XmlLicenseBuilder

Namespace: Babel.Licensing Assembly: Babel.Licensing.dll

Provides a custom constructor and validation for XML licenses. This class cannot be inherited.

public class XmlLicenseBuilder : ILicenseBuilder, ICreateCustomRestriction, ICreateCustomSignatureProvider, IReadableLicenseString

Inheritance

object ← XmlLicenseBuilder

Implements

ILicenseBuilder, ICreateCustomRestriction, ICreateCustomSignatureProvider, IReadableLicenseString

Inherited Members

object.GetType(), object.MemberwiseClone(), object.ToString(), object.Equals(object?), object.Equals(object?, object?), object.ReferenceEquals(object?, object?), object.GetHashCode()

Extension Methods

Licenseable.AddLicense<XmlLicenseBuilder>(XmlLicenseBuilder, ILicense), Licenseable.Load(ILicenseBuilder, string), Licenseable.RemoveLicense<XmlLicenseBuilder>(XmlLicenseBuilder, ILicense), Licenseable.Save<XmlLicenseBuilder>(XmlLicenseBuilder, string), Licenseable.SignWith(ILicenseBuilder, ISignatureProvider), Licenseable.SignWithKeys(ILicenseBuilder, string, string), Licenseable.ToReadableString(ILicenseBuilder, string), Licenseable.ValidateSignature(ILicenseBuilder)

Constructors

XmlLicenseBuilder(ISignatureProvider)

Create a new instance of class with the specified signature provider.

public XmlLicenseBuilder(ISignatureProvider signer)

Parameters

Name	Description
signer ISignatureProvider	The object used to digitally sign the license information.

Exceptions

Name	Description
ArgumentNullException	Thrown when one or more required arguments are null.

XmlLicenseBuilder()

Create a new instance of class.

public XmlLicenseBuilder()

Properties

AddXmlDeclaration

Gets or sets a value indicating whether the add XML declaration.

public bool AddXmlDeclaration { get; set; }

Property Value

bool

Encoding

Gets or sets the character encoding used to save the license.

public Encoding Encoding { get; set; }

Property Value

Encoding

Formatted

Gets or sets a value indicating whether the indent the generated XML.

public bool Formatted { get; set; }

Property Value

bool

HasSignature

Indicates whether the license has a signature.

public bool HasSignature { get; }

Property Value

bool

SignatureProvider

Gets or sets the signature provider. The signature provider is used to sign and verify the integrity of the license data.

public ISignatureProvider SignatureProvider { get; set; }

Property Value

ISignatureProvider

Examples

C#

XmlLicenseBuilder builder = new XmlLicenseBuilder();
builder.SignatureProvider = RSASignature.CreateFromKeyFile("KeyPair.snk");

Methods

AddOrUpdate(ILicense)

Adds a with a given key to the builder if the license does not already exists, or updates the if the key already exists.

public void AddOrUpdate(ILicense license)

Parameters

Name	Description
license ILicense	The object.

Exceptions

Name	Description
ArgumentNullException	Thrown when the license argument is null.

Load(Stream)

Loads the license from the specified stream.

public void Load(Stream stream)

Parameters

Name	Description
stream Stream	Specify the stream where to load the license.

Exceptions

Name	Description
ArgumentNullException	Thrown when the stream argument is null.
BabelLicenseException	Thrown when the stream contains bad data.

Load(string)

Loads the license from the given file.

public void Load(string path)

Parameters

Name	Description
path string	The file name where to save the license.

Exceptions

Name	Description
ArgumentNullException	Thrown when one or more required arguments are null.

LoadXml(string)

Loads the license from the specified XML document.

public void LoadXml(string xml)

Parameters

Name	Description
xml string	The XML license document.

Exceptions

Name	Description
ArgumentNullException	Thrown when the xml argument is null.
BabelLicenseException	Thrown when the xml contains bad license data.

Parse(string)

Parse the specified XML license string.

public void Parse(string license)

Parameters

Name	Description
license string	The XML license string.

Remove(ILicense)

Removes a with a given key from the .

public bool Remove(ILicense license)

Parameters

Name	Description
license ILicense	The object to be removed.

Returns

Name	Description
bool	true if the license is successfully removed, false if it fails to remove the license.

Exceptions

Name	Description
ArgumentNullException	Thrown when the license argument is null.

Save(Stream)

Saves the current license state to the specified stream.

public void Save(Stream stream)

Parameters

Name	Description
stream Stream	The stream where to write the license.

Examples

This sample shows how to generate and save an XML license to a MemoryStream.

C#

XmlLicense license = new XmlLicense();

license.Id = IdGenerator.Create("lic", 5);
license.Product = new Product();
license.Product.Id = IdGenerator.Create("prd", 5);

// Create and sign a license
XmlLicenseBuilder builder = new XmlLicenseBuilder();
builder.SignatureProvider = RSASignature.CreateFromKeyFile("KeyPair.snk");
builder.AddOrUpdate(license);
builder.Sign();

// Save the license 
MemoryStream stream = new MemoryStream();
builder.Save(stream);

Exceptions

Name	Description
ArgumentNullException	Thrown when the stream argument is null.

Save(string)

Saves the current license state to a given file.

public void Save(string path)

Parameters

Name	Description
path string	The file path where to save the license.

Exceptions

Name	Description
ArgumentNullException	Thrown when one or more required arguments are null.

Sign()

Add a signature to the current license object.

public void Sign()

Exceptions

Name	Description
InvalidOperationException	Thrown when the signature cannot be generated.

ToLicenses()

Converts this object to a object.

public IEnumerable<ILicense> ToLicenses()

Returns

Name	Description
IEnumerable<ILicense>	This object as a .

ToReadableString(string)

Creates and returns a string representation of the current XML license.

public string ToReadableString(string format)

Parameters

Name	Description
format string	Describes the format to use.

Returns

Name	Description
string	This XML license as a string.

Remarks

Available formats B: Not formatted XML

ToXml(bool)

Converts this instance to an XML string.

public string ToXml(bool formatted = true)

Parameters

Name	Description
formatted bool	Whether to format the XML output.

Returns

Name	Description
string	The XML license string.

Validate()

Validates the current license signature. This method doesn't validate license restrictions. Is not meant to be used to validate the license in client applications. To validate the license in client applications use the class.

public bool Validate()

Returns

Name	Description
bool	true if the signature id valid, false if the signature is not present or not valid.

Exceptions

Name	Description
InvalidOperationException	Thrown when the signature cannot be validated.

CreateCustomRestriction

Event queue for all listeners interested in CreateCustomRestriction events.

public event EventHandler<CreateCustomRestrictionEventArgs> CreateCustomRestriction

Event Type

EventHandler<CreateCustomRestrictionEventArgs>

Examples

This code creates an XML license with a custom restriction.

C#

// Create a digital signer
RSASignature signer = RSASignature.CreateFromKeyFile("Keys.snk");

// Minimum hardware requirements
// Total Memory 4 Gb, Two Cpu
int totalMemory = 4096;
int cpuCount = 2;

var license = new XmlLicense()
			  .WithUniqueId()
			  .ForProduct("Product", "1.0.0.0")
			  .LicensedTo("ACME", "[e-mail]")
			  .WithRestrictions(new MinimumRequirementsRestriction(totalMemory, cpuCount))
			  .SignWith(signer);

license.Save("Product.licenses");

VB

' Create a digital signer
Dim signer As RSASignature = RSASignature.CreateFromKeyFile("Keys.snk")

' Minimum hardware requirements
' Total Memory 4 Gb, Two Cpu
Dim totalMemory As Integer = 4096
Dim cpuCount As Integer = 2

Dim license = New XmlLicense() _
			.WithUniqueId() _
			.ForProduct("Product", "1.0.0.0") _
			.LicensedTo("ACME", "[e-mail]") _
			.WithRestrictions(New MinimumRequirementsRestriction(totalMemory, cpuCount)) _
			.SignWith(signer)

license.Save("Product.licenses")

To validate a custom restriction, handle the CreateCustomRestriction event and create the proper restriction object.

C#

XmlLicenseManager manager = new XmlLicenseManager();

manager.CreateCustomRestriction += (s, e) =>
{
	if (e.RestrictionName == "MinimumRequirements")
		e.Restriction = new MinimumRequirementsRestriction();
};

XmlLicense license = manager.Validate(File.ReadAllText("Product.licenses"));

VB

Dim manager As New XmlLicenseManager()
AddHandler manager.CreateCustomRestriction, Sub(s, e)
		If e.RestrictionName = "MinimumRequirements" Then
			e.Restriction = New MinimumRequirementsRestriction()
		End If
	End Sub

Dim license As XmlLicense = manager.Validate(File.ReadAllText("Product.licenses"))

This is the implementation of a custom restriction that is able to validate the machine minimum requirements in terms of available memory and total number of CPU present.

C#

class MinimumRequirementsRestriction : Restriction, IXmlSerializable
{
	private int _processorCount;
	private long _totalMemory;

	public override string Name
	{
		get { return "MinimumRequirements"; }
	}

	public long TotalMemory
	{
		get
		{
			return _totalMemory;
		}
	}

	public int ProcessorCount
	{
		get
		{
			return _processorCount;
		}
	}

	public MinimumRequirementsRestriction()
	{
	}

	public MinimumRequirementsRestriction(long totalMemory, int processorCount)
	{
		_totalMemory = totalMemory;
		_processorCount = processorCount;
	}

	public override ValidationResult Validate(ILicenseContext context, Type type, object instance)
	{
		ISystemInformation sys = (ISystemInformation)context.GetService(typeof(ISystemInformation));

		long totalMem = ToMegabytes(sys.TotalPhysicalMemory);
		if (totalMem < _totalMemory || sys.ProcessorCount < _processorCount)
		{
			// Cannot run on this machine
			return ValidationResult.NotPassed;                
		}            

		return base.Validate(context, type, instance);
	}

	private static long ToMegabytes(long bytes)
	{
		return bytes / 1024 / 1024;
	}

	public System.Xml.Schema.XmlSchema GetSchema()
	{
		return null;
	}

	public void ReadXml(System.Xml.XmlReader reader)
	{
		reader.MoveToContent();

		string totalMemory = reader.GetAttribute("totalMemory");
		if (!string.IsNullOrEmpty(totalMemory))
			_totalMemory = XmlConvert.ToInt64(totalMemory);

		string processorCount = reader.GetAttribute("processorCount");
		if (!string.IsNullOrEmpty(processorCount))
			_processorCount = XmlConvert.ToInt32(processorCount);

		Boolean isEmptyElement = reader.IsEmptyElement;
		reader.ReadStartElement();
		if (!isEmptyElement)
		{
			reader.ReadEndElement();
		}
	}

	public void WriteXml(System.Xml.XmlWriter writer)
	{
		if (TotalMemory > 0)
			writer.WriteAttributeString("totalMemory", XmlConvert.ToString(TotalMemory));

		if (ProcessorCount > 0)
			writer.WriteAttributeString("processorCount", XmlConvert.ToString(ProcessorCount));
	}
}

VB

Public Class MinimumRequirementsRestriction
	Inherits Restriction
	Implements IXmlSerializable

	Private _totalMemory As Long
	Private _processorCount As Int32

	Public Overrides ReadOnly Property Name As String
		Get
			Return "MinimumRequirements"
		End Get
	End Property

	Public ReadOnly Property TotalMemory As Long
		Get
			Return _totalMemory
		End Get
	End Property

	Public ReadOnly Property ProcessorCount As Long
		Get
			Return _processorCount
		End Get
	End Property

	Public Sub New()

	End Sub

	Public Sub New(ByVal totalMemory As Long, ByVal processorCount As Int32)
		Me._totalMemory = totalMemory
		Me._processorCount = processorCount
	End Sub

	Public Overrides Function Validate(context As ILicenseContext, type As Type, instance As Object) As ValidationResult
		Dim sys = DirectCast(context.GetService(GetType(ISystemInformation)), ISystemInformation)

		Dim totalMem = ToMegabytes(sys.TotalPhysicalMemory)
		If (totalMem < Me.TotalMemory Or sys.ProcessorCount < Me.ProcessorCount) Then
			' Cannot run on this machine
			Return ValidationResult.NotPassed
		End If

		Return MyBase.Validate(context, type, instance)
	End Function

	Private Shared Function ToMegabytes(ByVal value As Long) As Long
		Return value / 1024 / 1024
	End Function

	Public Function GetSchema() As Xml.Schema.XmlSchema Implements IXmlSerializable.GetSchema
		Return Nothing
	End Function

	Public Sub ReadXml(reader As Xml.XmlReader) Implements IXmlSerializable.ReadXml
		reader.MoveToContent()

		Dim totalMemory = reader.GetAttribute("totalMemory")
		If Not String.IsNullOrEmpty(totalMemory) Then
			Me._totalMemory = XmlConvert.ToInt64(totalMemory)
		End If
		Dim processorCount = reader.GetAttribute("processorCount")
		If Not String.IsNullOrEmpty(processorCount) Then
			Me._processorCount = XmlConvert.ToInt32(processorCount)
		End If
		Dim isEmptyElement = reader.IsEmptyElement
		reader.ReadStartElement()
		If Not isEmptyElement Then
			reader.ReadEndElement()
		End If
	End Sub

	Public Sub WriteXml(writer As Xml.XmlWriter) Implements IXmlSerializable.WriteXml
		If Me.TotalMemory > 0 Then
			writer.WriteAttributeString("totalMemory", XmlConvert.ToString(TotalMemory))
		End If
		If Me.ProcessorCount > 0 Then
			writer.WriteAttributeString("processorCount", XmlConvert.ToString(ProcessorCount))
		End If
	End Sub
End Class

CreateCustomSignatureProvider

Event queue for all listeners interested in CreateCustomSignatureProvider events.

public event EventHandler<CreateCustomSignatureProviderEventArgs> CreateCustomSignatureProvider

Event Type

EventHandler<CreateCustomSignatureProviderEventArgs>