简单的模板var替换，但扭曲

Question

So I'm setting up a system that has a lot of emails, and variable replacement within it, so I'm writing a class to manage some variable replacement for templates stored in the database.

Here's a brief example:

// template is stored in db, so that's how this would get loaded in 
$template = "Hello, %customer_name%, thank you for contacting %website_name%"; 
// The array of replacements is built manually and passed to the class 
// with actual values being called from db 
$replacements = array('%customer_name%'=>'Bob', '%website_name%'=>'Acme'); 
$rendered = str_replace(array_keys($replacements), $replacements, $template); 

Now, that works well and good for single var replacements, basic stuff. However, there are some places where there should be a for loop, and I'm lost how to implement it.

The idea is there'd be a template like this:

"hello, %customer_name%, thank you for requesting information on {products}"

Where, {products} would be an array passed to the template, which the is looped over for products requested, with a format like:

Our product %product_name% has a cost of %product_price%. Learn more at %product_url%.

So an example rendered version of this would be:

"hello, bob, thank you for requesting information on:

Our product WidgetA has a cost of $1. Learn more at example/A

Our product WidgetB has a cost of $2. Learn more at example/B

Our product WidgetC has a cost of $3. Learn more at example/C.

What's the best way to accomplish this?

Answer 1

$products = array('...');
function parse_products($matches)
{
    global $products;
    $str = '';
    foreach($products as $product) {
       $str .= str_replace('%product_name%', $product, $matches[1]); // $matches[1] is whatever is between {products} and {/products}
    }
    return $str;
}

$str = preg_replace_callback('#\{products}(.*)\{/products}#s', 'parse_products', $str);

The idea is to find string between {products} and {products}, pass it to some function, do whatever you need to do with it, iterating over $products array. Whatever the function returns replaces whole "{products}[anything here]{/products}".

The input string would look like that:

Requested products: {products}%product_name%{/products}