WooCommerce Require Category Minimum for Purchase

wc-require-cat-minimum.php

<?php
/**
 * only copy the opening php tag if needed
 * tutorial at: http://swwp.co/6l
 */
 
/**
 * Renders notices and prevents checkout if the cart
 * does not contain a minimum number of products in a category
 */
function sww_check_category_for_minimum() {

	// set the minimum quantity in the category to purchase
	$min_quantity = 6;

	// set the id of the category for which we're requiring a minimum quantity
	$category_id = 15;

	// get the product category
	$product_cat = get_term( $category_id, 'product_cat' );
	$category_name = '<a href="' . get_term_link( $category_id, 'product_cat' ) . '">' . $product_cat->name . '</a>';

	// get the quantity category in the cart
	$category_quantity = sww_get_category_quantity_in_cart( $category_id );

	if ( $category_quantity < $min_quantity ) {
		// render a notice to explain the minimum
		wc_add_notice( sprintf( 'Sorry, you must purchase at least %1$s products from the %2$s category to check out.', $min_quantity, $category_name ), 'error' );
	}

}
add_action( 'woocommerce_check_cart_items', 'sww_check_category_for_minimum' );


/**
 * Returns the quantity of products from a given category in the WC cart
 * 
 * @param int $category_id the ID of the product category
 * @return in $category_quantity the quantity of products in the cart belonging to this category
 */
function sww_get_category_quantity_in_cart( $category_id ) {

	// get the quantities of cart items to check against
	$quantities = WC()->cart->get_cart_item_quantities();
	
	// start a counter for the quantity of items from this category
	$category_quantity = 0;

	// loop through cart items to check the product categories
	foreach ( $quantities as $product_id => $quantity ) {

		$product_categories = get_the_terms( $product_id, 'product_cat' );
		
		// check the categories for our desired one
		foreach ( $product_categories as $category ) {

			// if we find it, add the line item quantity to the category total
			if ( $category_id === $category->term_id ) {
				$category_quantity += $quantity;
			}
		}
	}

	return $category_quantity;
}

I am trying to use this for a restaurant that does catering for a minimum of 25 people, and customers also have the ability to order regular carry-out menu items. Even with the category ID in there it still wont let non-category items to be ordered unless the quantity is 25. Any advice? You can contact me at clopton78@gmail.com

Hi Bekarice,

I'm getting an eval()'d error in line 45. I've added this snippet code in my "Code Snippet" plugin.
Would you please tell me what's causing that? Thank you.

function sww_check_category_for_minimum() {

// set the minimum quantity in the category to purchase
$min_quantity = 2;

// set the id of the category for which we're requiring a minimum quantity
$category_id = 7;

// get the product category
$product_cat = get_term( $category_id, 'product_cat' );
$category_name = '<a href="' . get_term_link( $category_id, 'product_cat' ) . '">' . $product_cat->name . '</a>';

// get the quantity category in the cart
$category_quantity = sww_get_category_quantity_in_cart( $category_id );

if ( $category_quantity < $min_quantity ) {
	// render a notice to explain the minimum
	wc_add_notice( sprintf( 'Sorry, you must purchase at least %1$s products from the %2$s category to check out.', $min_quantity, $category_name ), 'error' );
}

}
add_action( 'woocommerce_check_cart_items', 'sww_check_category_for_minimum' );

/**

• Returns the quantity of products from a given category in the WC cart

• @param int $category_id the ID of the product category

• @return in $category_quantity the quantity of products in the cart belonging to this category
  */
  function sww_get_category_quantity_in_cart( $category_id ) {

  // get the quantities of cart items to check against
  $quantities = WC()->cart->get_cart_item_quantities();

  // start a counter for the quantity of items from this category
  $category_quantity = 0;

  // loop through cart items to check the product categories
  foreach ( $quantities as $product_id => $quantity ) {

   $product_categories = get_the_terms( $product_id, 'product_cat' );
   
   // check the categories for our desired one
   foreach ( $product_categories as $category ) {
  
   	// if we find it, add the line item quantity to the category total
   	if ( $category_id === $category->term_id ) {
   		$category_quantity += $quantity;
   	}
   }
  

  }

  return $category_quantity;
  }

this does not work for variations you need to put in checks if product is a Variable Product lease ammend with below

$product_categories = get_the_terms( $product_id, 'product_cat');
    //check if it works else its a variation
    if(!$product_categories){
		$variation = wc_get_product($product_id);
		//get variation parent id number
		$parent_product_id = $variation->get_parent_id();
		//get categories of parent id number
		$product_categories = get_the_terms( $parent_product_id, 'product_cat');
		
		
		}

Thank you for that!
I have a question:
I want to do that on my E-commerce site. I have a lot of categories and I want that just in this one category it will require 4 units min (lets call it "66").
When I put this code its require to buy at least 4 units from a category "66". even when someone wants to buy from a different category it is required to buy from category "66".

Can you help me please?
Thanks

@bekarice thank you for solution!

function sww_check_category_for_minimum() {

// set the minimum quantity in the category to purchase
$min_quantity = 3;

// set the id of the category for which we're requiring a minimum quantity
$category_id = 89;

// get the product category
$product_cat = get_term( $category_id, 'product_cat' );
$category_name = '<a href="' . get_term_link( $category_id, 'product_cat' ) . '">' . $product_cat->name . '</a>';

// get the quantity category in the cart
$category_quantity = sww_get_category_quantity_in_cart( $category_id );

if ( $category_quantity < $min_quantity ) {
	// render a notice to explain the minimum
	wc_add_notice( sprintf( 'Sorry, you must purchase at least %1$s products from the %2$s category to check out.', $min_quantity, $category_name ), 'error' );
}

}
add_action( 'woocommerce_check_cart_items', 'sww_check_category_for_minimum' );

/**

• Returns the quantity of products from a given category in the WC cart

• @param int $category_id the ID of the product category

• @return in $category_quantity the quantity of products in the cart belonging to this category
  */
  function sww_get_category_quantity_in_cart( $category_id ) {

  // get the quantities of cart items to check against
  $quantities = WC()->cart->get_cart_item_quantities();

  // start a counter for the quantity of items from this category
  $category_quantity = 0;

  // loop through cart items to check the product categories
  foreach ( $quantities as $product_id => $quantity ) {

   $product_categories = get_the_terms( $product_id, 'product_cat' );
   
   // check the categories for our desired one
   foreach ( $product_categories as $category ) {
  
   	// if we find it, add the line item quantity to the category total
   	if ( $category_id === $category->term_id ) {
   		$category_quantity += $quantity;
   	}
   }
  

  }

  return $category_quantity;
  }

I have added this to function.php.
If I have less than 3 products from green grocery (category id- 89) it shows an error but let's say I don't want to buy 3rd item, instead I remove two items from green grocery category but when I remove that category products, the error still stays there - https://prnt.sc/115nxlu
How do I resolve tyis ?