Wapp

web-browser at that script.

Run the hello-world program as SCGI like this:

>
    wapptclsh main.tcl --scgi 9000

Then configure your web-server to send SCGI requests to TCP port 9000
for some specific URI, and point your web-browser at that URI.  By
default, the web-server must be on the same machine as the wapp script.
The --scgi option only accepts SCGI requests from IP address 127.0.0.1.
If your webserver is running on a different machine, use the --remote-scgi
option instead, probably with a --fromip option to specify the IP address
of the machine that is running the webserver.

1.2 Using Plain Old Tclsh
-------------------------

Wapp applications are pure TCL code.  You can run them using an ordinary
"tclsh" command if desired, instead of the "wapptclsh" shown above.  We
normally use "wapptclsh" for the following reasons:

     it should invoke the "wapp-allow-xorigin-params" interface to explicitly
     signal that cross-origin parameters are safe for that page.

  +  **SELF\_URL**  
     The URL for the current page, stripped of query parameter. This is
     useful for filling in the action= attribute of forms.

  +  **SERVER\_ADDR**  
     In SCGI mode only, this variable is the address of the webserver from which
     the SCGI request originates.

  +  **WAPP\_MODE**  
     This parameter has a value of "cgi", "local", "scgi", or "server" depending
     on how Wapp was launched.


### 3.1 URL Parsing Example

|REMOTE\_ADDR|→|IP address of the client|
|REMOTE\_PORT|→|TCP port of the client|
|REQUEST\_METHOD|→|"GET" or "POST" or "HEAD"|
|SAME\_ORIGIN|→|True if this request is from the same origin|
|SCRIPT\_FILENAME|→|Full pathname of the Wapp application script|
|SCRIPT\_NAME|→|Prefix of PATH\_INFO that identifies the application script|
|SELF\_URL|→|URL of this request without PATH\_TAIL|
|SERVER\_ADDR|→|IP address of the webserver sending an SCGI request|
|WAPP\_MODE|→|One of "cgi", "scgi", "remote-scgi", "server", or "local"|

4.0 URL Parsing
---------------

Assuming "env.tcl" is the name of the Wapp application script:

>

# Start up a listening socket.  Arrange to invoke wappInt-new-connection
# for each inbound HTTP connection.
#
#    port            Listen on this TCP port.  0 means to select a port
#                    that is not currently in use
#
#    wappmode        One of "scgi", "remote-scgi", "server", or "local".
#
#    fromip          If not {}, then reject all requests from IP addresses
#                    other than $fromip
#
proc wappInt-start-listener {port wappmode fromip} {
  if {[string match *scgi $wappmode]} {
    set type SCGI
    set server [list wappInt-new-connection \
                wappInt-scgi-readable $wappmode $fromip]
  } else {
    set type HTTP
    set server [list wappInt-new-connection \
                wappInt-http-readable $wappmode $fromip]
  }
  if {$wappmode=="local" || $wappmode=="scgi"} {
    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 $coninfo 2]
  if {$wappmode=="local"} {
    wappInt-start-browser http://127.0.0.1:$port/
  } elseif {$fromip!=""} {
    puts "Listening for $type requests on TCP port $port from IP $fromip"
  } else {
    puts "Listening for $type requests on TCP port $port"
  }
}

# Start a web-browser and point it at $URL
#

  }
}

# This routine is a "socket -server" callback.  The $chan, $ip, and $port
# arguments are added by the socket command.
#
# Arrange to invoke $callback when content is available on the new socket.
# The $callback will process inbound HTTP or SCGI content.  Reject the
# request if $fromip is not an empty string and does not match $ip.
#
proc wappInt-new-connection {callback wappmode fromip chan ip port} {
  upvar #0 wappInt-$chan W
  if {$fromip!="" && ![string match $fromip $ip]} {
    close $chan
    return
  }
  set W [dict create REMOTE_ADDR $ip REMOTE_PORT $port WAPP_MODE $wappmode \
         .header {}]
  fconfigure $chan -blocking 0 -translation binary
  fileevent $chan readable [list $callback $chan]
}

# Close an input channel

  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.
    #
    dict set W .remove_addr [dict get $W REMOTE_ADDR]
    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
      dict set W SERVER_ADDR [dict get $W .remove_addr]
      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
      dict set W SERVER_ADDR [dict get $W .remove_addr]
      set wapp $W
      wappInt-handle-request $chan 0
    }
  }
}

# Start up the wapp framework.  Parameters are a list passed as the
# single argument.
#
#    -server $PORT         Listen for HTTP requests on this TCP port $PORT
#
#    -local $PORT          Listen for HTTP requests on 127.0.0.1:$PORT
#
#    -scgi $PORT           Listen for SCGI requests on 127.0.0.1:$PORT
#
#    -remote-scgi $PORT    Listen for SCGI requests on TCP port $PORT
#
#    -cgi                  Handle a single CGI request
#
# With no arguments, the behavior is called "auto".  In "auto" mode,
# if the GATEWAY_INTERFACE environment variable indicates CGI, then run
# as CGI.  Otherwise, start an HTTP server bound to the loopback address
# only, on an arbitrary TCP port, and automatically launch a web browser
# on that TCP port.
#
# Additional options:
#
#    -fromip GLOB         Reject any incoming request where the remote
#                         IP address does not match the GLOB pattern.  This
#                         value defaults to '127.0.0.1' for -local and -scgi.
#
#    -nowait              Do not wait in the event loop.  Return immediately
#                         after all event handlers are established.
#
#    -trace               "puts" each request URL as it is handled, for
#                         debugging
#
#    -lint                Run wapp-safety-check on the application instead
#                         of running the application itself
#
#    -Dvar=value          Set TCL global variable "var" to "value"
#
#
proc wapp-start {arglist} {
  global env
  set mode auto
  set port 0
  set nowait 0
  set fromip {}
  set n [llength $arglist]
  for {set i 0} {$i<$n} {incr i} {
    set term [lindex $arglist $i]
    if {[string match --* $term]} {set term [string range $term 1 end]}
    switch -glob -- $term {
      -server {
        incr i;
        set mode "server"
        set port [lindex $arglist $i]
      }
      -local {
        incr i;
        set mode "local"
        set fromip 127.0.0.1
        set port [lindex $arglist $i]
      }
      -scgi {
        incr i;
        set mode "scgi"
        set fromip 127.0.0.1
        set port [lindex $arglist $i]
      }
      -remote-scgi {
        incr i;
        set mode "remote-scgi"
        set port [lindex $arglist $i]
      }
      -cgi {
        set mode "cgi"
      }
      -fromip {
        incr i
        set fromip [lindex $arglist $i]
      }
      -nowait {
        set nowait 1
      }
      -trace {
        proc wappInt-trace {} {
          set q [wapp-param QUERY_STRING]
          set uri [wapp-param BASE_URL][wapp-param PATH_INFO]

        }
      }
      default {
        error "unknown option: $term"
      }
    }
  }
  if {$mode=="auto"} {
    if {[info exists env(GATEWAY_INTERFACE)]
        && [string match CGI/1.* $env(GATEWAY_INTERFACE)]} {
      set mode cgi
    } else {

      set mode local
    }
  }
  if {$mode=="cgi"} {
    wappInt-handle-cgi-request


  } else {
    wappInt-start-listener $port $mode $fromip

    if {!$nowait} {
      vwait ::forever
    }
  }
}

# Call this version 1.0
package provide wapp 1.0