Wapp

  wapp "<h1>Hello, World!</h1>\n"
  wapp "<ol>"
  wapp-unsafe "<li><p><a href='$R/env'>Wapp Environment</a></p>\n"
  wapp-unsafe "<li><p><a href='$B/fullenv'>Full Environment</a>\n"
  wapp-unsafe "<li><p><a href='$B/lint'>Lint</a>\n"
  wapp-unsafe "<li><p><a href='$B/errorout'>Deliberate error</a>\n"
  wapp "</ol>"
  if {[dict exists $wapp showenv]} {
    wapp-page-env
  }
}
proc wapp-page-env {} {
  global wapp
  wapp-set-cookie env-cookie simple
  wapp "<h1>Wapp Environment</h1>\n"
  wapp-unsafe "<form method='GET' action='[dict get $wapp SELF_URL]'>\n"
  wapp "<input type='checkbox' name='showhdr'"

  wapp "<h1>Wapp Full Environment</h1>\n"
  wapp-unsafe "<form method='POST' action='[dict get $wapp SELF_URL]'>\n"
  wapp "<input type='checkbox' name='var1'"
  if {[dict exists $wapp showhdr]} {
    wapp " checked"
  }
  wapp "> Var1\n"
  wapp "<input type='submit' name='s1' value='Go'>\n"
  wapp "<input type='hidden' name='hidden-parameter-1' "
  wapp "value='the long value / of ?$ hidden-1..<hi>'>\n"
  wapp "</form>"
  wapp "<pre>\n"
  foreach var [lsort [dict keys $wapp]] {
    if {$var==".reply"} continue
    wapp-escape-html "$var = [list [dict get $wapp $var]]\n\n"
  }
  wapp "</pre>"

       && [info exists env(GATEWAY_INTERFACE)]
       && $env(GATEWAY_INTERFACE)=="CGI/1.0")
    || $mode=="cgi"
  } {
    wappInt-handle-cgi-request
    return
  }
  if {$mode=="scgi"} {
    wappInt-start-listener $port 1 0 1
  } elseif {$mode=="server"} {
    wappInt-start-listener $port 0 0 0
  } else {
    wappInt-start-listener $port 1 1 0
  }
  vwait ::forever
}

# Start up a listening socket.  Arrange to invoke wappInt-new-connection
# for each inbound HTTP connection.
#
#    localonly   -   If true, listen on 127.0.0.1 only
#
#    browser     -   If true, launch a web browser pointing to the new server
#
proc wappInt-start-listener {port localonly browser scgi} {
  if {$scgi} {
    set type SCGI
    set server [list wappInt-new-connection wappInt-scgi-readable]
  } else {
    set type HTTP
    set server [list wappInt-new-connection wappInt-http-readable]
  }
  if {$localonly} {
    set x [socket -server $server -myaddr 127.0.0.1 $port]
  } else {
    set x [socket -server $server $port]
  }
  set coninfo [chan configure $x -sockname]
  set port [lindex $coninfo 2]
  if {$browser} {
    wappInt-start-browser http://127.0.0.1:$port/
  } else {
    puts "Listening for $type requests on TCP port $port"
  }
}

# Start a web-browser and point it at $URL
#
proc wappInt-start-browser {url} {
  global tcl_platform
  if {$tcl_platform(platform)=="windows"} {
    exec cmd /c start $url &
  } elseif {$tcl_platform(os)=="Darwin"} {
    exec open $url &
  } elseif {[catch {exec xdg-open $url}]} {
    exec firefox $url &
  }
}

# Accept a new inbound HTTP request
#
proc wappInt-new-connection {callback chan ip port} {
  upvar #0 wappInt-$chan W
  set W [dict create REMOTE_ADDR $ip REMOTE_PORT $port .header {}]
  fconfigure $chan -blocking 0 -translation binary
  fileevent $chan readable [list $callback $chan]
}

# Close an input channel
#
proc wappInt-close-channel {chan} {
  if {$chan=="stdout"} {
    # This happens after completing a CGI request
    exit 0
  } else {
    unset ::wappInt-$chan
    close $chan
  }
}

# Process new text received on an inbound HTTP request
#
proc wappInt-http-readable {chan} {
  if {[catch [list wappInt-http-readable-unsafe $chan] msg]} {
    puts stderr "$msg\n$::errorInfo"
    wappInt-close-channel $chan
  }
}
proc wappInt-http-readable-unsafe {chan} {
  upvar #0 wappInt-$chan W wapp wapp
  if {![dict exists $W .toread]} {
    # If the .toread key is not set, that means we are still reading
    # the header
    set line [string trimright [gets $chan]]
    set n [string length $line]
    if {$n>0} {

  global wapp
  dict set wapp .reply {}
  dict set wapp .mimetype {text/html; charset=utf-8}
  dict set wapp .reply-code {200 Ok}

  # Set up additional CGI environment values
  #













  if {![dict exists $wapp HTTP_HOST]} {
    dict set wapp BASE_URL {}
  } elseif {[dict exists $wapp HTTPS]} {
    dict set wapp BASE_URL https://[dict get $wapp HTTP_HOST]
  } else {
    dict set wapp BASE_URL http://[dict get $wapp HTTP_HOST]
  }
  if {![dict exists $wapp REQUEST_URI]} {
    dict set wapp REQUEST_URI /
  } elseif {[regsub {\?.*} [dict get $wapp REQUEST_URI] {} newR]} {
    # Some servers (ex: nginx) append the query parameters to REQUEST_URI.
    # These need to be stripped off
    dict set wapp REQUEST_URI $newR
  }
  if {[dict exists $wapp SCRIPT_NAME]} {
    dict append wapp BASE_URL [dict get $wapp SCRIPT_NAME]
  } else {
    dict set wapp SCRIPT_NAME {}
  }
  if {![dict exists $wapp PATH_INFO]} {
    # If PATH_INFO is missing (ex: nginx) the construct it
    set URI [dict get $wapp REQUEST_URI]
    set skip [string length [dict get $wapp SCRIPT_NAME]]
    dict set wapp PATH_INFO [string range $URI $skip end]
  }
  if {[regexp {^/([^/]+)(.*)$} [dict get $wapp PATH_INFO] all head tail]} {
    dict set wapp PATH_HEAD $head
    dict set wapp PATH_TAIL [string trimleft $tail /]
  } else {
    dict set wapp PATH_INFO {}
    dict set wapp PATH_HEAD {}
    dict set wapp PATH_TAIL {}
  }
  dict set wapp SELF_URL [dict get $wapp BASE_URL]/[dict get $wapp PATH_HEAD]

  # Parse query parameters from the query string, the cookies, and
  # POST data
  #
  if {[dict exists $wapp HTTP_COOKIE]} {

   && [dict exists $wapp CONTENT]
   && [dict exists $wapp HTTP_REFERER]
   && [string match [dict get $wapp BASE_URL]/* [dict get $wapp HTTP_REFERER]]
  } {
    foreach qterm [split [string trim [dict get $wapp CONTENT]] &] {
      set qsplit [split $qterm =]
      set nm [lindex $qsplit 0]
      if {[regexp {^[a-z][-a-z0-9_]*$} $nm]} {
        dict set wapp $nm [wappInt-url-decode [lindex $qsplit 1]]
      }
    }
  }
  # To-Do:  Perhaps add support for multipart/form-data decoding.
  # Alternatively, perhaps multipart/form-data decoding can be done
  # by application code using a separate helper function, like

  }
  if {$len>0} {
    fconfigure stdin -translation binary
    dict set wapp CONTENT [read stdin $len]
  }
  wappInt-handle-request stdout 1
}

# Process new text received on an inbound SCGI request
#
proc wappInt-scgi-readable {chan} {
  if {[catch [list wappInt-scgi-readable-unsafe $chan] msg]} {
    puts stderr "$msg\n$::errorInfo"
    wappInt-close-channel $chan
  }
}
proc wappInt-scgi-readable-unsafe {chan} {
  upvar #0 wappInt-$chan W wapp wapp
  if {![dict exists $W .toread]} {
    # If the .toread key is not set, that means we are still reading
    # the header.
    #
    # An SGI header is short.  This implementation assumes the entire
    # header is available all at once.
    #
    set req [read $chan 15]
    set n [string length $req]
    scan $req %d:%s len hdr
    incr len [string length "$len:,"]
    append hdr [read $chan [expr {$len-15}]]
    foreach {nm val} [split $hdr \000] {
      if {$nm==","} break
      dict set W $nm $val
    }
    set len 0
    if {[dict exists $W CONTENT_LENGTH]} {
      set len [dict get $W CONTENT_LENGTH]
    }
    if {$len>0} {
      # Still need to read the query content
      dict set W .toread $len
    } else {
      # There is no query content, so handle the request immediately
      set wapp $W
      wappInt-handle-request $chan 0
    }
  } else {
    # If .toread is set, that means we are reading the query content.
    # Continue reading until .toread reaches zero.
    set got [read $chan [dict get $W .toread]]
    dict append W CONTENT $got
    dict set W .toread [expr {[dict get $W .toread]-[string length $got]}]
    if {[dict get $W .toread]<=0} {
      # Handle the request as soon as all the query content is received
      set wapp $W
      wappInt-handle-request $chan 0
    }
  }
}