XMLMapper

XMLMapper is a framework written in Swift that makes it easy for you to convert your model objects (classes and structs) to and from XML.

• Example
• Requirements
• Definition of the protocols
• How to use
  • Basic XML mapping
  • Advanced mapping
  • Swift 4.2 and unordered XML elements
  • Map CDATA wrapped values
  • XML Mapping example
• Requests subspec
• Communication
• Installation
• Special thanks
• License

Example

To run the example project, clone the repo, and run pod install from the Example directory first.

Requirements

• iOS 8.0+ / macOS 10.9+ / tvOS 9.0+ / watchOS 2.0+
• Xcode 9.1+
• Swift 3.1+

Definition of the protocols

XMLBaseMappable Protocol

var nodeName: String! { get set }

This property is where the name of the XML node is being mapped

mutating func mapping(map: XMLMap)

This function is where all mapping definitions should go. When parsing XML, this function is executed after successful object creation. When generating XML, it is the only function that is called on the object.

Note: This protocol should not be implemented directly. XMLMappable or XMLStaticMappable should be used instead

XMLMappable Protocol (sub protocol of XMLBaseMappable)

init?(map: XMLMap)

This failable initializer is used by XMLMapper for object creation. It can be used by developers to validate XML prior to object serialization. Returning nil within the function will prevent the mapping from occuring. You can inspect the XML stored within the XMLMap object to do your validation:

required init?(map: XMLMap) {
    // check if a required "id" element exists within the XML.
    if map.XML["id"] == nil {
        return nil
    }
}

XMLStaticMappable Protocol (sub protocol of XMLBaseMappable)

XMLStaticMappable is an alternative to XMLMappable. It provides developers with a static function that is used by XMLMapper for object initialization instead of init?(map: XMLMap).

static func objectForMapping(map: XMLMap) -> XMLBaseMappable?

XMLMapper uses this function to get objects to use for mapping. Developers should return an instance of an object that conforms to XMLBaseMappable in this function. This function can also be used to:

• validate XML prior to object serialization
• provide an existing cached object to be used for mapping
• return an object of another type (which also conforms to XMLBaseMappable) to be used for mapping. For instance, you may inspect the XML to infer the type of object that should be used for mapping

If you need to implement XMLMapper in an extension, you will need to adopt this protocol instead of XMLMappable.

How to use

To support mapping, a class or struct just needs to implement the XMLMappable protocol:

var nodeName: String! { get set }
init?(map: XMLMap)
mutating func mapping(map: XMLMap)

XMLMapper uses the <- operator to define how each property maps to and from XML:

<food>
  <name>Belgian Waffles</name>
  <price>5.95</price>
  <description>
    Two of our famous Belgian Waffles with plenty of real maple syrup
  </description>
  <calories>650</calories>
</food>

class Food: XMLMappable {
    var nodeName: String!

    var name: String!
    var price: Float!
    var description: String?
    var calories: Int?

    required init?(map: XMLMap) {}

    func mapping(map: XMLMap) {
        name <- map["name"]
        price <- map["price"]
        description <- map["description"]
        calories <- map["calories"]
    }
}

XMLMapper can map classes or structs composed of the following types:

• Int
• Bool
• Double
• Float
• String
• RawRepresentable (Enums)
• Array<Any>
• Dictionary<String, Any>
• Object<T: XMLBaseMappable>
• Array<T: XMLBaseMappable>
• Set<T: XMLBaseMappable>
• Dictionary<String, T: XMLBaseMappable>
• Dictionary<String, Array<T: XMLBaseMappable>>
• Optionals and Implicitly Unwrapped Optionals of all the above

Basic XML mapping

Convert easily an XML string to XMLMappable:

let food = Food(XMLString: xmlString)

Or an XMLMappable object to XML string:

let xmlString = food.toXMLString()

XMLMapper class can also provide the same functionality:

let food = XMLMapper<Food>().map(XMLString: xmlString)

let xmlString = XMLMapper().toXMLString(food)

Advanced mapping

Set nodeName property of your class to change the element’s name:

food.nodeName = "myFood"

<myFood>
  <name>Belgian Waffles</name>
  <price>5.95</price>
  <description>
    Two of our famous Belgian Waffles with plenty of real maple syrup
  </description>
  <calories>650</calories>
</myFood>

Map easily XML attributes using the attributes property of the XMLMap:

<food name="Belgian Waffles">
</food>

func mapping(map: XMLMap) {
    name <- map.attributes["name"]
}

Map array of elements:

<breakfast_menu>
  <food>
    <name>Belgian Waffles</name>
    <price>5.95</price>
    <description>
      Two of our famous Belgian Waffles with plenty of real maple syrup
    </description>
    <calories>650</calories>
  </food>
  <food>
    <name>Strawberry Belgian Waffles</name>
    <price>7.95</price>
    <description>
      Light Belgian waffles covered with strawberries and whipped cream
    </description>
    <calories>900</calories>
  </food>
</breakfast_menu>

func mapping(map: XMLMap) {
    foods <- map["food"]
}

Create your own custom transform type by implementing the XMLTransformType protocol:

public protocol XMLTransformType {
    associatedtype Object
    associatedtype XML

    func transformFromXML(_ value: Any?) -> Object?
    func transformToXML(_ value: Object?) -> XML?
}

and use it in mapping:

func mapping(map: XMLMap) {
    startTime <- (map["starttime"], XMLDateTransform())
}

Map nested XML elements by separating names with a dot:

<food>
  <details>
    <price>5.95</price>
  </details>
</food>

func mapping(map: XMLMap) {
    price <- map["details.price"]
}

---

Note: Nested mapping is currently supported only:

• for elements that are composed of only innerText (like the above example) and
• for attributes

This means that in order to map the actual price of the food in the following XML:

<food>
  <details>
    <price currency="euro">5.95</price>
  </details>
</food>

You need to use an XMLMappable object instead of a Float:

class Price: XMLMappable {
    var nodeName: String!

    var currency: String!
    var actualPrice: Float!

    required init?(map: XMLMap) {}

    func mapping(map: XMLMap) {
        currency <- map.attributes["currency"]
        actualPrice <- map.innerText
    }
}

Because of currency attribute existence. The same applies to the following XML:

<food>
  <details>
    <price>
      5.95
      <currency>euro</currency>
  </details>
</food>

You need to use an XMLMappable object like:

class Price: XMLMappable {
    var nodeName: String!

    var currency: String!
    var actualPrice: Float!

    required init?(map: XMLMap) {}

    func mapping(map: XMLMap) {
        currency <- map["currency"]
        actualPrice <- map.innerText
    }
}

Because of currency element existence.

---

Swift 4.2 and unordered XML elements

Starting from Swift 4.2, XML elements are highly likely to have different order each time you run your app. (This happens because they are represented by a Dictionary)

For this, since version 1.5.2 of the XMLMapper you can map and change the order of the nodes that appear inside another node using nodesOrder property of XMLMap:

class TestOrderedNodes: XMLMappable {
    var nodeName: String!

    var id: String?
    var name: String?
    var nodesOrder: [String]?

    init() {}
    required init?(map: XMLMap) {}

    func mapping(map: XMLMap) {
        id <- map["id"]
        name <- map["name"]
        nodesOrder <- map.nodesOrder
    }
}

let testOrderedNodes = TestOrderedNodes()
testOrderedNodes.id = "1"
testOrderedNodes.name = "the name"
testOrderedNodes.nodesOrder = ["id", "name"]
print(testOrderedNodes.toXMLString() ?? "nil")

Note: If you want to change the ordering of the nodes, make sure that you include, in the nodesOrder array, all the node names that you want to appear in the XML string

Map CDATA wrapped values

Since version 2.0.0 of XMLMapper, CDATA support has added. CDATA wrapped strings now are mapped as an Array<Data> by default, instead of String which was the case in the previous versions. That had as a side effect the disability to serialize CDATA wrapped values.

For example using the following code:

class Food: XMLMappable {
    var nodeName: String!
    
    var description: String?
    
    init() {}
    
    required init?(map: XMLMap) {}
        
    func mapping(map: XMLMap) {
        description <- map["description"]
    }
}

let food = Food()
food.nodeName = "Food"
food.description = "Light Belgian waffles covered with strawberries & whipped cream"
print(food.toXMLString() ?? "nil")

Your result was always:

<Food>
    <description>
        Light Belgian waffles covered with strawberries &amp; whipped cream
    </description>
</Food>

In version 2.0.0 we introduce the build in XMLCDATATransform type, which can be used like this:

class Food: XMLMappable {
    var nodeName: String!
    
    var description: String?
    
    init() {}
    
    required init?(map: XMLMap) {}
        
    func mapping(map: XMLMap) {
        description <- (map["description"], XMLCDATATransform())
    }
}

let food = Food()
food.nodeName = "Food"
food.description = "Light Belgian waffles covered with strawberries & whipped cream"
print(food.toXMLString() ?? "nil")

and the result will be:

<Food>
    <description>
        <![CDATA[
            Light Belgian waffles covered with strawberries & whipped cream
        ]]>
    </description>
</Food>

The breaking change here is that the deserialization of CDATA wrapped values cannot achieved, unless you use XMLCDATATransform type. For example if you try to map the above XML to the following model class:

class Food: XMLMappable {
    var nodeName: String!
    
    var description: String?
    
    required init?(map: XMLMap) {}
        
    func mapping(map: XMLMap) {
        description <- map["description"]
    }
}

You will end up with nil as the value of description property.

---

Note: That default behaviour can be changed if you run xmlObject(withString:encoding:options:) function of XMLSerialization yourself and pass as options the default set, including cdataAsString option.

For example, the following code will work:

class Food: XMLMappable {
    var nodeName: String!
    
    var description: String?
    
    required init?(map: XMLMap) {}
        
    func mapping(map: XMLMap) {
        description <- map["description"]
    }
}

let xmlString = """
<Food>
    <description>
        <![CDATA[
            Light Belgian waffles covered with strawberries & whipped cream
        ]]>
    </description>
</Food>
"""
let data = Data(xmlString.utf8) // Data for deserialization (from XML to object)
do {
    let xml = try XMLSerialization.xmlObject(with: data, options: [.default, .cdataAsString])
    let food = XMLMapper<Food>().map(XMLObject: xml)
} catch {
    print(error)
}

---

XML Mapping example

map XML:

 <?xml version="1.0" encoding="UTF-8"?>
 <root>
    <TestElementXMLMappable testAttribute="enumValue">
        <testString>Test string</testString>
        <testList>
            <element>
                <testInt>1</testInt>
                <testDouble>1.0</testDouble>
            </element>
            <element>
                <testInt>2</testInt>
                <testDouble>2.0</testDouble>
            </element>
            <element>
                <testInt>3</testInt>
                <testDouble>3.0</testDouble>
            </element>
            <element>
                <testInt>4</testInt>
                <testDouble>4.0</testDouble>
            </element>
        </testList>
        <someTag>
            <someOtherTag>
                <nestedTag testNestedAttribute="nested attribute">
                </nestedTag>
            </someOtherTag>
        </someTag>
    </TestElementXMLMappable>
 </root>

to classes:

class TestXMLMappable: XMLMappable {
    var nodeName: String!

    var testElement: TestElementXMLMappable!
    var testNestedAttribute: String?

    required init?(map: XMLMap) {}

    func mapping(map: XMLMap) {
        testElement <- map["TestElementXMLMappable"]
        testNestedAttribute <- map.attributes["TestElementXMLMappable.someTag.someOtherTag.nestedTag.testNestedAttribute"]
    }
}

enum EnumTest: String {
    case theEnumValue = "enumValue"
}

class TestElementXMLMappable: XMLMappable {
    var nodeName: String!

    var testString: String?
    var testAttribute: EnumTest?
    var testList: [Element]?
    var nodesOrder: [String]?

    required init?(map: XMLMap) {}

    func mapping(map: XMLMap) {
        testString <- map["testString"]
        testAttribute <- map.attributes["testAttribute"]
        testList <- map["testList.element"]
        nodesOrder <- map.nodesOrder
    }
}

class Element: XMLMappable {
    var nodeName: String!

    var testInt: Int?
    var testDouble: Float?

    required init?(map: XMLMap) {}

    func mapping(map: XMLMap) {
        testInt <- map["testInt"]
        testDouble <- map["testDouble"]
    }
}

Requests subspec

Note: Requests subspec has different minimum deployment targets due to Alamofire dependency. (currently iOS 10.0+ / macOS 10.12+ / tvOS 10.0+ / watchOS 3.0+)

Create and send easily request with XML body using Alamofire (added missing XMLEncoding struct)

Alamofire.request(url, method: .post, parameters: xmlMappableObject.toXML(), encoding: XMLEncoding.default)

Also map XML responses to XMLMappable objects using the Alamofire extension. For example a URL returns the following CD catalog:

<CATALOG>
    <CD>
        <TITLE>Empire Burlesque</TITLE>
        <ARTIST>Bob Dylan</ARTIST>
        <COUNTRY>USA</COUNTRY>
        <COMPANY>Columbia</COMPANY>
        <PRICE>10.90</PRICE>
        <YEAR>1985</YEAR>
    </CD>
    <CD>
        <TITLE>Hide your heart</TITLE>
        <ARTIST>Bonnie Tyler</ARTIST>
        <COUNTRY>UK</COUNTRY>
        <COMPANY>CBS Records</COMPANY>
        <PRICE>9.90</PRICE>
        <YEAR>1988</YEAR>
    </CD>
</CATALOG>

Map the response as follows:

Alamofire.request(url).responseXMLObject { (response: DataResponse<CDCatalog>) in
    let catalog = response.result.value
    print(catalog?.cds?.first?.title ?? "nil")
}

The CDCatalog object will look something like this:

class CDCatalog: XMLMappable {
    var nodeName: String!

    var cds: [CD]?

    required init?(map: XMLMap) {}

    func mapping(map: XMLMap) {
        cds <- map["CD"]
    }
}

class CD: XMLMappable {
    var nodeName: String!

    var title: String!
    var artist: String?
    var country: String?
    var company: String?
    var price: Double?
    var year: Int?

    required init?(map: XMLMap) {}

    func mapping(map: XMLMap) {
        title <- map["TITLE"]
        artist <- map["ARTIST"]
        country <- map["COUNTRY"]
        company <- map["COMPANY"]
        price <- map["PRICE"]
        year <- map["YEAR"]
    }
}

Last but not least, create easily and send SOAP requests, again using Alamofire:

let soapMessage = SOAPMessage(soapAction: "ActionName", nameSpace: "ActionNameSpace")
let soapEnvelope = SOAPEnvelope(soapMessage: soapMessage)

Alamofire.request(url, method: .post, parameters: soapEnvelope.toXML(), encoding: XMLEncoding.soap(withAction: "ActionNameSpace#ActionName"))

The request will look something like this:

POST / HTTP/1.1
Host: <The url>
Content-Type: text/xml; charset="utf-8"
Connection: keep-alive
SOAPAction: ActionNameSpace#ActionName
Accept: */*
User-Agent: XMLMapper_Example/1.0 (org.cocoapods.demo.XMLMapper-Example; build:1; iOS 11.0.0) Alamofire/4.5.1
Accept-Language: en;q=1.0
Content-Length: 251
Accept-Encoding: gzip;q=1.0, compress;q=0.5

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" soap:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
    <soap:Body>
        <m:ActionName xmlns:m="ActionNameSpace"/>
    </soap:Body>
</soap:Envelope>

Adding action parameters is as easy as subclassing the SOAPMessage class.

class MySOAPMessage: SOAPMessage {

    // Custom properties

    override func mapping(map: XMLMap) {
        super.mapping(map: map)

        // Map the custom properties
    }
}

Also specify the SOAP version that the endpoint use as follows:

let soapMessage = SOAPMessage(soapAction: "ActionName", nameSpace: "ActionNameSpace")
let soapEnvelope = SOAPEnvelope(soapMessage: soapMessage, soapVersion: .version1point2)

Alamofire.request(url, method: .post, parameters: soapEnvelope.toXML(), encoding: XMLEncoding.soap(withAction: "ActionNameSpace#ActionName", soapVersion: .version1point2))

and the request will change to this:

POST / HTTP/1.1
Host: <The url>
Content-Type: application/soap+xml;charset=UTF-8;action="ActionNameSpace#ActionName"
Connection: keep-alive
Accept: */*
User-Agent: XMLMapper_Example/1.0 (org.cocoapods.demo.XMLMapper-Example; build:1; iOS 11.0.0) Alamofire/4.5.1
Accept-Language: en;q=1.0
Content-Length: 248
Accept-Encoding: gzip;q=1.0, compress;q=0.5

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope/" soap:encodingStyle="http://www.w3.org/2003/05/soap-encoding">
    <soap:Body>
        <m:ActionName xmlns:m="ActionNameSpace"/>
    </soap:Body>
</soap:Envelope>

Unfortunately, there isn’t an easy way to map SOAP response, other than creating your own XMLMappable objects (at least not for the moment)

Communication

• If you need help, use Stack Overflow. (Tag ‘xmlmapper’)
• If you’d like to ask a general question, use Stack Overflow.
• If you found a bug, open an issue.
• If you have a feature request, open an issue.

Installation

CocoaPods

XMLMapper is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'XMLMapper'

To install the Requests subspec add the following line to your Podfile:

pod 'XMLMapper/Requests'

Carthage

To integrate XMLMapper into your Xcode project using Carthage, add the following line to your Cartfile:

github "gcharita/XMLMapper" ~> 1.6

Swift Package Manager

To add XMLMapper to a Swift Package Manager based project, add the following:

.package(url: "https://github.com/gcharita/XMLMapper.git", from: "1.6.0")

to the dependencies value of your Package.swift.

Special thanks

• Special thanks to Tristan Himmelman. This project is based in ObjectMapper for the most part, which is a great solution for JSON mapping. Also the Requests subspec is based on AlamofireObjectMapper.
• A special thanks to Nick Lockwood and his idea behind XMLDictionary
• A special thanks to Alamofire for the subspec dependency

License

XMLMapper is available under the MIT license. See the LICENSE file for more info.