Why?

Cforms are hard to do. In fact, I haven't been able to get them going in any useful way. Until such time as ProposalPublets has been done, this is a nice easy weay to get form-to-email up.
You don't need to do much customisation from the default publication to make this work.
This lets Lenya do CMS which it is good at, and lets something else handle the email sending part.
This is much easier for a novice lenya user to acheive.
users can still edit the text in the page above the form using BXE or whatever.

How?

We will call the new form "contact".

In your publication's paramater-doctype.xmap, do this.

  <map:components>
    <map:generators default="file"/>
    <map:transformers default="xslt"/>
    <map:readers default="resource"/>
    <map:serializers default="html"/>
    <map:matchers default="wildcard"/>
    <map:actions>
      <map:action logger="sitemap.action.sourcetype" name="sourcetype" src="org.apache.cocoon.acting.sourcetype.SourceTypeAction">
        <sourcetype name="xhtml">
          <document-element namespace="http://www.w3.org/1999/xhtml"/>
        </sourcetype>
        <sourcetype name="links">
          <document-element namespace="http://apache.org/lenya/pubs/default/1.0"/>
        </sourcetype>
+        <sourcetype name="contact">
+          <document-element namespace="http://www.my_organisation.com/lenya/contactform"/>
+        </sourcetype>
      </map:action>
    </map:actions>
  </map:components>

In your publication's xslt folder, add a new file contact2xhtml.xsl with the following contents:

<?xml version="1.0"?>

<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
>
  
<xsl:import href="xhtml2xhtml.xsl"/>
  
</xsl:stylesheet>

In your publication's xslt folder, add a new file page2xhtml-content.xsl. Copy and paste one of your other templates and edit it. Note that in the example below, I use a file called common.xsl and centrally manage lots of my interface in there, in one place. This saves headaches.

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE xsl:stylesheet [
<!ENTITY nbsp '&#160;'>
]>

<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns="http://www.w3.org/1999/xhtml"
    xmlns:xhtml="http://www.w3.org/1999/xhtml"
    xmlns:page="http://apache.org/cocoon/lenya/cms-page/1.0"
    xmlns:lenya="http://apache.org/cocoon/lenya/page-envelope/1.0" 
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:dcterms="http://purl.org/dc/terms/"
    xmlns:i18n="http://apache.org/cocoon/i18n/2.1"
    exclude-result-prefixes="page xhtml"
    >
    
    
<xsl:param name="root"/>
<xsl:param name="document-id"/>
<xsl:param name="raw"/>
<xsl:param name="document-type"/>
<xsl:param name="document-label"/>
<xsl:param name="url"/>
<xsl:param name="language"/>
<xsl:include href="common.xsl"/> 

<xsl:template match="cmsbody"> 
<html>
  <head>
    <title><xsl:value-of select="$document-label"/></title>
    <link href="{$root}/css/styles.css" rel="stylesheet" media="screen, print" type="text/css"/>
  </head>
  <body>
    
  <xsl:call-template name="header"/> 
  
    <div id="content_2">
    
       <xsl:apply-templates select="xhtml:div[@id = 'menu']"/>
    
       <div id="Content" class="bulleted">
         <xsl:attribute name="bxe_xpath">//xhtml:div[@id='Content']</xsl:attribute>
         <xsl:apply-templates select="//xhtml:div[@id = 'Content']"/>
       </div>
       
       <form action="/cgi-bin/formmail.cgi">
        <input type="hidden" name="your form handlers parameters, etc" value="whatever"/>
        <table border="0">
          <tr>
            <td colspan="4"><strong>Your details</strong></td>
          </tr>
          <tr>
            <td>Name: <span class="required small">(Required)</span></td>
            <td colspan="3"><input type="text" name="Name" size="55"/></td>
          </tr>

... rest of file .....

OK now the template's set up. Now we need to set up the pages in Lanya and trick them into using the new template.

Create a new 'contact us' page and set up the content how you want it.
Create a 'thank you' page and make it hidden in the navigation.
Configure your external form handler how you normally would for a static HTML site. Set it up to redirect users back to your 'thank you' page.
Go to the your_pub/content/authoring/contact/index_en.html (or wherever it is in your page tree/language) and edit the source. This part is a bit of a hack. An example is below. The main thing is to change the default namespace to the new namespace you created in the first code block above (http://www.my_organisation.com/lenya/contactform) and then make sure that all the html elements have an xhtml: prefix.
Reboot Lenya and you're away

<?xml version="1.0" encoding="UTF-8"?><html xmlns="http://www.my_organisation.com/lenya/contactform" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:lenya="http://apache.org/cocoon/lenya/page-envelope/1.0" xmlns:xhtml="http://www.w3.org/1999/xhtml" dc:dummy="FIXME:keepNamespace" dcterms:dummy="FIXME:keepNamespace" lenya:dummy="FIXME:keepNamespace" xhtml:dummy="FIXME:keepNamespace">
  <lenya:meta>
  </lenya:meta>
  <xhtml:head>
    <xhtml:title>Contact form</xhtml:title>
  </xhtml:head>
  <xhtml:body>
    <xhtml:p>get in touch with us using the form below.</xhtml:p>

  </xhtml:body>
</html>

HowToFormsUsingExternalHandler

Why?

How?