CS1520 Session 2 - Simple Router

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CS1520 recitation class slides

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CS1520 Session 2 - Simple Router

  1. 1. SIMPLE ROUTER Salim Malakouti
  2. 2. Goal  Work with dates in PHP  Handle a simple form  Get to know $_SERVER and $_GET variables more  Work with .htaccess files
  3. 3. What are we doing?  We are creating a website that has two functionalities:  Calendar  Shows the current date  Birthday  Receives birthday  Prints it and tells you your age
  4. 4. What else  Originally, the url of the pages are in the fomr:  localhost/example1/calendar.php  We want to change that to the style:  localhost/example1/calendar  Note that there are no .php extensions any more?
  5. 5. Where to start?  Download  Example 1  From:  http://salimm.me/courses/summer-2014/cs1520/  Or  http://salimm.me/courses/summer- 2014/cs1520/example1.zip
  6. 6. First lets take a tour  Example 1 code shown in the class
  7. 7. Calendar.php  Calendar.php ues the date function to current date. The arguments of the function indicates the format to report the date. For example:  date('l the jS') will return “Monday the 10th”  l stands for day in letters,  the stands for “the” and use to escape these characters  J stands for # of day in month and S stands for “th”  date(“d”) returns day number  date(“y”) returns 14 for 2014  date(“Y”) returns year in complete form (2014)  date(“d”) returns day of month with two leading zeros but date(“j”) returns them without leading zeros  date("F j, Y, g:i a"); returns May 19, 2014, 3:57 pm  See the full doc here:  http://php.net/manual/en/function.date.php
  8. 8. Birthday  Change birthday.php in pages to accept the inputs from user and print the following:  Current Date (date only)  Received birthday  Calculate and print approximate age in years
  9. 9. Birthday  Date  Do not use the code in calendar.php. Retrieve year, month and day individually using the date function and print the date yourself. (HINT: you can use “Y”,”m”,”d”. The difference between “Y” and “y” is that the later returns 14 for 2014.)  In the second line Print the Birthday of user (Where can you get that? Check the reserved variables $_GET, $_SERVER, $_POST)  In the third line print how old is the user in years  You will need to cast the current and input year to integers to be able to subtract them  Sample output  Today is 05/19/2014  Your bithday is 5/3/2000  You are 14 years old
  10. 10. Next we will create the Router  What do I we mean by a router?  Routers work similar to a map. It receives the URL user is requesting and allocates the PHP|JSP|RUBY|etc file that is needed to process that request  Why?  We will hide the structure of our code  Simplicity: user doesn’t have to use odd long URL like pages/birthday.php  Security: We don’t want the hackers to know the structure of our code  Users don’t have to know the file extensions that we are using  Less confusing and more secure (we don’t want the hackers to know the technology that we are using)  Etc.
  11. 11. HTTP Protocol  Before start with the code lets see what is HTTP protocol:  As we said last time: Is a protocol for communication between server and client  This communications are in form of requests and responses  (This is fairly an intuitive definition – refer to teacher’s slides for the more adequate ones.)
  12. 12. Example Request 1 Response 1 Request 2 Response 2 Request 3 Response 3
  13. 13. A sample request and respone
  14. 14. Lets check the requests and responses in our browser  Open chrome  Open Developer Tools  View>Developer>Developer Tools  Go to Network panel
  15. 15. A couple examples  http://localhost/example1  http://google.com  http://localhost/example1/pages/birthday.php  Submit the form
  16. 16. Request formats  Request:  GET  Request to get a page  HEAD  Request to get only the response’s header  POST  Request to send data to the server (form)  PUT  Request to put a file or etc in server side (file or database)  DELETE  Delete a file from serverside  Etc.
  17. 17. GET request in PHP  How can we access the responses and content of the requests?  $_SERVER  Include server info and request headers  $_GET  Includes al get data such as the data for the birthday form
  18. 18. How to do it?  Lets go back to our own example  We want to create a router file which here will be “index.php” that will receive all requests and invoke the required php file for it?  What do you think is the first step required here?
  19. 19. .htaccess  We need to redirect everything to “index.php” even if they are requesting something else.  How?  PHP can’t be used for that  We use .htaccess file processed by Apache Server
  20. 20. Creating .htaccess file  Create a .htaccess file in the root directory of your project with the following content # Turn rewriting on RewriteEngine On RewriteCond %{REQUEST_URI} !=/example1/index.php RewriteRule .* /example1/index.php
  21. 21. What does this do? # Turn rewriting on RewriteEngine On Turns on the RewriteEngine RewriteCond %{REQUEST_URI} !=/example1/index.php We will rewrite every request except ”example1/index.php” since we want to avoid recursive redirections RewriteRule .* /example1/index.php We will change everything to “/example1/index.php”
  22. 22. Creating the router  Check $_SERVER varaible usingthe following command and see the content  print_r($_SERVER);  How can you use these information to find which request is sent to “index.php” and which file to invoke for it?
  23. 23. REDIRECT_URL  Use $_SERVER['REDIRECT_URL'] and check which page has been requested  Use conditions  How to invoke the proper php file for the request?  Use include
  24. 24. Index.php format  Check for the following requests:  /example1/birthday  /example1/calendar  /example1/index.php or /example1/  Note that index.php by default is the router now. You need to have the content of the old index.php in file like main.php and invoke main.php when ever user is actually requesting index.php  Otherwise  Print : Erro: Invalid Reuqest!!!
  25. 25. Test your application  DONE

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