JMeter - Processing and handling JSON responses using BSF post processors

In one of my Jmeter posts I talked about how to post JSON data using a HttpSampler.
Now I want to show some cool stuff we can do using Jmeter's javascript/BSF support for handling JSON responses.

Suppose we have the following JSON response:

{ success: true, data:[ 1,2,3,4,5 ]  }

This string can be easily converted to a javascript object by using the eval function like this:

eval( 'var myObj = ' + prev.getResponseDataAsString() )

After the evaluation we can use the variable "myObj" as we wish and do things like accessing the success property:

log.info(myObj.success)

Or iterate over the list in the data property:

for (  var i = 0;  i < myObj.data.length; i++ ) {
     log.info(myObj.data[i])
}

We can also put the object in the implicit vars object so it can be used in another sampler, for example:

vars.putObject('myObj', myObj)

Generating CSV files using sqlcmd and groovy

Just sharing a simple groovy script I wrote for generating a CSV file from the database.
It depends on SQLServer's sqlcmd command line utility.
It takes 4 input parameters - needed to open a database connection, scans the current directory for .sql files then executes each of them using sqlcmd generating a .temp file. The temp file is then processed - the first and last 2 lines are removed - and renamed to a .csv file.

def username = args[0]
def password = args[1]
def host = args[2]
def database = args[3]
def dir = './'

def ant = new AntBuilder()
def p = ~/.*\.sql/
new File( dir ).eachFileMatch(p) { f ->

    def sqlFile = f.name
    def tempCsvFile = sqlFile.replaceAll(/.sql/,'')

    def cmd = "sqlcmd -S $host -U $username -P $password -d ${database} -i ${sqlFile} -W  -o ${tempCsvFile}.temp -s ;"
    def process = cmd.execute()
    process.waitFor()

    ant.move(file: "${tempCsvFile}.temp", tofile:"${tempCsvFile}.csv", overwrite: true ) {
 filterchain(){
  headfilter(lines:"-1", skip: "2")
  tailfilter(lines: "-1", skip: "2" )
  ignoreblank()
 }
    }
}

This could probably be achieved in many other ways.
But it worked like a charm for me!!

JMeter - POSTing / Sending JSON data

• Processing and handling JSON responses using BSF post processors
• Using BSF Assertion to fail samples based on JSON response
• Changing sample label/name at runtime

Recently I was load testing a RESTful mobile API where all the transmitted data were encoded as JSON. It took me some time to figure out how to simulate that in JMeter using a regular HTTPRequest sampler so I decided to share it with others.

NOTE: I successfuly used this technique for webservices exposed by the Jersey library as well as ASP.NET asmx webservices

It's quite simple. Assuming you need to send POST request to the /login URI passing two parameters: email and password encoded as JSON, like this:

{ email: 'myemail@email.com', password: 'mypassword' }

Just follow two basic steps:

Step 1 - Setting the "ContentType" http header attribute to "application/json"

• Add an HTTP Header Manager to your test plan;
• Add a new attribute: set name to "Content-Type" and value to "application/json"

Step 2 - Setting the JSON object as an unnamed http request parameter

• Add a HttpRequest sampler
• Add a new parameter, leave the name blank and set the value to the JSON string:  { 'email': 'myemail@email.com', 'password': 'mypassword' }

And last but not least: you can use variables and properties as you wish in the JSON string. Suppose you have a CSV Data Set Config which defines to external variables: email e pwd. You could use them in your sampler like this:

{ email: '${email}', password: '${pwd}' }