REST API - Head Tags Plugin error with NewsPaper theme

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3

Current WordPress version 5.4
I also tried with deactivating all the plugin still got the same error. but when I am hitting the endpoint 4 to 5 times it’s working. but with frontity connect it is throwing 500 error.

4

Thanks @mosamlife

Do you have access to the server error logs?

5

Hi @mosamlife! :wave:

Since you mention this, it seems to be the error on the server-side. To expand on what @Pablo has mentioned, if you can paste the log from the server that would help us troubleshoot it.

Is there any more helpful information in the client-side error in the browser console?

6

Hello @Pablo @mmczaplinski Thanks for quick reply. I found the solution It was my current theme that causing the issue with rest api head tags plugin. Current theme : NewsPaper

7

May we know what was it? Is it something we could solve?

8

yes you check the error here

Screenshot (7)
Screenshot (7)3840×2033 519 KB

9

Could you please check if you have the latest version of the Head Tags plugin?

10

I am already using the latest version

12

Ok, thanks @mosamlife. I guess the affected hook is wp_head then. Can we download the theme from somewhere to check it out?

13

Sure! I will send you in DM

14

Hi @mosamlife!

I did some tests with the theme you shared in DM and I was able to reproduce the problem. It looks like the NewsPaper theme is not compatible with the Head Tags plugin for some reasons:

  • The REST API - Head Tags plugin runs the wp_head hook for each post, page, etc. in order to render their tags. This means that for the same REST API request the wp_head hook has to run several times, one for each entity. The thing is that the NewsPaper theme is registering an action called td_js_generator to the wp_head hook that throws an error when it’s executed more than once. That’s the error you see.

    Fatal error: Uncaught ErrorException:
  td_js_buffer::add_to_header
  - the header JS was already rendered when you called td_js_buffer::add_to_header()

  • Apart from that, the NewsPaper theme is using a header.php template that renders the title outside of the wp_head hook, making that tag unable to be processed by the Head Tags plugin, and therefore not showing that tag in the REST API response.

    <!-- header.php -->
<head>
    <meta charset="<?php bloginfo( 'charset' );?>" />
    <!-- The title is rendered here -->
    <title><?php wp_title('|', true, 'right'); ?></title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="pingback" href="<?php bloginfo( 'pingback_url' ); ?>" />
    <!-- The theme is calling `wp_head` here -->
    <?php wp_head(); ?>
</head>

Having said that, you can add the following code as a workaround in the functions.php of your theme that would remove the action that throws the error and add the title only when a REST API request is made. I think it’s safe to remove the td_js_generator action as it only adds JavaScript code that the Head Tags plugin won’t return anyways.

add_action('rest_api_init', function() {
    // Remove the failing hook.
    remove_action('wp_head', 'td_js_generator', 10);
    // Add a new hook for the <title> tag.
    add_action('wp_head', function () {
        echo '<title>' . wp_title('|', false, 'right') . '</title>';
    });
});

I hope this workaround works for you. Cheers! :blush:

2 Likes
15

@David Thanks for the detailed investigation. I already applied my temporary fix for the same but your solution is pretty much straightforward

Thanks :smiley:

1 Like
16

Hey @David, would it make sense to create a list of disabled hooks in our plugin and add this one remove_action('wp_head', 'td_js_generator', 10); to the list?

I know this is going to be hard to maintain but at least we can add problematic hooks when a problem arises.

17

I think it would be better to let people know why those plugins are failing and how to make it work. Maybe with a “troubleshooting” section in the plugin docs or something like that.

What do you think? :thinking:

3 Likes
18

+1 for this @David

19

Sorry for the delay guys. If you think a troubleshooting section is better then it’s fine. Let’s add it.

@David can you take care of it?

20

Sure! I’ll link it here once it’s done. :smile:

1 Like
22

Hey, we published the Troubleshooting section in the docs some time ago and I forgot to share the link here! :sweat_smile:

Check it out :point_down:

https://docs.frontity.org/frontity-plugins/rest-api-head-tags#troubleshooting

1 Like
24

Hello. I came across the same error as mentioned by @mosamlife on my newspaper theme. I have added the workaround script into the function.php file, however it still doesn’t work. the same error still persist. may I know how do I continue?

25

@eching97 can you switch to Yoast 14 and @frontity/yoast? I think right now it’s a better option.