Alternative to include() in a loop for DB row templating? - php

Question

I'm writing a data provider class in PHP to help me speed up rendering of multiple-row SQL query results. Basically, the class has a bunch of SQL-related properties and methods to help with paginating, sorting and finally rendering the data. As for the latter, I want to be able to template the rows easily so I wrote a method called render() that can be called from a view file (in the MVC model) with a row template file as parameter. It looks similar to this:
public function render($row_template_file) {
if($result = mysql_query($this->query)) {
while($row = mysql_fetch_array($result)) {
include $row_template_file;
}
}
}
The actual method is more sophisticated than that (it checks whether the template file exists, uses data abstraction class rather than mysql_* functions etc.) but you get the general idea. The row template file is basically HTML that goes straight to the output, i.e.:
<div class="row">
<div class="foo"><?php echo $row['foo']; ?></div>
<div class="bar"><?php echo $row['bar']; ?></div>
</div>
This approach works fine, the only problem is include() in a loop is not a great idea performance-wise, especially when rendering a large number of rows. Is there anything I could replace it with while keeping the ability to template rows that way? There were few similar questions here, but all suggested solutions involved mixing logic with presentation which is what I want to avoid. I was thinking of creating an anonymous function during first iteration, then calling it in all subsequent iterations, but maybe I'm overthinking it or reinventing the wheel here. Any ideas?

Answer 1

Perhaps use php's printf() / sprintf() functions instead?
Thus your template file would contain code like:
<div class="row">
<div class="foo">%s</div>
<div class="bar">%s</div>
</div>
You only load it once into a variable, before the loop:
$tmpl = file_get_contents( $row_template_file);
Inside the loop you just put variables into the template:
printf( $tmpl, $row['foo'], $row['bar']);
See examples #3 and #4 in the link above for "Argument swapping" — way to use numbered positions in a template - to not worry about different order of arguments in different templates.
Hope that works for you.

Answer 2

The printf() / sprintf() solutions suggested are neat, but don't allow for including presentation-specific logic in the template, like, for instance:
<div class="gender">
<?php if($row['gender'] == 'f') : ?>
<img src="female_icon.gif" />
<?php else : ?>
<img src="male_icon.gif" />
<?php endif; ?>
</div>
I know, I shouldn't have written the template is "basically HTML" :-)
I've been playing with the anonymous function solution I mentioned in my question and even though it doesn't look very pretty, it works and is significantly faster than multiple includes, so I'm adding this as one of possible answers:
public function render($row_template_file) {
if($result = mysql_query($this->query)) {
$render_row = create_function('$row', '?>'.file_get_contents($row_template_file).'<?php ');
while($row = mysql_fetch_array($result)) {
$render_row($row);
}
}
}

Answer 3

This almost feels like a solution that's too easy, maybe I just don't get what the big problem is, but what about using a PHP-function?
function outputRow($row) {
echo '<div class="row">';
echo '<div class="foo">' . $row['foo'] . '</div>';
echo '<div class="bar">' . $row['bar'] . '</div>';
echo '</div>';
}
And instead of include, you call outputRow($row)

Answer 4

Create the template as a string with placeholders and replace values into it. Pass it in to the render() method.
Then, you'd just have to decide on how it's best to How you obtain the string - via file_get_contents (i'd go for this) or simply have it hard-coded into some "template" class, extract an interface out of it - and pass it around.

Answer 5

May be try to play with eval function. This comment on php.net might help you:
http://www.php.net/manual/ru/function.eval.php#108091