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I'm building an ExpressionEngine module in PHP.

In ExpressionEngine, one can access parameters passed to the module in a template using: $my_param = $this->EE->TMPL->fetch_param('my_param');

However, when I fetch a string that way, explode does not work on it:

public function get_tyres()
{
    $tyres = $this->EE->TMPL->fetch_param('tyres');
    echo($tyres);
    // this shows: '205/55R16M+S|205/55R16|205/55R16'
    // now I want to split it into single tyres, using the pipe as a delimiter

    $tyre_array = explode("|", $tyres);
    foreach($tyre_array as $tyre)
    {
        echo($tyre . '<br>');
    }
    // the above produces: '205/55R16M+S|205/55R16|205/55R16',        
    // where I'd expect it to produce:
    // 205/55R16M+S
    // 205/55R16
    // 205/55R16

}

I've tried to specifically cast to a string using $tyres = (string) $this->EE->TMPL->fetch_param('tyres');, with no luck.

I've also tried manually creating and exploding a string: $tyres = '205/55R16M+S|205/55R16|205/55R16'; which worked, but obviously I need to get the param from the template, not hard code it.

Lastly, I tried using preg_split and a regex, with no luck either: $tyre_array = preg_split('/\|/', $tyres); which also returned an array with the entire string in it.

What could be at work here? Is this a scope related thing? Is it an encoding-related thing? What to look for next?

Update

Okay, we're getting somewhere. I've added the following to the function:

for($i = 0; $i < strlen($tyres); $i++) {
    echo substr($tyres, $i, 1) . ", ";
}

Which returns... {, v, e, r, s, i, o, n, :, t, y, r, e, s, }, and that is in fact the variable passed to PHP in the HTML template:

{exp:my_module:tyres tyres="{version:tyres}"}
<h1>{tyre:name}</h1>
... more irrelevant HTML
{/exp:my_module:tyres}

This means it has something to do with the parsing order of ExpressionEngine. Apparently, the variable {version:tyres} isn't parsed yet. So I pass that variable to the module, it tries to explode it by the pipe character, but the string {version:tyres} does not contain a pipe, meaning it can't be exploded. ExpressionEngine then returns {version:tyres} as a whole, passes it back in to the template and then the variable is parsed as 205/55R16M+S|205/55R16|205/55R16.

I've tested this, and can confirm that exploding by ':' returns the array:

array (size=2)
  0 => string '{version' (length=8)
  1 => string 'tyres}' (length=6)

I will now look in to ExpressionEngine parse order. If anyone has an idea on how to work around this, I'd be happy to know ;-).

Rein
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    are you sure that the `|` in your string is actually the same `|` you're entering? Could be some completely different unicode char that happens to look the same. – Marc B Jul 31 '14 at 15:28
  • It should work. Check example: http://codepad.org/A3CmoaUE – Vaidas Jul 31 '14 at 15:29
  • Good question, but I am sure, because when I change the explode delimiter to, say `0` or `R` or `M`, which are all present in the string, the explode still returns an array with one item: the entire string, unexploded. – Rein Jul 31 '14 at 15:33
  • `echo htmlentities($tyres);` or view source for the echo—if you're looking in a rendered browser view, it could be that the string does not contain what you think it does. That said, pipes are not encoded by ExpressionEngine into something different, so your code should work. – Derek Jones Jul 31 '14 at 16:43
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    Try var_dump instead of echo. It'll give you more information about the type and contents of $tyres. – K.A.F. Jul 31 '14 at 16:53

2 Answers2

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I tested your code, copy and pasting your test string, and it works fine for me. Make sure your pipe ("|") is really the character you think it is, and not, say, some crazy unicode stuff that just looks like a pipe, but is actually Klingon for for 'staff', or something.

Try something like this as a reality check:

echo " the pipe is at " .strpos($tyres,"|"). " and I really hope this it says '12'";
JJ Rohrer
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  • Yes, it does work fine that way. When I hard code the string, it works. When it's fetched from the template, it does not work. Could it be that the template actually encodes the string a certain way? – Rein Jul 31 '14 at 15:34
  • It could be, which is why I suggested inserting the reality check code above, just put in your function somewhere. It says '12' for me, my guess it will 'false/blank' for you. If so, you'll at least narrow down the problem of figuring out what you really need to explode on. Your pipe is at position 12, so you could try something like: echo "
    the char at position 12 is (".substr($tyres,12,1).")"; and then get fancier if needed.     – JJ Rohrer Jul 31 '14 at 15:42
  • Considering you've now mentioned that you get the same issue i 0,r, or M, then try the substr method above, and then copy and paste the result back into your 'explode.' If that doesn't work, start researching how to get the exact character codes which, at least in other languages, are sometimes needed. I haven't had to do that in PHP. Try starting here: http://stackoverflow.com/questions/395832/how-to-get-code-point-number-for-a-given-character-in-a-utf-8-string – JJ Rohrer Jul 31 '14 at 15:53
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The answer lies in the ExpressionEngine parse order, as outlined here: https://ellislab.com/expressionengine/user-guide/templates/template_engine.html#rendering-stages

Because the template tag {exp:my_module:tyres} used a variable passed to it by a template tag that it was nested in, the variable wasn't parsed yet as the innermost tags are parsed first.

Adding the parameter parse="inward" to the outer template tag makes ExpressionEngine parse that tag first, passing the correct variable to the inner template tag.

See https://ellislab.com/expressionengine/user-guide/templates/plugins.html#changing-parsing-order for more on changing the parsing order.

Rein
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