How do I get the custom category URL from the custom post type?

Question

I'm using a custom post type "portfolio" to create new posts and categories. I'm trying to retrieve the correct category/taxonomy URL from the post. I'm a couple days in on this and could really use some help. Registering post and tax below:

function portfolioposttype() {

$labels = array(
    'name'               => __('Portfolio'),
    'singular_name'      => __('Project'),
    'add_new'            => __('Add New'),
    'add_new_item'       => __('Add New Project'),
    'edit_item'          => __('Edit Project'),
    'new_item'           => __('New Project'),
    'view_item'          => __('View Project'),
    'search_items'       => __('Search Projects'),
    'not_found'          => __('No projects found'),
    'not_found_in_trash' => __('No projects found in Trash'),
    'parent_item_colon'  => __('Parent Project:'),
    'menu_name'          => __('Portfolio')
);
$args = array(
    'labels'                => $labels,
    'supports'              => array('title','editor','thumbnail'),
    'taxonomies'            => array('portfolio-categories'),
    'public'                => true,
    'show_ui'               => true,
    'show_in_menu'          => true,
    'show_in_nav_menus'     => true,
    'exclude_from_search'   => true,
    'has_archive'           => true,
    'rewrite'               => array('slug'=>'case-study'), //singe project slug
    'capability_type'       => 'post',
    'menu_position'         => 5,
    'menu_icon'             => Z_BASE_URL.'functions/assets/img/icon-portfolio.png',
    'query_var'             => true
);
register_post_type('portfolio', $args );

$taxonomy_portfolio_category_labels = array(
    'name'                       => __('Portfolio Categories'),
    'singular_name'              => __('Category'),
    'search_items'               => __('Search Categories'),
    'popular_items'              => __('Popular Categories'),
    'all_items'                  => __('All Categories'),
    'parent_item'                => __('Parent Category'),
    'parent_item_colon'          => __('Parent Category:'),
    'edit_item'                  => __('Edit Category'),
    'update_item'                => __('Update Category'),
    'add_new_item'               => __('Add New Category'),
    'new_item_name'              => __('New Category'),
    'separate_items_with_commas' => __('Separate categories with commas'),
    'add_or_remove_items'        => __('Add or remove Categories'),
    'choose_from_most_used'      => __('Choose from most used Categories'),
    'menu_name'                  => __('Categories')
);
$taxonomy_portfolio_category_args = array(
    'labels'            => $taxonomy_portfolio_category_labels,
    'public'            => true,
    'show_in_nav_menus' => true,
    'show_ui'           => true,
    'show_tagcloud'     => false,
    'hierarchical'      => true,
    'rewrite'           => array('slug'=>'projects'), //category slug
    'query_var'         => true     
);
register_taxonomy('portfolio-categories',array('portfolio'),$taxonomy_portfolio_category_args);

} 
add_action('init','portfolioposttype');

So, from www.domain.com/case-study/sample-project-1

I need to be able to link it back to the category: www.domain.com/projects/category-1

There could be another www.domain.com/case-study/sample-project-2

that would link to www.domain.com/projects/category-2

I hope this makes sense and really appreciate any advice!

Answer 1

Once you have the post's term(s) (see get_the_terms) you can use get_term_link to get the term's link:

 $url = get_term_link('category-1','portfolio-categories');

You can pass the term object, the term slug, or the term ID. If you pass the term ID it must be cast as an integer.