Using Drupal as a server application user front-end (feasability question)

Question

I am very new to Drupal. I am currently watching videos and reading many online tutorials. I came to Drupal, because I understand it is a good CMS system (at least recommended by many, and the more I learn, the more I agree).

But, the more I learn, the more I am wondering whether it could solve another of my needs: acting as a user front-end for a server-side application. Let me describe this.

• I have a couple of experts entering technical information in a system (i.e. database). I understand I can create specific screens with specific fields in Drupal (that's great, no coding) and that it would be stored in the database when ready.

• After information is entered by experts, heavy time and cpu consuming asynchronous processes should be started in background and resulting information stored in the database.

• Next, users should be able to read results with another screen in Drupal.

Instead of performing the heavy processes on the web-server, I was wondering whether I could use another server to connect to the drupal database instance (with a deamon application written in Java for example), perform the heavy duty tasks, and store the information in that same database.

My questions are:

1. Is this realistic? Has anyone attempted this?

2. Is it easy for a 3rd party application to read data from a Drupal database and store results in it? Does Drupal offer specific modules faciliting this? Any documentation or tips available?

Thanks.

Answer 1

Here's my understanding:

• Drupal will allow you to quickly create a content-type to store the data you need, and customise how your users enter their data.
• It's possible to query the Drupal database directly, but if you're not familiar with Drupal's schema, you'll need to spend a little time understanding where your data is stored.
• Once you do understand the schema, you may find the database is over-normalised for your requirements, which will mean a lot of joins will be required. Might not be an issue depending on your infrastructure and the quantity/frequency of data you're talking about.
• There are several APIs you can use to get data out of the database (assuming Drupal 7):
  • For direct SQL queries, use db_query
  • For the Drupal db access layer, use db_select
  • For something you configure, you could use views which you could output to any number of formats (json, XML, HTML etc.)
  • There are dozens of other modules which will allow you to integrate with other systems, one of those might suit your purpose.
• Storing the processed information again will depend on how much the data has changed, and how it need to be stored. For example: are you just overriding the existing data? Will the new data be added to the existing nodes, or will new nodes be created? Regardless, you'll probably need a custom module for this.

Answer 2

Absolutely.

Do not be put off by the 'CMS' label, Drupal is actually quite a framework in itself. Drupal really does a good job for small to mid-sized applications, as the application gets larger though one has to tweak and push the limit a bit more. To be fair, this is true of most any PHP application.

I have built quite a few applications myself that leverage the power of Drupal, some internal, some public: production management, calendaring applications, rental/item reservation for 4000 items +, mailing list management, (and more).

In my (very humble) opinion, Drupal saves a lot of time, especially for the 'user-management' aspect of application building. As a bonus, you have the rest of the framework to play with when developping your app.

Hope that helps, happy coding, good-luck!