Go-Html-Utils
Some utility functions I use for querying DOM elements which are represented as *html.Node objects.
Main Features:
- getting nodes by condition (with multiple variations)
- getting attributes of nodes
- parsing a html node representing a html <table> element into a golang struct
- parsing a html node representing a html <select> element into a golang map[string]string
Examples:
Retrieving the htmlNode
log.Printf("GET: '%s'\n", someUrl.String())
res, err := http.DefaultClient.Get(someUrl)
if err != nil {
return err
}
defer res.Body.Close()
if res.StatusCode != http.StatusOK {
return errors.New(fmt.Sprintf("Got status code '%v', expected '%v'.", res.StatusCode, http.StatusOK))
}
htmlNode, err = html.Parse(res.Body)
if err != nil {
return err
}
Running queries:
Get all <div> elements
divs := GetNodesByCondition(htmlNode, MakeByTagNameCondition("div"))
if len(divs) == 0 {
return errors.New("no divs found")
}
Get all elements containing the class name ‘button’
buttons := GetNodesByCondition(htmlNode, MakeByClassNameCondition("button"))
if len(divs) == 0 {
return errors.New("no elements of class 'button' found")
}
Get first element that has attribute ‘name’ with value ‘Datum’
datum := GetNodeByCondition(htmlNode, MakeByAttributeNameAndValueCondition("name", "Datum"))
if datum == nil {
return errors.New("no element with attribute:value that is 'name':'Datum' found")
}
Combining conditions
Get first element with class name ‘clickable’ that has as tag ‘button’.
element := GetNodeByCondition(htmlNode, func(node *html.Node) bool {
return MakeByClassNameCondition('clickable')(node) && MakeByTagNameCondition('button')(node)
})
Parsing html <table> elements
table := GetNodeByCondition(htmlNode, MakeByTagNameCondition("table"))
htmlTable, err := ParseHtmlTable(table, true, true, "")
dates, columnIndex, found := htmlTable.GetColumnByKey("Datum")
Parsing html <select> elements
selectElement := GetNodeByCondition(htmlNode, MakeByTagNameCondition("select"))
availableOptions, currentlySelectedOption, err := ParseSelectHTMLNode(selectElement)
log.Printf("currently selected option has text content '%s' and option value '%s'\n", currentlySelectedOption, availableOptions[currentlySelectedOption])