How can I use a callback function for fields?

[rhodes]

I have a custom field in one of my RM categories, lets say textfield_1 in category_1

textfield_1 is a multiline textfield. Within the setting I've defined a callbach function to modify the value of this field. Unfortunately nothing happens.

    function myfield(&$content){
        $content = "abc";
    }

Where is my mistake?

 

[Mike]

Where have you set this callback? The only callback supported by default is for value matching, so it's only used when saving the value. It does actually take the value as the second argument by reference, so it can be modified at that time.

 

[rhodes]

The only callback supported by default is for value matching, so it's only used when saving the value.

thank you @Mike. I thought I could use the callback to process the field value every time the resource is viewed, not only during value matching. I have to save an array of IDs (22364,638482,79792) and fetch information from an external database according to these IDs when viewing a single resource. But then I cannot use RM for this purpose.

 

[rhodes]

One last question @Mike . If I want to use a callback function when viewing resource items, which would be the best starting point? The public controller?

 

[Mike]

There are a lot of different options, including controller extension approaches. That's probably the most common option. What are you trying to do specifically?

 

[rhodes]

I have a custom multiline textfield. Each line contains a text string and an ID, separated by comma

String 1,432
String 2,555
...
String n, 2367

When viewing the resource item I would like to process every single textfield line.

 

[Mike]

Your best bet may be to use the class extension system to extend XenResource_Model_Resource::prepareResource to "prepare" this custom field before display, and then you can use the prepared version in the template.