Make sure to run the statement in each of the. These two links lead into the personalized parts of the application. The main Mismatch page allows you to see the name and picture of the latest users, but not much else without being logged in. Download It! The complete source code for the Mismatch application is available for download from the Head First Labs web site: www. More specifically, the table is missing columns for storing a username and password for each user.
In fact, the purpose of is to provide an efficient means of uniquely identifying user rows. However, numeric IDs tend to be difficult to remember, and users really like being able to make up their own usernames for accessing personalized web applications. No one wants to be relegated to just being a number! Finish writing an SQL statement to add the username and password columns to the table positioned as shown, with username able to hold 32 characters, password able to hold 16 characters, and neither of them allowing NULL data.
Few people would want to try and remember a password longer than 16 characters! Good point Encryption in Mismatch involves converting a password into an unrecognizable format when stored in the database. Any application with user log-in support must encrypt passwords so that users can feel confident that their passwords are safe and secure. This log-in user interface needs to consist of text edit fields for the username and password, as well as a button for carrying out the log-in.
An application login requires a user interface for entering the username and password. Clicking the Log In buttonck makes the application che the username and password against the database.
The asterisks displayed in a password form field simply provide visual security, preventing someone from looking over your shoulder as you enter the password. When the form is submitted, the password itself is submitted, not the asterisks. If the username and password check out, the user is successfully logged in.
The result is an encrypted string that is exactly 40 hexadecimal characters long, regardless of the original password length. So the function actually generates a character code that uniquely represents the password. This is the actual password as entered into the password form field. The same SHA function works on the other end of the log-in equation by checking to see that the password entered by the user matches up with the encrypted password stored in the database. Instead of storing the actual passwo we store the character encrypted rd, code.
But the SHA function is a one-way encryption with no way back. This is because SHA generates the same character code as long as you provide it with the same string of text. This can be accomplished with a single SQL query that attempts to select a matching user row based on a password. This is the password entered by the user in order to log in.
Making room for the encrypted password The SHA function presents a problem for Mismatch since encrypted passwords end up being 40 characters long, but our newly created password column is only 16 characters long. In the case of SHA , the hash is the character hexadecimal encrypted string of text, which uniquely represents the original password. Q: Are there any other ways to encrypt passwords? A:SHA Yes. For a successful log-in, this must be the same password used when inserting the row.
Could we just use HTTP authentication since it requires a username and password to access protected pages? HTTP authentication will certainly work as a simple user log-in system. If you recall from the Guitar Wars high score application in the last chapter, HTTP authentication was used to restrict access to certain parts of an application by prompting the user for a username and password.
The standard HTTP authentication window, which is browser-specific, can serve as a simple log-in user interface. These headers result in the user being prompted for a username and password in order to gain access to the Admin page of Guitar Wars. This is the realm for the authentication, which applies to the entire application. Unless a user enters the correct username and password, they cannot see or use this page. Then annotate how those application pieces are impacted.
The home page plays no direct role in user log-ins because it needs to remain accessible by all. Viewing and editing profiles is restricted, meaning that only logged in users can access these pages. So the home page serves as both a teaser and a starting point—a teaser for visitors and a starting point for existing users who must log in to go any deeper into the application.
The idea is that profiles are visible to all users who log in, but remain private to guests. How does password encryption affect HTTP authentication? There are two different issues here: transmitting a password and storing a password. However, an argument could be made that encryption should also take place during the transmission of the password when the HTTP authentication window submits it to the server.
This kind of encryption is outside the scope of this chapter and, ultimately, only necessary when dealing with highly sensitive data. Read more. PHP 5. MySQL 5. Head Rush Ajax Head First. Privacy Policy. New eBooks. Search Engine. Head First PHP MySQL offers the same visually rich format that's turned every title in the Head First series into a bestseller, with plenty of exercises, quizzes, puzzles, and other interactive features to help you retain what you've learned.
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