Simple XML Parser implemented in Swift

What’s this?

This is a XML parser inspired by SwiftyJSON and SWXMLHash.

NSXMLParser in Foundation framework is a kind of “SAX” parser. It has enough performance but is a little inconvenient. So we have implemented “DOM” parser wrapping it.

Feature

• [x] access XML Document with “subscript”.
• [x] access XML Document as Sequence.
• [x] easy debugging XML pathes.

Requirement

• iOS 9.0+
• tvOS 9.0+
• macOS 10.10+
• Swift 5.0

Installation

Carthage

1. create Cartfile

github "https://github.com/yahoojapan/SwiftyXMLParser"

2. install

> carthage update

CocoaPods

1. create Podfile

platform :ios, '9.0'
use_frameworks!

pod "SwiftyXMLParser", :git => 'https://github.com/yahoojapan/SwiftyXMLParser.git'

2. install

> pod install

Example

import SwiftyXMLParser

let str = """
<ResultSet>
    <Result>
        <Hit index=\"1\">
            <Name>Item1</Name>
        </Hit>
        <Hit index=\"2\">
            <Name>Item2</Name>
        </Hit>
    </Result>
</ResultSet>
"""

// parse xml document
let xml = try! XML.parse(str)

// access xml element
let accessor = xml["ResultSet"]

// access XML Text

if let text = xml["ResultSet", "Result", "Hit", 0, "Name"].text {
    print(text)
}

if let text = xml.ResultSet.Result.Hit[0].Name.text {
    print(text)
}

// access XML Attribute
if let index = xml["ResultSet", "Result", "Hit", 0].attributes["index"] {
    print(index)
}

// enumerate child Elements in the parent Element
for hit in xml["ResultSet", "Result", "Hit"] {
    print(hit)
}

// check if the XML path is wrong
if case .failure(let error) =  xml["ResultSet", "Result", "TypoKey"] {
    print(error)
}

Usage

1. Parse XML

• from String

let str = """
<ResultSet>
    <Result>
        <Hit index=\"1\">
            <Name>Item1</Name>
        </Hit>
        <Hit index=\"2\">
            <Name>Item2</Name>
        </Hit>
    </Result>
</ResultSet>
"""

xml = try! XML.parse(str) // -> XML.Accessor

• from NSData

let str = """
<ResultSet>
    <Result>
        <Hit index=\"1\">
            <Name>Item1</Name>
        </Hit>
        <Hit index=\"2\">
            <Name>Item2</Name>
        </Hit>
    </Result>
</ResultSet>
"""

let string = String(decoding: data, as: UTF8.self)

xml = XML.parse(data) // -> XML.Accessor

• with invalid character

let srt = "<xmlopening>@ß123\u{1c}</xmlopening>"

let xml = XML.parse(str.data(using: .utf8))

if case .failure(XMLError.interruptedParseError) = xml {
  print("invalid character")
}

For more, see https://developer.apple.com/documentation/foundation/xmlparser/errorcode

2. Access child Elements

let element = xml.ResultSet // -> XML.Accessor

3. Access grandchild Elements

• with String

let element = xml["ResultSet"]["Result"] // -> <Result><Hit index=\"1\"><Name>Item1</Name></Hit><Hit index=\"2\"><Name>Item2</Name></Hit></Result>

• with Array

let path = ["ResultSet", "Result"]
let element = xml[path] // -> <Result><Hit index=\"1\"><Name>Item1</Name></Hit><Hit index=\"2\"><Name>Item2</Name></Hit></Result>

• with Variadic

let element = xml["ResultSet", "Result"] // -> <Result><Hit index=\"1\"><Name>Item1</Name></Hit><Hit index=\"2\"><Name>Item2</Name></Hit></Result>

• with @dynamicMemberLookup

let element = xml.ResultSet.Result // -> <Result><Hit index=\"1\"><Name>Item1</Name></Hit><Hit index=\"2\"><Name>Item2</Name></Hit></Result>

4. Access specific grandchild Element

let element = xml.ResultSet.Result.Hit[1] // -> <Hit index=\"2\"><Name>Item2</Name></Hit>

5. Access attribute in Element

if let attributeValue = xml.ResultSet.Result.Hit[1].attributes?["index"] {
  print(attributeValue) // -> 2
}

6. Access text in Element

• with optional binding

if let text = xml.ResultSet.Result.Hit[1].Name.text {
    print(text) // -> Item2
} 

• with custom operation

struct Entity {
  var name = ""
}
let entity = Entity()
entity.name ?= xml.ResultSet.Result.Hit[1].Name.text // assign if it has text

• convert Int and assign

struct Entity {
  var name: Int = 0
}
let entity = Entity()
entity.name ?= xml.ResultSet.Result.Hit[1].Name.int // assign if it has Int

and there are other syntax sugers, bool, url and double.

• assign text into Array

struct Entity {
  var names = [String]()
}
let entity = Entity()
entity.names ?<< xml.ResultSet.Result.Hit[1].Name.text // assign if it has text

7. Access CDATA

let str = """
<Data name="DATE">
    <value><![CDATA[2018-07-08]]></value>
</Data>
"""

// parse xml document
let xml = try! XML.parse(str)
        
if let cdata = xml.Data.value.element?.CDATA, 
   let cdataStr = String(data: cdata, encoding: .utf8) {
   print(cdataStr) // -> "2018-07-08"
}

7. Count child Elements

let numberOfHits = xml.ResultSet.Result.Hit.all?.count 

8. Check error

print(xml.ResultSet.Result.TypoKey) // -> "TypoKey not found."

9. Access as SequenceType

• for-in

for element in xml.ResultSet.Result.Hit {
  print(element.text)
}

• map

xml.ResultSet.Result.Hit.map { $0.Name.text }

10. Generate XML document

print(Converter(xml.ResultSet).makeDocument())

Work with Alamofire

SwiftyXMLParser goes well with Alamofire. You can parse the response easily.

import Alamofire
import SwiftyXMLParser

Alamofire.request(.GET, "https://itunes.apple.com/us/rss/topgrossingapplications/limit=10/xml")
         .responseData { response in
            if let data = response.data {
                let xml = XML.parse(data)
                print(xml.feed.entry[0].title.text) // outputs the top title of iTunes app raning.
            }
        }

In addition, there is the extension of Alamofire to combine with SwiftyXMLParser.

• Alamofire-SwiftyXMLParser

Migration Guide

Current master branch is supporting Xcode10.
If you wanna use this library with legacy swift version, read release notes and install the last compatible version.

License

This software is released under the MIT License, see LICENSE.