Prolific Notion » ASP.NET

Convert HTML to Plain Text in C# using Markdown

Simon Dingley — Wed, 04 Nov 2009 13:41:12 +0000

While working on my customisations to Tim Geyssens MailEngine I was looking for an accurate method of automatically creating a plain-text version of the HTML emails that were being sent out by the site. Further reading brought my attention to something called Markdown. After some hunting around with a little help from my friend Google I managed to find a markdown XSLT file. Using the XSLT I could transform my HTML email to plain-text with relative ease and accuracy. Of course in order to do this I would need a valid XML document and as my pages were already valid XHTML I had no problems there.

Here is my method for doing the conversion, all it requires is that you pass it the HTML you want to convert which must be valid XML:

/// 
/// Converts to HTML to plain-text.
/// 
/// The HTML.
/// The plain text representation of the HTML
private static string ConvertToText(string HTML)
{
    string text = string.Empty;

    XmlDocument xmlDoc = new XmlDocument();
    XmlDocument xsl = new XmlDocument();
    xmlDoc.LoadXml(HTML);
    xsl.CreateEntityReference("nbsp");
    xsl.Load(System.Web.HttpContext.Current.Server.MapPath("/xslt/Markdown.xslt"));

    //creating xslt
    XslTransform xslt = new XslTransform();
    xslt.Load(xsl, null, null);

    //creating stringwriter
    StringWriter writer = new System.IO.StringWriter();

    //Transform the xml.
    xslt.Transform(xmlDoc, null, writer, null);

    //return string
    text = writer.ToString();
    writer.Close();

    return text;
}

Download the XSLT file I used from here:

http://symphony-cms.com/downloads/xslt/file/20573/

I would love to hear from anyone that does this differently or if you can find any problems with the method I have chosen to implement for this solution.

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SmtpClient does not gracefully close the underlying TCP/IP connection

Simon Dingley — Mon, 02 Nov 2009 10:43:17 +0000

Some months back Tim Geyssens was kind enough to send me the source for his MailEngine addition to Umbraco before he released it on his blog. I made some customisations to the source to allow users to select templates and changed the filtering options slightly but other than that it worked jut fine for what I needed.

There was however one problem that became apparent when this was used in production. Sometimes, and apparently randomly the sending of mail would freeze when going to more than say 150 recipients. After a long time trying to track down the reason I stumbled across a post linking to the ‘SmtpClient does not gracefully close the underlying TCP/IP connection‘ issue on the Microsoft Connect website. I guessed it couldn’t do any harm to set the MaxTimeout property of the SmtpClient to 1 so I tried it and it seemed to work – so far so good however you should note the recent comment from someone with regards to using this method on IIS7.

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‘Sys’ is Undefined in ASP.NET AJAX

Simon Dingley — Mon, 12 Jan 2009 11:11:25 +0000

A project that I was updating recently didn’t start out its life as an ASP.NET AJAX enabled application so it was being upgraded to take advantage of some of the features and controls available in the AjaxControlToolkit. I added the necessary references to my project and added the assemblies to the Web.config and things seemed ok until I got to a page with an UpdatePanel on it and the dreaded ‘Sys’ is undefined error reared its ugly head. After a lot of head scratching and some failed Google-fu I finally manaeged to find a post which led me to my answer. I was missing the httpHandlers and httpModules configuration settings in my Web.config which if I had created a new ASP.NET AJAX enabled project from scratch would already have existed, adding them in and the error went away and now my UpdatePanel started to work as required.

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