Skip to main content

Regular Expression extractor and JMeter

When using JMeter for performance testing of RESTful services, you may come across situations when you have to extract response from one request and pass it on to another request. This can be accomplished using regular expression extractor. 

This post illustrates an example of extracting parameter from json expression without using any JMeter plugin. The drawback of using plugin is that you would have to make it available on each JMeter installation where you want to run the test.

Let's consider following JSON expression - 

{ 
   "access_token":"18b8b379-b875-467a-9f22-37b60024c1b9",
   "uid":"test user",
   "grant_type":"password",
   "scope":[  
      "uid",
      "cn"
   ],
   "realm":"employees",
   "cn":"",
   "token_type":"Bearer",
   "expires_in":3599
}

Let's assume that we want to fetch value of access_token from this expression.
Then following regular expression can be used - 

"access_token":"(.+?)"

Let's look at these special characters one by one -

1 opening and closing parenthesis () enclose the portion of matched string to be returned
2 . means match any character
3 + means one or more times
4 ? means stop when first match occurs

without ?, the .+ would continue beyond first quotation " until it finds last quotation " and indeed this is not what we want.

For this specific example it is more efficient to use following expression - 
"access_token":"([^"]+)"
Herein [^"] means match everything except "
And matcher stops as soon as it finds first quotation "

Did you know that you can also test regular expression from with in JMeter? Run your test with 1 user and open results in ViewResultsInTree listener. ViewResultsInTree listener has a drop down to show results in different views. Select RegExpTester, paste your regular expression and hit Test button :-)
Labels:

Comments

Post a Comment

Popular posts from this blog

SSO with SAML login scenario in JMeter

SAML(Security Assertion Markup Language) is increasingly being used to perform single sign-on(SSO) operations. As WikiPedia puts it, SAML is an XML-based open standard data format for exchanging authentication and authorization data between parties, in particular, between an identity provider and a service provider. With the rise in use of SAML in web applications, we may need to handle this in JMeter. This step-by-step tutorial shows SAML JMeter scenario to perform login operation. First request from JMeter is a GET request to fetch Login page. We need to fetch two values ‘SAMLRequest’ and ‘RelayState’ from the Login page response data. We can do this by using  Regular Expression Extractor . These two values need to be sent in POST request to service provider. Refer below image to see how to do this. We will get an HTML login page as a response to the request sent in 1st step. We need to fetch values of some hidden elements to pass it in the next request. We can do this b
Post a Comment
Read more

VBScript Code - Function to convert CSV file into excel and viceversa in QTP using VBScript

We at times are required to convert excel files into csv to read as flat files and sometime require to convert a csv file into excel file to use excel features on the data.   Below function shows how to convert an csv file into excel file and vice versa. We can also convert to other formats based on constants Here constant value 23 is used to create a csv file and constant -4143 to save a file as xls file. Once the destination file is created, we can delete the source file as shown below.  In case of any issue in understanding the code, please add in comment section Call func_ConversionCSVExcel("E:\Test.csv", "E:\Test_converted.xls", "csvtoexcel") Public Function func_ConversionCSVExcel(strSrcFile, strDestFile, Conversion) on error resume next Set objExcel = CreateObject("Excel.application") set objExcelBook = objExcel.Workbooks.Open(strSrcFile) objExcel.application.visible=false objExcel.application.displayalerts=
Post a Comment
Read more

Reading data from text file in SoapUI using groovy script

How to read data from text file in SoapUI. SoapUI Pro has some advance feature which is not in SaopUI as data fetching from external sources so in SoapUI we use Groovy script for that. Following are the peace of groovy script code for reading data from text file. 1. Reading all data from text file. //reading all txt file at once File file = new File("E://TestData.txt") fileContent = file.getText()                  log.info fileContent 2. Reading data line by line from text file. //reading text line by line File file1 = new File(" E://TestData.txt ") List textLine = file1.readLines() log.info textLine 3. Reading data randomly of any line from text file. //reading text randon line number File file2 = new File(" E://TestData.txt ") List textLine2 = file2.readLines() rowIndex  =  Math.abs(new Random().nextInt() % 4 + 1) log.info textLine2[rowIndex]
Post a Comment
Read more