Handling the Arrays in the MAP Policy

In this blog, we will learn how to handle Arrays in the MAP policy.

Introduction to the Map Policy in IBM API Connect

IBM API Connect (APIC) is a comprehensive API management solution that empowers developers to create, secure, manage, and socialize APIs across different environments. One of the key features of APIC is the Map policy, a powerful tool used to transform and manipulate data within your API flows.

The Map policy allows you to define how data is mapped from one format to another, enabling seamless integration between different systems and services. Whether you need to restructure JSON payloads, convert data types, or extract specific fields, the Map policy provides the flexibility to handle complex data transformations with ease.

Why Use the Map Policy?

In today’s API-driven world, data often needs to be transformed as it moves between different systems. The Map policy in IBM API Connect simplifies this process by allowing you to define how data should be structured, extracted, and transformed. This not only ensures that your APIs deliver the right data in the right format but also reduces the need for extensive backend processing.

In the following sections, we’ll explore how to effectively use the Map policy in IBM API Connect, with practical examples to guide you through various use cases. Whether you’re new to API development or an experienced developer, understanding the Map policy is essential for building robust and efficient APIs.

Key Features of the Map Policy:

• Data Transformation: The Map policy allows you to transform data structures, such as JSON, XML, and others, to meet the requirements of your backend systems or clients.
• Field Extraction: You can extract specific fields from the input data, making it easier to work with only the necessary information.
• Data Mapping: Map fields from the input payload to the output payload, enabling smooth data flow between different systems.
• Conditional Logic: Implement conditional logic within the Map policy to handle various scenarios based on the input data.

Implementing the Map Policy in IBM API Connect

The Map policy in IBM API Connect is a versatile tool that allows developers to manipulate, transform, and map data within an API. It is particularly useful when you need to reformat data, extract specific fields, or apply business logic to incoming or outgoing payloads. In this section, we’ll walk through the steps to implement a Map policy within IBM API Connect, focusing on a practical example to illustrate its use.

Step 1: Add the Map Policy to Your API Flow

Access API Connect:

1. Log in to the IBM API Connect management console.
2. Navigate to the API you want to modify or create a new API.

Open the Assembly Editor:

1. In the API editor, go to the “Assemble” tab.
2. This is where you define the flow of your API.

Add the Map Policy:

1. Drag and drop the Map policy from the policy palette into your API flow.
2. You can place the Map policy at any point in the flow where you need to transform the data (e.g., before sending a request to the backend or before returning a response to the client).

Step 2: Configure the Map Policy

Define Input and Output Data:

1. Click on the Map policy to open its configuration settings.
2. Specify the source of the input data, such as the request body, query parameters, or headers.
3. Define the structure of the output data. This could involve creating a new JSON object, selecting specific fields, or transforming existing data.

Mapping Fields

1. Use the interface to map fields from the input data to the output data.
2. For example, if you have an input JSON object with multiple fields, you can select specific fields to include in the output.
3. You can also create new fields in the output that are derived from the input data.

Example Input Data:

{
"shoppingcart":{ "customer"[
{"amount":5600,
"paymentType":"card"},
{"amount":4500,
"paymentType":"card"},
{"amount":2000,
"paymentType":"card"},
{"amount":5000,
"paymentType":"card"},
]
}
}

By using map policy in IBM APIC

Identifying the Required Output:

• Before you start mapping, you need to clearly understand what the output of your API should look like. This involves knowing which fields are necessary, how they should be structured, and any transformations that need to be applied.

Example: If the required output is an array of amounts extracted from a list of transactions, you need to ensure that only the amount fields are connected from the input to the output.

• After this we need to select array which we need to iterate over

We will get the desired output as

OUTPUT:

{
"result":{ "Amounts":[5600,4500,2000,5000]
}
}

Conclusion:

The Map policy in IBM API Connect provides a flexible and intuitive way to transform and manage data within your APIs. By following these steps, you can effectively implement data mappings that meet the needs of your application and its users. Whether you’re working with simple JSON objects or complex nested structures, the Map policy offers the tools you need to deliver the right data in the right format.