Insert page content into another page with a changed variable

Question

I'm trying to use this simple code to insert page (1) content into another page (2):

 <?php
$id = 216;
$p = get_page($id);
echo apply_filters('the_content', $p->post_content);
?>

So far so good. The inserted page (1), though, is some html code that at one point contains

value="<?php echo $url?>"

Is there any way I can edit the value of that variable in the code above, i.e. in page (2)?

Thank you!

Answer 1

Assuming you want to replace it with some static value (well, you can always change this anyway), some kind of find and replace snippet like this can do the trick:

$content = apply_filters( 'the_content', $post->post_content);
// set the replacement string value
$replace = "REPLACEMENT";
// make sure the quotes used are exact
$find_start = "<param name='filter' " . 'value="';
$find_end = '"';
// find the (end of) search string start position
$pos = strpos( $content, $find_start) + strlen( $find_start );
// get the content before (end of) search string
$before = substr( $content, 0, $pos );
// get content after search string
$after = substr( $content, $pos, strlen( $content ) );
// strip the after-content before end quote
$pos2 = strpos( $after, $find_end );
$after = substr( $after, $pos2, strlen( $after) );
// recombine content with replacement value
$content = $before . $replace . $after );
return $content;

Answer 2

There's a fundamental problem in your code, and one that suggests you're doing something very dangerous in your code.

Given this code:

$id = 216;
$p = get_page($id);
echo apply_filters('the_content', $p->post_content);

I would expect this to be running from a template file, however, the question claims that the post content contains this:

value="<?php echo $url?>"

This is not possible in normal WordPress, so you must be using a plugin that lets you put PHP tags inside post content. This is the source of all your problems. Because of this:

• Most WordPress knowledge is unusable to you
• The vast majority of tutorials will not work as they assume you're in a template file
• Large numbers of solutions simply won't work correctly

Using plugins that let you embed PHP inside a post is extremely unusual, and super important to know. A person unaware of this will suggest things that will not work.

This is one of those situations where the answer you seek is not possible using a plugin that lets you use PHP inside a posts content.

Additionally, it's incredibly dangerous from a security point of view. But there is a much easier way that uses standard WordPress practices

Thus, I do not believe it is possible to solve your problem as long as you persist with the plugin allowing you to embed PHP inside a post. Never use something that lets you store PHP code in the database and run it from the database.

Shortcodes

If you need to embed PHP logic inside a post/page, create a shortcode.

This way, your page can be something like this:

My page!

[kristynas_form foo="bar"]

In a plugin or your themes functions.php you can use something like this:

add_shortcode( 'kristynas_form', function( array $attributes )  {
    $foo = $attributes['bar'];
    return 'form HTML';
});

When the page gets rendered the shortcode gets swapped out. This is how you're supposed to implement things like iframes, forms, and other complex logic that appears inline.