New selectors with Canopy 0.7.3

New version of canopy has been released today. This version includes an improved set of selectors:

Relative selectors.

New functions elementWithin and elementsWithin provide an ability to select element/elements in DOM sub-tree:

elementWithin  : (string -> IWebElement -> IWebElement)
elementsWithin : (string -> ISearchContext -> IWebElement list)

You are able to write more complex page parsing code, for example like this:

elements "#div.section-item"
|> el ->
    let name = (el |> elementWithin "h2").Text
    let items = el |> elementsWithin "li a"
                   |> (fun a -> a.GetAttribute("href"))
    name, items)

XPath support.

From now, all selectors support XPath. There was also introduced new parent selector that returns parent web element.

parent : (IWebElement -> IWebElement)
"/some/xpath/query" << "some value"
"/some/xpath/query" == "some value"
let results = elements "xpath/query"

Options selectors.

Three new options selectors were added: someElement, someElementWithin, someParent. All the selectors behave in the following way:

  • Return Some(element) if exactly one element match to the selector
  • Return None if there is no such elements
  • Throw an exception in other cases.
someElement : (string -> IWebElement option)
someElementWithin : (string -> ISearchContext -> IWebElement option)
someParent : (ISearchContext -> IWebElement option)

With these selectors you can use all power of F# Options type:

let currentUser =
    someElement "#profile a"
    |> Option.bind (fun el -> el |> parent |> Some)
    |> Option.bind (fun el -> el |> getHref |> getParamFromUrl "id" |> Some)
    |> Option.bind (fun id -> Person(id) |> Some)

Feel free to try it in action!

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