Convert Postman Response to String in Simple Steps

Let’s talk about something that we all face during development: API Testing with Postman for your Development Team.

Yeah, I’ve heard of it as well, Postman is getting worse year by year, but, you are working as a team and you need some collaboration tools for your development process, right? So you paid Postman Enterprise for…. $49/month.

Now I am telling you: You Don’t Have to:

That’s right, APIDog gives you all the features that comes with Postman paid version, at a fraction of the cost. Migration has been so easily that you only need to click a few buttons, and APIDog will do everything for you.

How to Migrate Postman Collections/Environments to Apidog

APIDog has a comprehensive, easy to use GUI that makes you spend no time to get started working (If you have migrated from Postman). It’s elegant, collaborate, easy to use, with Dark Mode too!

Want a Good Alternative to Postman? APIDog is definitely worth a shot. But if you are the Tech Lead of a Dev Team that really want to dump Postman for something Better, and Cheaper, Check out APIDog!

Apidog An integrated platform for API design, debugging, development, mock, and testing

How to Convert Postman Response to String?

Postman is a powerful tool for API testing that allows developers to make requests and inspect responses with elegance and ease. One common task that arises when working with APIs is the need to convert responses into a string format, particularly when you are processing or validating response data in different contexts. In this comprehensive guide, we will explore how to convert Postman responses to strings, with attention to use cases, methods, and examples.

Understanding Postman Responses

What is a Postman Response?

A Postman response encapsulates the data returned by a server after an API call is made. This response typically contains a combination of status codes, headers, and the response body itself, which may be in JSON, XML, or other formats. In Postman, once a request is sent, the response is displayed in a user-friendly manner but may need to be transformed into a string for various programming tasks.

Types of Postman Responses

Postman can receive responses in several formats:

• JSON: The most common format, often used for APIs built on RESTful principles.
• XML: Employed by some older APIs and services providing structured markup.
• HTML: This may come from web services that provide an HTML representation of data.
• Plain Text: Some responses may be simple text outputs.

Each of these formats can be converted to a string with some minor variations, which we will discuss in the following sections.

Retrieving the Postman Response Data

Accessing Response Body

Before we can convert a Postman response to a string, it is crucial to understand how to access the response body. This is achieved using the Postman scripting feature, specifically within the Tests or Pre-request Script tabs where JavaScript code can be written.

To access the response data, you can utilize the pm.response object:

let responseBody = pm.response.text(); // To get the raw response as text

This method fetches the body of the response, which can be stored in a variable for easy use in string conversion.

Necessary Headers and Status Codes

When working with complex APIs, it is vital to ensure that the necessary headers are in place. Some APIs may require specific headers like Content-Type to indicate the response format. You can access headers as follows:

let contentType = pm.response.headers.get('Content-Type');

Understanding headers might be essential for proper parsing and converting, as they provide context to the data received.

Converting Postman Response to String

Using pm.response.text()

Once you have accessed the response body, converting it to a string can be accomplished using the pm.response.text() method. This method retrieves the string representation of the response body irrespective of its type.

Here is an example:

let responseBody = pm.response.text();
console.log(responseBody); // Output the response body as a string

If a JSON response is given, this method will convert it appropriately:

{
    "user": "john_doe",
    "age": 30,
    "verified": true
}

When you use pm.response.text(), the entire JSON data structure will be represented as a string.

Converting JSON to String Format

In scenarios where you want to further manipulate a JSON response and convert it to a string representation suitable for storage or comparison, it is advisable to use JSON.stringify().

Here’s how you can implement this:

let jsonResponse = pm.response.json(); // Parse the JSON response
let jsonString = JSON.stringify(jsonResponse); // Convert JSON to string
console.log(jsonString); // String representation of JSON.

The JSON.stringify() method guarantees that the object gets converted into a formatted string, especially when dealing with nested structures, arrays, and special data types.

Handling XML Responses

If your API returns an XML response, the conversion process is slightly different. Postman’s pm.response.text() method can still be used to retrieve the XML, but if you're looking to convert it into a string that can be processed or modified further, you would typically handle the XML as a string directly.

Here is how you can do so:

let xmlResponse = pm.response.text(); // Get XML response as text
console.log(xmlResponse); // Output the raw XML as a string.

If you wish to work with an XML DOM and hunt for specific nodes, you may need to parse the XML first and then stringify it if necessary. However, XML is frequently utilized as a string format natively by developers.

Converting HTML Responses

HTML responses can also be handled in a similar manner. Postman treats HTML response bodies as strings by default, allowing for immediate string operations:

let htmlResponse = pm.response.text(); // Raw HTML as string
console.log(htmlResponse); // Display HTML string.

Given that HTML is inherently a text format, no additional conversion to string is needed; however, extracting specific data using JavaScript string methods or regular expressions may be common in practical applications.

Validating the Response String

String Length and Content Checks

Strings derived from responses may need validation checks, such as confirming the length or ensuring specific content is present within the response. This ensures that the API returns expected results:

pm.test("Response content length is greater than zero", function () {
    let responseBody = pm.response.text();
    pm.expect(responseBody.length).to.be.greaterThan(0);
});

pm.test("Response should include user key", function () {
    let jsonResponse = pm.response.json();
    pm.expect(jsonResponse).to.have.property("user");
});

Automated tests using pm.test asserted here add another layer of verification for API functionality.

Error Handling and Edge Cases

When converting Postman response strings, it is essential to implement robust error handling. Response formats can vary widely, and incorrect assumptions can lead to errors.

Here’s how to build a safety net around string conversion:

try {
    let responseBody = pm.response.text();
    console.log(responseBody);
} catch (error) {
    console.error("Failed to convert response to string: ", error);
}

This simple construction allows you to catch any unforeseen errors during the conversion process and respond accordingly.

Practical Applications of Response String Conversion

Scripting and Automation

The ability to convert Postman responses to strings opens up extensive possibilities for scripting and automation. Scenarios include logging, testing, and transforming data dynamically.

Data Validation and Testing

In many testing scenarios, it may be necessary to validate the data returned from an API. By converting responses to strings, developers can write assertion tests against the content returned, validating that the API behaves as expected.

Storing API Responses

For cases where API responses need to be stored or cached for offline testing or as a method of revision logs, converting the responses to strings facilitates easy serialization and storage.

An example scenario would be utilizing Node.js or contemporary backend frameworks to handle responses:

const fs = require('fs');

let responseBody = pm.response.text();
fs.writeFile("apiResponse.txt", responseBody, (err) => {
    if (err) throw err;
    console.log("Response saved!");
});

This can significantly enhance workflows where app developers or testers require persistent copies of API responses.

In conclusion, the ability to convert Postman responses to strings is an essential task within the API development and testing landscape. It enhances accessibility to response content for further analysis, debugging, and validation. Understanding the methods outlined herein provides a foundation for efficient API interaction, ensuring developers have the tools necessary to transform and utilize response data effectively.

Let’s talk about something that we all face during development: API Testing with Postman for your Development Team.

Yeah, I’ve heard of it as well, Postman is getting worse year by year, but, you are working as a team and you need some collaboration tools for your development process, right? So you paid Postman Enterprise for…. $49/month.

Now I am telling you: You Don’t Have to:

That’s right, APIDog gives you all the features that comes with Postman paid version, at a fraction of the cost. Migration has been so easily that you only need to click a few buttons, and APIDog will do everything for you.

How to Migrate Postman Collections/Environments to Apidog

APIDog has a comprehensive, easy to use GUI that makes you spend no time to get started working (If you have migrated from Postman). It’s elegant, collaborate, easy to use, with Dark Mode too!

Want a Good Alternative to Postman? APIDog is definitely worth a shot. But if you are the Tech Lead of a Dev Team that really want to dump Postman for something Better, and Cheaper, Check out APIDog!

Apidog An integrated platform for API design, debugging, development, mock, and testing