[JDEV] Extended error handling

[Keith Minkler]

Hrmm..

That isn't following the DTD for the error tag, which (though i cannot find it right now) states that the contents of the <error/> tag may only be CDATA..  (also error codes may be found at http://docs.jabber.org/jpg/referror.html).  Instead, as long as you are writing both a custom server and client, it would probably be most protocol friendly for you to use <x/> tags to extend the error... such as:

<iq type='error' id='1002'>
  <query xmlns='jabber:iq:register'>
    <username>newuser</username>
    <email>spoon at fed.com</email>
    <password>babyfood</password>
  </query>
  <error code='406'>Not Acceptable</error>
  <x xmlns='custom:ns:error'>
    <field_error>
      <name>firstname</name>
      <errortype>nodata</errortype>
      <description>First name may not be left blank</description>
    </field_error>
    <field_error>
      <name>lastname</name>
      <errortype>nodata</errortype>
      <description>Last name may not be left blank</description>
    </field_error>
  </x>
</iq>

this way, you are not violating the <error/> tag's DTD, and your custom client may look for the <x/> tag with your given xmlns attribute.

this way you can extend the jabber protocol, without breaking clients that do not support your features, by simply defining your own namespace and DTD

Keith Minkler

On Wed, Dec 06, 2000 at 07:16:08PM -0600, Colin Madere wrote:
> 
> Hello JDEV,
> 
> My group is currently extending the error reporting (and field requirements)
> of the registration process in the Jabberd code.  We're implementing a
> server and client that requires more fields than the default
> (username/password) and we need to report more detailed errors for these
> added fields.
> 
> Basically, we have something working but I don't think it's clean enough.
> If there's suggestions, I'd like to hear them (on tag naming and hierarchy,
> mainly).
> 
> Here's an example of a registration request error returned to the client
> containing extended error codes for multiple fields:
> 
> <iq type='error' id='1002'>
>    <query xmlns='jabber:iq:register'>
>       <username>newuser</username>
>       <email>spoon at fed.com</email>
>       <password>babyfood</password>
> 	....possibly more fields here....
>       <key>3be0ed5fa106e18761cb22baec2715baa60b217c</key>
>    </query>
>    <error code='xxx'>
>       <field_error>
>          <name>firstname</name>
>          <errortype>nodata</errortype>
>          <description>First name may not be left blank</description>
>       </field_error>
>       <field_error>
>          <name>lastname</name>
>          <errortype>nodata</errortype>
>          <description>Last name may not be left blank</description>
>       </field_error>
>    </error>
> </iq>
> 
> A standard error code looks like:
> 
> <error code='xxx'>Username not available</error>
> 
> What mainly bugs me is the <field_error/> section... 
> 
> ** Also, any suggestions or resources for error codes?  Currently we're just
> using arbitrarily chosen unused codes.
> 
> Colin Madere