The application uses URL containing dynamic parameters and so a record/replay fails
http://www.mail-archive.com/jmeter-user@jakarta.apache.org/msg30317.html
Solution
This short tutorial deals with test scripts that interact with dynamic data, and we will choose a Spring Webflow example to write a test script against.
So we look around on Google for a sample Spring Webflow application which leads us to
Spring By Example Sample
I'm not going to use the JMeter Proxy Recorder because it seems to harm beginners more than it helps. Testers seem to get the impression that all they need to do is record and replay the script and they are done. So I shall use Firefox and LiveHttpHeaders. We are going to Login to the site and create a User
Step 1: Request the Login Page
http://www.springbyexample.org/simple-webflow/login.jsp
GET /simple-webflow/login.jsp HTTP/1.1
Response
HTTP/1.1 200 OK
Set-Cookie: JSESSIONID=[uniquevalue1]; Path=/simple-webflow
So the first request response shows that the system sets a cookie and the name should tell us that this is a session id. [TODO]. This should also indicate to us that we need to add a cookie manager. Note the status is 200 in the Response. This is the server telling us all is well.
Step 2: Submit Login
http://www.springbyexample.org/simple-webflow/loginProcess;jsessionid=[uniquevalue1]
POST /simple-webflow/loginProcess;jsessionid=[uniquevalue1]
HTTP/1.1
Cookie: JSESSIONID=[uniquevalue1]
Content-Type: application/x-www-form-urlencoded
Content-Length: 48
j_username=david&j_password=newyork&submit=Login
Response
HTTP/1.1 302 Moved Temporarily
Date: Tue, 17 Aug 2010 05:03:48 GMT
Set-Cookie: JSESSIONID=[uniquevalue2]; Path=/simple-webflow
Location: http://www.springbyexample.org/simple-webflow/index.jsp
----------------------------------------------------------
http://www.springbyexample.org/simple-webflow/index.jsp
GET /simple-webflow/index.jsp HTTP/1.1
Cookie: JSESSIONID=[uniquevalue2]
HTTP/1.1 302 Moved Temporarily
Location: http://www.springbyexample.org/simple-webflow/index.html
----------------------------------------------------------
http://www.springbyexample.org/simple-webflow/index.html
GET /simple-webflow/index.html HTTP/1.1
Cookie: JSESSIONID=[uniquevalue2]
HTTP/1.1 200 OK
a. The browser sends back the cookie that was previously set. However note that the URL also has a jsessionid which has the same value as the cookie that was set. This is known as URL rewriting. Our test will ignore this value because we will be using a Cookie manager
b. The server sends a 302 response to the request. This basically asks the browser to request a new URL (the one that the Location Response Header has). Note this can happen more than once as the next request too results in a 302 response, which finally results in a 200 status code.
HTTP Status Codes are discussed here
c. The server also sends a Set-Cookie for JSessionID again with a new value. This is usually done for security reasons. We can ignore this for JMeter because the Cookie manager will handle this for us. However the sampler that we use needs to have follow redirects set. If redirect automatically is set , JMeter would not get to see this Set-Cookie header and since the application has switched the session id , if you sent it the old session id (which was associated to the before login session)
Click the Create Link
http://www.springbyexample.org/simple-webflow/person.html
GET /simple-webflow/person.html HTTP/1.1
Cookie: JSESSIONID=[uniquevalue2]
Response
HTTP/1.1 302 Moved Temporarily
Location: http://www.springbyexample.org/simple-webflow/person.html?execution=e1s1
----------------------------------------------------------
http://www.springbyexample.org/simple-webflow/person.html?execution=e1s1
GET /simple-webflow/person.html?execution=e2s1 HTTP/1.1
Cookie: JSESSIONID=[uniquevalue2]
HTTP/1.1 200 OK
Date: Tue, 17 Aug 2010 05:06:04 GMT
Clicking the Create link also resulted in a 302 code so the browser issued a new request. But take a look at the URL. It has a parameter named execution with a value e1s1. Now click the link again.
Click Create link again
http://www.springbyexample.org/simple-webflow/person.html
GET /simple-webflow/person.html HTTP/1.1
Cookie: JSESSIONID=[uniquevalue2]
Response
HTTP/1.1 302 Moved Temporarily
Location: http://www.springbyexample.org/simple-webflow/person.html?execution=e2s1
----------------------------------------------------------
http://www.springbyexample.org/simple-webflow/person.html?execution=e2s1
GET /simple-webflow/person.html?execution=e2s1 HTTP/1.1
Cookie: JSESSIONID=[uniquevalue2]
HTTP/1.1 200 OK
The "execution" parameter value changes! So if you run the same test multiple times , the value has to be different. This is a common cause of failure of Record / Replay tests. Some of the data is dynamic. This data can be of various forms
a. Something the application framework needs
b. Something where the data varies (E.g. the UserId, the Product ID). Typically a user friendly string is shown on the screen but when the user performs an action , an id (usually a key in the database) is what is used by the application
c. Dynamic fields (E.g. DHTML based applications) which get added on the fly.
To deal with this parameter/URL we need to be able to extract the value from previous requests in our JMeter scripts.
If you haven't developed the application it may be difficult to identify whats dynamic and whats not. The easy way is to record the script twice(With different data) and observe what changes. e.g. if you browse a product catalog , change the product.
Submit the form
http://www.springbyexample.org/simple-webflow/person.html?execution=e2s1
POST /simple-webflow/person.html?execution=e2s1
HTTP/1.1
Cookie: JSESSIONID=[uniquevalue2]
Content-Length: 56
id=&firstName=deepak&lastName=shetty&_eventId_save=Save
Response
HTTP/1.1 302 Moved Temporarily
Location: http://www.springbyexample.org/simple-webflow/person/search.html
----------------------------------------------------------
http://www.springbyexample.org/simple-webflow/person/search.html
GET /simple-webflow/person/search.html HTTP/1.1
Cookie: JSESSIONID=[uniquevalue2]
HTTP/1.1 200 OK
Unfortunately the application has a visual bug, the added user does not show. However if you do a view source on the page and search for the username you created you can find it.
Click Logout
http://www.springbyexample.org/simple-webflow/logout
GET /simple-webflow/logout HTTP/1.1
Cookie: JSESSIONID=[uniquevalue2]
Response
HTTP/1.1 302 Moved Temporarily
Set-Cookie: SPRING_SECURITY_REMEMBER_ME_COOKIE=""; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/simple-webflow
Location: http://www.springbyexample.org/simple-webflow/logoutSuccess.jsp
----------------------------------------------------------
http://www.springbyexample.org/simple-webflow/logoutSuccess.jsp
GET /simple-webflow/logoutSuccess.jsp HTTP/1.1
Cookie: JSESSIONID=[uniquevalue2]
HTTP/1.1 200 OK
Set-Cookie: JSESSIONID=[uniquevalue3]; Path=/simple-webflow
The JMeter Script
Now that we know the above we can get to writing the script
Most of the script is pretty much standard(All Samplers use follow redirects and we have added a Cookie Manager), till we get to the point where we need to extract out the URL.
The Request Create Sampler extracts out the URL. Since we know that the application is going to redirect us , the extracter will extract out the last URL we will be on
The Post Create Data Sampler simply uses this extracted URL
Note that all samplers have assertions that verify the behavior, so if something goes wrong the Assertion should fail. For e.g. after creating the user we verify that the user we created exists on the page. When requesting a page the assertions verify some text on the page that is unique to the page.
Run the test, we get no errors! Modify the ThreadGroup to have two threads and two iterations. Run the test , everything should pass. Now look at the View Results Tree listener. You should see the redirects being followed (multiple children results under a parent). But do you see different values for the execution parameter? No - This is because each thread is its own session and each user will start with the same parameter value. Even having multiple iterations on the thread group doesnt give you different values because we are logging out at the end of the script so the next iteration is a new session.
Try adding a Loop controller to create 10 users. Note that the loop controller must enclose the Request Create and Post Create samplers (because we need to extract a new value for the execution parameter every time!). Using View results tree you can now observe the execution parameter changing.
Sample Script
Spring Webflow.jmx
Spring Webflow with loop.jmx
