I created a basic web page and used the net/url library to listen to a port (html / 80) on my local-host (127.0.0.1) The program then uses (net/send-url to make the user's web browser to connect to the local-host at 80, at which point the listener responds with a html formatted web-page. Creating the code for the webpage is difficult in racket, as the escape character "" must be used before symbols (quotation marks especially) so that we can use them in the strings of html code and not have them be parsed by racket. These libraries would be integral to designing a web-server based in racket, and if used in combination with modular html/scripts/web-languages, could create an interesting way of hosting online-applications. Given a static public ip, this program could be simply modified to host publicly, and the send-url function can already be used to open a browser to any public page.
It will print whether the server port is open or closed, then the function to close the port will be returned when the listener and handler is instantiated. When a user connects to the port, the program will print to the output that a user connected. When the port is closed, this will also print to the repl.
Listener for connection at port:
(define listener (tcp-listen port-no 5 #t))
(define (rept)
(handle listener)
(rept))Racket function to print the html code for the sample webpage
(define (function in out)
(print "user connected")
(regexp-match #rx"(\r\n|^)\r\n" in)
; Send reply:
(display "HTTP/1.0 200 Okay\r\n" out)
(display "Server: k\r\nContent-Type: text/html\r\n\r\n" out)
(display "<html><body>" out )
(display "<h1>Hi there. The test is working!</h1>" out)
(display "<a href=\"https://github.com/kennysandbum/FP1\" style=\" color: black\">Project Repo</a>" out)
(display "<a href=\"https://mitpress.mit.edu/sicp/\"> <img src=\"http://www.cs.uml.edu/ecg/pub/uploads/OPLspr16/sicp-cover.jpg\" alt=\"Textbook\"> </a>" out)
(display "</body></html>" out))Screenshot of webpage opened by program
Screenshot of output printed by the program to the repl
