Web I - 05 - HTTP Protocol
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The document provides an overview of the HTTP request/response cycle in web development, illustrating how a user interacts with a web server through various requests, including GET and POST methods. It details the processes involved when a user submits a form, how data is sent and received, and includes examples of server responses. Additionally, it covers scenarios such as successful data retrieval and handling of 404 errors for nonexistent pages.
Web I - 05 - HTTP Protocol
- 2. 1 INTRODUCTION 2 HTML 3 TABLES 4 FORMS 5 HTTP 6 CSS 7 CSS FRAMEWORKS 8 DIGITAL MEDIA 2 9 USABILITY
- 4. 1. User makes request
- 5. 2. Browser sends HTTP request to server GET /comp1274/randyc/lab10done/enter country htm HTTP/1 1 /comp1274/randyc/lab10done/enter_country.htm HTTP/1.1 Accept: */* Accept-Language: en-us,en-ca;q=0.5 Accept-Encoding: gzip, deflate User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; InfoPath.1; .NET CLR 2.0.50727) Host: csweb2.mtroyal.ca Connection: Keep-Alive HTTP Request Browser Web Server
- 6. 3. Server receives and processes the HTTP request HTTP Request q Browser Web Server Retrieve Requested file
- 7. 4. Server sends HTTP response back HTTP/1.1 HTTP/1 1 200 OK Server: Microsoft-IIS/5.0 Server Date: Thu, 30 Mar 2006 19:50:54 GMT Content-Type: text/html HTTP Accept-Ranges: bytes Response Last-Modified: Fri, 24 Mar 2006 17:50:50 GMT Content-Length: 209 Browser <HTML><HEAD><TITLE>Enter A Country</TITLE></HEAD> <BODY> <FORM METHOD=POST ACTION=form_filter.asp> Enter Country Search: <INPUT TYPE=TEXT NAME=Search><P> <INPUT TYPE=SUBMIT> </FORM> </BODY></HTML>
- 8. 5. Browser displays response
- 9. 6. User submits data
- 10. 7. Browser sends HTTP request to server POST /comp1274/randyc/lab10done/form_filter.asp HTTP/1.1 p y p Accept: */* Referer: http://csweb2.mtroyal.ca/comp1274/randyc/lab10done/enter_country.htm Accept-Language: en-us,en-ca;q=0.5 Accept Lang age en s en ca q 0 5 Content-Type: application/x-www-form-urlencoded Accept-Encoding: gzip, deflate User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; InfoPath.1; .NET CLR 2.0.50727) Host: csweb2.mtroyal.ca Content-Length: 13 Connection: Keep-Alive Cache-Control: no-cache Search=Canada User entered form data goes here in the http request header as a name=value pair
- 11. Digression: What if GET rather than POST? g W G OS <FORM METHOD=GET ACTION=form_filter.asp> Then the user entered form data is added to the requested URL GET /comp1274/randyc/lab10done/form_filter.asp?Search=Canada HTTP/1.1 Versus <FORM METHOD=POST ACTION=form_filter.asp> Then the user entered form data is added to the end of HTTP request header POST /comp1274/randyc/lab10done/form_filter.asp HTTP/1.1 rest of HTTP request header goes here Search=Canada
- 12. 8. Server receives and processes the HTTP request HTTP Request q Browser Web Server Server processes the request
- 13. 9. Server script generates response sent back to b browser HTTP/1.1 200 OK / Server: Microsoft-IIS/5.0 Date: Thu, 30 Mar 2006 19:51:06 GMT Content-Length: 164 Content-Type: text/html Cache control: Cache-control: private <HTML><HEAD><TITLE>Reading Recordsets</TITLE></HEAD> <BODY> <H2>Countries</H2> <TABLE BORDER=1> <TR><TD>2</TD><TD>Canada</TD></TR> </TABLE> / / </BODY></HTML>
- 14. 10. Browser displays the response
- 15. HTTP EXAMPLE 2
- 16. 1. User makes request
- 17. 2. Browser sends HTTP request to server GET /comp1274/randyc/lab10done/data_browser.asp HTTP/1.1 Accept: */* Accept-Language: en-us,en-ca;q=0.5 p g g q Accept-Encoding: gzip, deflate User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; InfoPath.1; .NET CLR 2.0.50727) Host: csweb2.mtroyal.ca Connection: Keep-Alive
- 18. 3. Server receives and processes the HTTP request HTTP Request q Browser Web Server Server processes the request
- 19. 4. Server script generates response sent back to b browser HTTP/1.1 200 OK / Server: Microsoft-IIS/5.0 Date: Thu, 30 Mar 2006 19:51:06 GMT Content-Length: 1590 Content-Type: text/html Cache-control: private <HTML><HEAD><TITLE>Data Browser</TITLE></HEAD> <BODY> <HR>SELECT * FROM Movies WHERE RunTime < 90<HR> <TABLE BORDER=1> <TR> <TD><B>Title</B></TD> <TD><B>Release Date</B></TD> <TD><B>Run Time</B></TD> </TR> ...
- 20. 5. Browser displays the response
- 21. 6. User makes request (click on a link)
- 22. 7. Browser sends HTTP request to server GET /comp1274/randyc/lab10done/movie.asp?ID=84 HTTP/1.1 Accept: */* Referer: http://csweb2.mtroyal.ca/comp1274/randyc/lab10done/data_browser.asp Accept-Language: en-us,en-ca;q=0.5 Accept-Encoding: gzip, deflate User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; InfoPath.1; .NET CLR 2.0.50727) Host: csweb2.mtroyal.ca Connection: Keep-Alive
- 23. 8. Server receives request, processes it, and generates response HTTP/1.1 200 OK Server: Microsoft‐IIS/5.0 Date: Thu, 30 Mar 2006 19:51:06 GMT Content‐Length: 585 Content‐Type: text/html Cache‐control: private p <HTML><HEAD><TITLE>Nightmare Before Christmas, The</TITLE></HEAD> <BODY> <H1>Nightmare Before Christmas, The</H1> Directed by <B>Henry Selick</B><BR> Released on 12/9/1994<BR> Released on 12/9/1994<BR> Movie length is 76 minutes <H2>Summary</H2> ...
- 24. 9. Browser displays the response
- 25. HTTP EXAMPLE 3
- 26. 1. User makes request
- 27. 2. Browser sends HTTP request to server GET /comp1274/randyc/lab10done/does_not_exist.asp HTTP/1.1 p y p Accept: */* Accept-Language: en-us,en-ca;q=0.5 Accept-Encoding: g ip Accept Encoding gzip, deflate User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; InfoPath.1; .NET CLR 2.0.50727) Host: csweb2 mtroyal ca csweb2.mtroyal.ca Connection: Keep-Alive
- 28. 3. Server receives and processes the HTTP request HTTP Request q Browser Web Server Server processes the request
- 29. 4. Server receives request, processes it, and generates response HTTP/1.1 404 Object Not Found Server: Microsoft-IIS/5.0 Date: Thu, 30 Mar 2006 19:51:06 GMT Content-Length: 4040 Content-Type: text/html Cache-control: private p <html> ... <title>The page cannot be found</title> ... <body> <table> ... The Th page you are l ki looking f for might h i ht have b been removed, h d it d had its ...
- 30. 5. Browser displays the response