CODEWITHSUNDEEP
javajavascripthtmlxpathselenium-webdriver
star95
star95

Reputation: 111

Selenium 2 : finding web element locators programmatically

I am tired of manually finding locators (id,xpath,css,linkText etc..) for web elements from my web page source. It also consumes more efforts. So, to avoid that I want to write a code that interacts with page source directly and generates locators details (e.g. id="xyz" , xpath ="html/body/table/tr/td/a" etc.) To achieve this ,I think I can generate ID locator by using split() function of String object. But, what I don't know is how to generate xpaths, css and linkText locators for all page components?

Upvotes: 1

Views: 3879

Answers (2)

David Lovering
David Lovering

Reputation: 11

There are (at present) no "tools" that do even a marginally decent job of synthesizing reliable and concise xpath or css based locators. I've been writing selenium and HTML/CSS code for nearly the duration of the industry, and the so-called CASE-methods that purport to do this job better than humans produces laughably flawed output more often that it generates useful material. However, I would add a codicil: there is hope.

By taking careful stock of the various XPath and CSS methods (see http://www.w3schools.com/xpath/xpath_axes.asp for some general guidelines) and using only the most minimal locator strings that will pass muster in Firebug, Selenium IDE and other similar plug-ins, one can progress gradually towards a better approach. In general one should (where possible) use only one component from an object's attribute list and avoid using dynamically defined quantities. Best practices would encourage picking class, name or id only if they are "immutable".

Mutability is a tricky issue: simply dragging a cursor over an object or clicking on it may change the class or css characteristics. Sometimes this can be surmounted by using only the "fixed" portion of the offending attribute. For example, a class might initially be 'tabContent', but when the cursor is placed over the corresponding object it might change to 'tabContentMouseOver'. You get the idea. By using an xpath locator string //*[contains(@class,'tabContent')] you stand a better than even chance of hitting the desired object, irrespective of whether it is clicked, highlighted, or even disabled.

The next "trick" I'd encourage you to consider is using the "buddy" principle; many objects (button-like ones in particular) nowadays consist of an image with no dynamic properties wrapped by a div that manages its event-driven behavior. For such situations you might find that //div[@eventproxy='tabObject']/following::img[contains(@src,'tabImage') and text()='Contents'] or something similar will cover all the bases. Contents will vary with your situation of course.

Make vigorous use of the hierarchical axes methods ('following' is one I use quite often), but only where necessary; sometimes '//' will suffice instead.

Penalize yourself for every unnecessary character, and reward yourself for methods which are concise and can weather frequent and severe code changes. Above all, persevere.

In general I avoid using "pure" CSS locators for the following reason -- they were never intended as locators. "Cascading Style Sheets" by their very nature are designed to impact the maximum number of web objects possible, and are very rarely unique to any one piece of content. Web-coders are notorious for changing these on the fly to produce spiffy new effects or restructure content to suit customer demands; why hitch your tests to content that is known to fluctuate? Besides, everything CSS can do (and I do mean EVERYTHING) can also be done inside XPaths if you so choose.

The canard about XPaths being "slower" than CSS methods I believe has been disproved often enough that it should be taken with several tablespoons of salt. Still, if you really feel more comfortable with CSS techniques, go for it! Experience will educate you better than any blurb you find in stackoverflow ever will.

Upvotes: 1

Jens Erat
Jens Erat

Reputation: 38732

Although I'd generally recommend to construct XPath expressions on your own (as you can better exploit things to mach against like class attributes), probably the most reasonable and convenient automatic way to determine XPath expressions for selenium is to use either Firebug's or Chrome Developer Tool's "Find XPath" feature. They both at least use @id attributes to shorten XPath expressions.

If you want to write some code yourself, eg. for embedding in other tools you use, you might want to have a look at the answers of "PHP XML - Find out the path to a known value" which solves the problem in PHP, or another one with answers for Javascript: "Javascript get XPath of a node".

If you're using any tools not working on the DOM (Selenium/Firebug/Chrome Dev' Tools/JavaScript will do), watch out for the problems I described in "Why does my XPath query (scraping HTML tables) only work in Firebug, but not the application I'm developing?".

Upvotes: 1

Related Questions