ace0930

@greenshady Hi, I’m trying to use the hook pre_set_site_transient_update_themes to receive update ( for theme ) from my own API. I’m following the turtorial here, but I saw others articles has this line of code if (empty($transient->checked)) { return $transient; } which I’m not sure what it does and if I need it. Thank you!

Update: Use offsetX and offsetY instead.

@hirenbhanderi Exactly, but how does WordPress get the base URL localhost/example before putting it into the wp_option table, that’s what I’m asking…

As I have mentioned that the $_SERVER['SERVER_NAME'] only returns localhost, so I wonder how WordPress finds localhost/example.

@hirenbhanderi Hi, get_site_url() is also using get_option ( 'siteurl' ) if you look at the source code.

I’m not asking how to get the base URL like which function to use, I’m asking how WordPress gets the siteurl…Haha

@threadi You saved my day, thank you so much!

@threadi To be honest, I still do not fully understand. But do you mean the function handle_data () will not be include/require on the form page? If it’s true, then my question is solved.

@threadi From the doc

Remember that header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP.

Normally, we will have another file/script to handle the form like, right?
Assume index.php has a form and it looks like this:

<form action="process.php" method="post"></form>

Then in the process.php file, we use $_POST to get the data like this ( call this “example-1” for later reference ):

$name = $_POST['name'];

header ( "Location: https://example.com" ); // Redirect user to https://example.com after processing the data.

But if we put the processing code above on the same file ( index.php ) and it looks like this ( call this “example-2” for later reference ):

<form action="process.php" method="post"></form>

<?php
$name = $_POST['name'];

header ( "Location: https://example.com" );
?>

It would cause an error because there is already an output ( the form ) before the header ().

Now let’s get back to the “WordPress” way of handling form, we will use the hook admin_post_{$action} with a function like:

add_action( admin_post_handle_data, handle_data );

Then we write the processing code inside handle_data like the below:

function handle_data () {
   $name = $_POST['name'];

   header ( "Location: https://example.com" );
}

The form page is created by add_menu_page with the admin_menu hook.

My question is:
1) Will this function handle_data () be include/require on the form page? If it does, it will look like the “example-2”.

2) If the question “1)” is a yes, then the sequence matter, whether it’s admin_post first or admin_menu first. If it’s admin_post first, then the function handle_data () is before the form; If it’s the admin_menu first, then the function handle_data () is after the form.

Or am I complicating it, WordPress will just do the traditional way like “example-1” where the processing code is in another script/file?

• This reply was modified 2 years, 4 months ago by ace0930.

@threadi Hi, sorry but I don’t think you understand the question…

@bcworkz It returns NULL when I echo prepare () if I %s the table name.

And I found this line in the source code:
$query = preg_replace( '/(?<!%)%s/', "'%s'", $query ); // Quote the strings, avoiding escaped strings like %%s.

I believe it becomes 'table_name' ( note the quotes ) if %s the table name, and 'table_name' is different from table_name.

@bcworkz Nonono, you didn’t get the point. I didn’t put the wp_safe_redirect on the first line of the page like:

<?php wp_safe_redirect ( $example ); ?>

<form></form>

Instead, it’s in a function that would be called once the form is submitted to the admin-post.php with this hook. And it looks like this:

<?php function send () { wp_safe_redirect ( $example ); } ?>

<form></form>

Which mean the wp_safe_redirect ( $example ) will not trigger until the function is called.

@bcworkz Is that mean the $table_name shouldn’t be replace by %slike the below:
$wpdb -> prepare ( "SELECT !value! FROM !$table_name! WHERE !name! = %s", $name )

Instead and although the below matches the principle of sprintf but it won’t work with $wpdb -> prepare:
$wpdb -> prepare ( "SELECT !value! FROM %s WHERE !name! = %s", array ( $table_name, $name ) )

@bcworkz Nope, it seems you misunderstood my point. It’s my fault not to mention that the redirect code is in a function that will be triggered after the form is submitted using this method. So the redirect code is not on the page itself…

Thank you so much for your advice!

@bcworkz Okay, cannot believe this mistake took me two days, I think I know why.

Because the action of the form is set to admin-post.php, of course, the current URL would always be that…LOL

But you may still explain why $_SERVER['REQUEST_URI'] may cause so many redirect error.

@bcworkz I found a relevant question although I don’t understand what the answer is talking about: https://wordpress.stackexchange.com/questions/25764/cant-pass-table-to-wpdb-prepare

quotation marks are added to the table name

So $table_name = $wpdb -> prefix . testing; will become "wp_testing" according to the answer? Why is that so?

And you said:

Even though including a variable in the first string arg works, it’s incorrect. All vars should be passed in the second arg’s array.

??

@bcworkz I have also tried:

$url = 'https://' . $_SERVER['SERVER_NAME'] . $_SERVER['PHP_SELF'] . '?' . $_SERVER['QUERY_STRING'];

It redirects to: https://example.com/wp-admin/admin-post.php?.

With the original code:
https://' . $_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI']

It always redirects to https://example.com/wp-admin/admin-post.php