Swiftpack.co - Package - MaxDesiatov/XMLCoder

XMLCoder

Encoder & Decoder for XML using Swift's Codable protocols.

CI Status Version License Platform Coverage

This package is a fork of the original ShawnMoore/XMLParsing with more features and improved test coverage.

Example

import XMLCoder

let xmlStr = """
<note>
    <to>Bob</to>
    <from>Jane</from>
    <heading>Reminder</heading>
    <body>Don't forget to use XMLCoder!</body>
</note>
"""

struct Note: Codable {
    var to: String
    var from: String
    var heading: String
    var body: String
}

guard let data = xmlStr.data(using: .utf8) else { return }

let note = try? XMLDecoder().decode(Note.self, from: data)

let returnData = try? XMLEncoder().encode(note, withRootKey: "note")

Advanced features

These features are available in 0.4.0 release or later:

Stripping namespace prefix

Sometimes you need to handle an XML namespace prefix, like in the XML below:

<h:table xmlns:h="http://www.w3.org/TR/html4/">
  <h:tr>
    <h:td>Apples</h:td>
    <h:td>Bananas</h:td>
  </h:tr>
</h:table>

Stripping the prefix from element names is enabled with shouldProcessNamespaces property:

struct Table: Codable, Equatable {
    struct TR: Codable, Equatable {
        let td: [String]
    }

    let tr: [TR]
}


let decoder = XMLDecoder()

// Setting this property to `true` for the namespace prefix to be stripped
// during decoding so that key names could match.
decoder.shouldProcessNamespaces = true

let decoded = try decoder.decode(Table.self, from: xmlData)

Dynamic node coding

XMLCoder provides two helper protocols that allow you to customize whether nodes are encoded and decoded as attributes or elements: DynamicNodeEncoding and DynamicNodeDecoding.

The declarations of the protocols are very simple:

protocol DynamicNodeEncoding: Encodable {
    static func nodeEncoding(for key: CodingKey) -> XMLEncoder.NodeEncoding
}

protocol DynamicNodeDecoding: Decodable {
    static func nodeDecoding(for key: CodingKey) -> XMLDecoder.NodeDecoding
}

The values returned by corresponding static functions look like this:

enum NodeDecoding {
    // decodes a value from an attribute
    case attribute

    // decodes a value from an element
    case element

    // the default, attempts to decode as an element first,
    // otherwise reads from an attribute
    case elementOrAttribute 
}

enum NodeEncoding {
    // encodes a value in an attribute
    case attribute

    // the default, encodes a value in an element
    case element

    // encodes a value in both attribute and element
    case both
}

Add conformance to an appropriate protocol for types you'd like to customize. Accordingly, this example code:

struct Book: Codable, Equatable, DynamicNodeEncoding {
    let id: UInt
    let title: String
    let categories: [Category]

    enum CodingKeys: String, CodingKey {
        case id
        case title
        case categories = "category"
    }

    static func nodeEncoding(forKey key: CodingKey) 
    -> XMLEncoder.NodeEncoding {
        switch key {
        case Book.CodingKeys.id: return .both
        default: return .element
        }
    }
}

works for this XML:

<book id="123">
    <id>123</id>
    <title>Cat in the Hat</title>
    <category>Kids</category>
    <category>Wildlife</category>
</book>

Coding key value intrinsic

Suppose that you need to decode an XML that looks similar to this:

<?xml version="1.0" encoding="UTF-8"?>
<foo id="123">456</foo>

By default you'd be able to decode foo as an element, but then it's not possible to decode the id attribute. XMLCoder handles certain CodingKey values in a special way to allow proper coding for this XML. Just add a coding key with stringValue that equals "value" or "" (empty string). What follows is an example type declaration that encodes the XML above, but special handling of coding keys with those values works for both encoding and decoding.

struct Foo: Codable, DynamicNodeEncoding {
    let id: String
    let value: String

    enum CodingKeys: String, CodingKey {
        case id
        case value
        // case value = "" would also work
    }

    static func nodeEncoding(forKey key: CodingKey) 
    -> XMLEncoder.NodeEncoding {
        switch key {
        case CodingKeys.id:
            return .attribute
        default:
            return .element
        }
    }
}

Installation

Requirements

  • Xcode 10.0 or later
  • Swift 4.2 or later
  • iOS 9.0 / watchOS 2.0 / tvOS 9.0 / macOS 10.10 or later

CocoaPods

CocoaPods is a dependency manager for Swift and Objective-C Cocoa projects. You can install it with the following command:

$ gem install cocoapods

Navigate to the project directory and create Podfile with the following command:

$ pod install

Inside of your Podfile, specify the XMLCoder pod:

# Uncomment the next line to define a global platform for your project
# platform :ios, '9.0'

target 'YourApp' do
  # Comment the next line if you're not using Swift and don't want to use dynamic frameworks
  use_frameworks!

  # Pods for Test
  pod 'XMLCoder', '~> 0.4.1'

end

Then, run the following command:

$ pod install

Open the the YourApp.xcworkspace file that was created. This should be the file you use everyday to create your app, instead of the YourApp.xcodeproj file.

Carthage

Carthage is a dependency manager that builds your dependencies and provides you with binary frameworks.

Carthage can be installed with Homebrew using the following command:

$ brew update
$ brew install carthage

Inside of your Cartfile, add GitHub path to XMLCoder:

github "MaxDesiatov/XMLCoder" ~> 0.4.1

Then, run the following command to build the framework:

$ carthage update

Drag the built framework into your Xcode project.

Swift Package Manager

Swift Package Manager is a tool for managing the distribution of Swift code. It’s integrated with the Swift build system to automate the process of downloading, compiling, and linking dependencies.

Once you have your Swift package set up, adding XMLCoder as a dependency is as easy as adding it to the dependencies value of your Package.swift.

dependencies: [
    .package(url: "https://github.com/MaxDesiatov/XMLCoder.git", from: "0.4.1")
]

Contributing

This project adheres to the Contributor Covenant Code of Conduct. By participating, you are expected to uphold this code. Please report unacceptable behavior to xmlcoder@desiatov.com.

Coding Style

This project uses SwiftFormat to enforce formatting style. We encourage you to run SwiftFormat within a local clone of the repository in whatever way works best for you either manually or automatically via an Xcode extension, build phase or git pre-commit hook etc. Please check SwiftFormat documentation for more details.

SwiftFormat also runs within our Travis CI setup and a CI build can fail with incosistent formatting. We require CI builds to pass for any PR before merging.

Test Coverage

Our goal is to keep XMLCoder stable and to serialize any XML correctly according to XML 1.0 standard. All of this can be easily tested automatically and we're slowly improving test coverage of XMLCoder and don't expect it to decrease. PRs that decrease the test coverage have a much lower chance of being merged. If you add any new features, please make sure to add tests, likewise for changes and any refactoring in existing code.

Github

link
Stars: 81
Help us keep the lights on

Dependencies

Releases

0.4.1 - Apr 12, 2019

A bugfix release removing unused Xcode project scheme to improve build time for Carthage users.

Notable changes

0.4.0 - Apr 8, 2019

This is a release with plenty of new features that allow you to parse many more XML variations than previously. Compatibility with Xcode 10.2 and Swift 5.0 is also improved. A huge thank you to @JoeMatt and @regexident for their contributions, to @hodovani for maintaining the project, and to @Inukinator, @qmoya, @Ma-He, @khoogheem and @thecb4 for reporting issues during development!

Notable changes

  • Ordered encoding: this was one of the most requested changes and it's finally here! 🎉 Now both keyed and unkeyed elements are encoded in the exactly same order that was used in original containers. This is applicable to both compiler-generated encoding implementations (just reorder properties or cases in your CodingKeys enum if you have it) and manually implemented func encode(to: Encoder).
  • Stripping namespace prefix: now if your coding key string values contain an XML namespace prefix (e.g. prefix h in <h:td>Apples</h:td>), you can set shouldProcessNamespaces property to true on your XMLDecoder instance for the prefix to be stripped before decoding keys in your Decodable types.
  • Previously it was possible to customize encoding with NodeEncodingStrategy, but no such type existed for decoding. A corresponding NodeDecodingStrategy type was added with nodeDecodingStrategy property on XMLDecoder.
  • Thanks to the previous change, XMLCoder now provides two helper protocols that allow you to easily customize whether nodes are encoded and decoded as attributes or elements for conforming types: DynamicNodeEncoding and DynamicNodeDecoding.
  • Previously if you needed to decode or encode an XML element with both attributes and values, this was impossible to do with XMLCoder. Now with the addition of coding key value intrinsic, this is as easy as adding one coding key with a specific string raw value ("value" or empty string "" if you already have an XML attribute named "value").

Closed issues

  • Crash: Range invalid bounds in XMLStackParser.swift #83
  • Document DynamicNodeEncoding and attributed intrinsic #80
  • Fix nested attributed intrinsic #78
  • nodeEncodingStrategy #49
  • XmlEncoder: ordering of elements #17
  • Can’t reach an XML value #12

Merged pull requests

0.3.1 - Feb 6, 2019

A bugfix release that adds missing CFBundleVersion in generated framework's Info.plist (#72 reported by @stonedauwg).

Changes

0.3.0 - Jan 22, 2019

A maintenance release focused on fixing bugs, improving error reporting and overall internal architecture of the library. For this release we've started tracking test coverage and were able to increase it from 11.8% to 75.6%. 🎉 Thanks to @hodovani and @regexident for their work on improving test coverage in this release.

Additions

You can now set errorContextLength: UInt property on XMLDecoder instance, which will make it add a snippet of XML of at most this length from parser state when a parsing error occurs. This change was provided by @hodovani and can greatly help with attempts to parse invalid XML, where previously only a line and column number were reported.

Deprecations

NodeEncodingStrategies was renamed to NodeEncodingStrategy for consistency. NodeEncodingStrategies is still available as a deprecated typealias, which will be removed in future versions. Thanks to @regexident for cleaning this up and providing many more changes in this release that make XMLCoder better and easier to use.

Changes

0.2.1 - Nov 18, 2018

  • watchOS deployment target set to 2.0 for Carthage (@MaxDesiatov)