Subpage of a URL Alias and hook_menu

Question

Im slowly getting back into Drupal after much time away and beginning to pick it up and the learning curve is building back up.

So much so I always like to throw out pre-defined conventions as too restrictive while keeping the rough framework to build something bigger for what I want to do.

In my case, it's a scheduler program. But mine is in the context for a church, but could work equally well elsewhere

However the idea is that each type can have a sub type, a schedule gets applied to the type and the back end calendar generates the calendar entries for the schedule. This then gets displayed in a number of ways, from an eventually RSS feed to hook into an Android application, to a Calendar and everything else in between.

Each calendar item needs to be overwritable in that it's a generic item that may have additional certain applicable details rather than being a unique entity in its own right.

This list of types should be output with a link then to each type while I alter the page then to generate a list of next upcoming schedules for that item. Click on a date and get entries for that date. etc

It's all going pretty well until I realise I need to start referring to things by database Id instead of having a nice URL because frankly, database calendar entries don't as such have a nice URL.

One of the things I would have liked to have done is to have a URL alias against a node for my event type, eg, somecategory/sometype but then to be able to use the hook_menu system to get somecategory/sometype/% (where % could be sun, mon, tue, wed etc). Bearing in mind somecategory, sometype will be variable depending on user input, only % will have a list of specific possible - sun throu sat.

Trouble is, it doesn't look like you can do it, so I've just had to use an alias such as calendar/type/%

Any thoughts on this hook_menu issue, and any thoughts overall? 2000 lines of code into this thing and Im wondering why Im doing this (oh yeah, I like doing things my way).

Simon

Answer 1

I had a similar (not quite so flexible) issue.

Basically a node lives at node/NID or a url-alias path. I didnt want to write a custom hook_menu to make something so flexible as somecategory/sometype/% -- but i really think you should be able to.

I used the module view_mode_page

On the manage display page for a given content type, you can assign patterns for view modes so that they will become a page at the given path. For instance, if you want to show the teaser at a specific URL, you could do node/%/teaser. If you also use Display Suite or other modules that allow you to create new view modes, you can use these modes to display one or more fields from a node at a separate URL.

Restrictions: currently, the node path must be contained in the URL. This means view mode pages must follow the form [node path/node alias]/[view mode url]. These pages are added via hook_menu. Multiple wildcard characters can be used.

I used it to set many urls for a node of the form: 'url_pattern' => 'instructors/%/'.$val

where instructors/% IS a node alias and $val is a value from a Taxonomy Term field attached to the node. Eg, I get N-subpage urls for however many terms are in this vocabulary for each node of this content type.

I then use Display Suite to create a dynamic field for a custom view mode I associated for this node and url path; I also used Display Suite to create the custom view_mode (or maybe it was the FieldUI I forget). The dyanmic field a View that takes an argument that is the wildcard in the url.

Here's a snippet of code using the view_mode_page API:

  /*
   * Implementation of hook_view_mode_page_get_patterns() from module
   * view_mode_page.
   *
   * This lets me define additional node urls (per NID) with a custom
   * view mode.
   *
   * I then use this view_mode along with Display Suite and custom Fields
   * to completely alter how the node is viewed on that page, and only
   * show a View of related downloadable course files.
   */
  function MYMODULE_view_mode_page_get_patterns($results, $content_type,  $view_mode) {
    $results2 = array();
    $defaults = array('content_type' => 'course', 'view_mode' => 'course_materials_list_view', 'show_title' => 0, 'title' => '');

    // TODO: change this to like a Taxonomy Tree lookup.
    $terms = array('activities-and-handouts', 'administrative', 'assignments', 'data-recordings-and-transcripts','lectures','quizzes-exams','readings-and-reading-handouts');
    foreach ($terms as $pos => $val) {
      $results2[$pos] = (Object) array_merge($defaults, array('url_pattern' => 'instructors/%/'.$val));
    }
    return $results = $results2;
  }

This basically works for me. Breadcrumbs aren't totally happy. It's NOT exactly what you're asking but might help as it's very related. Good luck.

Answer 2

First off, to avoid any conflict, the path for a menu handled by a module should have a part that is specific for that module; the Node module uses node as first part for its menu callbacks, and the User module uses user.
Imagine what would happen if the Node module used %title/%nid as menu path for the node pages. (%title is not a placeholder Drupal currently defines.) It would be enough the node title were user, and the node page would override a user profile, or vice versa. This doesn't actually happens because node pages have a path like node/%nid, and user profiles have a path like user/%uid. (For each user ID there would be a node with that ID; that is the reason they are not enough to disambiguate a node page from a user profile page.)

In your case, the menu path cannot be somecategory/sometype, but it should be mymodule/somecategory/sometype. (Replace mymodule with the short name of the module you are implementing.)

if somecategory, and sometype are values you could obtain from a function, you can use the approach followed by the Search module, which uses the following code in its hook_menu() implementation.

foreach (search_get_info() as $module => $search_info) {
  $path = 'search/' . $search_info['path'];
  $items[$path] = array(
    'title' => $search_info['title'], 
    'page callback' => 'search_view', 
    'page arguments' => array($module, ''), 
    'access callback' => '_search_menu_access', 
    'access arguments' => array($module), 
    'type' => MENU_LOCAL_TASK, 
    'file' => 'search.pages.inc', 
    'weight' => $module == $default_info['module'] ? -10 : 0,
  );
  $items["$path/%menu_tail"] = array(
    'title' => $search_info['title'], 
    'load arguments' => array('%map', '%index'), 
    'page callback' => 'search_view', 
    'page arguments' => array($module, 2), 
    'access callback' => '_search_menu_access', 
    'access arguments' => array($module),
    // The default local task points to its parent, but this item points to
    // where it should so it should not be changed. 
    'type' => MENU_LOCAL_TASK, 
    'file' => 'search.pages.inc', 
    'weight' => 0,
    // These tabs are not subtabs. 
    'tab_root' => 'search/' . $default_info['path'] . '/%',
    // These tabs need to display at the same level. 
    'tab_parent' => 'search/' . $default_info['path'],
  );
}

If somecategory, and sometype are completely arbitrary values entered from users in some way, then you could use the following definition for the menu callback.

  $items[mymodule/%/%/%mymodule_weekday] = array(
    'load arguments' => array(1, 2),
    'page callback' => 'mymodule_calendar_view', 
    'page arguments' => array(3), 
    'weight' => $module == $default_info['module'] ? -10 : 0,
  );

  function mymodule_weekday_load($weekday, $category, $type) {
    // Return an array, or an object basing on the arguments.
    // Return FALSE is the arguments contain values that are not acceptable.
  }

For a path like mymodule/my_category/my_type/sun, mymodule_weekday_load() will be called as mymodule_weekday_load('sun', 'my_category', 'my_type'). When the load function returns FALSE the user will get a 404 error page.

The string mymodule I am using here is just an example. What a module normally use is its short name, except in the case the module is extending a menu defined from another module. For example, the Book module uses book/export/%/% as path for its exporting page, but uses node/%node/outline for its page that allows to set the outline to which the node belongs.

As examples of load callbacks, you can look at node_load(), and user_load().

References

• hook_menu()
• Wildcard usage and core's wildcards
• Dynamic argument replacement (wildcard) Wildcard Loader Arguments