kdkocev / xmlparser

A xml renderer and parser for Scala

Xml Parser

A project for parsing and rendering objects from and to XML

How to use:

Renderer

1. Define an implicit way to render your type in the companion object

  case class Word(word: String)
  object Word {
    implicit val writes: XmlWrites[Word] = x => XmlObject("word", Seq(XmlLiteral(x.word)))
  }

2. Use

  val obj = Word("Hello!")
  
  XML.write(obj).toString // mustEqual "<word>Hello!</word>"

Note: Also works with complex and nested types that you defined XmlWrites for

Parser

1. Define an implicit way to read your type from string

  case class User(id: Int, name: String)
  object User {
    implicit val reads: XmlReads[User] = x =>
      XmlSuccess(
        User(
          id = (x \! "id").as[Int].get,
          name = (x \! "name").as[String].get
         )
      )
  }

Note: This is not the best example but it is simplified for demo purposes

2. Use

    val xml = "<user><id>12</id><name>John</name></user>"
    val result = User(Some(12), "John")
    
    XmlParser.parse(xml).as[User] // mustEqual XmlSuccess(result)

Format

Format is a more concise way to define XmlReads and XmlWrites at the same time

    case class User(id: Int, name: String)
    object User {
      implicit val fmt: XmlFormat[User] = XmlFormat(
        xmlValue => {
          val id = (xmlValue \! "id").as[Int].get
          val name = (xmlValue \! "name").as[String].get
          XmlSuccess(User(id, name))
        },
        user => XmlObject("user", Seq(
          XmlObject("id", Seq(XmlLiteral(user.id))),
          XmlObject("name", Seq(XmlLiteral(user.name)))
        ))
      )
    }

    ...

    val o = User(123, "Jeff")
    val xml = "<user><id>123</id><name>Jeff</name></user>"
    
    XML.write(o).toString // mustEqual xml
    XML.read[User](XmlParser.parse(xml)) // mustEqual XmlSuccess(o)

For examples, please check the *Spec.scala files

TODO:

• Make a macro for auto xml rendering on ADTs
• Recognise XmlObject definitions from Map[String -> Map[...]]
• A way to define implicit XmlReads easier
• Add more examples to the Readme
• Code cleanup