"context" on a drupal page

Question

This question is a general one, and I've already posted a version of it here. I'm hoping, though, that I'll have a better chance of getting a response, and of being useful to more people, by asking in this forum.

Associating content together when it all loads on a drupal page is tricky business. In drupal, each page, no matter the site, is basically the same: you have main content in the middle (a view, a node, or multiple nodes), with blocks surrounding that central content. To make the blocks somehow aware of whats in the middle, (much less aware of each other) you either have to do some really fancy footwork in your own custom module, or you have to make "arguments" available in the URL.

I've been studying the spaces/context/features/purl suite of modules provided by developmentseed, and I've also looked into the Panels/Ctools modules made by Earl Miles (the guy who wrote views). While both provide tools to make my job easier, my understanding of each is that I'm still required to place "arguments" in the URL if I want the contents of my blocks defined by my "context" (I use that in the general sense, and not in the specific sense meant by either the context module, or the concept of context in Ctools).

Am I missing something, or is that where we're at with Drupal?

Finally, I should say in closing that I am aware of other modules that help with this kind of thing on a limited, case-by-case basis. The Views attach module and the Node reference views module, for instance, each take a stab at solving this issue for a very specific use case. They're both good modules, and there are others like them, but I'd really like to find a solution to this problem in general.

Answer 1

I guess I do not really understand what you're aiming at, but I'll try nonetheless:

For every non static website, be it based on Drupal or anything else, there are two basic things providing the 'context' for the decision on what content to deliver for given a request.

The first and most important thing is obviously the request itself. This is the only information that is always guaranteed to be there. In most cases, this will simply be a GET request, and with those, the URL is implicitly the main source of 'context' available. POST requests can provide a bit more 'context' besides the URL, but for your question, one could argue that they are just a more complicated variation of a GET request, providing some more 'arguments' besides the ones from the URL (and in most cases, one could turn a POST request into a GET request with a more elaborated URL anyways).

The second 'context providing' thing is the session. Whatever mechanism session handling is based on (predominantly cookies nowadays), the goal is always the same, namely to carry some 'state' information across the boundary of inherently stateless requests. It does this by tying a given request to information from previous requests, stored on the server side. This allows to 'enrich' the information that is available for the decision on what content to deliver for a request. Basically, one could look at it as a way of adding some more 'arguments' to the request.

And that's it. Any other information needed for assembling a response needs to somehow be derived from the information given in the request (and one could say that session handling is already the main process of doing so, by adding 'context' based on a cookie or some other identifier coming with the request).

Drupal reflects this process pretty well, IMHO, as it first assembles the 'main' content for a response based on the URL, with additional information (e.g. about the user) 'attached' in the session. It is only after the main content got assembled via calling $return = menu_execute_active_handler() in index.php, that the other elements of a response get added (e.g. blocks, menus, etc.), by calling theme('page', $return);.

So whatever 'context' it is that you want to 'pass' to those other elements, you either have to 'reextract' it from the information already used for assembling the main content (URL, session), or you have to store it temporarily during the generation of the main context. You can do this in many ways, e.g. by adding it to the information already stored in the session, by using static caching within some functions, by setting global variables (don't ;), by passing stuff through the database, etc...

So again, I do not seem to understand what you are aiming at. What is it that you are missing here?

Answer 2

Good answer from Henrik but I'd like to add that there can be quite a lot of information in the request beside maintaining state with cookies. Think important HTTP headers like accept or language or even X-REQUESTED-WITH. Most webframeworks wrap this information into one convenient datastructure. Unfortunately from the answers given I have to conclude that drupal doesn't.