Changing content-type programmatically

I have a web service (and am developing another) which can return various types of data: html, xml, and json. Presently, the only way I know to make this work is to setup a template for each content type and change my calls as follows:

www.tld.com/service.html?action=get_data_html
www.tld.com/service.xml?action=get_data_xml
www.tld.com/service.json?action=get_data_json

I have three resources which all have the same [[service]] call in the content but with different aliases and templates that set the content type.

This seems like a kludge to me and I seek a cleaner way to do it. Is there any way to set the content type from within a snippet to make this interface cleaner?

You could use this: http://php.net/manual/en/function.header.php

Quote from: thapriest86 at Dec 06, 2012, 04:10 PM

You could use this: http://php.net/manual/en/function.header.php

I looked at that as an option. I'm betting it would collide with the header information that MODx automatically generates from the value specified in the template. Am I wrong?

You could setup the seperate resources with the right content type (that sets the header for you), or, you could take a plugin approach similar to how InstantAPI does it: https://github.com/aladage/InstantAPI/blob/master/core/components/instantapi/elements/plugins/InstantAPI.php

There might be a way to use a plugin to change the content type on the fly, maybe OnWebPageLoad or something?

Quote from: kc64 at Dec 06, 2012, 04:17 PM

I looked at that as an option. I'm betting it would collide with the header information that MODx automatically generates from the value specified in the template. Am I wrong?

Hmm, you might be right, haven't put this in to test, just came to mind. In that case i'd personally go for setting up separate resources, like Mark mentioned above.

Yes, the three thread approach is exactly what I am doing already as stated above. This is a less than elegant solution however which I would like to avoid using in the future.

Sorry, I said "thread." I meant "resource."

You should be able to do it with a plugin; the resource type and content type are fields in the site_content table like any other, so they could be changed on-the-fly early in the parsing process by a plugin.

Quote from: sottwell at Dec 06, 2012, 11:42 PM

You should be able to do it with a plugin; the resource type and content type are fields in the site_content table like any other, so they could be changed on-the-fly early in the parsing process by a plugin.

Interesting idea. To what event would you bind the implementation? I looked at OnWebPageComplete, OnWebPageInit, and OnWebPagePrerender but none of these seems appropriate.

Hm. That's hard for me to say at this point. I knew how the events were triggered in Evo's parser, but I'm not yet familiar with Revo's parsing process. I would think as soon as the resource is sufficiently loaded for a full resource object to be available but before any processing has begun. The plugin would need to modify the resource object's content_type property. Perhaps OnLoadWebDocument:

Fires directly before the Response is sent and after a Resource is loaded.

The resource can be referenced via $modx->resource.