Dynamic Web Sites DECO 3001 Tutorial 6 – Form Presented by Ji Soo Yoon 30 April 2004 Slides adopted from and A Practical Guide To Active Server Pages 3.0 ©2000 Manas Tungarehttp://aurora.wells.edu/~ccs/cs310/02/cs310.htm

Active Server Pages Revisited An Active Server Page is a text script with extension.asp An ASP typically contains HTML, client and server scripts  ASP code is bracketed in  Pre-processed (like SSIs) before the page is sent to the client  Statements in VBScript (similar to VB) or in JavaScript  Uses built-in ASP objects  Uses prewritten active server components (called COM objects stored in.dll or.exe files)  Can build new COM objects (harder)

“Hello World” Example <% Dim I ' declare our loop index variable %> <% For I = 1 To 5 Step 1 %> ” >Hello World <% Next ' bounce back to the top of the loop %>

Advantages Easier to code Faster execution with multiple hits  Each CGI program loads separate code  Two ASP pages can use the same.dll file which is loaded only once Expected availability of Microsoft and third party COM objects  Can be developed in (almost) any language Fostered by Microsoft

Disadvantages Evolving rapidly Hard to gain detailed information of different components Fostered by Microsoft

Intrinsic Objects ASP programs have access to intrinsic objects  Request  Response  Application  Session  Server Each of the objects has a set of collections, methods, properties and events which provide them with all their functionality

Request Object Information returned with the HTTP header (GET) or body (POST) Properties  TotalBytes (the size of data in HTTP header) Collections  ClientCertificate (for security)  Cookies  Form  QueryString  ServerVariables

Request.QueryString The information sent using GET Request.QueryString is everything after the ? Request.QueryString("name")  Gets value for  If this is from a form, it will be associated with an input box with NAME= name

Request.Form The information sent from a form via POST Request.Form(“name”) gets the value assigned to an input box with NAME= name

Request.ServerVariables Environment variables in HTTP header CGI equivalent: environment variables  See 2.cgi

Response Object Control over information sent to the client in the HTTP response: when, how, what Properties  Buffer, CacheControl, Charset, ContentType, Expires,... Collections  Cookies Methods  AddToHeader, AppendToLog, Clear, End, Flush, Redirect  Write (most frequently-used)

Other Intrinsic Objects Application  An application is all files that can be accessed through a directory and its subdirectories  Allows variables and objects with application-level scope  Application_OnStart event when first client requests a file Session  Tracks the current user’s info, Initialized via Session_OnStart Server  Properties: ScriptTimeout  Methods: CreateObject, HTMLEncode, MapPath, URLEncode Server.ScriptTimeout = 100 Server.CreateObject(“ADODB.Connection”))

Installable Components ASP programs have access to intrinsic objects (Request, Response, Application, Session, Server) Other objects can be “installed”  Standard library  Built for a particular application COM is the interface standard for these objects which have methods and properties Examples:  Collaboration Data Objects: CDONTS  ActiveX Data Objects: ADODB  Others: Ad Rotator, Content Linking, Content Rotator, Counters, File Access, Page Counter, Permission Checker

Collaboration Data Objects (CDO) CDO adds messaging functions to applications. CDONTS is a COM library for NT designed to send mail through SMTP To create the CDONTS object Dim objCDOMail 'The CDO object Set objCDOMail = Server.CreateObject("CDONTS.NewMail") This has Attributes: From, To, Subject, Body, Cc, Bcc, AttachFile,... Method: Send Procedure:  assign values to the attributes  apply Send

Sending a simple message Dim objCDOMail Set objCDOMail = Server.CreateObject("CDONTS.NewMail") objCDOMail.To = “Receiver Address” objCDOMail.From = “Sender Address” objCDOMail.Subject = “Subject” objCDOMail.Body = “Body” objCDOMail.Send Set objCDOMail = Nothing

File Access Access to a file system via the FileSystemObject  Server.CreateObject(“Scripting.FileSystemObjec t”) File system has folders, drives, files Methods: CreateFolder, CreateTextFile, DriveExists, DeleteFile, GetFile, OpenTextFile,... Text file methods: Read, ReadLine, Write,

ADO: Active Data Objects ADODB.Connection: to a data provider (db) ADODB.Recordset: the records returned from a query (or a whole table) ADODB.Field: a component in a recordset ADODB.Command: an SQL statement that returns a recordset ADODB.Parameter: holds parameters in an SQL statement ADODB.Error, ADODB.Property

Connection Object A connection to the database. Can be used for more than one query. Properties  ConectionTimeout  CommandTimeout  ConnectionString Methods  Open  Close

Example Set DataConn = Server.CreateObject("ADODB.Connection") DataConn.ConnectionTimeout = 15 'property DataConn.CommandTimeout = 30 ‘property Note, this has no connection to any data yet. DataConn.Open "DBQ=" & Server.MapPath("database.mdb") & ";Driver={Microsoft Access Driver (*.mdb)}; DriverId=25; MaxBufferSize=8192; Threads=20;", "username", "password" An Access database, database.mdb on the default directory Fill in correct “username” and” password”

Recordset Object Records in a query or table from the connection It must be opened to have anything in it Properties  ActiveConnection: the current data source  Fields: in the table  BOF, EOF: of the recordset Methods  AddNew  Delete  MoveFirst, MoveNext, MoveLast  Open, Close

Command Object Not necessary (one can just type in when a recordset is opened), but a neat way to define and reuse commands Properties  CommandText  CommandType (adcmdText = SQL, adcmdTable = table name, Methods  Execute

File Access Access to a file system via the FileSystemObject  Server.CreateObject(“Scripting.FileSystemObjec t”) File system has folders, drives, files Methods: CreateFolder, CreateTextFile, DriveExists, DeleteFile, GetFile, OpenTextFile,... Text file methods: Read, ReadLine, Write,

More ADODB Major objects: Connection and Recordset Possible interfaces to a database  via a connection – previous slides  directly – slides to come Recordset Connection Recordset DB Recordset

Comparison Connection  Cleaner  Allows multiple recordsets without recreating and duplicating the connection  Easier to change in one place Just recordset  Less code to write (not a good reason)

Using a connection Set DataConn =Server.CreateObject("ADODB.Connection") strConnString = "DRIVER={Microsoft Access Driver... DataConn.Open strConnString, strUserId, strPasswd Set rsObj = Server.CreateObject("ADODB.Recordset") cmdSQL = “SELECT…” rsObj.Open cmdSQL, DataConn, CursorType, LockType,.. The first param is an SQL statement, a table, procedure name The second param is a connection object or string with connection text

Using a recordset: With intermediate variables: strConnString = "DRIVER={Microsoft Access... Set rsObj= Server.CreateObject("ADODB.Recordset") rsObj.Open cmdSQL, strConnString, … More confusing, put everything in the Open command: rsObj.Open “SELECT…”, "DRIVER={Microsoft Access…”, …

ASP Components Components (e.g. ADODB) have classes  e.g. Connection, Recordset, Field, Command,.. Classes have methods  e.g. Open, Close,.. The ADODB.dll is available to ASP pages and supports this component An object is created in an ASP page with the create method of Server  Server.CreateObject(“component_name.class_name”)  objDataConn =Server.CreateObject(“ADODB.Connection”) The object then has access to the methods of the class

Developing components Most easily built in VB. Ref: Shelly Powers. Open VB Select File/New Project/ActiveX DLL You get Project1 and a Class1 window Change Project1 name to NewCom in Project/Properties Change Class1 name to CLA in the window for Class 1 Build functions for AddNew, Remove, … in the (Code) window Public Function AddNew() End Function Make/Project creates NewCom.dll regsvr32 NewCom.dll registers it objCLA = Server.CreateObject(“NewCOM.CLA”) creates an instance

ASP Learning and Code Sites ASP Lessons  ASP Tutorial  ASP Tips  ADO Connection String Samples  Microsoft’s ASP Site  Other ASP Sites 