ExtractionRule Class

Article
04/26/2013

Base class used to define rules for obtaining data from a Web response that is generated by a Web performance test.

Inheritance Hierarchy

Object
Microsoft.VisualStudio.TestTools.WebTesting.ExtractionRule
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Namespace: Microsoft.VisualStudio.TestTools.WebTesting
Assembly: Microsoft.VisualStudio.QualityTools.WebTestFramework (in Microsoft.VisualStudio.QualityTools.WebTestFramework.dll)

Syntax

'Declaration
Public MustInherit Class ExtractionRule

public abstract class ExtractionRule

public ref class ExtractionRule abstract

[<AbstractClass>]
type ExtractionRule =  class end

public abstract class ExtractionRule

The ExtractionRule type exposes the following members.

Constructors

	Name	Description
	ExtractionRule	Initializes a new instance of the ExtractionRule class.

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Properties

	Name	Description
	ContextParameterName	Gets or sets the context name of the extracted property.
	RuleDescription	Obsolete. This method is no longer used. Use the DisplayNameAttribute on the class to set a description for this rule.
	RuleName	Obsolete. This method is no longer used. Use the DisplayNameAttribute on the class to set a display name for this rule.

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Methods

	Name	Description
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object.)
	Extract	When overridden in a derived class, this method extracts information from a HtmlDocument and places it into the WebTestContext.
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Remarks

The ExtractionRule class must be inherited by any extraction rule whether it is user-written or built-in. Extraction rules that are associated with the request definition are run after a response has been received, and the results of the extraction are added to the WebTestContext.

Notes to Inheritors

When you inherit from ExtractionRule, you must override the following members: Extract, RuleDescription, and RuleName.

Examples

The following custom extraction rule extracts check boxes from the HtmlDocument and places the status of the found check boxes into the context.

using System;
using Microsoft.VisualStudio.TestTools.WebTesting;

namespace ClassLibrary2
{
    public class ExtractCheckBoxes : ExtractionRule
    {
        private string myContextParameter = "ExtractCBoxParam";
        private bool isChecked = true;

        public override string ContextParameterName
        {
            get { return myContextParameter; }
            set
            {
                if (value != string.Empty)
                    myContextParameter = value;
            }
        }

        public bool FindCheckedBoxes
        {
            get { return isChecked; }
            set { isChecked = value; }
        }

        public override string RuleName
        {
            get { return "Extract Check Boxes"; }
        }

        public override string RuleDescription
        {
            get { return "Extract check boxes based on whether they are" +
                    " checked or not."; }
        }

        public override void Extract(object sender, ExtractionEventArgs e)
        {   
            e.Success = false;
            
            if (e.Response.HtmlDocument != null)
            {   // Gets all input tags
                foreach (HtmlTag tag in e.Response.HtmlDocument
                    .GetFilteredHtmlTags(new string[] { "input" }))
                {   // Verify that current tag is a checkbox
                    if (tag.GetAttributeValueAsString("type") == "checkbox")
                    {   // Is the checkbox checked
                        if (tag.GetAttributeValueAsString("checked") == "CHECKED")
                        {   // Add checked check boxes to context
                            if (isChecked)
                            {
                                e.WebTest.Context.Add(myContextParameter + "_" +
                                    tag.GetAttributeValueAsString("id"),
                                    "Is Checked");
                                e.Success = true;
                            }
                        }
                        else // The checkbox is not checked
                        {   // Add non-checked boxes to context
                            if (!isChecked)
                            {
                                e.WebTest.Context.Add(myContextParameter + "_" +
                                    tag.GetAttributeValueAsString("id"),
                                    "Is Not Checked");
                                e.Success = true;
                            }
                        }
                    }
                }
            }
            if (e.Success)
                e.Message = "Extracted check boxes.";
            else
                e.Message = "No check boxes extracted.";
        }
    }
}

Imports System
Imports Microsoft.VisualStudio.TestTools.WebTesting

Namespace ClassLibrary2
    Public Class ExtractCheckBoxes
        Inherits ExtractionRule

        Private myContextParameter As String = "ExtractCBoxParam"
        Private isChecked As Boolean = True

        Public Overrides Property ContextParameterName() As String
            Get
                Return myContextParameter
            End Get
            Set(ByVal value As String)
                If (value <> String.Empty) Then
                    myContextParameter = value
                End If
            End Set
        End Property

        Public Property FindCheckedBoxes() As Boolean
            Get
                Return isChecked
            End Get
            Set(ByVal value As Boolean)
                isChecked = value
            End Set
        End Property

        Public Overrides ReadOnly Property RuleName() As String
            Get
                Return "Extract Check Boxes"
            End Get
        End Property

        Public Overrides ReadOnly Property RuleDescription() As String
            Get
                Return "Extract check boxes based on whether they are" + _
                    " checked or not."
            End Get
        End Property

        Public Overrides Sub Extract(ByVal sender As Object, ByVal e As ExtractionEventArgs)
            e.Success = False
            If Not e.Response.HtmlDocument Is Nothing Then
                ' Gets all input tags
                Dim tag As HtmlTag
                For Each tag In e.Response.HtmlDocument.GetFilteredHtmlTags(New String() {"input"})
                    ' Verify if current tag is a checkbox
                    If tag.GetAttributeValueAsString("type") = "checkbox" Then
                        ' Is the check box checked
                        If tag.GetAttributeValueAsString("checked") = "CHECKED" Then
                            ' Add checked checkbox to context
                            If isChecked = True Then
                                e.WebTest.Context.Add(myContextParameter + "_" + _
                                tag.GetAttributeValueAsString("id"), "Is Checked")
                                e.Success = True
                            End If
                        Else ' The check box is not checked
                            If isChecked = False Then
                                ' Add non-checked boxes to context
                                e.WebTest.Context.Add(myContextParameter + "_" + _
                                tag.GetAttributeValueAsString("id"), "Is Not Checked")
                                e.Success = True
                            End If
                        End If
                    End If
                Next
            End If
            If e.Success = True Then
                e.Message = "Extracted check boxes."
            Else
                e.Message = "No check boxes extracted."
            End If
        End Sub
    End Class
End Namespace

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Inheritance Hierarchy

ExtractionRule Class

Inheritance Hierarchy

Syntax

Constructors

Properties

Methods

Remarks

Examples

Thread Safety

See Also

Reference

Other Resources

Inheritance Hierarchy

Additional resources