Ms Active Server Pages: Cs-422 Dick Steflik

MS Active Server Pages CS-422 Dick Steflik

Microsoft Active Server Pages • Core technologies – – – – – – –

MS Internet Information Server MS Internet Explorer (IE4.0) VBScript Java ActiveX SQL Server & Access COM, DCOM

Microsoft ASP Architecture Windows NT/W2000

HTML IIS

JavaScript VBScript

VBScript

Java ActiveX

Data Base, (ODBC, Access, SQLServer)

IE 4.0

Windows DNA • Windows Distributed interNet Architecture – Microsoft’s initiative for distributed computing over the Internet – 3-tier computing with a Microsoft flavor – DNA guidelines require all distributed clients to support both Windows and non-Windows clients along with both Windows and non-Windows datasources

• ASP and Distributed Computing – using distributed computing you should be able to plug in anywhere to get the information you need, when you need it – The ASP architecture is central to Microsoft’s fulfilling this promise

How ASP works •

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ASP.DLL - this is an ISAPI filter that is invoked in response to IIS receiving a request for a file of type .asp, it alters the HTTP response stream in accordance with information in the HTTP request combined with codes found in the document. The document is parsed looking for VBScript delimiters; <% … %> or <%=…%> undelimited information (text and HTML) is passed back to the requesting client, as is. delimited text is processed by the VBScript processor, and either resolved to text and returned to the client or maintained in the VBScript environment as variable or program state data. The delimitor form <%=…%> is a short cut for using the Write method of the Response object to write programatic information directly back to the client

VBScript •

a subset of the Visual Basic programming language – doesn’t include VBs visual components

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a set of predefined objects – – – – – – –

Application object ASPError object ObjectContext object Request object Response object Server object Session object

Application object •

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An ASP application is made up of all of the files that can be accessed through an application virtual directory and its subdirectories, this is called an ASP application context and it’s the same for all clients the Application object allows you to share information among all clients currently using the application. The Application object is created as soon as the first client access the application and exists until: the web service is stopped or the application us unloaded via the admin console. Allows instantiation of variables and objects with application level scope. This can also be done via the GLOBAL.ASA file These are essentially global variables , accessible to all colients of the application

Applications object Contents Collection • •

Contains all application-level scope variables and objects has three properties: – item; set or retrieve the value of a specific member (specified by a key or index position) • to set - Application.Contents.Item(“PI”) = 3.14 • to get - xyz = Application.Contents.Item(“PI”)

– key; name of a specific element – count; total # of elements in the collection

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methods: – – – – –

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Remove; RemoveAll StaticObjects Lock Unlock

Events: OnEnd ; On Start

ASPError object • •

Allows detailed viewing of the last error that occurred Object is read-only; to use you must call GetLastError method of Server object – ex. –

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Properties: – – – – – – – – –

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Dim objMyASPError set objMyASPError = Server.GetLastError

ASPCode-numeric code for the ASP error ASPDescription-more descriptive than ASPCode Category - type of error (textual) Column-character column of the error Description - better desc than the ASPDescription File - full path to file containg error Line - line number of error Number - error code Source- line of source code causing the error

Methods: none Events: none

ObjectContext object • • • • •

Used with database trancaction for making transactional scripts allows creation of units of code that either fail or pass; no partial successes allowed; real useful in database applications Properties: none Collections: none Methods: – SetAbort – SetComplete

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Events: – OnTransactionAbort – OnTransactionCommit

Request object • •

Gives access to information in the HTTP request header Properties: – TotalBytes - read-only, total number of bytes sent in the request header

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Collections: – ClientCertificate - information about any digital certificates – Cookies - cookie info from the client • http://www.netscape.com/std/cookie_spec.html • http://www.cookiecentral.com/unofficial_cookie_faq.html

– Form - retrieve info posted via a POST : ex. Request.Form.Item(“name”) – QueryString - allow retrieval of info posted via a GET – ServerVariables - pre-defined server environment info (next slide)

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Methods: – BinaryRead

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Events: none

ServerVariables •

Most other header information and server info

ALL_HTTP

HTTP_ACCEPT

PATH_TRANSLATED

ALL_RAW

HTTP_AUTHORIZATION

QUERY_STRING

APPL_MD_PATH

HTTP_ACCEPT-LANGUAGE

REMOTE_ADDR

APPL_PHYSICAL_PATH

HTTP_CONNECTION

REMOTE_HOST

AUTH_PASSWORD

HTTP_HOST

REQUEST_METHOD

AUTH_TYPE

HTTP_REFERER

SCRIPT_NAME

AUTH_USER

HTTP_USER_AGENT

SERVER_NAME

CERT_COOKIE

HTTPS_KEYSIZE

SERVER_PORT

CERT_FLAGS

HTTPS_SECRETKEYSIZE

SERVER_PORT_SECURE

CERT_ISSUER

HTTPS_SERVER_ISSUER

SERVER_PROTOCOL

CERT_KEYSIZE

HTTPS_SERVER_SUBJECT

SERVER_SOFTWARE

CERT_SECRETKEYSIZE

INSTANCE_ID

URL

CERT_SERIALNUMBER

INSTANCE_META_PATH

CERT_SERVER_SUBJECT

LOCAL_ADDR

CERT_SUBJECT

LOGON_USER

CONTENT_TYPE

PATH_INFO

CONTENT_LENGTH

Response object • •

Provides control over what goes into the HTTP response header Properties; – – – – – – – –

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Buffer CacheControl Charset Expires ExpiresAbsolute IsClientConnected PICS Status

Collections: Cookies Methods: – – – – – – –

AddHeader AppendToLog BinaryWrite Clear Flush Redirect Write

Server object • •

Miscellaneous functions Properties: – ScriptTimeout - to limit long running scripts - default 90 sec

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Collections: none Methods: – – – – – – –

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CreateObject - Creates an object on the server (seperately installed objs) Execute - call and execute one ASP script from inside another GetLastError - get the Last Error Object HTMLEncode - used to display the actual HTML code MapPath - given the virtual or relative path get the actual path on server Transfer - redirect execution from onescript to another URLEncode - URL encodes a string

Events: none

Session object • •

Allows recording and management of a user session Properties: – – – –

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CodePage - integer representation of CodePage to be used to display LCID - int to specify special formating based on locale SessionID-unique ID that identifies the session Timeout- minutes that webserver will maintain the session

Collections: – Contents - all variables and objects with session-level scope – StaticObjects - all vars and objects added via