How to use Rules to add custom shipping cost per product?

Question

I use Drupal Commerce on Drupal 7 site, using product displays and products.

Each product has a shipping cost field.

At checkout, the shipping costs of all products in the order need to be collected and shown.

My approach is this: I use the Commerce Flat Rate module which creates the Flat Rate shipping method. I then create a flat rate shipping service ´Custom Shipping Cost´. Then I create a new shipping Rule ´Apply custom shipping costs´ which has a loop that needs to get the field value of the field ´custom shipping cost´ for each product in the order.

Question: how should a rule look like that gets the field values of a product connected to a line item and adds it to the shipping cost.

The following rules (which are nested) are not working. I figured out using Rules logs that in the third rule, Entity has field is not passed. I try to get the product field value which needs to be added to the total shipping rate.

0.528 ms Evaluating the action component_rules_get_shipping_price_field_value. [edit]
" Evaluating rule get local shipping price field value. [edit]
0 ms Evaluating rule get local shipping price field value.
0.049 ms Evaluating conditions of rule get local shipping price field value. [edit]
0.11 ms The condition entity_has_field evaluated to FALSE [edit]
0.113 ms AND evaluated to FALSE.
0.123 ms Finished evaluation of rule get local shipping price field value.

================================================

{ "rules_apply_custom_product_shipping_costs" : {
    "LABEL" : "Apply custom product shipping costs",
    "PLUGIN" : "reaction rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "rules", "commerce_shipping" ],
    "ON" : { "commerce_shipping_calculate_rate" : [] },
    "DO" : [
      { "drupal_message" : { "message" : "Calculating shipping rates." } },
      { "variable_add" : {
          "USING" : {
            "type" : "commerce_price",
            "value" : { "value" : { "amount" : 0, "currency_code" : "USD" } }
          },
          "PROVIDE" : { "variable_added" : { "custom_shipping_cost" : "Custom shipping cost" } }
        }
      },
      { "component_rules_get_local_shipping_rate" : {
          "price" : [ "custom-shipping-cost" ],
          "line_item" : [ "commerce-line-item" ]
        }
      },
      { "component_rules_get_international_shipping_rate" : {
          "price" : [ "custom-shipping-cost" ],
          "line_item" : [ "commerce-line-item" ]
        }
      }
    ]
  }
}

==================

{ "rules_get_local_shipping_rate" : {
    "LABEL" : "Set local shipping rate",
    "PLUGIN" : "rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "rules", "commerce_line_item" ],
    "USES VARIABLES" : {
      "price" : { "label" : "price", "type" : "commerce_price" },
      "line_item" : { "label" : "line item", "type" : "commerce_line_item" }
    },
    "IF" : [
      { "data_is" : { "data" : [ "line-item:type" ], "value" : "shipping" } },
      { "data_is" : {
          "data" : [ "line-item:commerce-shipping-service" ],
          "value" : "local_shipping_rate"
        }
      }
    ],
    "DO" : [
      { "drupal_message" : { "message" : "Start loop: collect line item local shipping price field values" } },
      { "LOOP" : {
          "USING" : { "list" : [ "line-item:order:commerce-line-items" ] },
          "ITEM" : { "lineitem" : "lineitem" },
          "DO" : [
            { "variable_add" : {
                "USING" : {
                  "type" : "commerce_price",
                  "value" : { "value" : { "amount" : 0, "currency_code" : "USD" } }
                },
                "PROVIDE" : { "variable_added" : { "custom_shipping_cost" : "custom shipping cost" } }
              }
            },
            { "component_rules_get_shipping_price_field_value" : {
                "custom_shipping_cost" : [ "custom_shipping_cost" ],
                "line_item" : [ "line_item" ]
              }
            },
            { "commerce_line_item_unit_price_add" : {
                "commerce_line_item" : [ "line-item" ],
                "amount" : [ "price:amount" ],
                "component_name" : "flat_rate_local_shipping_rate",
                "round_mode" : "1"
              }
            },
            { "drupal_message" : { "message" : "Single product shipping cost is" } },
            { "drupal_message" : { "message" : [ "custom-shipping-cost:amount" ] } }
          ]
        }
      }
    ]
  }
}

==============

{ "rules_get_shipping_price_field_value" : {
    "LABEL" : "get local shipping price field value",
    "PLUGIN" : "rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "rules" ],
    "USES VARIABLES" : {
      "custom_shipping_cost" : { "label" : "custom shipping cost", "type" : "commerce_price" },
      "line_item" : { "label" : "line item", "type" : "commerce_line_item" }
    },
    "IF" : [
      { "entity_has_field" : { "entity" : [ "line-item" ], "field" : "commerce_product" } },
      { "entity_has_field" : {
          "entity" : [ "line-item:commerce-product" ],
          "field" : "field_shipping_rate_local_countr"
        }
      }
    ],
    "DO" : [
      { "drupal_message" : { "message" : "line item has field commerce_product" } },
      { "data_set" : {
          "data" : [ "custom-shipping-cost" ],
          "value" : [ "line-item:commerce-product:field-shipping-rate-local-countr" ]
        }
      }
    ]
  }
}

=========================== EDIT The following issue was causing my problem: In this whole rules setup i used multiple variables as line items. I mistakenly used a lineitem variable outside the loop, instead of the lineitem variable inside the loop. at a certain point i had lineitem and line-item and mixed them up which made it not work. Also, the product needed to be added as variable in the loop.

Answer 1

Below is an attempt to answer this (most important?) part of your question:

The following rules (which are nested) are not working. I figured out using Rules logs that in the third rule, Entity has field is not passed. I try to get the product field value which needs to be added to the total shipping rate.

• In your 3rd rule, add another parameter, to also pass the "Commerce Product" that the line item is related to. Say you name that "product_related_to_item".
• In your 2nd rule, pass the value of that extra parm (= product_related_to_item) to invoke the 3rd rule, using the line item token related to the product (for sure you'll have that in your 2nd rule).
• In your 3rd rule, replace your 2nd "Entity has field" by a similar Rules Condition, but now referring to the (same) field for entity product_related_to_item (not sure if you still need your first Rules Condition then, homework for you ...).

By doing these corrections, the typical Rules magic (after you add such Rules Condition) applies again. E.g you can use their values in subsequent Rules Actions. And yes I know/realize, this may look like "this makes no sense", or "you're basically doiing the same thing". At least that's what I first thought myself just a few days ago when I ran into a similar issue. But sure enough, this was the solution (and it turned out this has to do with some limitation when processing "referenced entities (i.e. product referenced in a line item) in Rules.

Answer 2

The following approach worked, thanks to hints of Pierre Vriens, although my specific use case is a bit complex because it uses two product fields for local and international shipping. I also used extra variables here and there, to make tokens available in system messages..so not all variables are actually required to make this work.