Printing a function on a content type page?

Question

So if I have a custom function with a DB query within template.php such as

function innovista_get_page_children() {

 $result = db_query("SELECT link_path FROM {menu_links}");
 return $result;

}

and I have a content type specific template page, then how do I echo the results in the template file?

I tried this:

<?php
$results = innovista_get_page_children();
foreach($results as $result){
    print $result;
}
?>

I get the following error

Recoverable fatal error: Object of class stdClass could not be converted to string in include() (line 83 of /var/www/vhosts/vidanlawnes.co.uk/innovista2/sites/all/themes/innovista/node--level_1.tpl.php).

If I remove print $result; and replace with print 'hello'... e.g

<?php
$results = innovista_get_page_children();
foreach($results as $result){
//print $result;
print 'hello ';
}
?>

It echoes hello out multiple times, so the query is providing results, but I can't seem to print them as $result. Any ideas?

Thanks for your time

Answer 1

The error message itself is clear I think. You are trying to print an object as a string. otherwise, your query seems correct.

function innovista_get_page_children() {

 $result = db_query("SELECT link_path FROM {menu_links}");
 return $result;

}


<?php
$results = innovista_get_page_children();
print '<pre>';
foreach($results as $result){
    print_r($result);
}
print '</pre>';
?>

Now you will see a formatted variable information of each $result. it will look like

stdClass Object (
  [link_path] => admin/structure/views 
)

So when you print the results, it will be like,

<?php
    $results = innovista_get_page_children();
    foreach($results as $result){
      print $result->link_path;
      print '<br/>';
    }
?>

However, keep in mind that it's never OK to print link paths or database queries like this. It will cause huge performance problems and will arise security problems. Try to use url() and/or l() functions for links (suggested it because you seem to make a link). Also, in most cases, there is a function for core/contrib modules to retrive data.

Answer 2

Every theme function/template runs hook_preprocess_HOOK() and hook_process_hook() before executing the function/template. hook_preprocess_HOOK is where you'd want to set up any new variables. The hook is passed an array of variables by reference, and you add to that array. The key of the array becomes the name of the variable in your template. People often try to keep all the logic out of the template file in this way. For example to set up a variable $foo in a page template (ie what's used for theme('page', ...)) you could do this.

/**
 * Implements hook_preprocess_page().
 */
MYMODULE_preprocess_page(&$vars) {
  $vars['foo'] = 'bar';
}

Answer 3

First I dont suggest put your function in template.php directly, (you can put in in custom module)
I suggest you act more professionaler in function, This code showed your are begginer in drupal developing,
however . this code have to work because template.php function in exist form basic drupal bootstrapping.
Your problem is your function maybe not return anything and $var will be empty. When I was begginer in drupal put my global fuction in themplate.php and use them in every where i want, test something like this

function myfunction() {

      $result = db_query("SELECT field FROM {table} WHERE field = 'query' ");
       if ($result)
       return $result;
       else
       return "sorry,no result";
     }

and in your tpl file

<?php 
      $myvar = mytheme_myfunction();
      print $myvar;
?>

I know this is not principle method but sometimes we just need it just work. :)