I am trying to validate an incoming input xmlDocument against a an existing XmlSchemaSet. Following is the code:
public class ValidateSchemas
{
private bool _isValid = true;
public List<string> errorList = new List<string>();
public bool ValidateDocument(XmlDocument businessDocument)
{
XmlSchemaSet schemaSet = SchemaLoader.Loader();
bool isValid = Validate(businessDocument, SchemaLoader._schemaSet);
return isValid;
}
public bool Validate(XmlDocument document, XmlSchemaSet schema)
{
ValidationEventHandler eventHandler = new ValidationEventHandler(HandleValidationError);
document.Schemas = schema;
document.Validate(eventHandler);
return _isValid;
}
private void HandleValidationError(object sender, ValidationEventArgs ve)
{
_isValid = false; errorList.Add(ve.Message);
}
}
The code works fine from a validation perspective. However the errorList captures only the first node error. It does not capture the other node errors. Looks like the event is getting fired only once. How to accomplish this, please help. Please note I am getting xmldocument as input , hence not using a reader.
That's exactly the expected behavior of XmlDocument.Validate method. Once it finds a validation error it stops validate process and returns the error. So, the user has to fix that error and validate again.
This behavior is different from the Visual studio error list. For example, if you have a single syntax error in the code sometimes it returns 100s of errors. But actually you have to fix only one at one place. So, there can be both pros and cons depends on the circumstance. However, I don't think you could easily get all the validation errors for a XMLDocument, it works in a different way inherently.
Related
I would like to check the better approach to check for XML documents that contain external resource.
I have received this error during veracode analysis.
Configure the XML parser to disable external entity resolution.
I can set the XMLResolve to null, but we depend on third party dlls too. So, I would like to validate the xml if it contains any external resource and reject the file immediately.
We do not use DTDs for our XML documents.
So here are the two options that I could think of. I guess both are almost the same. Just wanted to make sure if I'm missing anything.
//Check for DTD element in XML, if it contains, ignore this document.
public bool IsValid(string xml)
{
if (xml.Contains("<!DOCTYPE"))
{
return false;
}
return true;
}
or
public bool IsValid(string xml)
{
XmlReaderSettings xs = new XmlReaderSettings() {DtdProcessing = DtdProcessing.Prohibit};
try
{
XmlReader.Create(xml, xs);
return true;
}
catch (Exception ex)
{
return false;
}
}
Also, this will only resolve DTDs, how can we check for other external resources like entities and schemas? What is the process to check for all the external entities? Thanks for your help.
I'm using AngleSharp to parse HTML5 at the moment what I'm doing is wrapping the elements I want to parse with a little bit of HTML to make it a valid HTML5 and then use the parser on that, is there a better of doing it? meaning, parsing specific elements directly and validate that the structure is indeed HTML5?
Hm, a little example would be nice. But AngleSharp does support fragment parsing, which sounds like the thing you want. In general fragment parsing is also applied when you set properties like InnerHtml, which transform strings to DOM nodes.
You can use the ParseFragment method of the HtmlParser class to get a list of nodes contained in the given source code. An example:
using AngleSharp.Parser.Html;
// ...
var source = "<div><span class=emphasized>Works!</span></div>";
var parser = new HtmlParser();
var nodes = parser.ParseFragment(source, null);//null = no context given
if (nodes.Length == 0)
Debug.WriteLine("Apparently something bad happened...");
foreach (var node in nodes)
{
// Examine the node
}
Usually all nodes will be IText or IElement types. Also comments (IComment) are possible. You will never see IDocument or IDocumentFragment nodes attached to such an INodeList. However, since HTML5 is quite robust it is very likely that you will never experience "errors" using this method.
What you can do is to look for (parsing) errors. You need to provide an IConfiguration that exposes an event aggregator, which collects such events. The simplest implementation for aggregating only such events (without possibility of adding / removing multiple handlers) is the following:
using AngleSharp.Events;
// ...
class SimpleEventAggregator : IEventAggregator
{
readonly List<HtmlParseErrorEvent> _errors = new List<HtmlParseErrorEvent>();
public void Publish<TEvent>(TEvent data)
{
var error = data as HtmlParseErrorEvent;
if (error != null)
_errors.Add(error);
}
public List<HtmlParseErrorEvent> Errors
{
get { return _errors; }
}
public void Subscribe<TEvent>(ISubscriber<TEvent> listener) { }
public void Unsubscribe<TEvent>(ISubscriber<TEvent> listener) { }
}
The simplest way to use the event aggregator with a configuration is to instantiate a new (provided) Configuration. Here as a sample snippet.
using AngleSharp;
// ...
var errorEvents = new SimpleEventAggregator();
var config = new Configuration(events: errorEvents);
Please note: Every error that is reported is an "official" error (according to W3C spec.). These errors do not indicate that the provided code is malicious or invalid, just that something is not following the spec and that a fallback had to be applied.
Hope this answers your question. If not, then please let me know.
Update Updated the answer for the latest version of AngleSharp.
I'm quite new in programming multi-threading and I could not understand from the xelium example how I could execute a javascript and get the return value.
I have tested:
browser.GetMainFrame().ExecuteJavaScript("SetContent('my Text.')", null, 0);
the javascript is executed, but I this function don’t allow me to get the return value.
I should execute the following function to get all the text the user have written in the box..
browser.GetMainFrame().ExecuteJavaScript("getContent('')", null, 0);
the function TryEval should do this…
browser.GetMainFrame().V8Context.TryEval("GetDirtyFlag", out returninformation , out exx);
But this function can’t be called from the browser, I think it must be called from the renderer? How can I do so?
I couldn’t understand the explanations about CefRenderProcessHandler and OnProcessMessageReceived.. How to register a Scriptable Object and set my javascript & parameters?
Thx for any suggestions how I could solve this!
I have been struggling with this as well. I do not think there is a way to do this synchronously...or easily :)
Perhaps what can be done is this:
From browser do sendProcessMessage with all JS information to renderer
process. You can pass all kinds of parameters to this call in a structured way so encapsulating the JS method name and params in order should not be difficult to do.
In renderer process (RenderProcessHandler onProcessMessageReceived method) do TryEval on the V8Context and get the return value via out parameters and sendProcessMessage back to the
browser process with the JS return value (Note that this supports ordinary return semantics from your JS method).You get the browser instance reference in the onProcessMessageReceived so it is as easy as this (mixed pseudo code)
browser.GetMainFrame().CefV8Context.tryEval(js-code,out retValue, out exception);
process retValue;
browser.sendProcessMessage(...);
Browser will get a callback in the WebClient in onProcessMessageReceived.
There is nothing special here in terms of setting up JS. I have for example a loaded html page with a js function in it. It takes a param as input and returns a string. in js-code parameter to TryEval I simply provide this value:
"myJSFunctionName('here I am - input param')"
It is slightly convoluted but seems like a neat workable approach - better than doing ExecuteJavaScript and posting results via XHR on custom handler in my view.
I tried this and it does work quite well indeed....and is not bad as it is all non-blocking. The wiring in the browser process needs to be done to process the response properly.
This can be extended and built into a set of classes to abstract this out for all kinds of calls..
Take a look at the Xilium demo app. Most of the necessary wiring is already there for onProcessMessage - do a global search. Look for
DemoRendererProcessHandler.cs - renderer side this is where you will invoke tryEval
DemoApp.cs - this is browser side, look for sendProcessMessage - this will initiate your JS invocation process.
WebClient.cs - this is browser side. Here you receive messages from renderer with return value from your JS
Cheers.
I resolved this problem by returning the result value from my JavaScript function back to Xilium host application via an ajax call to a custom scheme handler. According to Xilium's author fddima it is the easiest way to do IPC.
You can find an example of how to implement a scheme handler in the Xilium's demo app.
Check out this post: https://groups.google.com/forum/#!topic/cefglue/CziVAo8Ojg4
using System;
using System.Windows.Forms;
using Xilium.CefGlue;
using Xilium.CefGlue.WindowsForms;
namespace CefGlue3
{
public partial class Form1 : Form
{
private CefWebBrowser browser;
public Form1()
{
InitializeCef();
InitializeComponent();
}
private static void InitializeCef()
{
CefRuntime.Load();
CefMainArgs cefArgs = new CefMainArgs(new[] {"--force-renderer-accessibility"});
CefApplication cefApp = new CefApplication();
CefRuntime.ExecuteProcess(cefArgs, cefApp);
CefSettings cefSettings = new CefSettings
{
SingleProcess = false,
MultiThreadedMessageLoop = true,
LogSeverity = CefLogSeverity.ErrorReport,
LogFile = "CefGlue.log",
};
CefRuntime.Initialize(cefArgs, cefSettings, cefApp);
}
private void Form1_Load(object sender, EventArgs e)
{
browser = new CefWebBrowser
{
Visible = true,
//StartUrl = "http://www.google.com",
Dock = DockStyle.Fill,
Parent = this
};
Controls.Add(browser);
browser.BrowserCreated += BrowserOnBrowserCreated;
}
private void BrowserOnBrowserCreated(object sender, EventArgs eventArgs)
{
browser.Browser.GetMainFrame().LoadUrl("http://www.google.com");
}
}
}
using Xilium.CefGlue;
namespace CefGlue3
{
internal sealed class CefApplication : CefApp
{
protected override CefRenderProcessHandler GetRenderProcessHandler()
{
return new RenderProcessHandler();
}
}
internal sealed class RenderProcessHandler : CefRenderProcessHandler
{
protected override void OnWebKitInitialized()
{
CefRuntime.RegisterExtension("testExtension", "var test;if (!test)test = {};(function() {test.myval = 'My Value!';})();", null);
base.OnWebKitInitialized();
}
}
}
I need to implement a C# method that needs to validate an XML against an external XSD and return a Boolean result indicating whether it was well formed or not.
public static bool IsValidXml(string xmlFilePath, string xsdFilePath);
I know how to validate using a callback. I would like to know if it can be done in a single method, without using a callback. I need this purely for cosmetic purposes: I need to validate up to a few dozen types of XML documents so I would like to make is something as simple as below.
if(!XmlManager.IsValidXml(
#"ProjectTypes\ProjectType17.xml",
#"Schemas\Project.xsd"))
{
throw new XmlFormatException(
string.Format(
"Xml '{0}' is invalid.",
xmlFilePath));
}
There are a couple of options I can think of depending on whether or not you want to use exceptions for non-exceptional events.
If you pass a null as the validation callback delegate, most of the built-in validation methods will throw an exception if the XML is badly formed, so you can simply catch the exception and return true/false depending on the situation.
public static bool IsValidXml(string xmlFilePath, string xsdFilePath, XNamespace namespaceName)
{
var xdoc = XDocument.Load(xmlFilePath);
var schemas = new XmlSchemaSet();
schemas.Add(namespaceName, xsdFilePath);
try
{
xdoc.Validate(schemas, null);
}
catch (XmlSchemaValidationException)
{
return false;
}
return true;
}
The other option that comes to mind pushes the limits of your without using a callback criterion. Instead of passing a pre-defined callback method, you could instead pass an anonymous method and use it to set a true/false return value.
public static bool IsValidXml(string xmlFilePath, string xsdFilePath, XNamespace namespaceName)
{
var xdoc = XDocument.Load(xmlFilePath);
var schemas = new XmlSchemaSet();
schemas.Add(namespaceName, xsdFilePath);
Boolean result = true;
xdoc.Validate(schemas, (sender, e) =>
{
result = false;
});
return result;
}
I am writing an app (something like Notepad) in C#. I'm using Properties.Settings class to save user preferences. It was working fine until suddenly when it started showing this exception message anytime I try to run it.
Configuration system failed to initialize
I noticed that the error originated from this part of the code:
private void TextPad_Load(object sender, EventArgs e)
{
rtbText.WordWrap = Properties.Settings.Default.WordWrap;
rtbText.Font = Properties.Settings.Default.DefFont;
rtbText.ForeColor = Properties.Settings.Default.ForeColor;
rtbText.BackColor = Properties.Settings.Default.BackColor;
if (Properties.Settings.Default.ShowLast)
{
OpenLocalFile(Properties.Settings.Default.LastFile);
}
// There are other lines which are not relevant to this question
}
I moved the supposedly lines to the form constructor immediately after InitializeComponent(); but I still got the same error.
Actually the compiler is telling the error originates from this in Settings.Designer.cs:
[global::System.Configuration.UserScopedSettingAttribute()]
[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
[global::System.Configuration.DefaultSettingValueAttribute("False")]
public bool WordWrap {
get {
return ((bool)(this["WordWrap"]));
}
set {
this["WordWrap"] = value;
}
If I remove rtbText.WordWrap = Properties.Settings.Default.WordWrap; from TextPad_Load, it shows
[global::System.Configuration.UserScopedSettingAttribute()]
[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
[global::System.Configuration.DefaultSettingValueAttribute("Consolas, 9.75pt")]
public global::System.Drawing.Font DefFont {
get {
return ((global::System.Drawing.Font)(this["DefFont"]));
}
set {
this["DefFont"] = value;
}
The only solution now is either to remove those lines from TextPad_Load (which makes the idea loading user preferences useless) or starting a new project (which I have done, anyway). Can someone please explain what the exception message means and maybe I can get a solution (in case I run into it again)? Microsoft VS Help is not giving me anything tangible.
Thanks
It might help to throw away your existing .config files.
After changes in the Properties.Settings the old file might not be valid any more (changed names, or removed items no longer recognized).
Note that user scoped settings are stored in (drive):\Users(usr)\AppData\Local\Microsoft...something