Cannot use a symlink for jquery

I wanted to have a symlink in my public/javascripts folder that pointed to the current version of jQuery that my project was using rather than specify the version in my layout, or use a copy. However Rails won't load the library if I do this.

Fundamental Approach

We keep css in stylesheets, so lets stop embedding javascript in our html and keep it in separate scripts. The issue is then how do we apply our javascript to our html in an effective manner.

The favoured solution is to use lowpro. This is an additional javascript library that clarifies the addition of javascript behaviours to elements in the DOM using css selectors. What this means is that you can write a behavior (say the generation of a form to post a DELETE) which will be applied to all elements with the css class 'delete_link'. Currently the javascript to do this is a bit hairy for me, but if I can get to grips with it then it should be very cool.

The main effect of this is on the workflow of developing a web app. Basically you can now turn off javascript, get your web app to work properly (ideally with good webrat based story tests), and then add your javascript for extra functionality as a separate process. Done properly this second process won't touch your html (except perhaps to add css selectors - although they should be already there if your html is semantic).

Need to do a test application to investigate this further.

There are several issues to consider here

• obtrusive javascript
• supporting browsers where javascript is disabled
• restful design and current browser limitations

restful design and current browser limitations

Restful design stipulates that to delete a resource you should call its url using the delete method on it. So with an item foo you would use the same url to delete and show foo

• www.example.com/foo with GET to show
• www.example.com/foo with DELETE to delete

However current browsers only support the GET and POST verbs, so we have to get around this. What Rails does is overload POST passing the method (PUSH, DELETE, HEAD?). This means a form has to be created for each delete link. Rails uses javascript to create this form on the fly (and the very convenient confirmation dialog. This approach allows us to use the correct REST url to delete things.

supporting browsers where javascript is disabled

When javascript is disabled it becomes harder to delete things. If we try and use a link to delete we will instead send a GET and show foo. Rails does this because without javascript we cannot rely on the additional safety of a browser side confirmation. So Rails says we should not use a link for deleting but instead use a button (use method button_to). However buttons are clunky so people expect to be able to work around this limitation. There are a couple of solutions to this problem

1. use a button rather than a link, and lose the ability to confirm that action
2. insist on javascript so we can use pretty links to delete and have our confirm
3. create another url for deleting things which will show a confirmation form when javascript is disabled and then post the DELETE (this breaks the RESTFUL design a little)
4. wait for browser to support DELETE

obtrusive javascript

Another problem highlighted by this issue is the yukky javascript that the Rails helpers insert directly into our HTML. If we have a table of items that can be deleted we end up with 5 lines of convoluted javascript for each item. So we have our beautiful semantic html polluted by reams of 'obtrusive javascript'. I'll talk about this issue further in a separate post

references

Railscast 77