The Old Joel on Software Forum: Part 3 (of 5)

IPc

Using VB6 and VB6 alone, what are the ways in which one application could talk to another application assuming both the applications run on different computers which are geographically dispersed over a vast distance, say accross continents? Two ways, IMHO I have known and practiced are:

(1) Socket programming using a native protocol for messaging. This is painful as you have to define message types and do your own parsing, all kinds of transmission checks and data validation, client request authentication etc.

(2) Using the Remote Data Service. Have a database at the server end in the other continent hosted on SQL Server 2000 or something and then connect there using the IP address of the server on 1433 (or if you may wish to move the default port to protect yourself from malicious spyware).

What else?

Sathyaish Chakravarthy
Monday, November 10, 2003

XML messages over HTTP.

Be nice for somebody to actally use XML for its intended purpose.

Ged Byrne
Monday, November 10, 2003

You mean I post XML files using either FTP or HTTP with the Inet control or with wininet.dll?

Thanks for the input. One more question in this context. Would XML not slow things a bit? Just a doubt I have. No conviction, have not even heard it probably but just an apprehension about the packing of data in XML and http transmission might make it look a little slower than a real-time tranmission of data.

Sathyaish Chakravarthy
Monday, November 10, 2003

> Would XML not slow things a bit?

If there's a lot of network latency, the overhead of using XML will be lost in the noise.

Portabella
Monday, November 10, 2003

It depends on the size of the messages, the design of the schema, and the type of data.

But look at it this way - XML may be a bit "chunkier" than RPC/Sockets, but you can whip out a SOAP/HTTP solution in an afternoon. Creating a comparably robust setup with sockets will take a week or two.

Philo

Philo
Monday, November 10, 2003

You're damn right, Philo. I've been considering that - ease for myself too along the way.

Sathyaish Chakravarthy
Monday, November 10, 2003

XML-RPC, simpler than SOAP. There are several COM implementations, but the only one I could get to work to call a routine in a PHP page from VB (5) was this one:

http://www.enappsys.com/backend/vbXMLRPC_Index.jsp

Frederic Faure
Monday, November 10, 2003

That is awesome. Thanks very much.

Sathyaish Chakravarthy
Monday, November 10, 2003

Simple XML over HTTP, rather than SOAP or XML-RPC is also an option.

It's been dignified with the acronym "REST". See:

http://internet.conveyor.com/RESTwiki/moin.cgi/FrontPage

Portabella
Monday, November 10, 2003

I haven't heard anyone mention message queueing yet.

Sgt. Sausage
Monday, November 10, 2003

>http://internet.conveyor.com/RESTwiki/moin.cgi/FrontPage

That also happens to be the first wiki I've been to.

Sathyaish Chakravarthy
Monday, November 10, 2003