In this tutorial, we will explore the scripting language used in Postman. Postman is a powerful API testing and development tool that allows users to send requests to APIs and receive responses. With its scripting capabilities, users can automate tasks, create complex workflows, and perform advanced operations.
JavaScript: The Scripting Language
JavaScript is the scripting language used in Postman. JavaScript is a versatile programming language that is widely used for web development. It is a client-side scripting language, meaning it runs on the client’s browser rather than on the server.
In Postman, JavaScript is used to write scripts that execute before, during, or after sending API requests. These scripts can be used to modify request headers, extract data from responses, set variables, make assertions, and much more.
Scripting in Postman
Scripting in Postman allows users to extend the functionality of their API tests and collections. With scripts, you can:
- Create dynamic variables: Use script statements to generate random values or compute values based on existing data.
- Modify request headers: Add or remove headers before sending a request.
- Extract data from responses: Parse JSON or XML responses to retrieve specific data for further processing.
- Create assertions: Verify response status codes, content types, or specific values within the response body.
- Create custom workflows: Define complex workflows by chaining requests together and using control flow statements like loops and conditionals.
The Pre-request Script
The pre-request script is executed before sending a request. It allows you to dynamically modify the request before it is sent. This can be useful for setting authentication headers, generating tokens, or adding dynamic parameters.
To write a pre-request script in Postman, navigate to the “Pre-request Script” tab of a request and start coding in JavaScript.
The Test Script
The test script is executed after receiving a response. It allows you to extract data from the response, perform assertions, and set environment variables based on the response data.
To write a test script in Postman, navigate to the “Tests” tab of a request and start coding in JavaScript.
Postman Sandbox
The JavaScript code written in Postman scripts runs within a sandboxed environment called the “Postman Sandbox”. This sandbox provides additional functionality specific to Postman, such as access to request and response objects, environment variables, and various utility functions.
The Postman Sandbox also includes built-in libraries that can be used within scripts. These libraries include:
- pm: The Postman object model that provides access to request and response details.
- pm.environment: Allows you to read and write environment variables.globals: Allows you to read and write global variables.collectionVariables: Provides access to collection variables.
- _lodash: A utility library that provides useful functions for manipulating data.
In Conclusion
In this tutorial, we have explored the scripting language used in Postman – JavaScript. We have learned how scripting in Postman can be used to extend the functionality of API tests, create dynamic variables, modify headers, extract data from responses, and perform assertions.
By leveraging the power of JavaScript and the Postman Sandbox, you can automate your API testing workflows and perform advanced operations with ease.