Character String Traveling Paths

PHP Tutorials - Herong's Tutorial Examples

∟Localization Overview of Web Applications

∟Character String Traveling Paths

This section describes steps of connection paths that character strings must travel through in a typical Web based application: output characters strings come from PHP files or data base tables and input character strings come from user's Web browser.

In a typical Web based application, character strings will travel from one part of the application to another part. Here are some possible paths character strings may travel through.

From PHP file to Web browser: The following diagram illustrates steps that character strings must travel through from a PHP file to a browser screen. It also shows the computing technologies that are used at different steps:

A1. Key Sequences from keyboard
      |
      |- Text editor
      v
A2. PHP File
      |
      |- PHP CGI engine
      v
A3. HTML Document
      |
      |- Web server
      v
A4. HTTP Response
      |
      |- Internet TCP/IP Connection
      v
A5. HTTP Response
      |
      |- Web browser
      v
A6. Visual characters on the screen

From Database to Web browser: The following diagram illustrates steps that character strings must travel through from a database table to a browser screen. It also shows computing technologies that are used at different steps:

B1. Byte sequences in storage
      |
      |- Database server
      v
B2. Byte stream
      |
      |- Database connection driver
      v
B3. Byte stream
      |
      |- PHP Application
      v
B4. HTTP Response
      |
      |- Internet TCP/IP Connection
      v
B5. HTTP Response
      |
      |- Web browser
      v
B6. Visual characters on the Screen

From Web browser to Database: The following diagram illustrates steps that character strings must travel from a Web browser to a database table. It also shows computing technologies that are used at different steps:

C1. Key sequences on keyboard
      |
      |- Language input tool (optional)
      v
C2. Byte sequences
      |
      |- Browser input form
      v
C3: HTTP request
      |
      |- Internet TCP/IP Connection
      v
C4. HTTP request
      |
      |- Web server
      v
C5. CGI variables and input stream
      |
      |- PHP Application
      v
C6. PHP variables
      |
      |- Database connection driver
      v
C7. Byte stream
      |
      |- Database server
      v
C8. Byte sequence in storage

Since all computing technologies are using ASCII encoding by default, text of ASCII characters can safely travel through those steps without any issues.

However, for non ASCII characters, we have to watch out each steps carefully to make sure that characters are not damaged and are encoded and decoded correctly.

Now I will try to provide some tutorials in this chapter and next 5 chapters to show you how to handle characters correctly in different steps of different connection paths.