Restricting the menu to certain users: a way to filter based on the value of a specific field

Question

In my main wp navbar I have a menu item called 'Research' that I only want to show up in researchers in WordPress.

Researchers will be defined by a user metadata field called wpum_relationship_to_lib, which is a multi-select field that includes options for researcher, student, employee, etc.

It is important that researcher must be one of the options the user chooses to access this menu, and wpum_relationship_to_lib does not define a WordPress role.

All menus are main menus. Also, I need to hide the menu until I log in. See my code which is not limiting the menu correctly.

function restrict_menu_to_researchers($items, $args) {
  
  // 检查菜单是否分配给所需位置
  if ($args->theme_location === 'primary') {

    // 检查用户是否已登录
    if (is_user_logged_in()) {

      $user_id = get_current_user_id();
      $relationship_values = get_user_meta($user_id, 'wpum_relationship_to_lib', true);
            
      // 检查用户是否为“researcher”
      if (is_array($relationship_values) && in_array('researcher', $relationship_values)) {

        // 允许研究人员访问菜单
        return $items; 

      } else {
        foreach ($items as $key => $item) {
          if ($item->title == 'Research') {
            // 隐藏非研究人员的“Research”菜单
            unset($items[$key]); 
          }
        } 
      }
    } else {
      foreach ($items as $key => $item) {
        if ($item->title == 'Research') {
          // 隐藏未登录用户的“Research”菜单
          unset($items[$key]);
        }
      }
    }
  }
  return $items;
}
add_filter('wp_nav_menu_objects', 'restrict_menu_to_researchers', 10, 2);

Answer 1

The code provided is mostly correct. However, there is a small problem in the conditional statement when checking the user relationship value. I updated the code to ensure that the "Research" menu item only appears for users who have selected "researcher" as one of their relationship values ​​in the wpum_relationship_to_lib meta field. It also hides the Research menu for non-logged-in users. I haven't tested the code, so any comments are welcome. #joshmoto's code is valid, but in the foreach loop, the condition !in_array($menu_object->title, $relationship_array) checks if the menu object title is not in the relationship array. From what I understand from the question, you want to check if the value "researcher" is in the relational array. Therefore, you should update the condition to in_array('researcher', $relationship_array).

function restrict_menu_to_researchers($items, $args) {
  // 检查菜单是否分配给所需位置
  if ($args->theme_location === 'primary') {
    // 检查用户是否已登录
    if (is_user_logged_in()) {
      $user_id = get_current_user_id();
      $relationship_values = get_user_meta($user_id, 'wpum_relationship_to_lib', true);
      
      // 检查用户是否选择了“researcher”作为其关系值之一
      if (is_array($relationship_values) && in_array('researcher', $relationship_values, true)) {
        // 允许研究人员使用菜单
        return $items;
      } else {
        // 隐藏非研究人员的“Research”菜单
        foreach ($items as $key => $item) {
          if ($item->title === 'Research') {
            unset($items[$key]);
          }
        }
      }
    } else {
      // 隐藏非登录用户的“Research”菜单
      foreach ($items as $key => $item) {
        if ($item->title === 'Research') {
          unset($items[$key]);
        }
      }
    }
  }
  return $items;
}
add_filter('wp_nav_menu_objects', 'restrict_menu_to_researchers', 10, 2);

Answer 2

I got the answer. The interesting thing is that it is case sensitive. I just need to use the following code. But on the test platform, it works without this line of code. I didn't even know this could be for lowercase letters:

(is_array($relationship_values) && in_array('researcher', array_map('strtolower', $relationship_values))) { ...

Thank you everyone for your help and time. –