Bug: Not possible manipulate results of renderSection() on View Layouts

[natanfelles]

Describe the bug
It is not possible to manipulate the string result of a View Layout $this->renderSection() without using ob_* functions due the void function works with echo and not return.

CodeIgniter4/system/View/View.php

Lines 496 to 510 in 6d019e5

	public function renderSection(string $sectionName)
	{
	if (! isset($this->sections[$sectionName]))
	{
	echo '';
	return;
	}
	foreach ($this->sections[$sectionName] as $key => $contents)
	{
	echo $contents;
	unset($this->sections[$sectionName][$key]);
	}
	}

This example https://codeigniter4.github.io/userguide/outgoing/view_layouts.html#creating-a-layout show a echo but it is not necessary.

CodeIgniter 4 version
4.0.3

Affected module(s)
View Layouts

Expected behavior, and steps to reproduce if appropriate

Expect to can save result of renderSection() in a variable.

Context

• OS: Ubuntu
• Web server [PHP built in]
• PHP version [7.4]

[samsonasik]

@natanfelles I created PR #3031 for it.

[lonnieezell]

This example https://codeigniter4.github.io/userguide/outgoing/view_layouts.html#creating-a-layout show a echo but it is not necessary.

You're right, it's not necessary but it's a cleaner syntax than using full tags.

You did not state why this is a problem. What's your use case for needing to do that?

[natanfelles]

I have a layout with meta description:

<meta name="description" content="<?= $this->renderSection('description') ?>">

It works nice. But I need to show the meta only if the section has content.

So:

<php if( $this->renderSection('description')): ?> // <-- the problem
<meta name="description" content="<?= $this->renderSection('description') ?>">
<?php endif ?>

But it is not possible because renderSection do not return, it echo

[samsonasik]

@natanfelles in #3031 I added 2nd parameter $echoed that can be set to false for that to avoid bc break.

[lonnieezell]

Sorry, I don't find this a good use case. The whole purpose of the templating features are for templating, not for conditional logic. By using it in the way you are here, you're processing the contents of that section twice, which is an unnecessary performance hit, also.

I can't see very many reasons why you can't handle meta values in the controller or a library and pass it in. You already know the data going into that view so can make the determination in the controller layer instead of the view layer. If you're using View Cells and that's the issue, then you could fire off an event that collects all of the meta data from all of your systems into an array or class, then pass that into your view layer.

[natanfelles]

$desc = $this->renderSection('description'); // <-- the problem
<php if($desc): ?> 
<meta name="description" content="<?= $desc?>">
<?php endif ?>

There is no way to set values from an extended to a main layout. I will try View Cells.

[natanfelles]

Oh, tested with $this->setVar('description', 'abc123'); on an extended layout and it is possible pass the $description variable to the main layout.