Comment décoder viewstate

Utilisation Fiddler et de saisir le point de vue de l'état dans la réponse et le coller dans le bas à gauche de la zone de texte puis décoder.

Voici le code source d'un état d'affichage de visualisation de Scott Mitchell article sur l'état d'affichage (25 pages)

using System;
using System.Collections;
using System.Text;
using System.IO;
using System.Web.UI;
namespace ViewStateArticle.ExtendedPageClasses
{
///<summary>
///Parses the view state, constructing a viaully-accessible object graph.
///</summary>
public class ViewStateParser
{
//private member variables
private TextWriter tw;
private string indentString = "   ";
#region Constructor
///<summary>
///Creates a new ViewStateParser instance, specifying the TextWriter to emit the output to.
///</summary>
public ViewStateParser(TextWriter writer)
{
tw = writer;
}
#endregion
#region Methods
#region ParseViewStateGraph Methods
///<summary>
///Emits a readable version of the view state to the TextWriter passed into the object's constructor.
///</summary>
///<param name="viewState">The view state object to start parsing at.</param>
public virtual void ParseViewStateGraph(object viewState)
{
ParseViewStateGraph(viewState, 0, string.Empty);    
}
///<summary>
///Emits a readable version of the view state to the TextWriter passed into the object's constructor.
///</summary>
///<param name="viewStateAsString">A base-64 encoded representation of the view state to parse.</param>
public virtual void ParseViewStateGraph(string viewStateAsString)
{
//First, deserialize the string into a Triplet
LosFormatter los = new LosFormatter();
object viewState = los.Deserialize(viewStateAsString);
ParseViewStateGraph(viewState, 0, string.Empty);    
}
///<summary>
///Recursively parses the view state.
///</summary>
///<param name="node">The current view state node.</param>
///<param name="depth">The "depth" of the view state tree.</param>
///<param name="label">A label to display in the emitted output next to the current node.</param>
protected virtual void ParseViewStateGraph(object node, int depth, string label)
{
tw.Write(System.Environment.NewLine);
if (node == null)
{
tw.Write(String.Concat(Indent(depth), label, "NODE IS NULL"));
} 
else if (node is Triplet)
{
tw.Write(String.Concat(Indent(depth), label, "TRIPLET"));
ParseViewStateGraph(((Triplet) node).First, depth+1, "First: ");
ParseViewStateGraph(((Triplet) node).Second, depth+1, "Second: ");
ParseViewStateGraph(((Triplet) node).Third, depth+1, "Third: ");
}
else if (node is Pair)
{
tw.Write(String.Concat(Indent(depth), label, "PAIR"));
ParseViewStateGraph(((Pair) node).First, depth+1, "First: ");
ParseViewStateGraph(((Pair) node).Second, depth+1, "Second: ");
}
else if (node is ArrayList)
{
tw.Write(String.Concat(Indent(depth), label, "ARRAYLIST"));
//display array values
for (int i = 0; i < ((ArrayList) node).Count; i++)
ParseViewStateGraph(((ArrayList) node)[i], depth+1, String.Format("({0}) ", i));
}
else if (node.GetType().IsArray)
{
tw.Write(String.Concat(Indent(depth), label, "ARRAY "));
tw.Write(String.Concat("(", node.GetType().ToString(), ")"));
IEnumerator e = ((Array) node).GetEnumerator();
int count = 0;
while (e.MoveNext())
ParseViewStateGraph(e.Current, depth+1, String.Format("({0}) ", count++));
}
else if (node.GetType().IsPrimitive || node is string)
{
tw.Write(String.Concat(Indent(depth), label));
tw.Write(node.ToString() + " (" + node.GetType().ToString() + ")");
}
else
{
tw.Write(String.Concat(Indent(depth), label, "OTHER - "));
tw.Write(node.GetType().ToString());
}
}
#endregion
///<summary>
///Returns a string containing the <see cref="IndentString"/> property value a specified number of times.
///</summary>
///<param name="depth">The number of times to repeat the <see cref="IndentString"/> property.</param>
///<returns>A string containing the <see cref="IndentString"/> property value a specified number of times.</returns>
protected virtual string Indent(int depth)
{
StringBuilder sb = new StringBuilder(IndentString.Length * depth);
for (int i = 0; i < depth; i++)
sb.Append(IndentString);
return sb.ToString();
}
#endregion
#region Properties
///<summary>
///Specifies the indentation to use for each level when displaying the object graph.
///</summary>
///<value>A string value; the default is three blank spaces.</value>
public string IndentString
{
get
{
return indentString;
}
set
{
indentString = value;
}
}
#endregion
}
}

Et voici une page simple pour lire l'état d'affichage à partir d'une zone de texte et de graphique à l'aide du code ci-dessus

private void btnParse_Click(object sender, System.EventArgs e)
{
//parse the viewState
StringWriter writer = new StringWriter();
ViewStateParser p = new ViewStateParser(writer);
p.ParseViewStateGraph(txtViewState.Text);
ltlViewState.Text = writer.ToString();
}

Voici un autre décodeur qui fonctionne bien à partir de 2014: http://viewstatedecoder.azurewebsites.net/

Cette travaillé sur l'entrée à laquelle le Ignatu décodeur a échoué avec "Les données sérialisées est pas valide" (bien qu'il laisse le BinaryFormatter-données sérialisées non décodé, ne montrant que sa longueur).

C'est un peu "indigènes" .NET qui permet de convertir ViewState chaîne en StateBag
Le Code est ci-dessous:

public static StateBag LoadViewState(string viewState)
{
System.Web.UI.Page converterPage = new System.Web.UI.Page();
HiddenFieldPageStatePersister persister = new HiddenFieldPageStatePersister(new Page());
Type utilClass = typeof(System.Web.UI.BaseParser).Assembly.GetType("System.Web.UI.Util");
if (utilClass != null && persister != null)
{
MethodInfo method = utilClass.GetMethod("DeserializeWithAssert", BindingFlags.NonPublic | BindingFlags.Static);
if (method != null)
{
PropertyInfo formatterProperty = persister.GetType().GetProperty("StateFormatter", BindingFlags.NonPublic | BindingFlags.Instance);
if (formatterProperty != null)
{
IStateFormatter formatter = (IStateFormatter)formatterProperty.GetValue(persister, null);
if (formatter != null)
{
FieldInfo pageField = formatter.GetType().GetField("_page", BindingFlags.NonPublic | BindingFlags.Instance);
if (pageField != null)
{
pageField.SetValue(formatter, null);
try
{
Pair pair = (Pair)method.Invoke(null, new object[] { formatter, viewState });
if (pair != null)
{
MethodInfo loadViewState = converterPage.GetType().GetMethod("LoadViewStateRecursive", BindingFlags.Instance | BindingFlags.NonPublic);
if (loadViewState != null)
{
FieldInfo postback = converterPage.GetType().GetField("_isCrossPagePostBack", BindingFlags.NonPublic | BindingFlags.Instance);
if (postback != null)
{
postback.SetValue(converterPage, true);
}
FieldInfo namevalue = converterPage.GetType().GetField("_requestValueCollection", BindingFlags.NonPublic | BindingFlags.Instance);
if (namevalue != null)
{
namevalue.SetValue(converterPage, new NameValueCollection());
}
loadViewState.Invoke(converterPage, new object[] { ((Pair)((Pair)pair.First).Second) });
FieldInfo viewStateField = typeof(Control).GetField("_viewState", BindingFlags.NonPublic | BindingFlags.Instance);
if (viewStateField != null)
{
return (StateBag)viewStateField.GetValue(converterPage);
}
}
}
}
catch (Exception ex)
{
if (ex != null)
{
}
}
}
}
}
}
}
return null;
}

En ligne Viewstate Spectateur par Lachlan Keown:

http://lachlankeown.blogspot.com/2008/05/online-viewstate-viewer-decoder.html