REST Assured Tutorial 50 – How to set Content-Type for request in Rest Assured

Introduction

As a part of End to End REST Assured Tutorial, in this post, we will learn to why and how to set the Content-Type header in Rest Assured for a request.

Content-Type is a header that indicates the media type or MIME( Multipurpose Internet Mail Extensions ) type or type of a file. When we hit any POST or PUT API requests we may need to pass a payload. That payload can be in any supported format by API such as XML, JSON, etc. We need to use the Content-Type header to let the server know the format of the payload for a request which will be sent.

Similarly, Content-Type for response indicates the format of the response returned. It is not mandatory that the Content-Type of request and response should be the same.

Prerequisite

I have used below dependency of Rest Assured library for this post:-

    io.rest-assured
    rest-assured
    4.3.1
    test

Why we may need to set Content-Type explicitly for a request?

Postman tool automatically adds a Content-Type header based on the request body we select. For example, if select request body format as JSON then Postman will add automatically a header named “Content-Type” with value as “application/json“. This does not happen automatically in Rest Assured and you may get an unexpected response as a server may not identify the format of payload.

Let’s see an example where we are not setting up Content-Type explicitly. We are passing a payload which is in a JSON format.

package RestAssuredBasicConcepts;

import org.testng.annotations.Test;

import io.restassured.RestAssured;

public class SetContentTypeForRequest {
	
	@Test
	public void WIthoutSettingContentType()
	{
		RestAssured
		.given()
		.log()
		.all()
		.body("{\r\n" + 
				"    \"firstname\" : \"Jim\",\r\n" + 
				"    \"lastname\" : \"Brown\",\r\n" + 
				"    \"totalprice\" : 111,\r\n" + 
				"    \"depositpaid\" : true,\r\n" + 
				"    \"bookingdates\" : {\r\n" + 
				"        \"checkin\" : \"2018-01-01\",\r\n" + 
				"        \"checkout\" : \"2019-01-01\"\r\n" + 
				"    },\r\n" + 
				"    \"additionalneeds\" : \"Breakfast\"\r\n" + 
				"}")
		.post("https://restful-booker.herokuapp.com/booking")
		.then()
		.log()
		.all();
	}

}

Output

[RemoteTestNG] detected TestNG version 7.0.1
Request method:	POST
Request URI:	https://restful-booker.herokuapp.com/booking
Proxy:			
Request params:	
Query params:	
Form params:	
Path params:	
Headers:		Accept=*/*
				Content-Type=text/plain; charset=ISO-8859-1
Cookies:		
Multiparts:		
Body:
{
    "firstname" : "Jim",
    "lastname" : "Brown",
    "totalprice" : 111,
    "depositpaid" : true,
    "bookingdates" : {
        "checkin" : "2018-01-01",
        "checkout" : "2019-01-01"
    },
    "additionalneeds" : "Breakfast"
}
HTTP/1.1 500 Internal Server Error
Server: Cowboy
Connection: keep-alive
X-Powered-By: Express
Content-Type: text/plain; charset=utf-8
Content-Length: 21
Etag: W/"15-/6VXivhc2MKdLfIkLcUE47K6aH0"
Date: Tue, 29 Sep 2020 07:42:56 GMT
Via: 1.1 vegur

Internal Server Error
PASSED: WIthoutSettingContentType

===============================================
    Default test
    Tests run: 1, Failures: 0, Skips: 0
===============================================


===============================================
Default suite
Total tests run: 1, Passes: 1, Failures: 0, Skips: 0
===============================================

We are passing a JSON payload to request but observe in output that it takes Content-Type as “text/plain” and return a response as “Internal server error“. Sever could not understand the correct format of the request payload and failed. This is the reason we should set Content-Type for a request properly.

Adding Content-Type to a request in Rest Assured

As Content-Type is a header we can pass it as a key-value pair using methods discussed here. An example is as below:-

package RestAssuredBasicConcepts;

import org.testng.annotations.Test;

import io.restassured.RestAssured;

public class SetContentTypeForRequest {
	
	@Test
	public void settingContentTypeAsHeader()
	{
		RestAssured
		.given()
		.log()
		.all()
		.header("Content-Type", "application/json")
		.body("{\r\n" + 
				"    \"firstname\" : \"Jim\",\r\n" + 
				"    \"lastname\" : \"Brown\",\r\n" + 
				"    \"totalprice\" : 111,\r\n" + 
				"    \"depositpaid\" : true,\r\n" + 
				"    \"bookingdates\" : {\r\n" + 
				"        \"checkin\" : \"2018-01-01\",\r\n" + 
				"        \"checkout\" : \"2019-01-01\"\r\n" + 
				"    },\r\n" + 
				"    \"additionalneeds\" : \"Breakfast\"\r\n" + 
				"}")
		.post("https://restful-booker.herokuapp.com/booking")
		.then()
		.log()
		.all();
	}

}

Output

[RemoteTestNG] detected TestNG version 7.0.1
Request method:	POST
Request URI:	https://restful-booker.herokuapp.com/booking
Proxy:			
Request params:	
Query params:	
Form params:	
Path params:	
Headers:		Accept=*/*
				Content-Type=application/json; charset=UTF-8
Cookies:		
Multiparts:		
Body:
{
    "firstname": "Jim",
    "lastname": "Brown",
    "totalprice": 111,
    "depositpaid": true,
    "bookingdates": {
        "checkin": "2018-01-01",
        "checkout": "2019-01-01"
    },
    "additionalneeds": "Breakfast"
}
HTTP/1.1 200 OK
Server: Cowboy
Connection: keep-alive
X-Powered-By: Express
Content-Type: application/json; charset=utf-8
Content-Length: 195
Etag: W/"c3-E5R+AIhAHdRg+t7MhfO18uLvLAw"
Date: Tue, 29 Sep 2020 07:52:19 GMT
Via: 1.1 vegur

{
    "bookingid": 21,
    "booking": {
        "firstname": "Jim",
        "lastname": "Brown",
        "totalprice": 111,
        "depositpaid": true,
        "bookingdates": {
            "checkin": "2018-01-01",
            "checkout": "2019-01-01"
        },
        "additionalneeds": "Breakfast"
    }
}
PASSED: WIthoutSettingContentType

===============================================
    Default test
    Tests run: 1, Failures: 0, Skips: 0
===============================================


===============================================
Default suite
Total tests run: 1, Passes: 1, Failures: 0, Skips: 0
===============================================

In the above approach, if you misspell the header name and its expected values then you will get an unexpected response. So to overcome that RequestSpecification class provided a below method:-

RequestSpecification contentType(ContentType contentType);

ContentType is an enum which contains members as “ANY”, “JSON”, “XML” etc. If I want to set Content -Type as JSON then I will use contentType() method as below:-

contentType(ContentType.JSON)

A complete example is as below:-

package RestAssuredBasicConcepts;

import org.testng.annotations.Test;

import io.restassured.RestAssured;
import io.restassured.http.ContentType;

public class SetContentTypeForRequest {
	
	@Test
	public void settingContentTypeAsContentType()
	{
		RestAssured
		.given()
		.log()
		.all()
		.contentType(ContentType.JSON)
		.body("{\r\n" + 
				"    \"firstname\" : \"Jim\",\r\n" + 
				"    \"lastname\" : \"Brown\",\r\n" + 
				"    \"totalprice\" : 111,\r\n" + 
				"    \"depositpaid\" : true,\r\n" + 
				"    \"bookingdates\" : {\r\n" + 
				"        \"checkin\" : \"2018-01-01\",\r\n" + 
				"        \"checkout\" : \"2019-01-01\"\r\n" + 
				"    },\r\n" + 
				"    \"additionalneeds\" : \"Breakfast\"\r\n" + 
				"}")
		.post("https://restful-booker.herokuapp.com/booking")
		.then()
		.log()
		.all();
	}

}

Output

[RemoteTestNG] detected TestNG version 7.0.1
Request method:	POST
Request URI:	https://restful-booker.herokuapp.com/booking
Proxy:			
Request params:	
Query params:	
Form params:	
Path params:	
Headers:		Accept=*/*
				Content-Type=application/json; charset=UTF-8
Cookies:		
Multiparts:		
Body:
{
    "firstname": "Jim",
    "lastname": "Brown",
    "totalprice": 111,
    "depositpaid": true,
    "bookingdates": {
        "checkin": "2018-01-01",
        "checkout": "2019-01-01"
    },
    "additionalneeds": "Breakfast"
}
HTTP/1.1 200 OK
Server: Cowboy
Connection: keep-alive
X-Powered-By: Express
Content-Type: application/json; charset=utf-8
Content-Length: 195
Etag: W/"c3-Hgn0HOW7t3wbXoNXHOll0aSCOGo"
Date: Tue, 29 Sep 2020 07:58:29 GMT
Via: 1.1 vegur

{
    "bookingid": 12,
    "booking": {
        "firstname": "Jim",
        "lastname": "Brown",
        "totalprice": 111,
        "depositpaid": true,
        "bookingdates": {
            "checkin": "2018-01-01",
            "checkout": "2019-01-01"
        },
        "additionalneeds": "Breakfast"
    }
}
PASSED: settingContentTypeAsContentType

===============================================
    Default test
    Tests run: 1, Failures: 0, Skips: 0
===============================================


===============================================
Default suite
Total tests run: 1, Passes: 1, Failures: 0, Skips: 0
===============================================

You can download/clone the above sample project from here.

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