WireMock – Request Matching with JSON Mappings

WireMock is a tool for mocking HTTP-based APIs that runs in the unit tests, on the desktop, or in the test environment. Read more about WireMock in this article: Introduction to WireMock. One of the most important features of WireMock is Request Matching. WireMock supports matching of requests to stubs and verification queries using the following attributes: URL, HTTP Method, Query parameters, Headers, Cookies, Request body, etc. So in this article, we are going to see how Request Matching works with JSON Mappings in WireMock.

Prerequisites:

• Refer to this article and install WireMock on your local machine: How to Download and Install WireMock?
• Refer to this article and install Postman on your local machine: How to Download and Install Postman on Windows?
• Create Your First Mocked API Endpoint with WireMock

1. URL Matching

In WireMock, the URLs can be matched either by equality or by regular expression. And you can match just the path of the URL or the path and query together. Let’s see both scenarios with examples.

Example: Equality matching on the path only

Syntax:

{
  "request": {
    "urlPath": "provide your url here"
    ...
  },
  ...
}

Now let’s demonstrate this with the help of Postman. Open your Postman and send a POST request to the following URL

http://<host>:<port>/__admin/mappings

with the following JSON request body

{
    "request": {
        "method": "GET",
        "urlPath": "put your url as per your requirement"
    },
    "response": {
        "status": 200,
        "body": "put your body here"
    }
}

For example in this article our URL is

URL:

http://localhost:8080/__admin/mappings

And the JSON request body is

Request Body:

{
    "request": {
        "urlPath": "/gfg/user1",
        "method": "GET"
    },
    "response": {
        "status": 200,
        "body": "Welcome to Lazyroar!"
    }
}

Click on the Send button now and in the Response, you can see the following Response Body with the status code 201 Created.

Response Body:

{
    "id": "0eb73cc1-2070-44be-a1c9-3db40a97cea9",
    "request": {
        "urlPath": "/gfg/user1",
        "method": "GET"
    },
    "response": {
        "status": 200,
        "body": "Welcome to Lazyroar!"
    },
    "uuid": "0eb73cc1-2070-44be-a1c9-3db40a97cea9"
}

Please refer to the below image if you are stuck somewhere

 

Now, let’s test our Stubbed API. Again open a new tab in Postman and send a GET request to the following URL

http://localhost:8080/gfg/user1

And you are going to get the following response in the Response body.

Welcome to Lazyroar!

Please refer to the below image if you are stuck somewhere

 

Example: Regex matching on the path only

Syntax:

{
  "request": {
    "urlPathPattern": "/your/([a-z1-9]*)"
    ...
  },
  ...
}

Now let’s demonstrate this with the help of Postman. Open your Postman and send a POST request to the following URL

http://localhost:8080/__admin/mappings

And the JSON request body is

Request Body:

{
    "request": {
        "urlPathPattern": "/gfg/([a-z1-9]*)",
        "method": "GET"
    },
    "response": {
        "status": 200,
        "body": "Welcome to Lazyroar Portal!"
    }
}

Click on the Send button now and in the Response, you can see the following Response Body with the status code 201 Created.

Response Body:

{
    "id": "ed9fe262-2b79-4862-9889-39378d553a35",
    "request": {
        "urlPathPattern": "/gfg/([a-z1-9]*)",
        "method": "GET"
    },
    "response": {
        "status": 200,
        "body": "Welcome to Lazyroar Portal!"
    },
    "uuid": "ed9fe262-2b79-4862-9889-39378d553a35"
}

Please refer to the below image if you are stuck somewhere

 

Now, let’s test our Stubbed API. Again open a new tab in Postman and send a GET request to the following URL

http://localhost:8080/gfg/user1345689

Note: You can put anything lies in a-z and 1-9 after /gfg/

And you are going to get the following response in the Response body.

Welcome to Lazyroar Portal!

Please refer to the below image if you are stuck somewhere

 

Similarly, you can also try the demonstration in your Postman for the following Request Matching.

Equality matching on path and query

Syntax:

{
  "request": {
    "url": "/your/url?and=query"
    ...
  },
  ...
}

Regex matching on path and query

Syntax:

{
  "request": {
    "urlPattern": "/your/([a-z1-9]*)\\?and=query"
    ...
  },
  ...
}

2. Matching Other Attributes

Apart from the URL, all request attributes can be matched using some operators. 

Equality

Syntax:

{
  "request": {
    ...
    "headers": {
      "Content-Type": {
        "equalTo": "application/xml"
      }
    }
    ...
  },
  ...
}

Case-insensitive equality

Syntax:

{
  "request": {
    ...
    "headers": {
      "Content-Type": {
        "equalTo": "application/xml",
        "caseInsensitive": true
      }
    }
    ...
  },
  ...
}

3. JSON Equality

It will be a match if the attribute is valid JSON and is a semantic match for the expected value.

Syntax:

{
  "request": {
    ...
    "bodyPatterns" : [ {
      "equalToJson" : { "name": "Lazyroar" }
    } ]
    ...
  },
  ...
}

4. XML Equality

It will be a match if the attribute value is valid XML and is semantically equal to the expected XML document.

Syntax:

{
  "request": {
    ...
    "bodyPatterns" : [ {
      "equalToXml" : "<thing>Lazyroar</thing>"
    } ]
    ...
  },
  ...
}

5. Basic Authentication Matching 

In WireMock, you can also match on HTTP basic authentication. 

Syntax:

{
    "request": {
        "method": "GET",
        "url": "/basic-auth",
        "basicAuth": {
            "username": "your user name",
            "password": "your password"
        }
    },
    "response": {
        "status": 200
    }
}