PHP/Wordpress: IF/ELSE executing both conditions - php

Question

Have been reading through multiple similar questions and went over my syntax many times, but I can't figure out why my PHP code is executing both conditions.
I'm trying to replace the url of an element with the string from a custom field if the field is not empty. If the field is empty, I want to output the permalink normally. What happens is that the code concatenates both the string from the custom field and the permalink when the field is not empty. If i remove the string in the field, it works fine.
<div class="profile-content">
<a href="
<?php
if ( the_field('direct_resource_link') != '') {
the_field('direct_resource_link');
} else {
the_permalink($id);
} ?>
"><h5><?php the_title(); ?></h5></a>
<div class="profile-footer">
Thanks!
Dan.

Answer 1

EDIT after comment from original poster
My initial assessment (left below for reference) was correct. You are using function that will print/echo content instead of returning it. Your if will always evaluate to false, because you are calling function that returns nothing; and PHP thinks that nothing and empty string are the same thing.
You didn't see that when field was empty, because the_field() for empty field printed empty string (or nothing at all), i.e. it didn't modify value printed by the_permalink() in any way/
According to ACF documentation, the_field() is accompanied by get_field() which returns value instead of printing it.
Your code should look like that:
<div class="profile-content">
<a href="
<?php
if ( get_field('direct_resource_link') ) {
the_field('direct_resource_link');
} else {
the_permalink($id);
} ?>
"><h5><?php the_title(); ?></h5></a>
<div class="profile-footer">
My initial post
What happens is that you run function the_field('direct_resource_link') and compare it's return value to ''; if that value is empty, you run the_permalink($id);.
It's hard to tell what the_field() is and what it is supposed to do, but I guess that it prints value instead of returning it. So if field is empty, it prints nothing, resulting in pure run of the_permalink(). If field is not empty, it prints it content and returns nothing. Since nothing is equal to empty string, PHP proceeds with else branch and invokes the_permalink() that prints additional info.
Solution: modify the_field() to return value instead of printing it, or make additional function that will query for value and return it, and use that function in if statement.

Answer 2

Miroslaw Zalewski already answered your question here, so this is simply to show you the kind of code needed to fix your issue:
function get_the_field($field) {
ob_start();
the_field($field);
return ob_get_clean();
}
This code will start an output buffer (which will capture all echo'd data), run the_field and return (and delete) the output buffer (the echo'd data from the_field). This means you can simply do the following:
...
<?php
$theField = get_the_field('direct_resource_link');
if ( $theField != '') {
echo $theField;
} else {
the_permalink($id);
}
?>
...

Answer 3

This can all be simplified. the_field() echoes a meta value. You don't want that...Instead, you want to return the value to check it, before conditionally echoing it. You can do this using get_field().
In the simplest form, your final code would look like the following:
<a href="<?php get_field('direct_resource_link') ? the_field('direct_resource_link') : the_permalink($id); ?>">
<h5><?php the_title(); ?></h5>
</a>