The Request Object (Part 1 of 4)

The request object has a lot of different collections, properties, and events methods. The outline is as follows: Properties TotalBytes Collections ClientCertificate Cookies Form QueryString ServerVariables Methods BinaryRead The TotalBytes Property returns the total number of bytes that have been posted to the server. This value is read only. This is not used much however it does come in handy sometimes.  The first too collections that we will look at are the Form and Querystring collections. These are the most commonly used in ASP although the others are very useful once you get the hang of things. Both the Form and the QueryString collections are related to the tags in HTML. When using the form tag in HTML there is a property called method. Method has two values associated with it: GET and POST. When using the GET you need to retrieve the value sent from the form using the QueryString collection. When POST is used you need to use the Form collection. The QueryString collection however is very useful for a number of things other than just retrieving the form information. An example is if you look at the address of this page you will see default.asp?ID=8. The ?ID=8 is a querystring and it is used to retrieve the article you requested, but more on that later. The Cookies collection is pretty straight forward. It allows you to get and set values for a cookie that is stored on the clients machine. Cookies are not evil as some people have said they are. They are an efficient and safe way for a web programmer to store information about a user. Lets say you wanted to allow the user to set the background color on your web page so that every time they come to the site they see their chosen colors. How would you know it was them and what their settings are. There are two ways: 1) Have them log in every time and then store their info in a database that you pull it from. 2) Store a cookie with this information in it on their machine. The ClientCertificates Collection is very similar to the Cookies collection however it is used to gain information about the certificate that the user connected with. This is used in secure sites so I will not expand upon it very much here. The ServerVariables collection is a very useful collection that allows you to gain access to a number of variables relating to the server and the request. The variables are sent to the server in the form of an HTTP header which is information hidden for the user. I will show you in the examples how to retreive these value and also put them to use. The BinaryRead method allows you to read in binary format the information set to the server. This method is not used much unless you are dealing with uploading files. We will expand more on this later.