Check if XML Element Exists in Swift

Question

I need to check if an element exists in my XML that's retrieved from calling a web service. I need to run a certain function if a particular element does not exist.

Here is what I have so far. This works if all of these elements are there. I need to make sure the "MembershipNumber" element exists.

func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String]) {

    attributes = attributeDict as NSDictionary

    element = elementName
    if ((elementName as NSString).isEqual(to: "MembershipInfo")) {
        paidYear = ""
        county = ""
        name = ""
        dueDateString = ""
        membershipNumber = ""
    }
}

func parser(_ parser: XMLParser, foundCharacters string: String) {
    if element == "MembershipNumber" {
        membershipNumber.append(string)
        print("NUMBER: \(membershipNumber)")
    }
    if element == "County" {
        let counties = Counties().counties
        county.append(counties[string]!)
        print("COUNTY: \(county)")
    }

    if element == "PaidYear" {
        paidYear.append(string)
        print("PAID YEAR: \(paidYear)")
    }

    if element == "DueDate" {
        dueDateString.append(string)
        print("Due Date: \(dueDateString)")
    }

    if element == "Name" {
        if name == "" {
            name.append(string)
            print("NAME: \(name)")
        }
    }
}

Answer 1

Store the names of all elements inside didStartElement in an array until this method called

 optional func parserDidEndDocument(_ parser: XMLParser)

then check the array content for that element name

Answer 2

You can do nice XML parsing with Fuzi.

Get XML document from XML string:

guard let xml = try? XMLDocument(string: xmlString) else {
    return
}

Get XML element with XPath if it exists:

guard let membershipNumber = xml.firstChild(xpath: "/MembershipNumber") else {
    return
}