Querying, scraping, and parsing of HTML. Good for snapshot testing too!
This package supports the Gleam Erlang target.
gleam add presentable_soup@1import presentable_soup as soup
pub fn main() -> Nil {
// You've got some HTML. Maybe this is downloaded from a website, or it's
// generated in your tests. Anything is fine.
let document = "
<!doctype html>
<head>
<title>Presentable Soup Webpage</title>
</head>
<body>
<h1 id=\"title\">Presentable Soup</h1>
<p>Is it good? Yes I think it might be!</p>
<aside>
<p>Low memory use even for large documents.</p>
</aside>
</body>
</html>
"
// Construct a query, which is a description of what elements to match,
// similar to a CSS selector.
//
// The `element` function matches a single element where all the items in the
// list match. This is a query for a `h1` element with the id `"title"`.
let query = soup.element([
soup.tag("h1"),
soup.id("title"),
])
// The `find` function can be used to find a single element in the document
// that matches the query.
echo soup.find(in: document, matching: query)
// -> Ok(soup.Element([#("id", "title")], [soup.Text("Presentable Soup")]))
// The `find_all` function call be used to find all the elements the match
// the query.
echo soup.find_all(in: document, matching: soup.element([soup.tag("p")]))
// -> Ok([
// soup.Element([], [soup.Text("Is it good? Yes I think it might be!")]),
// soup.Element([], [soup.Text("Low memory use even for large documents.")]),
// ])
// The `descendant` function can be used to make a more complex query that
// matches elements within some other element.
// This query matches any `p` element that is within an `aside` element.
let query =
soup.element([soup.tag("aside")])
|> soup.descendant([soup.tag("p")])
echo soup.find_all(in: document, matching: query)
// -> Ok([
// soup.Element([], [soup.Text("Low memory use even for large documents."),
// ]))
}
// The returned elements can be rendered as HTML. This is especially useful
// for snapshot testing!
// Don't test your generated HTML by looking for sub-strings, instead query
// for the parts of the page that matter for each test and then snapshot it
// with a library like Giacomo Cavalieri's Birdie.
pub fn contact_page_test() {
let webpage = my_app.handle_request("/contact")
// Query the page. In this test I want to focus on the contact form.
let query = soup.element([soup.tag("form"), soup.class("contact-form")])
let assert Ok(found) = soup.find_all(webpage, query) as "html must be valid"
// Render the matched HTML, create a descriptive snapshot string, and
// snapshot it!
let snapshot =
"Contact page `form` with class `contact-form`\n\n"
<> soup.elements_to_string(found)
birdie.snap("contact page form", snapshop)
}Further documentation can be found at https://hexdocs.pm/presentable_soup.
