Why does the following Regex extractor of JMeter always returning the default value?

Question

Following the Response data for a request.

<li><a href="xyzw.do?ab=1111111111110&amp;method=abcde&amp;maintab=D&_UID_=111Y-T00O-U00U-PCDE-ZA7C-QQ99-0I00-0550" target="_top">
                    Letter</a>

Following is my regex extractor values

reference name : val
regular expression : <li><a href="abcde.do?ab=(.+?)
Template : $1$
match : -1
default value : error

I want the value of ab to be extracted. In this case 1111111111110

I tried the following:

Changed (.+?) to (.+), (\d+) etc.
Changed -1 as 0

Above attempts doesn't give any fruitful output. I always see 'error' assigned to 'val'

Additional info: There are several <li></li> blocks like this, but there is only one <li></li> block that has xyzw.do in it.

I want the value 1111111111110 to be extracted. This value changes for each user. — sofs1, Mar 23 '15 at 21:47
can you give another example ? will there be `?ab=` always before the value you want to extract ? — apgp88, Mar 23 '15 at 21:48

score 0 · Answer 1 · edited May 23 '17 at 12:28

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Parsing HTML with regex is not the best idea: Using regular expressions to parse HTML: why not?

In addition to HTML parsing troubles, this won't handle another order of parameters, eg: xyzw.do?method=abcde&ab=1111111111110&maintab=D&_UID_=111Y-T00O-U00U-PCDE-ZA7C-QQ99-0I00-0550 won't match. Trying to handle this without doing actual HTML parsing first will lead you to a never-ending pit of screen scraping despair.

Your regex <li><a href="abcde.do?ab=(.+?) has some special characters that need to be escaped: it is saying "e followed by any character", and it also saying the "o" is optional (so abcde.doab= would match, as would abcdeXdab= -- but a including a question mark would cause it to fail).

The .+ also means it will match the remainder of the string. the ? greedy modifier after the + is irrelevant since there's no following pattern to end matching.

Working regex: <a href="xyzw\.do\?ab=(\d+)

See https://regex101.com/r/qW1iF7/1

edited May 23 '17 at 12:28

Community

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answered Mar 23 '15 at 21:52

gregmac

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This one doesn't work either. I read somewhere online that JMeter uses Perl type regex. But I see you have chosen PHP in the link. Would that be causing any issue? – sofs1 Mar 23 '15 at 22:02
I chose Perl-compatible regex (PCRE). I know nothing about JMeter. Apparently it uses [OROMatcher](https://www.savarese.org/oro/docs/OROMatcher/Syntax.html#Perl5Expressions). You could try `[0-9]` instead of `\d` .. otherwise, follow the usual regex debug exercise: pare back the regex until it works (even if it's not what you want, eg just `[0-9]+`), then slowly build back up. – gregmac Mar 23 '15 at 22:07
Hi, What would be regex like,if I want the value of href to be set for the variable val. "xyzw.do?ab=1111111111110&method=abcde&maintab=D&_UID_=111Y-T00O-U00U-PCDE-ZA7C-QQ99-0I00-0550" Remember, there are several other

sofs1

Mar 23 '15 at 22:55

score 0 · Answer 2 · answered Mar 23 '15 at 21:53

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This regex should work in this case,

\?ab=(\d+)

Regex101 Demo

It uses the concept of group capture

answered Mar 23 '15 at 21:53

apgp88

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He's already using a capturing group; that's what the `1` refers to in the template expression (`$1$`). The problem is that it isn't capturing anything. – Alan Moore Mar 23 '15 at 22:16
Yeah. I tried to extract someother simple regex, but for that also it return the default value. – sofs1 Mar 23 '15 at 22:32
Hi, What would be regex like,if I want the value of href to be set for the variable val. "xyzw.do?ab=1111111111110&method=abcde&maintab=D&_UID_=111Y-T00O-U00U-PCDE-ZA7C-QQ99-0I00-0550" Remember, there are several other

sofs1

Mar 23 '15 at 22:56

score 0 · Answer 3 · answered Mar 24 '15 at 06:50

It should be as simple as follows:

Reference name: val
Regular Expression: ab=(.+?)&
Template: $1$

You can use View Results Tree listener for testing your regular expressions against the response:

Regex Tester

See How to debug your Apache JMeter script guide for more details on getting to the bottom of any problems with test design or execution.

Why does the following Regex extractor of JMeter always returning the default value?

3 Answers3