can xpath be used in outgoing SOAP request (envelope) regardless of SOAP server config?

Question

I'm trying to figure out two things:

1. Can Xpath be used to query a SOAP-based web services server?

2. Is this built into the SOAP protocol such that any good SOAP server would handle the requests correctly without having to add custom handling of XPath queries?

The two questions may seem redundant, but I'm breaking them because:

1. I don't know if what I have in mind makes sense/would be the right use of XPath,

2. If it does make sense, is it already an understood feature of the SOAP protocol (and thus might explain why I can't find any specific documentation for the Web Service I'm actually dealing with.)

Here is the real-world scenario, if that helps:

I have a calendar database (very simple, MySQL), and I want to update my MS Exchange calendar via EWS. Whenever I push events out from my db to my calendar, two things are true:

1. The date range will always be the same (the start of the week through the end of the week of when the push happens).

2. The UID of each event will have an indicator that it was sent out by this specific app.

So, before any events are pushed to the calendar, I would like to delete any events that are within that date range and have the app-indicator in the UID, so that I don't get doubles of calendar items, or worse, old items on my calendar that no longer are right.

Since I'm having trouble finding the right way to do such a query/delete/add all in one request, I was thinking that XPath was the less-proprietary solution. But I'm not even sure where the XPath query would be amended to the request, or even if the best of xml parsers would derive the intended goal.

Sorry this was more long winded then I meant it to be. Short version: can I use XPath within a SOAP request? If so, how?

Answer 1

1 - Can Xpath be used to query a SOAP-based web services server?

Umm. No. XPath is a highly dependent language, it can't do anything on its own. Like CSS, it needs an interpreter and a DOM around to work.

2 - Is this built into the SOAP protocol such that any good SOAP server would handle the requests correctly without having to add custom handling of XPath queries?

No. SOAP is a data exchange protocol built on top of HTTP. It is used to exchange objects (that have been serialized as XML) in a predictable and programmable manner. Even though XPath has a connection to XML, it has no intrinsic connection to SOAP.

I'm afraid I can't give a more specific answer than "probably not", since despite your explanation I have no idea what you are actually trying to do. To get a more specific answer, you would have to show your code (or the pseudo code that reflects your idea).

Answer 2

The SOAP service in question could implement a method that takes the XPath query as input (where the XPath query is just sent as a string parameter to the SOAP method). Then implement logic on the SOAP server that executes the XPath query and deletes the records. BUT this would only be using XPath as a format for the query, it has nothing to do with SOAP being xml! The format of the query parameter could also be SQL.

I have worked with a SOAP method that does a query based on a gml structure (map vector data in xml form). The method took a filter parameter as a string that contained valid gml, and returned the result as another string containing map data in valid gml.