--- schema_version: "1" id: 22be20deef8652064ec9756c838524c2400bd614f640a44acbd157b0baf6147d title: Migrating an APIkit-based Application collection: mulesoft version: current locale: en-us portal_url: https://docs.salesforce.com/mulesoft/current/en-us/mule-runtime/4.4/migration-example-complex.md canonical_url: https://docs.mulesoft.com/mule-runtime/4.4/migration-example-complex source_site: docs.mulesoft.com content_type: documentation content_hash: 8c909de1632803c02141321c625bcc1d2546fea915e42af0ee74bd85a71782de description: MuleSoft Documentation Site release: "4.4" latest: false --- # Migrating an APIkit-based Application This example covers the necessary steps for successfully migrate an APIkit-based application from Mule 3 to Mule 4. The following REST API performs CRUD (create, read, update and delete) operations over a MySQL database. ![api-main in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-main.png) ![api-console in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-console.png) ![get:/product:api-config flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-get-products.png) ![get:/product/{id}:api-config flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-get-product-id.png) ![post:/product:application/json:api-config flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-post-product.png) ![delete:/product/{id}:api-config flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-delete-product.png) ![put:/product/{id}:application/json:api-config flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-put-product.png) ![api-apiKitGlobalExceptionMapping flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-globalexceptionmapping.png) ## [](#migrating-property-placeholders)Migrating Property Placeholders Mule 4 supports property placeholders either as `.yaml` or `.properties` configuration files. 1. Create a folder with the name `config` under `/src/main/resources` project directory. 2. Create a configuration file with the name `configuration.yaml` inside the newly created config folder. 3. Migrate property placeholders from `.properties` to `.yaml` format. configuration.properties http.host=0.0.0.0 http.port=8081 mysql.password=pa$$w0rd mysql.port=3306 mysql.user=admin mysql.database=products mysql.host=corp.services.com autodiscovery.api.version=1.0.0:1762946 autodiscovery.api.name=groupId:com.mulesoft.retailer.manufacturingit.apis:assetId:product-api-database anypoint.platform.client\_id=1f702j71hu9z2x88v9vd19v7h248s589 anypoint.platform.client\_secret=87v8V47668701Dd574B0531255d6287d configuration.yaml http: host: "0.0.0.0" port: "8081" mysql: password: "pa$$w0rd" port: "3306" user: "admin" database: "products" host: "corp.services.com" autodiscovery: api: name: "groupId:com.mulesoft.retailer.manufacturingit.apis:assetId:product-api-database" version: "1.0.0:1762946" anypoint: platform: client\_id: "1f702j71hu9z2x88v9vd19v7h248s589" client\_secret: "87v8V47668701Dd574B0531255d6287d" 4. Replace the standard Spring element `` with the new Global Element `configuration-properties`. Configuration XML for Property Placeholders in Studio 6. ```xml ``` The `file` attribute points to the new configuration file in YAML format located under `/src/main/resources/config` folder. Configuration XML for Property Placeholders in Studio 7. ```xml ``` ## [](#migrating-global-http-listener-configuration)Migrating Global HTTP Listener Configuration Configuration XML for Global HTTP Listener Configuration in Studio 6. ```xml ``` The minimal configuration requires specifying `host` and `port` in the inner `http:listener-connection` element. We use the placeholders defined in the previous step. Configuration XML for Global HTTP Listener Configuration in Studio 7. ```xml ``` ## [](#migrating-mysql-global-configuration)Migrating MySQL Global Configuration The database connector facilitates setting up _Derby_, _MySQL_ and _Oracle_ databases for use in a Mule app. 1. In the Mule Palette, click `Add Module` and select `Database Connector` among the available modules. 2. Add a `Database Config` Global Configuration Element. 3. In Database Config > Connection, select MySQL Connection. 4. In MySQL JDBC Driver, click Add Dependency and configure the Maven information for the driver. mysql mysql-connector-java 5.1.6 5. Complete MySQL Global Configuration with `host`, `port`, `user`, `password` and `database` using previously defined placeholders. Configuration XML for MySQL Global Configuration in Studio 6. ```xml ``` Configuration XML for MySQL Global Configuration in Studio 7. ```xml ``` ## [](#migrating-api-autodiscovery-configuration)Migrating API Autodiscovery Configuration The `api-platform-gw` global element is required for registering an API in Anypoint Platform. Configuration XML for API Autodiscovery Configuration in Studio 6. ```xml ``` In Mule Runtime 4.x, the `apiName`, `version`, and `create` attributes were removed. Just the `apiId` and `flowRef` attributes are required. `apiId` is generated by API Manager and visible on the API instance dashboard. For API Autodiscovery Configuration in Mule Runtime 4.x: 1. Add the following Namespace, Schema `global.xml` Configuration file. xmlns:api-gateway="http://www.mulesoft.org/schema/mule/api-gateway" http://www.mulesoft.org/schema/mule/api-gateway http://www.mulesoft.org/schema/mule/api-gateway/current/mule-api-gateway.xsd 2. Add the required Autodiscovery Dependency Information to project `pom.xml` file. com.mulesoft.anypoint mule-module-autodiscovery 4.0.0 Configuration XML for API Autodiscovery Configuration in Studio 7. ```xml ``` ## [](#migrating-global-validation-configuration)Migrating Global Validation Configuration Configuration XML for Global Validation Configuration in Studio 6. ```xml ``` Opposite to Mule Runtime 3.x, adding the Validation Module to the Mule Palette is required to proceed with the configuration. 1. In the Mule Palette, click `Add Module` and select `Validation Module` among the available modules. 2. Add a `Validation Config` Global Configuration Element. Configuration XML for Global Validation Configuration in Studio 7. ```xml ``` ## [](#migrating-get-products-flow)Migrating _get-products-flow_ `get-products-flow` returns products from the database filtering by `Product Category` and/or `Product Name` also supporting paginated queries with `offset` and `maxResults` parameters. ![get-products-flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-get-products-flow.png) Figure 1. get-products-flow in Studio 6 Configuration XML for get-products-flow in Studio 6. ```xml ``` 1. There are no changes regarding `get-products-flow` definition. ```xml ``` 2. Create a package with the name `variables` under `src/main/resources` folder. 3. Create the file `set-queryCategory-variable.dwl` under `src/main/resources/variables` folder and write a DW script for setting `queryCategory` flow variable. %dw 2.0 output application/java var queryCategory = attributes.queryParams.category --- if (queryCategory != null) queryCategory else '%%' 4. Create the file `set-queryLimit-variable.dwl` under `src/main/resources/variables` folder and write a DW script for setting `queryLimit` flow variable. %dw 2.0 output application/java --- attributes.queryParams.maxResults as Number 5. Create the file `set-queryName-variable.dwl` under `src/main/resources/variables` folder and write a DW script for setting `queryName` flow variable. %dw 2.0 output application/java var queryName = attributes.queryParams.name --- if (queryName != null) queryName else '%%' 6. Create the file `set-queryOffset-variable.dwl` under `src/main/resources/variables` folder and write a DW script for setting `queryOffset` flow variable. %dw 2.0 output application/java --- attributes.queryParams.offset as Number 7. Add a `Transform component` to replace the logic inside `message-properties-transformer` and set the variables `queryOffset`, `queryLimit`, `queryName` and `queryCategory` referencing to its DW script. ```xml ``` 8. Add a `db:select` element, referencing the MySQL Global Configuration. Use the colon (:) syntax in parametrized queries. Parameters must be supplied as key-value pairs into the `db:input-parameters` element. ```xml SELECT p.id, p.name, p.description, p.product_number, p.manufactured, p.colors, p.categories, p.stock, p.safety_stock_level, p.standard_cost, p.list_price, p.size, p.size_unit_measure_code, p.weight, p.weight_unit_measure_code, p.days_to_manufacture, p.images, p.modified_date, p.created_date FROM product p WHERE LOWER(p.name) like :name AND LOWER(p.categories) like :category LIMIT :limit OFFSET :offset ``` 9. Create a package with the name `mappings` under `src/main/resources` folder. 10. Create the file `get-products-response.dwl` under `src/main/resources/mappings` folder. 11. Migrate `get-products-response.dwl` DW 1.0 script to DW 2.0. Transformation for get-products-response in DW 1.0. %dw 1.0 %output application/json --- payload map { id: $.id, categories: ($.categories default "") splitBy ",", colors: ($.colors default "") splitBy ",", images: ($.images default "") splitBy ",", createdDate: $.created\_date as :string {format: "yyyy-MM-dd"}, modifiedDate: $.modified\_date as :string {format: "yyyy-MM-dd"}, safetyStockLevel: $.safety\_stock\_level as :number, stock: $.stock as :number, daysToManufacture: $.days\_to\_manufacture, name: $.name, description: $.description, listPrice: $.list\_price, manufactured: $.manufactured, productNumber: $.product\_number, size: $.size, sizeUnitMeasureCode: $.size\_unit\_measure\_code, standardCost: $.standard\_cost, weightUnitMeasureCode: $.weight\_unit\_measure\_code, weight: $.weight } Transformation for get-products-response in DW 2.0. %dw 2.0 output application/json --- payload map { id: $.id, categories: ($.categories default "") splitBy ",", colors: ($.colors default "") splitBy ",", images: ($.images default "") splitBy ",", createdDate: $.created\_date as String {format: "yyyy-MM-dd"}, modifiedDate: $.modified\_date as String {format: "yyyy-MM-dd"}, safetyStockLevel: $.safety\_stock\_level as Number, stock: $.stock as Number, daysToManufacture: $.days\_to\_manufacture, name: $.name, description: $.description, listPrice: $.list\_price, manufactured: $.manufactured, productNumber: $.product\_number, size: $.size, sizeUnitMeasureCode: $.size\_unit\_measure\_code, standardCost: $.standard\_cost, weightUnitMeasureCode: $.weight\_unit\_measure\_code, weight: $.weight } 12. Finally, add a `Transform component` that sets the payload using the DW 2.0 transformation. ```xml ``` Configuration XML for get-products-flow in Studio 7. ```xml SELECT p.id, p.name, p.description, p.product_number, p.manufactured, p.colors, p.categories, p.stock, p.safety_stock_level, p.standard_cost, p.list_price, p.size, p.size_unit_measure_code, p.weight, p.weight_unit_measure_code, p.days_to_manufacture, p.images, p.modified_date, p.created_date FROM product p WHERE LOWER(p.name) like :name AND LOWER(p.categories) like :category LIMIT :limit OFFSET :offset ``` ![get-products-flow in Studio 7](/mulesoft/current/en-us/mule-runtime/4.4/_images/m4-apikit-based-example-get-products-flow.png) Figure 2. get-products-flow in Studio 7 ## [](#migrating-get-product-by-id-flow)Migrating _get-product-by-id-flow_ `get-product-by-id-flow` returns a product from the database filtering by `id`. If there isn’t a product with the required id, an `HTTP 404 Not Found` error is returned. ![get-product-by-id-flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-get-product-by-id-flow.png) Figure 3. get-product-by-id-flow in Studio 6 Configuration XML for get-product-by-id-flow in Studio 6. ```xml ``` 1. There are no changes regarding `get-product-by-id-flow` definition. ```xml ``` 2. Create `set-productId-variable.dwl` under `src/main/resources/variables` folder. Add the following logic for getting the `id` from `uriParams`. %dw 2.0 output application/java --- attributes.uriParams.id 3. Add a `Transform component` that references the DW script that sets a variable with the `productId` value received as a `URI parameter`. ```xml ``` 4. Add a `db:select` element, referencing the MySQL Global Configuration. Use the colon (:) syntax in parametrized queries. Parameters must be supplied as key-value pairs into the `db:input-parameters` element. ```xml SELECT p.id, p.name, p.description, p.product_number, p.manufactured, p.colors, p.categories, p.stock, p.safety_stock_level, p.standard_cost, p.list_price, p.size, p.size_unit_measure_code, p.weight, p.weight_unit_measure_code, p.days_to_manufacture, p.images, p.modified_date, p.created_date FROM product p where p.id = :id ``` 5. Add a `validation:is-true` element after the `db:select` that checks if the query has returned results. If not, throw an `APP:NOT_FOUND` error. Notice that as `MEL` has been replaced by `DataWeave` as the default expression language, `[payload.size() > 0]` is rewritten as `[sizeOf(payload) > 0]`. ```xml ``` 6. Create `get-product-by-id-response.dwl` file under `src/main/resources/mappings` folder and migrate DataWeave script for building JSON response from 1.0 to 2.0. Transformation for get-product-by-id-response in DW 1.0. %dw 1.0 %output application/json %var product = payload\[0\] --- { id: product.id, name: product.name, description: product.description, manufactured: product.manufactured, productNumber: product.product\_number, colors: (product.colors default "") splitBy "," , categories:(product.categories default "") splitBy "," , safetyStockLevel: product.safety\_socket\_level, standardCost: (product.standard\_cost default "0.0") as :string {format: "##.##"} as :number, listPrice: (product.list\_price default "0.0") as :string {format: "##.##"} as :number, stock: product.stock, safetyStockLevel: product.safety\_stock\_level, daysToManufacture: product.days\_to\_manufacture, size: product.size, sizeUnitMeasureCode: product.size\_unit\_measure\_code, weight: product.weight, weightUnitMeasureCode: product.weight\_unit\_measure\_code, daysToManufacture: product.days\_to\_manufacture, images: (product.images splitBy "," default null), modifiedDate: (product.modified\_date default "") as :date {format: "yyyy-MM-dd"}, createdDate: (product.created\_date default "") as :date {format: "yyyy-MM-dd"} } Transformation for get-product-by-id-response.dwl in DW 2.0. %dw 2.0 output application/json var product = payload\[0\] --- { id: product.id, name: product.name, description: product.description, manufactured: product.manufactured, productNumber: product.product\_number, colors: (product.colors default "") splitBy "," , categories:(product.categories default "") splitBy "," , safetyStockLevel: product.safety\_socket\_level, standardCost: (product.standard\_cost default "0.0") as String {format: "##.##"} as Number, listPrice: (product.list\_price default "0.0") as String {format: "##.##"} as Number, stock: product.stock, safetyStockLevel: product.safety\_stock\_level, daysToManufacture: product.days\_to\_manufacture, size: product.size, sizeUnitMeasureCode: product.size\_unit\_measure\_code, weight: product.weight, weightUnitMeasureCode: product.weight\_unit\_measure\_code, daysToManufacture: product.days\_to\_manufacture, images: (product.images splitBy "," default null), modifiedDate: (product.modified\_date default "") as Date {format: "yyyy-MM-dd"}, createdDate: (product.created\_date default "") as Date {format: "yyyy-MM-dd"} } 7. Finally, add a `Transform component` that sets the payload using the DW 2.0 transformation. ```xml ``` Configuration XML for get-product-by-id-flow in Studio 7. ```xml SELECT p.id, p.name, p.description, p.product_number, p.manufactured, p.colors, p.categories, p.stock, p.safety_stock_level, p.standard_cost, p.list_price, p.size, p.size_unit_measure_code, p.weight, p.weight_unit_measure_code, p.days_to_manufacture, p.images, p.modified_date, p.created_date FROM product p where p.id = :id ``` ![get-product-by-id-flow in Studio 7](/mulesoft/current/en-us/mule-runtime/4.4/_images/m4-apikit-based-example-get-product-by-id-flow.png) Figure 4. get-product-by-id-flow in Studio 7 ## [](#migrating-post-product-flow)Migrating _post-product-flow_ `post-product-flow` inserts a product in the database. ![post-product-flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-post-product-flow.png) Figure 5. post-product-flow in Studio 6 Configuration XML for post-product-flow in Studio 6. ```xml ``` 1. There are no changes regarding `post-product-flow` definition. ```xml ``` 2. Create a `json-to-java.dwl` file into `src/main/resources/mappings` folder to transform the JSON request into a JAVA map. %dw 2.0 output application/java --- payload 3. Create a `json-product-to-java.dwl` file into `src/main/resources/mappings` and migrate the original script from DW 1.0 to 2.0. Transformation for json-product-to-java.dwl in DW 1.0. %dw 1.0 %output application/java --- { categories: payload.categories joinBy ",", colors: payload.colors joinBy ",", daysToManufacture: payload.daysToManufacture, description: payload.description, images: payload.images joinBy ",", listPrice: payload.listPrice, (manufactured: 1) when payload.manufactured == true, (manufactured: 0) when payload.manufactured == false, name: payload.name, productNumber: payload.productNumber, safetyStockLevel: payload.safetyStockLevel, size: payload.size, sizeUnitMeasureCode: payload.sizeUnitMeasureCode, standardCost: payload.standardCost, stock: payload.stock, weight: payload.weight, weightUnitMeasureCode: payload.weightUnitMeasureCode } Transformation for json-product-to-java.dwl in DW 2.0. %dw 2.0 output application/java fun getManufacturedCode(value) = if (value == true) 1 else 0 --- { categories: payload.categories joinBy ",", colors: payload.colors joinBy ",", daysToManufacture: payload.daysToManufacture, description: payload.description, images: payload.images joinBy ",", listPrice: payload.listPrice, manufactured: getManufacturedCode(payload.manufactured), name: payload.name, productNumber: payload.productNumber, safetyStockLevel: payload.safetyStockLevel, size: payload.size, sizeUnitMeasureCode: payload.sizeUnitMeasureCode, standardCost: payload.standardCost, stock: payload.stock, weight: payload.weight, weightUnitMeasureCode: payload.weightUnitMeasureCode } 4. Add a `Transform component` that sets `originalPayload` and `newPayload` using the previously created DataWeave transformations. ```xml ``` 5. For configuring the details of the transaction, replace the Mule 3.x `transactional` scope with the new `try` scope and set the `transactionalAction` attribute to `ALWAYS_BEGIN`. ```xml ``` 6. Add a `db:insert` element into the `Try scope`, referencing the MySQL Global Configuration. Parameters must be supplied as key-value pairs into the `db:input-parameters` element. Notice also the inclusion of `db:auto-generated-keys-column-name` tag for setting the payload with the `ID` that was auto-generated by the Database engine. ```xml insert into product(name, description, product_number, manufactured, colors, categories, stock, safety_stock_level, standard_cost, list_price, size, size_unit_measure_code, weight, weight_unit_measure_code, days_to_manufacture, images, modified_date, created_date) values(:name, :description, :product_number, :manufactured, :colors, :categories, :stock, :safety_stock_level, :standard_cost, :list_price, :size, :size_unit_measure_code, :weight, :weight_unit_measure_code, :days_to_manufacture, :images, CURDATE(), CURDATE()); ``` 7. Create a `post-product-response.dwl` file under `src/main/resources/mappings` and migrate the response transformation from DataWeave 1.0 to 2.0. Notice the difference getting the generated `id` from the payload with the expression `payload.generatedKeys.GENERATED_KEY`. Transformation for post-product-response.dwl in DW 1.0. %dw 1.0 %output application/json --- flowVars.originalPayload ++ id: payload\[0\].GENERATED\_KEY Transformation for post-product-response.dwl in DW 2.0. %dw 2.0 output application/json --- vars.originalPayload ++ id: payload.generatedKeys.GENERATED\_KEY 8. Add a `Transform component` and set the payload with the DataWeave script. ```xml ``` Configuration XML for post-product-flow in Studio 7. ```xml insert into product(name, description, product_number, manufactured, colors, categories, stock, safety_stock_level, standard_cost, list_price, size, size_unit_measure_code, weight, weight_unit_measure_code, days_to_manufacture, images, modified_date, created_date) values(:name, :description, :product_number, :manufactured, :colors, :categories, :stock, :safety_stock_level, :standard_cost, :list_price, :size, :size_unit_measure_code, :weight, :weight_unit_measure_code, :days_to_manufacture, :images, CURDATE(), CURDATE()); ``` ![post-product-flow in Studio 7](/mulesoft/current/en-us/mule-runtime/4.4/_images/m4-apikit-based-example-post-product-flow.png) Figure 6. post-product-flow in Studio 7 ## [](#migrating-put-product-flow)Migrating _put-product-flow_ `put-product-flow` updates a product in the database based on the specified `id`. ![put-product-flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-put-product-flow.png) Figure 7. put-product-flow in Studio 6 Configuration XML for put-product-flow in Studio 6. ```xml ``` 1. There are no changes regarding `put-product-flow` definition. ```xml ``` 2. Create a `put-json-product-to-java.dwl` file under `src/main/resources/mappings` folder and migrate the original script from DW 1.0 to 2.0. Transformation for put-json-product-to-java.dwl in DW 1.0. %dw 1.0 %output application/java --- { categories: payload.categories joinBy ",", colors: payload.colors joinBy ",", daysToManufacture: payload.daysToManufacture, description: payload.description, images: payload.images joinBy ",", listPrice: payload.listPrice, manufactured: payload.manufactured, name: payload.name, productNumber: payload.productNumber, safetyStockLevel: payload.safetyStockLevel, size: payload.size, sizeUnitMeasureCode: payload.sizeUnitMeasureCode, standardCost: payload.standardCost, stock: payload.stock, weight: payload.weight, weightUnitMeasureCode: payload.weightUnitMeasureCode } Transformation for put-json-product-to-java.dwl in DW 2.0. %dw 2.0 output application/java --- { categories: payload.categories joinBy ",", colors: payload.colors joinBy ",", daysToManufacture: payload.daysToManufacture, description: payload.description, images: payload.images joinBy ",", listPrice: payload.listPrice, manufactured: payload.manufactured, name: payload.name, productNumber: payload.productNumber, safetyStockLevel: payload.safetyStockLevel, size: payload.size, sizeUnitMeasureCode: payload.sizeUnitMeasureCode, standardCost: payload.standardCost, stock: payload.stock, weight: payload.weight, weightUnitMeasureCode: payload.weightUnitMeasureCode } 3. Add a `Transform component` that sets `updatePayload` using the previously created DataWeave transformation and `id` with `variables/set-productId-variable.dwl` script. ```xml ``` 4. For configuring the details of the transaction, replace the Mule 3.x `transactional` scope with the new `try` scope and set the `transactionalAction` attribute to `ALWAYS_BEGIN`. ```xml ``` 5. Add a `db:update` element into the `Try scope`, referencing the MySQL Global Configuration. Parameters must be supplied as key-value pairs into the `db:input-parameters` element. ```xml update product set name = :name, description = :description, product_number = :product_number, manufactured = :manufactured, colors = :colors, categories= :categories, stock = :stock, safety_stock_level = :safety_stock_level, standard_cost = :standard_cost, list_price = :list_price, size = :size, size_unit_measure_code = :size_unit_measure_code, weight = :weight, weight_unit_measure_code = :weight_unit_measure_code, days_to_manufacture = :days_to_manufacture, images = :images, modified_date = CURDATE() where id = :id ``` 6. Add a `Transform component` and set the `httpStatus` variable with `204` using `set-httpStatus-with-204.dwl` file into `src/main/resources/variables`. ```xml ``` Configuration XML for put-product-flow in Studio 7. ```xml update product set name = :name, description = :description, product_number = :product_number, manufactured = :manufactured, colors = :colors, categories= :categories, stock = :stock, safety_stock_level = :safety_stock_level, standard_cost = :standard_cost, list_price = :list_price, size = :size, size_unit_measure_code = :size_unit_measure_code, weight = :weight, weight_unit_measure_code = :weight_unit_measure_code, days_to_manufacture = :days_to_manufacture, images = :images, modified_date = CURDATE() where id = :id ``` ![put-product-flow in Studio 7](/mulesoft/current/en-us/mule-runtime/4.4/_images/m4-apikit-based-example-put-product-flow.png) Figure 8. put-product-flow in Studio 7 ## [](#migrating-delete-product-flow)Migrating _delete-product-flow_ `delete-product-flow` deletes the product record from the MySQL database with the `id` specified as a `URI parameter` returning an HTTP 204 status code. ![delete-product-flow in Studio 6](/mulesoft/current/en-us/mule-runtime/4.4/_images/m3-apikit-based-example-delete-product-flow.png) Figure 9. delete-product-flow in Studio 6 Configuration XML for delete-product-flow in Studio 6. ```xml ``` 1. There are no changes regarding `delete-product-flow` definition. ```xml ``` 2. Add a `Transform component` that references the DW script that sets a variable with the `productId` value received as a `URI parameter`. ```xml ``` 3. For configuring the details of the transaction, replace the Mule 3.x `transactional` scope with the new `try` scope and set the `transactionalAction` attribute to `ALWAYS_BEGIN`. ```xml ``` 4. Add a `db:delete` element into the `Try scope`, referencing the MySQL Global Configuration. Parameters must be supplied as key-value pairs into the `db:input-parameters` element. Opposite to Mule 3.x, the previously defined `productId` flow variable must be accessed as `vars.productId` instead of `flowVars.productId`. ```xml delete from product where id=:productId ``` 5. Create a `set-httpStatus-with-204.dwl` file under `src/main/resources/variables` as follows. %dw 2.0 output application/java --- 204 6. Set `httpStatus` variable with the value `204` using a `Transform Component` for defining a `NO CONTENT` response code. ```xml ``` To return a specific HTTP Status code, instead of setting a `http.status` property, APIkit in Mule 4 requires setting a variable with the name `httpStatus`. Configuration XML for delete-product-flow in Studio 7. ```xml delete from product where id=:productId ``` ![delete-product-flow in Studio 7](/mulesoft/current/en-us/mule-runtime/4.4/_images/m4-apikit-based-example-delete-product-flow.png) Figure 10. delete-product-flow in Studio 7 ## [](#migrating-backend-flows)Migrating Backend Flows To migrate backend flows: For each Backend Flow generated by APIkit, add a `flow-ref` to its implementation. \+ .Configuration XML for Backend Flows in Studio 6. ```xml ``` + \+ .Configuration XML for Backend Flows in Studio 7. ```xml ``` ## [](#extending-default-apikit-global-exception-strategies)Extending default APIkit Global Exception Strategies 1. Add `APP:NOT_FOUND` exception type to the ApiKit-generated 404 mapping to handle the exception thrown by the `validation:is-true` element in `get-product-by-id-flow`. You can repeat this process for any other errors you want to map to a specific status code. Configuration XML for ApiKit Mapping 404 in Studio 6. ```xml ``` Configuration XML for ApiKit Mapping 404 in Studio 7. ```xml ``` 2. Add a Generic ApiKit Mapping 500 for all the non previously managed exceptions. Configuration XML for Generic ApiKit Mapping 500 in Studio 6. ```xml ``` Configuration XML for Generic ApiKit Mapping 500 in Studio 7. ```xml ```