Passing body to POST request:-

We know that we need to pass a payload ( JSON or XML) to POST request. REST Assured makes it very handy to pass body to request. We can pass body as a String or a JSON file or a XML file or a Java Object or a byte array. as of now we will pass body as a String.

Non-BDD Style:-

package RestfulBooker.postExamples;
import org.hamcrest.Matchers;
import io.restassured.RestAssured;
import io.restassured.http.ContentType;
import io.restassured.response.Response;
import io.restassured.response.ValidatableResponse;
import io.restassured.specification.RequestSpecification;
 
public class NonBDDStylePostRequest {
	
	public static void main(String[] args) {
		// There is no need to add escape character manually. Just paste string within double
		// quotes. It will automatically add escape sequence as required.
		String jsonString = "{\"username\" : \"admin\",\"password\" : \"password123\"}";
		
		// Create a request specification
		RequestSpecification request= RestAssured.given();
		
		// Setting content type to specify format in which request payload will be sent.
		// ContentType is an ENUM.
		request.contentType(ContentType.JSON);
		//Adding URI
		request.baseUri("https://restful-booker.herokuapp.com/auth");
		// Adding body as string
		request.body(jsonString);
		
		// Calling POST method on URI. After hitting we get Response
		Response response = request.post();
		
		// Printing Response as string
		System.out.println(response.asString());
		
		// Get Validatable response to perform validation
		ValidatableResponse validatableResponse = response.then();
		
		// Validate status code as 200
		validatableResponse.statusCode(200);
		
		// Validate token field is null
		// SInce response is one to one mapping so passing key name will give you value.
		// Below method validates that value of token is not null.
		validatableResponse.body("token", Matchers.notNullValue());
		
		// Validate token length is 15
		validatableResponse.body("token.length()", Matchers.is(15));
		
		// Validate token is an alphanumeric value
		validatableResponse.body("token", Matchers.matchesRegex("^[a-z0-9]+$"));
	}
 
}

BDD Style:-

package RestfulBooker.postExamples;
import org.hamcrest.Matchers;
import io.restassured.RestAssured;
import io.restassured.http.ContentType;
public class BDDStylePostRequest {
	public static void main(String[] args) {
		
		// There is no need to add escape character manually. Just paste string within double
		// quotes. It will automatically add escape sequence as required.
		String jsonString = "{\"username\" : \"admin\",\"password\" : \"password123\"}";
			
		//GIVEN
		RestAssured
		.given()
			.baseUri("https://restful-booker.herokuapp.com/auth")
			.contentType(ContentType.JSON)
			.body(jsonString)
		// WHEN
		.when()
			.post()
		// THEN
		.then()
			.assertThat()
			.statusCode(200)
			.body("token", Matchers.notNullValue())
			.body("token.length()", Matchers.is(15))
			.body("token", Matchers.matchesRegex("^[a-z0-9]+$"));
	}
}