Invoke a function before the action hook

For this specific problem you can use Rilwis metabox plugin, where you can define custom metabox along with the validation.

Related Posts:

  1. add_action reference a class
  2. Remove parent theme action in child
  3. How to know what priority to use with add_action()?
  4. How to do_action and get a return value?
  5. Remove an action from an external Class
  6. Can my “add_action” function know the name of the hook calling it?
  7. Does the event ‘wp_version_check’ even exist? What is it doing?
  8. Unable to prevent function using save_post firing twice
  9. Difference between do_action(‘admin_enqueue_scripts’, $hook_suffix) and do_action(“admin_print_styles-$hook_suffix”) syntax
  10. Cron jobs in a class
  11. Add something to beginning of the content
  12. When and Where to use wp_insert_post()
  13. Why, Where, and When to use reference pointers in filters/hooks?
  14. Add a Custom Field in Comment Box AFTER text area BUT BEFORE Send button
  15. Using wp_insert_post and post_update_meta but need to fire save_post afterward
  16. enqueuing React script and hooking its target div fails to load script
  17. Having an add_action( ‘user_new_form’,) [closed]
  18. Using auth_redirect returns cannot modify header information
  19. What would cause the ‘wp’ action to fire twice per page (but only once per post) in Firefox only?
  20. Problem:Save Several Duplicate posts in The Database and then Error nesting level of ‘100’ reached
  21. How to remove an action added by a child theme of Genesis
  22. I don’t understand why I need a lower priority to remove an action with a higher priority to make it work
  23. wp_get_attachment_metadata returns false with add_action() ‘add_attachment’ hook
  24. Manually add admin bar
  25. Is there a way to expose additional fields to the Bulk Action > Edit functionality?
  26. do_action pass array argument as reference not copy [duplicate]
  27. how can I use add_action with external class which the function contain 2 argument?
  28. remove_action not working with procedural function
  29. Why Should We Use wp_clear_scheduled_hook and What it Does?
  30. Woocommerce Change placement with wrapper
  31. Which action fire in front-end single post only
  32. Unable to show error message using wp_login action
  33. WP action is not triggering a do_action() call within?
  34. Mustn’t do_action be accompanied with a function?
  35. where is the documentation for add_action() parameters?
  36. How to set a different value in the generator meta tag?
  37. Call add_action() in function wordpress
  38. How to remove function?
  39. Validate form in functions.php, send errors back to template
  40. What is the callback sent to add_submenu_page() invoked by WordPress?
  41. remove_action returns FALSE
  42. Remove action from shortcode
  43. How can I trigger actions manually?
  44. Write automatic title at save_post (infinite loop)
  45. Add meta field after post has been published
  46. add_action() in switch statement
  47. Problem with get_the_excerpt when using an add_action(‘the_content’) containing script tags
  48. Using Nested add_action()
  49. Are the hooks in the dashboard such as “load-$page_slug$” and “admin-head-$page_slug$” reliable and consistent throughout installs?
  50. Is there way to run a code every time when any cron is run?
  51. Remove Action from Plugin within extended class and no assigned variable
  52. Payment before publishing post
  53. add_action and do_action
  54. Add “add to cart” button in WooCommerce [closed]
  55. How can I unhook this action that was added via $this?
  56. add_action on a specific page
  57. Gravity Forms parameters return 1
  58. Form action unfamiliar
  59. Generate payment URL in custom email [closed]
  60. Why is my css and js not enqueued until footer?
  61. Which hook to add action on specific page?
  62. Action Scheduler not running
  63. W3TC manual cache flush does not work
  64. Run a function on all posts
  65. Remove an action added within a class in a WordPress plugin
  66. add_action.. will work if function is empty?
  67. call custom action after delete account
  68. Dynamic name of cron event
  69. Trying to write a function in an external php file to manage admin menu visibility
  70. remove_action: Initial attempt failed while a later attempt worked
  71. Action inside another action not working
  72. register_post_type not working in wordpress 3.6
  73. action wp_set_comment_status never gets fired when i change the comment status [closed]
  74. How to use add_action inside files included by theme’s functions.php
  75. What do I put in the form action attr on top of form wordpress
  76. WordPress sent multiple requests on update
  77. do_action in API call
  78. Add Tag to post after publishing
  79. How do I dequeue js/css at the last possible moment?
  80. Custom query_var to get URL paramater not working
  81. do_action doesn’t trigger if it’s in a template that gets loaded via REST endpoint
  82. add_action where function has arguments
  83. Load actions and filters only for the admin CPT list
  84. wpdb->insert creates duplicate rows
  85. Remove action from plugin
  86. Need data from two different actions
  87. WP_LIST_TABLE bulk action
  88. Understanding and using did_action() in a conditional statement
  89. Adding a conditional to work on certain pages/page templates to an add_action()
  90. Why is this require statement not working?
  91. Adapting functions from Genesis theme
  92. Dealing with html forms [closed]
  93. Adding add_action function
  94. XML Imported Custom Posts
  95. using media_handle_sideload() to add mp4 files to Media Library
  96. OOP – add_action
  97. do_action in header, add action later?
  98. Passing arguments in add_action inside search template
  99. save post running twice and creating two database entries – how do I disable this?
  100. remove an action hook function on a plugin from a theme
tech