Palm OS Network Programming

Designing FtpView

FtpView is a limited FTP client application created in this book, which provides only enough functionality to demonstrate the usage of TCP sockets. We demonstrate establishing and accepting connections and exchanging data over these connections. FtpView illustrates these techniques by supporting login to an FTP server, listing the server’s current directory, and logging out from the server.

Functional Analysis

FtpView provides moderate, read-only access to FTP servers. We develop this application in Chapter 6 through Chapter 12. When complete, FtpView will allow the user to log in to and out from the FTP server, and retrieve the listing of files in the server’s root directory. Figure 3-1 shows the application flow for FtpView.

Figure 3-1. FtpView application flow

When the user starts the application, the only available option is to begin an FTP session. Once the session has begun, the user can list the server directory contents or log out. The user can list the server directory as often as they like during the session, but when the user logs out from the FTP server, the session is ended and she is back where she started. The user must begin a new session by logging in to an FTP server again before she can list the server files or log out again. We will examine in turn each of the following FTP operations: login, list, and logout.

Login

The user starts an FTP session ...