XDocument will not parse html entities (e.g. ) but XmlDocument will - c#

I am currently converting our old parsers that run on XmlDocument to the XDocument. I do this mainly to get the Linq querying and the added linenumber info.
My xml contains an element like this:
<?xml version="1.0"?>
<fulltext>
hello this is a failed textnode
and I don't know how to parse it.
</fulltext>
My problem is that while XmlDocument seems to have no problem reading that node with:
var xmlDocument = new XmlDocument();
var physicalPath = GetPhysicalPath(uploadFolderFile);
try
{
xmlDocument.Load(physicalPath);
}
catch (XmlException xmlException)
{
_log.Warn("Problems with the document", xmlException);
}
The example above parses the document fine but when I try to do:
XDocument xmlDocument;
var physicalPath = GetPhysicalPath(uploadFolderFile);
var xmlStream = new System.IO.StreamReader(physicalPath);
try
{
xmlDocument = XDocument.Load(xmlStream, LoadOptions.SetLineInfo | LoadOptions.SetBaseUri);
}
catch (XmlException)
{
_log.Warn("Trying to clean document for HexaDecimal", xmlException);
}
It fails to read the document because of the character
The special character seems to be allowed in XML version 1.1 but changing the description doesn't help.
I have thought about just parsing the document with XmlDocument and then converting it; but that seems to be counterintuitive. Can anybody help with this problem?

Ok...so I sort of found a solution to this problem.
First of all I try to parse the xml using the following code:
private XDocument GetXmlDocument(String physicalPath)
{
XDocument xmlDocument;
var xmlStream = new System.IO.StreamReader(physicalPath);
try
{
xmlDocument = XDocument.Load(xmlStream, LoadOptions.SetLineInfo);
}
catch (XmlException)
{
//_log.Warn("Trying to clean document for HexaDecimal", xmlException);
xmlDocument = XmlSanitizingStream.TryToCleanXMLBeforeParsing(physicalPath);
}
return xmlDocument;
}
If it fails to load the document, then I will try to clean it using the technique used in this blogpost:
http://seattlesoftware.wordpress.com/2008/09/11/hexadecimal-value-0-is-an-invalid-character/
It will not remove the character I mentioned before, but it will remove any character not allowed by the XML standard.
Then, after sanitizing the XML, I add an XMLReader and set its settings to not check characters:
public static XDocument TryToCleanXMLBeforeParsing(String physicalPath)
{
string xml;
Encoding encoding;
using (var reader = new XmlSanitizingStream(File.OpenRead(physicalPath)))
{
xml = reader.ReadToEnd();
encoding = reader.CurrentEncoding;
}
byte[] encodedString;
if (encoding.Equals(Encoding.UTF8)) encodedString = Encoding.UTF8.GetBytes(xml);
else if (encoding.Equals(Encoding.UTF32)) encodedString = Encoding.UTF32.GetBytes(xml);
else encodedString = Encoding.Unicode.GetBytes(xml);
var ms = new MemoryStream(encodedString);
ms.Flush();
ms.Position = 0;
var settings = new XmlReaderSettings {CheckCharacters = false};
XmlReader xmlReader = XmlReader.Create(ms, settings);
var xmlDocument = XDocument.Load(xmlReader);
ms.Close();
return xmlDocument;
}
Since I've cleaned the document removing illegal characters before I add the ignore characters to the reader, I am pretty sure that I do not read a malformed XML document. Worst case scenario is I get a malformed XML and it will throw an error anyways.
I only use this for parsing and it should only be used to read the data. This will not make the XML well-formed and will in many cases throw exceptions elsewhere in your code. I am only using this because I cannot change what the customer is sending us and I have to read it as is.

Related

Remove all hexadecimal characters before loading string into XML Document Object?

I have an xml string that is being posted to an ashx handler on the server. The xml string is built on the client-side and is based on a few different entries made on a form. Occasionally some users will copy and paste from other sources into the web form. When I try to load the xml string into an XMLDocument object using xmldoc.LoadXml(xmlStr) I get the following exception:
System.Xml.XmlException = {"'', hexadecimal value 0x0B, is an invalid character. Line 2, position 1."}
In debug mode I can see the rogue character (sorry I'm not sure of it's official title?):
My questions is how can I sanitise the xml string before I attempt to load it into the XMLDocument object? Do I need a custom function to parse out all these sorts of characters one-by-one or can I use some native .NET4 class to remove them?
Here you have an example to clean xml invalid characters using Regex:
xmlString = CleanInvalidXmlChars(xmlString);
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(xmlString);
public static string CleanInvalidXmlChars(string text)
{
string re = #"[^\x09\x0A\x0D\x20-\xD7FF\xE000-\xFFFD\x10000-x10FFFF]";
return Regex.Replace(text, re, "");
}
A more efficient way to not error out on invalid XML characters would be to use the CheckCharacters flag in XmlReaderSettings.
var xmlDoc = new XmlDocument();
var xmlReaderSettings = new XmlReaderSettings { CheckCharacters = false };
using (var stringReader = new StringReader(xml)) {
using (var xmlReader = XmlReader.Create(stringReader, xmlReaderSettings)) {
xmlDoc.Load(xmlReader);
}
}

How to Json To Xml

I am new for Json and I have a simple problem.
I am trying to convert json file to xml file with c#. But it throw an exception.
The Code is ;
private void TakeXML()
{
string json = ReadText();
XmlDocument doc = (XmlDocument)Newtonsoft.Json.JsonConvert.DeserializeXmlNode(json);
XmlTextWriter writer = new XmlTextWriter("json.xml", null);
writer.Formatting = Formatting.Indented;
doc.Save(writer);
}
The ReadText function is;
private string ReadText()
{
FileStream fs = new FileStream(#"C:\Users\Sinan\Desktop\bina.json", FileMode.Open, FileAccess.Read);
StreamReader sr = new StreamReader(fs);
string json;
try
{
json = sr.ReadToEnd();
return json;
}
catch (Exception)
{
return null;
}
finally
{
sr.Close();
fs.Dispose();
}
}
for XmlDocument doc = (XmlDocument)Newtonsoft.Json.JsonConvert.DeserializeXmlNode(json); line, it said that;
"JSON root object has multiple properties. The root object must have a single property in order to create a valid XML document. Consider specifing a DeserializeRootElementName."
I am searching to solve this problem but ı haven't found it. İf you help me in this regard, I will be glad. Thank you.
In method DeserializeXmlNode specify the root node name in second parameter as shown in below code:
XmlDocument doc =
(XmlDocument)
Newtonsoft.Json.JsonConvert.DeserializeXmlNode(json, "rootNodeName");
// second parameter
Although if you can give json string then it would be easy to give exact answer.
Reference link: Converting JSON to XML

Convert utf-8 XML document to utf-16 for inserting into SQL

I have an XML document that has been created using utf-8 encoding. I want to store that document in a sql 2008 xml column but I understand I need to convert it to utf-16 in order to do that.
I've tried using XDocument to do this but I'm not getting a valid XML result after the conversion. Here is what I've tried to do the conversion on (Utf8StringWriter is a small class that inherits from StringWriter and overloads Encoding):
XDocument xDoc = XDocument.Parse(utf8Xml);
StringWriter writer = new StringWriter();
XmlWriter xml = XmlWriter.Create(writer, new XmlWriterSettings()
{ Encoding = writer.Encoding, Indent = true });
xDoc.WriteTo(xml);
string utf16Xml = writer.ToString();
The data in the utf16Xml is invalid and when trying to insert into the database I get the error:
{"XML parsing: line 1, character 38, unable to switch the encoding"}
However the initial utf8Xml data is definitely valid and contains all the info I need.
UPDATE:
The initial XML is obtained by using XMLSerializer (with an Utf8StringWriter class) to create the xml string from an existing object model (engine). The code for this is:
public static void Serialise<T>(T engine, ref StringWriter writer)
{
XmlWriter xml = XmlWriter.Create(writer, new XmlWriterSettings() { Encoding = writer.Encoding });
XmlSerializer xs = new XmlSerializer(engine.GetType());
xs.Serialize(xml, engine);
}
I have to leave this like this as that code is out of my control to change.
Before I even send the utf16Xml string to the failing database call I can view it via the Visual Studio debugger and I notice that the entire string is not present and instead I get a string literal was not closed error on the XML viewer.
The error is on first line XDocument xDoc = XDocument.Parse(utf8Xml);. Most likely you converted utf8 stream into a string (utf8xml), but encoding specified in the string is still utf-8, so XML reader fails. If it is true than load XML directly from stream using Load instead of converting it to string first.
Set the encoding of the document to UTF-16 after you have parsed it from utf8xml
XDocument xDoc = XDocument.Parse(utf8Xml);
xDoc.Declaration.Encoding = "utf-16";
StringWriter writer = new StringWriter();
XmlWriter xml = XmlWriter.Create(writer, new XmlWriterSettings()
{ Encoding = writer.Encoding, Indent = true });
xDoc.WriteTo(xml);
string utf16Xml = writer.ToString();
Here's what I had to do to make it work. This just converts the XML to utf-16
string getUtf16Xml(System.Xml.XmlDocument xmlDoc)
{
System.Xml.Linq.XDocument xDoc = System.Xml.Linq.XDocument.Parse(xmlDoc.OuterXml);
xDoc.Declaration.Encoding = "utf-16";
return xDoc.ToString();
}
Then I can save the results to the DB.

How to get Xml as string from XDocument?

I am new to LINQ to XML. After you have built XDocument, how do you get the OuterXml of it like you did with XmlDocument?
You only need to use the overridden ToString() method of the object:
XDocument xmlDoc ...
string xml = xmlDoc.ToString();
This works with all XObjects, like XElement, etc.
I don't know when this changed, but today (July 2017) when trying the answers out, I got
"System.Xml.XmlDocument"
Instead of ToString(), you can use the originally intended way accessing the XmlDocument content: writing the xml doc to a stream.
XmlDocument xml = ...;
string result;
using (StringWriter writer = new StringWriter())
{
xml.Save(writer);
result = writer.ToString();
}
Several responses give a slightly incorrect answer.
XDocument.ToString() omits the XML declaration (and, according to #Alex Gordon, may return invalid XML if it contains encoded unusual characters like &).
Saving XDocument to StringWriter will cause .NET to emit encoding="utf-16", which you most likely don't want (if you save XML as a string, it's probably because you want to later save it as a file, and de facto standard for saving files is UTF-8 - .NET saves text files as UTF-8 unless specified otherwise).
#Wolfgang Grinfeld's answer is heading in the right direction, but it's unnecessarily complex.
Use the following:
var memory = new MemoryStream();
xDocument.Save(memory);
string xmlText = Encoding.UTF8.GetString(memory.ToArray());
This will return XML text with UTF-8 declaration.
Doing XDocument.ToString() may not get you the full XML.
In order to get the XML declaration at the start of the XML document as a string, use the XDocument.Save() method:
var ms = new MemoryStream();
using (var xw = XmlWriter.Create(new StreamWriter(ms, Encoding.GetEncoding("ISO-8859-1"))))
new XDocument(new XElement("Root", new XElement("Leaf", "data"))).Save(xw);
var myXml = Encoding.GetEncoding("ISO-8859-1").GetString(ms.ToArray());
Use ToString() to convert XDocument into a string:
string result = string.Empty;
XElement root = new XElement("xml",
new XElement("MsgType", "<![CDATA[" + "text" + "]]>"),
new XElement("Content", "<![CDATA[" + "Hi, this is Wilson Wu Testing for you! You can ask any question but no answer can be replied...." + "]]>"),
new XElement("FuncFlag", 0)
);
result = root.ToString();
While #wolfgang-grinfeld's answer is technically correct (as it also produces the XML declaration, as opposed to just using .ToString() method), the code generated UTF-8 byte order mark (BOM), which for some reason XDocument.Parse(string) method cannot process and throws Data at the root level is invalid. Line 1, position 1. error.
So here is a another solution without the BOM:
var utf8Encoding =
new UTF8Encoding(encoderShouldEmitUTF8Identifier: false);
using (var memory = new MemoryStream())
using (var writer = XmlWriter.Create(memory, new XmlWriterSettings
{
OmitXmlDeclaration = false,
Encoding = utf8Encoding
}))
{
CompanyDataXml.Save(writer);
writer.Flush();
return utf8Encoding.GetString(memory.ToArray());
}
I found this example in the Microsoft .NET 6 documentation for XDocument.Save method. I think it answers the original question (what is the XDocument equivalent for XmlDocument.OuterXml), and also addresses the concerns that others have pointed out already. By using the XmlWritingSettings you can predictably control the string output.
https://learn.microsoft.com/en-us/dotnet/api/system.xml.linq.xdocument.save
StringBuilder sb = new StringBuilder();
XmlWriterSettings xws = new XmlWriterSettings();
xws.OmitXmlDeclaration = true;
xws.Indent = true;
using (XmlWriter xw = XmlWriter.Create(sb, xws)) {
XDocument doc = new XDocument(
new XElement("Child",
new XElement("GrandChild", "some content")
)
);
doc.Save(xw);
}
Console.WriteLine(sb.ToString());
Looking at these answers, I see a lot of unnecessary complexity and inefficiency in pursuit of generating the XML declaration automatically. But since the declaration is so simple, there isn't much value in generating it. Just KISS (keep it simple, stupid):
// Extension method
public static string ToStringWithDeclaration(this XDocument doc, string declaration = null)
{
declaration ??= "<?xml version=\"1.0\" encoding=\"utf-8\"?>\r\n";
return declaration + doc.ToString();
}
// Usage
string xmlString = doc.ToStringWithDeclaration();
// Or
string xmlString = doc.ToStringWithDeclaration("...");
Using XmlWriter instead of ToString() can give you more control over how the output is formatted (such as if you want indentation), and it can write to other targets besides string.
The reason to target a memory stream is performance. It lets you skip the step of storing the XML in a string (since you know the data must end up in a different encoding eventually, whereas string is always UTF-16 in C#). For instance, for an HTTP request:
// Extension method
public static ByteArrayContent ToByteArrayContent(
this XDocument doc, XmlWriterSettings xmlWriterSettings = null)
{
xmlWriterSettings ??= new XmlWriterSettings();
using (var stream = new MemoryStream())
{
using (var writer = XmlWriter.Create(stream, xmlWriterSettings))
{
doc.Save(writer);
}
var content = new ByteArrayContent(stream.GetBuffer(), 0, (int)stream.Length);
content.Headers.ContentType = new MediaTypeHeaderValue("text/xml");
return content;
}
}
// Usage (XDocument -> UTF-8 bytes)
var content = doc.ToByteArrayContent();
var response = await httpClient.PostAsync("/someurl", content);
// Alternative (XDocument -> string -> UTF-8 bytes)
var content = new StringContent(doc.ToStringWithDeclaration(), Encoding.UTF8, "text/xml");
var response = await httpClient.PostAsync("/someurl", content);

Problem with XElement and XslCompiledTransform

I'm having some trouble using a combination of XElement and XslCompiledTransform. I've put the sample code I'm using below. If I get my input XML using the GetXmlDocumentXml() method, it works fine. If I use the GetXElementXml() method instead, I get an InvalidOperationException when calling the Transform method of XslComiledTransform:
Token Text in state Start would result in an invalid XML document. Make sure that the ConformanceLevel setting is set to ConformanceLevel.Fragment or ConformanceLevel.Auto if you want to write an XML fragment.
The CreateNavigator method on both XElement and XmlDocument returns an XPathNavigator. What extra stuff is XmlDocument doing so this all works, and how can I do the same with XElement? Am I just doing something insane?
static void Main(string[] args)
{
XslCompiledTransform stylesheet = GetStylesheet(); // not shown for brevity
IXPathNavigable input = this.GetXElementXml();
using (MemoryStream ms = this.TransformXml(input, stylesheet))
{
XmlReader xr = XmlReader.Create(ms);
xr.MoveToContent();
}
}
private MemoryStream TransformXml(
IXPathNavigable xml,
XslCompiledTransform stylesheet)
{
MemoryStream transformed = new MemoryStream();
XmlWriter writer = XmlWriter.Create(transformed);
stylesheet.Transform(xml, null, writer);
transformed.Position = 0;
return transformed;
}
private IXPathNavigable GetXElementXml()
{
var xml = new XElement("x", new XElement("y", "sds"));
return xml.CreateNavigator();
}
private IXPathNavigable GetXmlDocumentXml()
{
var xml = new XmlDocument();
xml.LoadXml("<x><y>sds</y></x>");
return xml.CreateNavigator();
}
Oh, that was easy. The solution was to wrap the XElement in an XDocument object. Problem solved!

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