The log in process is not a difficult one to understand, but there are a lot of little steps that must be absolutely correct for us to be authenticated. You will have to check with the MLS office to get the exact parameters to MD5. They sometimes vary from office to office, but most MLS systems will post this information to their websites. Even though there is a standard, there are slight variations from office to office, and you will need to check before you get started.

Once you do log in successfully and receive your session variable, you will be able to freely request information, perform searches for properties and even download raw images to place into a database. Of course the obvious benefit for using RETS is the ability to get current information and place it into a database without having to retype or parse some very tricky html page. Using RETS can open the door to many business opportunities. With the knowledge you have in connecting and pulling information from other computers, it may open doors later on for similar systems.

One quick note on this whole login process - what we have just looked at is a digest method of authentication. This type of authenticating is used by other types of web services in different areas and is not specific to RETS. The code is not proprietary to RETS but a common way to gain access to a server, and RETS uses XML to send back data, so that too is not proprietary. This same code, with some modifications, can be used for other login scripts. This is another reason why trying something on your own will usually benefit you and future programs.

There are a few RETS clients out there, but building one from scratch will give you a custom application that you can change and upgrade yourself at any time. Things you learn from one project will usually carry over to another one - at least that's what I have found. One thing that I wouldn't suggest you do yourself is put up crown molding in a room - your thumbs and brain will thank you.