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ITEC 325
2018spring
ibarland

intro: web requests and responses

So:

upshot: So, the essence of the situation is that the server and browser are functions with the type-signatures:
server : string → string (or, if you have very specific classes, Url → HtmlStr)
browser : string → void (or HtmlDoc → void).

        Client                             Server

        Browser            ->request->
                            (URL)
                                           WebServer (Apache)
                                             - look up file:
                                             - possibly redirect...
                                             - what if file exists, but no permissions?
                                             - what if file doesn't exist?
                                             - what if URL is a directory?
                                             - what if request from a mobile platform?
                                             - process any php (as configured)
                                               which may invoke other programs, db connections, etc
                            <-response<-
                            (html, jpg,
                             html+javascript,
                             ...)
        
       Browser
        ...makes a gui window,
           lays out text/color/pictures
           Displays response
        Also:
        ...makes add'l URL requests... [Ad blocker!]
        ...runs javascript...
        ...invokes plug-ins or passes to OS...

A couple of choices made by web servers we care about:



Further things to mention (if not today, then perhaps later:)


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