Every day, I get somewhere around 20 hits for the SOAP media type registration draft, referred from an old O’Reilly weblog entry of mine on SOAPAction. It turns out that this article is the first result returned when Googling for “SOAPAction”.
I feel a bit bad about this, because I only recently realized that the behaviour I described in that blog isn’t per any of the specs (obviously I don’t use SOAP at all 8-). I was extrapolating about its semantics based on some investigations into self-description and previous attempts at SOAP-like technologies such as RFC 2774 and PEP (specifically, this part, i.e. the 420 response code).
If SOAPAction/action were to be as I described there – and IMO, this would make it vastly more useful (i.e. make it useful at all 8-) – then the behaviour would have to have been specified to fault if the intent indicated by the value of the SOAPAction field were not understood. Obviously that isn’t the case today.
Sorry for the confusion.