I am porting a legacy application to Symfony2 and I am struggling because routing doesn’t include query string parameters. Some quick examples: Suppose you have a search page for books where you can filter results based on criteria:
http://www.bookstore.com/books?author=Stephen+King&maxPrice=20
The nice thing about query string parameters in a case like this is you can have any number of filters, use the ones you want for any given request, and not crowd the URL with filters you’re not using.
Let’s say we rewrote the routing for the above query using the Symfony2 routing component. It might look like this:
http://www.mybookstore.com/book/any_title/stephen%20king/any_release_date/max_price_20/any_min_price/any_format/any_category
Even not taking into account how arbitrarily long an unclean that URL is I still don’t think it is as intuitive because each ‘segment’ of that route is not a key value pair but instead just a value (e.g. author=Stephen+King > /stephen%20king/).
You can of course access query string parameters in the controller by passing the Request object into the action method (e.g. indexAction(Request $request) {) but then validating them and passing them into other parts of the application becomes a hassle (i.e. where I find myself now). What if you are using the Knp Menu Bundle to build your sidebar and you want parts to be marked as .current based on query string parameters? There is no functionality for that, just functionality to integrate with Symfony2 routes.
And how to validate that your query string parameters are acceptable? I am currently looking at validating them like a form to then pass them into the database to generate a query. Maybe this is the way the Symfony2 team envisioned handling them? If so I’d just really like to know why. It feels like I’m fighting the application.
I ended up actually asking Fabien this question at Symfony Live San Francisco 2012. There was another talk at the same conference in regards to this question and I will share with you the slides here:
http://www.slideshare.net/Wombert/phpjp-urls-rest#btnNext
Basically in the slides you can see that the author agrees with me in that query string parameters should be used for filtering. What they should not be used for is determining a content source. So a route should point to a product (or whatever) and query string parameters should then be used in your controller to apply whatever logic you require to filter that content source (as per Fabien).
I ended up creating an entity in my application that I bind all my query string parameters to and then manipulate, much the same way forms are handled. In fact when you think about it it’s basically the same thing.