exists in several assemblies. I called mine Dave.Web.Ajax
3) Copy all the files and folders from the source installed directory (C:Program Files (x86)Microsoft ASP.NETASP.NET 2.0 AJAX Extensionsv1.0.61025SourceSystem.Web.Extensions on my computer) into your new project directory and include them in the project.
4) Make sure your Default Namespace on the project is something good – again Dave.Web.Ajax in my case.

Get the Missing Files
1) Start the .Net Reflector (if you’re a serious .Net developer, you should have downloaded this to your computer long ago, btw)
2) Open the official System.Web.Extensions.dll file
3) Save all the Resources into a new Resources folder in your project. When you save them, drop the “System.Web.Resources” part of the filename if it’s there.
4) You should now have a file called AtlasWeb.resources in your folder
5) Open a VS Command Prompt and in your resources folder run
resgen AtlasWeb.resources AtlasWeb.resx. This will generate the resx file that you need in visual studio to dynamically generate the class.

Setup your Embedded Resources
1) In VS, include all the files in the Resources in your project (except the *.resources files) if you haven’t already.
2) Select them all and set the Build Action to Embedded Resource
3) Click on the AtlasWeb.resx file and set the Custom Tool property to “ResXFileCodeGenerator”. This will generate the AtlasWeb.Designer.cs file which gives you a real class with properties for each item in the resource file.
NOTE) You might need to repeat this process (and the resgen.exe process) for the other *.resources files, but I haven’t done it and havn’t had any issues yet.

Rename the Namespace and cleanup
If you are going to stick with using the System.Web.* namespace, then you can skip this step.
1) Basically, I handled this in an iterative fashion. I did a project Find-and-Replace for “System.Web.” and replaced with “Dave.Web.Ajax.” Of course this process will break stuff because now objects that are really in the System.Web namespace (and not in the System.Web.Extensions assembly) will dissappear.
2) Get your iteration on: compile, add “using System.Web.something;” to a file with the error, compile, repeat.

Fix the Embedded Resource references
At this point, your project should compile and if you reference it in a web project in place of the System.Web.Extensions.dll file (or the GAC reference) the web project should compile too. But as soon as you load up a page with AJAX controls on it, you will get a runtime error saying the Resource File could not be found.

Update the reference names of your embedded .js files to be fully qualified. Your new fully qualified resource name will be “DefaultNamespace.Resources.Filename.js” Mine is “Dave.Web.Ajax.Resources.MicrosoftAjax.js” for example.

There are references in these files
UIScriptManager.cs:931,935
UIWebResourceUtil.cs:64+
UITimer.cs:147

Update those references to use the fully qualified names. After that, in WebResourceUtil.cs there is an optimization in the SystemWebExtensionsContainsWebResource(string) function that you have to modify. It does a switch statement on the length of the input string before comparing to the resource name string. Update each case conditional to be the length of the string in that case statement. If you forget this step you will be very confused why it says it can’t find a resource that you know is there…

Now, all embedded resources need an assembly reference so that they can be detected using reflection (which is how the AJAX library looks for a valid embedded resource). I just created a dummy class called Scripts.cs inside the Resources file so I could include the assembly attributes:

[assembly: System.Web.UI.WebResource("Dave.Web.Ajax.Resources.MicrosoftAjax.debug.js", "text/javascript")] [assembly: System.Web.UI.WebResource("Dave.Web.Ajax.Resources.MicrosoftAjax.js", "text/javascript")] [assembly: System.Web.UI.WebResource("Dave.Web.Ajax.Resources.MicrosoftAjaxTimer.debug.js", "text/javascript")] [assembly: System.Web.UI.WebResource("Dave.Web.Ajax.Resources.MicrosoftAjaxTimer.js", "text/javascript")] [assembly: System.Web.UI.WebResource("Dave.Web.Ajax.Resources.MicrosoftAjaxWebForms.debug.js", "text/javascript")] [assembly: System.Web.UI.WebResource("Dave.Web.Ajax.Resources.MicrosoftAjaxWebForms.js", "text/javascript")] namespace Dave.Web.Ajax.Resources { class Scripts { } }

Just make sure you have a WebResource attribute for each of the javascript files in the project.

That’s it
Assuming you’ve gotten this far, you must be dedicated or desperate. Now you can go in and make your mods to any of the AJAX files and you’re good to go. Hopefully this was helpful and I wish I could just post the project, but rules is rules.

Its been about 6 hours since I finished my conversion, so its pretty fresh in my head, but I may have forgotten a step somewhere. I’ll try to answer questions in the comments but I’m pretty busy these days and I just blew half my day because the release of AJAX doesn’t play well inside iframes (which is the whole reason I had to do this mod).

Good luck to you.