Dan Driscoll's Blog

Last year I described the general structure of WSDAPI's WSDXML sections and provided some hints for creating and consuming these structures. I've received a few requests since then to provide more concrete examples of how to build these structures in...

OASIS has just announced that version 1.1 of DPWS , WS-Discovery , and SOAP-over-UDP are now officially standards! The links to the RDDL and spec pages currently point to the Committee Specification 1 (CS1) revisions of the specs, but OASIS will update...

The SOAP Message Transmission Optimization Mechanism is a building-block spec that DPWS profiles so that specifications built on top can use it in a consistent and device-friendly way. MTOM isn't used in any of DPWS's messages, but it is available to...

It's been a while since I last provided an update on the standardization of DPWS, WS-Discovery, and SOAP-over-UDP. I'm pleased to say that the standardization committee has produced Committee Specification versions of these three specs--that doesn't mean...

Traditional big web services, like a billing system or a service running in the cloud, nearly always have fixed addresses--often HTTP URLs. Smaller web services, such as those on a PC or a device, often have logical identifiers ("urn:uuid:c3de740f-9227...

DPWS defines two different levels of metadata: the Device delivers metadata about the entire device, and about the relationship between the Device and its Hosted Services; and each Hosted Service delivers metadata about itself (and optionally about its...

The roles of Types in WS-Discovery messages is really clear for generic, non-DPWS services. Types are qualified names expressed in the <d:Types> element of WS-Discovery messages, and these names identify a set of operations; the service advertised...

Just under six months ago, DPWS, WS-Discovery and SOAP-over-UDP entered standardization in the OASIS WS-DD technical committee . An incredible amount of work and progress has been made during that time, and the committee has just published the second...

A lot of WSDAPI objects implement IUnknown , so the expose the Release() method. A few more also support Terminate() . What's the difference, and which should you call? Ultimately, you should always refer to the documentation , as rules for specific...

It has never been particularly easy to choose a Web Services stack on which to build your application. Microsoft has produced many over the years (for example, WCF and WSDAPI) and other software vendors produce even more. The feature sets of these stacks...

WS-Eventing is one of the building-block specifications that DPWS profiles and makes available for solution authors. Some applications require the device to send notification messages back to the client; e.g., a printer sends a message to the PC when...

The Devices Profile for Web Services isn’t exactly a Profile in all senses of the word. Yes, it does select and constrain underlying specifications like SOAP and WS-Discovery, but it also does very un-profile things like define schema. One of the things...

We've just published a whitepaper on DPWS, WS-Discovery, and SOAP-over-UDP over at MSDN. This is a great guide for those of you who want a good technical introduction to how all three specifications work. Special thanks go to Ram Jeyaraman for doing...

UUIDs (related to GUIDs ) are used frequently in computing applications. If you don't know these by name, you will probably recognize the 128-bit value in the format in which it is typically rendered: 7673868d-231e-490d-9c4f-19288e7e668d This...

Last week OASIS announced the formation of a technical committee to standardize DPWS, WS-Discovery, and SOAP-over-UDP. This is big news for all three specifications (and the people who implement and rely on them), as it gives us an opportunity to collaborate...

As I promised in my last post , here's a guide to the WSDXML_* structures used in DOM processing in WSDAPI. Before I get started, a quick statement on DOM: Document Object Model is a way of representing XML nodes as static structures in memory. The structure...

Reader Nitin raises a good question: how does an app put extensible data into the Subscribe message that's used to set up events? Example scenario: WSD Scan Nitin's question asks specifically about the WSD Scan protocol built into Vista and Servier...

Those of you working in or around Web Services (or those of you who just read my blog for sheer excitement) have probably seen acronyms like DPWS and WSDAPI tossed around. Some of these are pretty straightforward, but the interplay between them is subtle...

I briefly discussed WSDAPI's WS-Discovery interfaces in part 4 of WSDAPI 101 , but I didn't describe in detail which interface to use to solve a specific problem. So to fill in that gap, I'll cover each of the situations that map to these objects and...

This is the fifth article in the WSDAPI 101 series. You'll learn the most by starting at the beginning, although it's not required to understand the content in this article. Now that we know all about the pieces required in a device-oriented Web Services...

This is the fourth article in the WSDAPI 101 series. You'll learn the most by starting at the beginning, although it's not required to understand the content in this article. WSDAPI 101 Part 3 was all about that cool adapter layer that sits between...

QueryInterface isn't a particularly controversial topic (and I haven't heard any grumbling about my last post ) but I always invite you to verify everything I say on your own--partly to ensure that mistakes I make don't make their way too far into the...

I'm sure you've had enough of attachments by now, so I'm going to talk about something entirely different: how WSDAPI base interfaces work on objects that have multiple derived interfaces. You know, like IWSDAttachment. Oops. Here's the deal: WSDAPI...

Since my monologue on the IWSDAttachment object last week, it's occured to me that there's a much simpler way to explain which programming patterns you have to use when reading from or writing to WSDAPI attachments. Here's a table that describes it...

This is the third article in the WSDAPI 101 series. You'll learn the most by starting at the beginning, although it's not required to understand the content in this article. Now that we understand the layering presented in WSDAPI 101: Part 2 , we can...