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Chapter 4. Working with Files in Your E-Commerce Application. Objectives: Working with Files in E-Commerce Application. How to use #Include file in ASP page. Redirect a customer to a new ASP page file. Use File Access Component to store customer information in a text file.
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Chapter 4 Working with Files in Your E-Commerce Application Objectives: • Working with Files in E-Commerce Application. • How to use #Include file in ASP page. • Redirect a customer to a new ASP page file. • Use File Access Component to store customer information in a text file.
Including files in an ASP Page • Can be included using server-side #INCLUDE directive (used with ASP & HTML files). • Reason to include files: • To add same content to a number of pages at your website. • When you need to use a standard set of functions and procedures within multiple ASP pages. • Two forms of the directive: • <!-- #INCLUDE FILE=“somefile.ASP” --> • <!-- #INCLUDE VIRTUAL=“somefile.ASP” --> • The files can be included dynamically.
Using File Redirection • The Request object has a method called Redirect to automatically redirect a customer to new file. • You can pass query string variables with redirect method but not TARGET attribute (redirecting to particular window/frame). • Not all browser support this.
Don’t Use Redirect Method • Reasons: • Place more strain on your Web server bcoz it forces the browser to retrieve two pages instead of one. • Redirects aren’t fully supported by all browsers. Will get the message like:302: Object has moved. • Instead use Response.End
Using the File Access Components • File Access Components are used to create and read text files. • Used to record information from HTML forms of Web Site.
Objects of File Access Components • FileSystemObject – Includes all the basic methods for working with the file system. • TextStream – Used for reading & writing to a text file. • File – Represents an individual file. • Folder– Represent a file folder (a directory). • Drive- Represents a disk drive or network share.
TextStream Object • CreateTextFile() method of FileSytemObject object is used to create text file and return reference to the TextStream Object. • It has 3 parameters of which one is compulsory and two are optional. They are: • FileSpecifier – Required parameter that specifies the path of the file to create. • Overwrite – Optional, by default value is TRUE. • Unicode-Optional, By default is FALSE. Indicates file using the ASCII character set should be created.
Three Methods of TextStream used to write a text file: • Write(string)- Writes a string to text file. • WriteLine(String)- Writes a string to text file and appends a newline character. String argument is optional. • WriteBlankLines(lines) – Writes indicated number of blank lines to the text file.
Reading a Text File • The four properties of FileSystemObjext used while reading are: • AtEndOfLine-New line character is detected. Default value is TRUE. • AtEndOfStream-Indicates the end of the text file is reached. • Column-This property indicates the current character position in a line. • Line-Indicates a current Line in a file.
Contd….. • The four objects of TextStream object used to read a text file are: • Read(character)- Reads specified number of characters from the text file. • ReadLine-Reads single line from the text file. • ReadAll()- Reads entire content of the text file. • Skip(character)- Skips specified number of characters. • SkipLine- Skips one line in text file.
Opening the Text File • The file must be opened before read from or write into it. • The following are the arguments used with OpenTextFile() method. • FileSpecifier-Required, specifies the path of the file to be open. • IOMode-Optional. Indicate file to be opened is to read/write/append. (1-R, 2-W,8-A). • Format-Optional. Specifies format of the file. By default it is ASCII.
Managing Text Files • Methods of FileSystemObject to manage file are: • CopyFile() • MoveFile() • DeleteFile() • FileExists() • Display the files in the folder use FileSystemObject & Folder object.