reading attributes with no quotes using XmlTextReader

[apiringmvp]

All,

So I am creating a function that gets a short blurb of html from a
blog. I would like to retain all html formating and images. The code
below works well, with the exception of one issue.

My issue:
---------------------
When a blog's html has attributes with no quotes i get an exception.

Here's the example of the blog I am dealing with.
<p align=center>Some text from the blog.</p>

Questions:
----------------------
Is there a way to get the XmlTextReader to allow attributes without
quotes?

If not, do you like RegExs for this replace?

Then, Does anyone know any RegExs that could do this replace?


Code:
----------------------
public static string GetContentShortBlurb(string content, int len)
{
try
{
using (System.IO.MemoryStream ms = new
System.IO.MemoryStream())
{
if (!content.TrimStart(' ', '\r',
'\n').StartsWith("<"))
content = "<p>" + content + "</p>";

byte[] cb = System.Text.Encoding.UTF8.GetBytes("<doc>"
+ content + "</doc>");
ms.Write(cb, 0, cb.Length);
ms.Position = 0;

// create Reader for parsing
XmlTextReader xr = new XmlTextReader(ms);

// Create Writer for output
System.Text.StringBuilder sb = new
System.Text.StringBuilder();
XmlWriterSettings xws = new XmlWriterSettings();
xws.ConformanceLevel = ConformanceLevel.Fragment;
xws.Encoding = new System.Text.UTF8Encoding(false);
XmlWriter xw = XmlTextWriter.Create(sb, xws);

xr.Read();

int strCount = 0;
int nodesToEnd = 0;
while (strCount < len)
{
xr.Read();

if (xr.NodeType == XmlNodeType.EndElement)
{
if (xr.Name == "doc") break;

xw.WriteEndElement();
nodesToEnd--;
}

if (xr.NodeType == XmlNodeType.Element)
{
xw.WriteStartElement(xr.Name);

nodesToEnd++;

// write attributes
while (xr.MoveToNextAttribute())
{
xw.WriteAttributeString(xr.Name, xr.Value);
}
}

if (xr.NodeType == XmlNodeType.Text)
{
string inner = xr.Value;
if (inner.Length + strCount > len)
{
inner = inner.Substring(0,
inner.LastIndexOf(' ', len - strCount)) + " ...";
}
xw.WriteString(inner);
strCount += inner.Length;
}
}

for (int i = 0; i < nodesToEnd; i++)
xw.WriteEndElement();

xr.Close();
xw.Close();


return Regex.Replace(sb.ToString(), "<\\?xml\\b[^>]*>",
"");
}
}
catch (Exception ex)
{
// Just do the standard old string trim
string stripHtmlEx = "</?([A-Z][A-Z0-9]*)\\b[^>]*>";
string output = Regex.Replace(content, stripHtmlEx, "");
if (output.Length > len)
output = "<p>" + output.Substring(0,
output.LastIndexOf(' ', len)).Replace("\r\n", "</p>\r\n<p>") + "
....</p>";
return output;
}
}

 

[Karl Seguin]

You're problem, which you might already know, is that you are trying to use
a XML Text Reader to read non-XML content. XML strictly requires all
attributes to be enclosed in double quotes. HTML is based on SGML which
doesn't have such a requirement. XHTML on the other hand is based on XML
and so you shouldn't have any problems.

All this to say that there probably isn't a way to make XmlTExtReader work
without quote - if it did, it wouldn't be an Xml reader...Unfortunetly,
there isn't an SgmlTextReader - which is really what you should be using.

You could try to use regular expressions to turn your content into valid
XML, but I think you'll keep running into new issues with this...first it'll
be missing double quotes, then missing closing tags....

Using a regular expression or even just string manipulation (index of and
substrings) is probably the right way to go...

Karl


--
http://www.openmymind.net/
http://www.fuelindustries.com/

All,

So I am creating a function that gets a short blurb of html from a
blog. I would like to retain all html formating and images. The code
below works well, with the exception of one issue.

My issue:
---------------------
When a blog's html has attributes with no quotes i get an exception.

Here's the example of the blog I am dealing with.
<p align=center>Some text from the blog.</p>

Questions:
----------------------
Is there a way to get the XmlTextReader to allow attributes without
quotes?

If not, do you like RegExs for this replace?

Then, Does anyone know any RegExs that could do this replace?


Code:
----------------------
public static string GetContentShortBlurb(string content, int len)
{
try
{
using (System.IO.MemoryStream ms = new
System.IO.MemoryStream())
{
if (!content.TrimStart(' ', '\r',
'\n').StartsWith("<"))
content = "<p>" + content + "</p>";

byte[] cb = System.Text.Encoding.UTF8.GetBytes("<doc>"
+ content + "</doc>");
ms.Write(cb, 0, cb.Length);
ms.Position = 0;

// create Reader for parsing
XmlTextReader xr = new XmlTextReader(ms);

// Create Writer for output
System.Text.StringBuilder sb = new
System.Text.StringBuilder();
XmlWriterSettings xws = new XmlWriterSettings();
xws.ConformanceLevel = ConformanceLevel.Fragment;
xws.Encoding = new System.Text.UTF8Encoding(false);
XmlWriter xw = XmlTextWriter.Create(sb, xws);

xr.Read();

int strCount = 0;
int nodesToEnd = 0;
while (strCount < len)
{
xr.Read();

if (xr.NodeType == XmlNodeType.EndElement)
{
if (xr.Name == "doc") break;

xw.WriteEndElement();
nodesToEnd--;
}

if (xr.NodeType == XmlNodeType.Element)
{
xw.WriteStartElement(xr.Name);

nodesToEnd++;

// write attributes
while (xr.MoveToNextAttribute())
{
xw.WriteAttributeString(xr.Name, xr.Value);
}
}

if (xr.NodeType == XmlNodeType.Text)
{
string inner = xr.Value;
if (inner.Length + strCount > len)
{
inner = inner.Substring(0,
inner.LastIndexOf(' ', len - strCount)) + " ...";
}
xw.WriteString(inner);
strCount += inner.Length;
}
}

for (int i = 0; i < nodesToEnd; i++)
xw.WriteEndElement();

xr.Close();
xw.Close();


return Regex.Replace(sb.ToString(), "<\\?xml\\b[^>]*>",
"");
}
}
catch (Exception ex)
{
// Just do the standard old string trim
string stripHtmlEx = "</?([A-Z][A-Z0-9]*)\\b[^>]*>";
string output = Regex.Replace(content, stripHtmlEx, "");
if (output.Length > len)
output = "<p>" + output.Substring(0,
output.LastIndexOf(' ', len)).Replace("\r\n", "</p>\r\n<p>") + "
...</p>";
return output;
}
}

 

[John Timney \(MVP\)]

Your stuck to using string manipulation, and its not likely to be the
easiest task.

I have to ask - if its from a blog, why cant you syndicate the RSS and
consume it

--
--
Regards

John Timney (MVP)
VISIT MY WEBSITE:
http://www.johntimney.com
http://www.johntimney.com/blog

All,

So I am creating a function that gets a short blurb of html from a
blog. I would like to retain all html formating and images. The code
below works well, with the exception of one issue.

My issue:
---------------------
When a blog's html has attributes with no quotes i get an exception.

Here's the example of the blog I am dealing with.
<p align=center>Some text from the blog.</p>

Questions:
----------------------
Is there a way to get the XmlTextReader to allow attributes without
quotes?

If not, do you like RegExs for this replace?

Then, Does anyone know any RegExs that could do this replace?


Code:
----------------------
public static string GetContentShortBlurb(string content, int len)
{
try
{
using (System.IO.MemoryStream ms = new
System.IO.MemoryStream())
{
if (!content.TrimStart(' ', '\r',
'\n').StartsWith("<"))
content = "<p>" + content + "</p>";

byte[] cb = System.Text.Encoding.UTF8.GetBytes("<doc>"
+ content + "</doc>");
ms.Write(cb, 0, cb.Length);
ms.Position = 0;

// create Reader for parsing
XmlTextReader xr = new XmlTextReader(ms);

// Create Writer for output
System.Text.StringBuilder sb = new
System.Text.StringBuilder();
XmlWriterSettings xws = new XmlWriterSettings();
xws.ConformanceLevel = ConformanceLevel.Fragment;
xws.Encoding = new System.Text.UTF8Encoding(false);
XmlWriter xw = XmlTextWriter.Create(sb, xws);

xr.Read();

int strCount = 0;
int nodesToEnd = 0;
while (strCount < len)
{
xr.Read();

if (xr.NodeType == XmlNodeType.EndElement)
{
if (xr.Name == "doc") break;

xw.WriteEndElement();
nodesToEnd--;
}

if (xr.NodeType == XmlNodeType.Element)
{
xw.WriteStartElement(xr.Name);

nodesToEnd++;

// write attributes
while (xr.MoveToNextAttribute())
{
xw.WriteAttributeString(xr.Name, xr.Value);
}
}

if (xr.NodeType == XmlNodeType.Text)
{
string inner = xr.Value;
if (inner.Length + strCount > len)
{
inner = inner.Substring(0,
inner.LastIndexOf(' ', len - strCount)) + " ...";
}
xw.WriteString(inner);
strCount += inner.Length;
}
}

for (int i = 0; i < nodesToEnd; i++)
xw.WriteEndElement();

xr.Close();
xw.Close();


return Regex.Replace(sb.ToString(), "<\\?xml\\b[^>]*>",
"");
}
}
catch (Exception ex)
{
// Just do the standard old string trim
string stripHtmlEx = "</?([A-Z][A-Z0-9]*)\\b[^>]*>";
string output = Regex.Replace(content, stripHtmlEx, "");
if (output.Length > len)
output = "<p>" + output.Substring(0,
output.LastIndexOf(' ', len)).Replace("\r\n", "</p>\r\n<p>") + "
...</p>";
return output;
}
}

 

[Rad [Visual C# MVP]]

You are going to run into very serious problems using an XMLTextReader
to operate on HTML. HTML is almost always NOT valid XML.

You'd rather use regular expressions to manipulate the text.

All,

So I am creating a function that gets a short blurb of html from a
blog. I would like to retain all html formating and images. The code
below works well, with the exception of one issue.

My issue:
---------------------
When a blog's html has attributes with no quotes i get an exception.

Here's the example of the blog I am dealing with.
<p align=center>Some text from the blog.</p>

Questions:
----------------------
Is there a way to get the XmlTextReader to allow attributes without
quotes?

If not, do you like RegExs for this replace?

Then, Does anyone know any RegExs that could do this replace?


Code:
----------------------
public static string GetContentShortBlurb(string content, int len)
{
try
{
using (System.IO.MemoryStream ms = new
System.IO.MemoryStream())
{
if (!content.TrimStart(' ', '\r',
'\n').StartsWith("<"))
content = "<p>" + content + "</p>";

byte[] cb = System.Text.Encoding.UTF8.GetBytes("<doc>"
+ content + "</doc>");
ms.Write(cb, 0, cb.Length);
ms.Position = 0;

// create Reader for parsing
XmlTextReader xr = new XmlTextReader(ms);

// Create Writer for output
System.Text.StringBuilder sb = new
System.Text.StringBuilder();
XmlWriterSettings xws = new XmlWriterSettings();
xws.ConformanceLevel = ConformanceLevel.Fragment;
xws.Encoding = new System.Text.UTF8Encoding(false);
XmlWriter xw = XmlTextWriter.Create(sb, xws);

xr.Read();

int strCount = 0;
int nodesToEnd = 0;
while (strCount < len)
{
xr.Read();

if (xr.NodeType == XmlNodeType.EndElement)
{
if (xr.Name == "doc") break;

xw.WriteEndElement();
nodesToEnd--;
}

if (xr.NodeType == XmlNodeType.Element)
{
xw.WriteStartElement(xr.Name);

nodesToEnd++;

// write attributes
while (xr.MoveToNextAttribute())
{
xw.WriteAttributeString(xr.Name, xr.Value);
}
}

if (xr.NodeType == XmlNodeType.Text)
{
string inner = xr.Value;
if (inner.Length + strCount > len)
{
inner = inner.Substring(0,
inner.LastIndexOf(' ', len - strCount)) + " ...";
}
xw.WriteString(inner);
strCount += inner.Length;
}
}

for (int i = 0; i < nodesToEnd; i++)
xw.WriteEndElement();

xr.Close();
xw.Close();


return Regex.Replace(sb.ToString(), "<\\?xml\\b[^>]*>",
"");
}
}
catch (Exception ex)
{
// Just do the standard old string trim
string stripHtmlEx = "</?([A-Z][A-Z0-9]*)\\b[^>]*>";
string output = Regex.Replace(content, stripHtmlEx, "");
if (output.Length > len)
output = "<p>" + output.Substring(0,
output.LastIndexOf(' ', len)).Replace("\r\n", "</p>\r\n<p>") + "
...</p>";
return output;
}
}