Wapp

# but without any warranty; without even the implied warranty of
# merchantability or fitness for a particular purpose.
#
#---------------------------------------------------------------------------
#
# Design rules:
#
#   (1)  All identifiers in the global namespace begin with "wapp"
#   (1)  All identifiers in the global namespace begin with "w3"
#
#   (2)  Indentifiers intended for internal use only begin with "wappInt"
#   (2)  Indentifiers intended for internal use only begin with "w3Int"
#
package require Tcl 8.6

# Add text to the end of the HTTP reply.  No interpretation or transformation
# of the text is performs.  The argument should be enclosed within {...}
#
proc wapp {txt} {
  global wapp
  dict append wapp .reply $txt
proc w3 {txt} {
  global w3
  dict append w3 .reply $txt
}

# Add text to the page under construction.  Do no escaping on the text.
#
# Though "unsafe" in general, there are uses for this kind of thing.
# For example, if you want to return the complete, unmodified content of
# a file:
#
#         set fd [open content.html rb]
#         wapp-unsafe [read $fd]
#         w3-unsafe [read $fd]
#         close $fd
#
# You could do the same thing using ordinary "wapp" instead of "wapp-unsafe".
# The difference is that wapp-safety-check will complain about the misuse
# of "wapp", but it assumes that the person who write "wapp-unsafe" understands
# You could do the same thing using ordinary "w3" instead of "w3-unsafe".
# The difference is that w3-safety-check will complain about the misuse
# of "w3", but it assumes that the person who write "w3-unsafe" understands
# the risks.
#
# Though occasionally necessary, the use of this interface should be minimized.
#
proc wapp-unsafe {txt} {
  global wapp
  dict append wapp .reply $txt
proc w3-unsafe {txt} {
  global w3
  dict append w3 .reply $txt
}

# Add text to the end of the reply under construction.  The following
# substitutions are made:
#
#     %html(...)          Escape text for inclusion in HTML
#     %url(...)           Escape text for use as a URL

# In other words, use "%(...)%" instead of "(...)" to include the TCL string
# to substitute.
#
# The %unsafe substitution should be avoided whenever possible, obviously.
# In addition to the substitutions above, the text also does backslash
# escapes.
#
# The wapp-trim proc works the same as wapp-subst except that it also removes
# The w3-trim proc works the same as w3-subst except that it also removes
# whitespace from the left margin, so that the generated HTML/CSS/Javascript
# does not appear to be indented when delivered to the client web browser.
#
if {$tcl_version>=8.7} {
  proc wapp-subst {txt} {
    global wapp
  proc w3-subst {txt} {
    global w3
    regsub -all -command \
       {%(html|url|qp|string|unsafe){1,1}?(|%)\((.+)\)\2} $txt wappInt-enc txt
    dict append wapp .reply [subst -novariables -nocommand $txt]
       {%(html|url|qp|string|unsafe){1,1}?(|%)\((.+)\)\2} $txt w3Int-enc txt
    dict append w3 .reply [subst -novariables -nocommand $txt]
  }
  proc wapp-trim {txt} {
    global wapp
  proc w3-trim {txt} {
    global w3
    regsub -all {\n\s+} [string trim $txt] \n txt
    regsub -all -command \
       {%(html|url|qp|string|unsafe){1,1}?(|%)\((.+)\)\2} $txt wappInt-enc txt
    dict append wapp .reply [subst -novariables -nocommand $txt]
       {%(html|url|qp|string|unsafe){1,1}?(|%)\((.+)\)\2} $txt w3Int-enc txt
    dict append w3 .reply [subst -novariables -nocommand $txt]
  }
  proc wappInt-enc {all mode nu1 txt} {
    return [uplevel 2 "wappInt-enc-$mode \"$txt\""]
  proc w3Int-enc {all mode nu1 txt} {
    return [uplevel 2 "w3Int-enc-$mode \"$txt\""]
  }
} else {
  proc wapp-subst {txt} {
    global wapp
  proc w3-subst {txt} {
    global w3
    regsub -all {%(html|url|qp|string|unsafe){1,1}?(|%)\((.+)\)\2} $txt \
           {[wappInt-enc-\1 "\3"]} txt
    dict append wapp .reply [uplevel 1 [list subst -novariables $txt]]
           {[w3Int-enc-\1 "\3"]} txt
    dict append w3 .reply [uplevel 1 [list subst -novariables $txt]]
  }
  proc wapp-trim {txt} {
    global wapp
  proc w3-trim {txt} {
    global w3
    regsub -all {\n\s+} [string trim $txt] \n txt
    regsub -all {%(html|url|qp|string|unsafe){1,1}?(|%)\((.+)\)\2} $txt \
           {[wappInt-enc-\1 "\3"]} txt
    dict append wapp .reply [uplevel 1 [list subst -novariables $txt]]
           {[w3Int-enc-\1 "\3"]} txt
    dict append w3 .reply [uplevel 1 [list subst -novariables $txt]]
  }
}

# There must be a wappInt-enc-NAME routine for each possible substitution
# in wapp-subst.  Thus there are routines for "html", "url", "qp", and "unsafe".
# There must be a w3Int-enc-NAME routine for each possible substitution
# in w3-subst.  Thus there are routines for "html", "url", "qp", and "unsafe".
#
#    wappInt-enc-html           Escape text so that it is safe to use in the
#    w3Int-enc-html           Escape text so that it is safe to use in the
#                               body of an HTML document.
#
#    wappInt-enc-url            Escape text so that it is safe to pass as an
#    w3Int-enc-url            Escape text so that it is safe to pass as an
#                               argument to href= and src= attributes in HTML.
#
#    wappInt-enc-qp             Escape text so that it is safe to use as the
#    w3Int-enc-qp             Escape text so that it is safe to use as the
#                               value of a query parameter in a URL or in
#                               post data or in a cookie.
#
#    wappInt-enc-string         Escape ", ', \, and < for using inside of a
#    w3Int-enc-string         Escape ", ', \, and < for using inside of a
#                               javascript string literal.  The < character
#                               is escaped to prevent "</script>" from causing
#                               problems in embedded javascript.
#
#    wappInt-enc-unsafe         Perform no encoding at all.  Unsafe.
#    w3Int-enc-unsafe         Perform no encoding at all.  Unsafe.
#
proc wappInt-enc-html {txt} {
proc w3Int-enc-html {txt} {
  return [string map {& &amp; < &lt; > &gt; \" &quot; \\ &#92;} $txt]
}
proc wappInt-enc-unsafe {txt} {
proc w3Int-enc-unsafe {txt} {
  return $txt
}
proc wappInt-enc-url {s} {
  if {[regsub -all {[^-{}\\@~?=#_.:/a-zA-Z0-9]} $s {[wappInt-%HHchar {&}]} s]} {
proc w3Int-enc-url {s} {
  if {[regsub -all {[^-{}\\@~?=#_.:/a-zA-Z0-9]} $s {[w3Int-%HHchar {&}]} s]} {
    set s [subst -novar -noback $s]
  }
  if {[regsub -all {[\\{}]} $s {[wappInt-%HHchar \\&]} s]} {
  if {[regsub -all {[\\{}]} $s {[w3Int-%HHchar \\&]} s]} {
    set s [subst -novar -noback $s]
  }
  return $s
}
proc w3Int-enc-qp {s} {
  if {[regsub -all {[^-{}\\_.a-zA-Z0-9]} $s {[w3Int-%HHchar {&}]} s]} {
    set s [subst -novar -noback $s]
  }
  if {[regsub -all {[\\{}]} $s {[w3Int-%HHchar \\&]} s]} {
    set s [subst -novar -noback $s]
  }
  return $s
}
proc wappInt-enc-qp {s} {
  if {[regsub -all {[^-{}\\_.a-zA-Z0-9]} $s {[wappInt-%HHchar {&}]} s]} {
    set s [subst -novar -noback $s]
  }
  if {[regsub -all {[\\{}]} $s {[wappInt-%HHchar \\&]} s]} {
    set s [subst -novar -noback $s]
  }
  return $s
}
proc wappInt-enc-string {s} {
proc w3Int-enc-string {s} {
  return [string map {\\ \\\\ \" \\\" ' \\' < \\u003c \n \\n \r \\r
  	     \f \\f \t \\t \x01 \\u0001 \x02 \\u0002 \x03 \\u0003
  	     \x04 \\u0004 \x05 \\u0005 \x06 \\u0006 \x07 \\u0007
  	     \x0b \\u000b \x0e \\u000e \x0f \\u000f \x10 \\u0010
  	     \x11 \\u0011 \x12 \\u0012 \x13 \\u0013 \x14 \\u0014
  	     \x15 \\u0015 \x16 \\u0016 \x17 \\u0017 \x18 \\u0018
  	     \x19 \\u0019 \x1a \\u001a \x1b \\u001b \x1c \\u001c
  	     \x1d \\u001d \x1e \\u001e \x1f \\u001f} $s]
}

# This is a helper routine for wappInt-enc-url and wappInt-enc-qp.  It returns
# This is a helper routine for w3Int-enc-url and w3Int-enc-qp.  It returns
# an appropriate %HH encoding for the single character c.  If c is a unicode
# character, then this routine might return multiple bytes:  %HH%HH%HH
#
proc wappInt-%HHchar {c} {
proc w3Int-%HHchar {c} {
  if {$c==" "} {return +}
  return [regsub -all .. [binary encode hex [encoding convertto utf-8 $c]] {%&}]
}


# Undo the www-url-encoded format.
#
# HT: This code stolen from ncgi.tcl
#
proc wappInt-decode-url {str} {
proc w3Int-decode-url {str} {
  set str [string map [list + { } "\\" "\\\\" \[ \\\[ \] \\\]] $str]
  regsub -all -- \
      {%([Ee][A-Fa-f0-9])%([89ABab][A-Fa-f0-9])%([89ABab][A-Fa-f0-9])} \
      $str {[encoding convertfrom utf-8 [binary decode hex \1\2\3]]} str
  regsub -all -- \
      {%([CDcd][A-Fa-f0-9])%([89ABab][A-Fa-f0-9])}                     \
      $str {[encoding convertfrom utf-8 [binary decode hex \1\2]]} str
  regsub -all -- {%([0-7][A-Fa-f0-9])} $str {\\u00\1} str
  return [subst -novar $str]
}

# Reset the document back to an empty string.
#
proc wapp-reset {} {
  global wapp
  dict set wapp .reply {}
proc w3-reset {} {
  global w3
  dict set w3 .reply {}
}

# Change the mime-type of the result document.
#
proc wapp-mimetype {x} {
  global wapp
  dict set wapp .mimetype $x
proc w3-mimetype {x} {
  global w3
  dict set w3 .mimetype $x
}

# Change the reply code.
#
proc wapp-reply-code {x} {
  global wapp
  dict set wapp .reply-code $x
proc w3-reply-code {x} {
  global w3
  dict set w3 .reply-code $x
}

# Set a cookie
#
proc wapp-set-cookie {name value} {
  global wapp
  dict lappend wapp .new-cookies $name $value
proc w3-set-cookie {name value} {
  global w3
  dict lappend w3 .new-cookies $name $value
}

# Unset a cookie
#
proc wapp-clear-cookie {name} {
  wapp-set-cookie $name {}
proc w3-clear-cookie {name} {
  w3-set-cookie $name {}
}

# Add extra entries to the reply header
#
proc wapp-reply-extra {name value} {
  global wapp
  dict lappend wapp .reply-extra $name $value
proc w3-reply-extra {name value} {
  global w3
  dict lappend w3 .reply-extra $name $value
}

# Specifies how the web-page under construction should be cached.
# The argument should be one of:
#
#    no-cache
#    max-age=N             (for some integer number of seconds, N)
#    private,max-age=N
#
proc wapp-cache-control {x} {
  wapp-reply-extra Cache-Control $x
proc w3-cache-control {x} {
  w3-reply-extra Cache-Control $x
}

# Redirect to a different web page
#
proc wapp-redirect {uri} {
  wapp-reset
  wapp-reply-code {303 Redirect}
  wapp-reply-extra Location $uri
proc w3-redirect {uri} {
  w3-reset
  w3-reply-code {303 Redirect}
  w3-reply-extra Location $uri
}

# Return the value of a wapp parameter
# Return the value of a w3 parameter
#
proc wapp-param {name {dflt {}}} {
  global wapp
  if {![dict exists $wapp $name]} {return $dflt}
  return [dict get $wapp $name]
proc w3-param {name {dflt {}}} {
  global w3
  if {![dict exists $w3 $name]} {return $dflt}
  return [dict get $w3 $name]
}

# Return true if a and only if the wapp parameter $name exists
# Return true if a and only if the w3 parameter $name exists
#
proc wapp-param-exists {name} {
  global wapp
  return [dict exists $wapp $name]
proc w3-param-exists {name} {
  global w3
  return [dict exists $w3 $name]
}

# Set the value of a wapp parameter
# Set the value of a w3 parameter
#
proc wapp-set-param {name value} {
  global wapp
  dict set wapp $name $value
proc w3-set-param {name value} {
  global w3
  dict set w3 $name $value
}

# Return all parameter names that match the GLOB pattern, or all
# names if the GLOB pattern is omitted.
#
proc wapp-param-list {{glob {*}}} {
  global wapp
  return [dict keys $wapp $glob]
proc w3-param-list {{glob {*}}} {
  global w3
  return [dict keys $w3 $glob]
}

# By default, Wapp does not decode query parameters and POST parameters
# By default, W3 does not decode query parameters and POST parameters
# for cross-origin requests.  This is a security restriction, designed to
# help prevent cross-site request forgery (CSRF) attacks.
#
# As a consequence of this restriction, URLs for sites generated by Wapp
# As a consequence of this restriction, URLs for sites generated by W3
# that contain query parameters will not work as URLs found in other
# websites.  You cannot create a link from a second website into a Wapp
# websites.  You cannot create a link from a second website into a W3
# website if the link contains query planner, by default.
#
# Of course, it is sometimes desirable to allow query parameters on external
# links.  For URLs for which this is safe, the application should invoke
# wapp-allow-xorigin-params.  This procedure tells Wapp that it is safe to
# w3-allow-xorigin-params.  This procedure tells W3 that it is safe to
# go ahead and decode the query parameters even for cross-site requests.
#
# In other words, for Wapp security is the default setting.  Individual pages
# In other words, for W3 security is the default setting.  Individual pages
# need to actively disable the cross-site request security if those pages
# are safe for cross-site access.
#
proc wapp-allow-xorigin-params {} {
  global wapp
  if {![dict exists $wapp .qp] && ![dict get $wapp SAME_ORIGIN]} {
    wappInt-decode-query-params
proc w3-allow-xorigin-params {} {
  global w3
  if {![dict exists $w3 .qp] && ![dict get $w3 SAME_ORIGIN]} {
    w3Int-decode-query-params
  }
}

# Set the content-security-policy.
#
# The default content-security-policy is very strict:  "default-src 'self'"
# The default policy prohibits the use of in-line javascript or CSS.
#
# Provide an alternative CSP as the argument.  Or use "off" to disable
# the CSP completely.
#
proc wapp-content-security-policy {val} {
  global wapp
proc w3-content-security-policy {val} {
  global w3
  if {$val=="off"} {
    dict unset wapp .csp
    dict unset w3 .csp
  } else {
    dict set wapp .csp $val
    dict set w3 .csp $val
  }
}

# Examine the bodys of all procedures in this program looking for
# unsafe calls to various Wapp interfaces.  Return a text string
# unsafe calls to various W3 interfaces.  Return a text string
# containing warnings. Return an empty string if all is ok.
#
# This routine is advisory only.  It misses some constructs that are
# dangerous and flags others that are safe.
#
proc wapp-safety-check {} {
proc w3-safety-check {} {
  set res {}
  foreach p [info command] {
    set ln 0
    foreach x [split [info body $p] \n] {
      incr ln
      if {[regexp {^[ \t]*wapp[ \t]+([^\n]+)} $x all tail]
      if {[regexp {^[ \t]*w3[ \t]+([^\n]+)} $x all tail]
       && [string index $tail 0]!="\173"
       && [regexp {[[$]} $tail]
      } {
        append res "$p:$ln: unsafe \"wapp\" call: \"[string trim $x]\"\n"
        append res "$p:$ln: unsafe \"w3\" call: \"[string trim $x]\"\n"
      }
      if {[regexp {^[ \t]*wapp-(subst|trim)[ \t]+[^\173]} $x all cx]} {
        append res "$p:$ln: unsafe \"wapp-$cx\" call: \"[string trim $x]\"\n"
      if {[regexp {^[ \t]*w3-(subst|trim)[ \t]+[^\173]} $x all cx]} {
        append res "$p:$ln: unsafe \"w3-$cx\" call: \"[string trim $x]\"\n"
      }
    }
  }
  return $res
}

# Return a string that descripts the current environment.  Applications
# might find this useful for debugging.
#
proc wapp-debug-env {} {
  global wapp
proc w3-debug-env {} {
  global w3
  set out {}
  foreach var [lsort [dict keys $wapp]] {
  foreach var [lsort [dict keys $w3]] {
    if {[string index $var 0]=="."} continue
    append out "$var = [list [dict get $wapp $var]]\n"
    append out "$var = [list [dict get $w3 $var]]\n"
  }
  append out "\[pwd\] = [list [pwd]]\n"
  return $out
}

# Tracing function for each HTTP request.  This is overridden by wapp-start
# Tracing function for each HTTP request.  This is overridden by w3-start
# if tracing is enabled.
#
proc wappInt-trace {} {}
proc w3Int-trace {} {}

# Start up a listening socket.  Arrange to invoke wappInt-new-connection
# Start up a listening socket.  Arrange to invoke w3Int-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".
#    w3mode        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]} {
proc w3Int-start-listener {port w3mode fromip} {
  if {[string match *scgi $w3mode]} {
    set type SCGI
    set server [list wappInt-new-connection \
                wappInt-scgi-readable $wappmode $fromip]
    set server [list w3Int-new-connection \
                w3Int-scgi-readable $w3mode $fromip]
  } else {
    set type HTTP
    set server [list wappInt-new-connection \
                wappInt-http-readable $wappmode $fromip]
    set server [list w3Int-new-connection \
                w3Int-http-readable $w3mode $fromip]
  }
  if {$wappmode=="local" || $wappmode=="scgi"} {
  if {$w3mode=="local" || $w3mode=="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:$port/
  if {$w3mode=="local"} {
    w3Int-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 $URL
#
proc wappInt-start-browser {url} {
proc w3Int-start-browser {url} {
  global tcl_platform
  if {$tcl_platform(platform)=="windows"} {
    exec cmd /c start $url &
  } elseif {$tcl_platform(os)=="Darwin"} {
    exec open $url &
  } elseif {[catch {exec -ignorestderr xdg-open $url}]} {
    exec firefox $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
proc w3Int-new-connection {callback w3mode fromip chan ip port} {
  upvar #0 w3Int-$chan W
  if {$fromip!="" && ![string match $fromip $ip]} {
    close $chan
    return
  }
  set W [dict create REMOTE_ADDR $ip REMOTE_PORT $port WAPP_MODE $wappmode \
  set W [dict create REMOTE_ADDR $ip REMOTE_PORT $port W3_MODE $w3mode \
         .header {}]
  fconfigure $chan -blocking 0 -translation binary
  fileevent $chan readable [list $callback $chan]
}

# Close an input channel
#
proc wappInt-close-channel {chan} {
proc w3Int-close-channel {chan} {
  if {$chan=="stdout"} {
    # This happens after completing a CGI request
    exit 0
  } else {
    unset ::wappInt-$chan
    unset ::w3Int-$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]} {
proc w3Int-http-readable {chan} {
  if {[catch [list w3Int-http-readable-unsafe $chan] msg]} {
    puts stderr "$msg\n$::errorInfo"
    wappInt-close-channel $chan
    w3Int-close-channel $chan
  }
}
proc wappInt-http-readable-unsafe {chan} {
  upvar #0 wappInt-$chan W wapp wapp
proc w3Int-http-readable-unsafe {chan} {
  upvar #0 w3Int-$chan W w3 w3
  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} {
      if {[dict get $W .header]=="" || [regexp {^\s+} $line]} {

      if {[info exists ::argv0]} {
        set a0 [file normalize $argv0]
      } else {
        set a0 /
      }
      dict set W SCRIPT_FILENAME $a0
      dict set W DOCUMENT_ROOT [file dir $a0]
      if {[wappInt-parse-header $chan]} {
      if {[w3Int-parse-header $chan]} {
        catch {close $chan}
        return
      }
      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
        set w3 $W
        w3Int-handle-request $chan
      }
    }
  } 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
      set w3 $W
      w3Int-handle-request $chan
    }
  }
}

# Decode the HTTP request header.
#
# This routine is always running inside of a [catch], so if
# any problems arise, simply raise an error.
#
proc wappInt-parse-header {chan} {
  upvar #0 wappInt-$chan W
proc w3Int-parse-header {chan} {
  upvar #0 w3Int-$chan W
  set hdr [split [dict get $W .header] \n]
  if {$hdr==""} {return 1}
  set req [lindex $hdr 0]
  dict set W REQUEST_METHOD [set method [lindex $req 0]]
  if {[lsearch {GET HEAD POST} $method]<0} {
    error "unsupported request method: \"[dict get $W REQUEST_METHOD]\""
  }

  }
  return 0
}

# Decode the QUERY_STRING parameters from a GET request or the
# application/x-www-form-urlencoded CONTENT from a POST request.
#
# This routine sets the ".qp" element of the ::wapp dict as a signal
# This routine sets the ".qp" element of the ::w3 dict as a signal
# that query parameters have already been decoded.
#
proc wappInt-decode-query-params {} {
  global wapp
  dict set wapp .qp 1
  if {[dict exists $wapp QUERY_STRING]} {
    foreach qterm [split [dict get $wapp QUERY_STRING] &] {
proc w3Int-decode-query-params {} {
  global w3
  dict set w3 .qp 1
  if {[dict exists $w3 QUERY_STRING]} {
    foreach qterm [split [dict get $w3 QUERY_STRING] &] {
      set qsplit [split $qterm =]
      set nm [lindex $qsplit 0]
      if {[regexp {^[a-z][a-z0-9]*$} $nm]} {
        dict set wapp $nm [wappInt-decode-url [lindex $qsplit 1]]
        dict set w3 $nm [w3Int-decode-url [lindex $qsplit 1]]
      }
    }
  }
  if {[dict exists $wapp CONTENT_TYPE] && [dict exists $wapp CONTENT]} {
    set ctype [dict get $wapp CONTENT_TYPE]
  if {[dict exists $w3 CONTENT_TYPE] && [dict exists $w3 CONTENT]} {
    set ctype [dict get $w3 CONTENT_TYPE]
    if {$ctype=="application/x-www-form-urlencoded"} {
      foreach qterm [split [string trim [dict get $wapp CONTENT]] &] {
      foreach qterm [split [string trim [dict get $w3 CONTENT]] &] {
        set qsplit [split $qterm =]
        set nm [lindex $qsplit 0]
        if {[regexp {^[a-z][-a-z0-9_]*$} $nm]} {
          dict set wapp $nm [wappInt-decode-url [lindex $qsplit 1]]
          dict set w3 $nm [w3Int-decode-url [lindex $qsplit 1]]
        }
      }
    } elseif {[string match multipart/form-data* $ctype]} {
      regexp {^(.*?)\r\n(.*)$} [dict get $wapp CONTENT] all divider body
      regexp {^(.*?)\r\n(.*)$} [dict get $w3 CONTENT] all divider body
      set ndiv [string length $divider]
      while {[string length $body]} {
        set idx [string first $divider $body]
        set unit [string range $body 0 [expr {$idx-3}]]
        set body [string range $body [expr {$idx+$ndiv+2}] end]
        if {[regexp {^Content-Disposition: form-data; (.*?)\r\n\r\n(.*)$} \
             $unit unit hdr content]} {
          if {[regexp {name="(.*)"; filename="(.*)"\r\nContent-Type: (.*?)$}\
                $hdr hr name filename mimetype]
              && [regexp {^[a-z][a-z0-9]*$} $name]} {
            dict set wapp $name.filename \
            dict set w3 $name.filename \
              [string map [list \\\" \" \\\\ \\] $filename]
            dict set wapp $name.mimetype $mimetype
            dict set wapp $name.content $content
            dict set w3 $name.mimetype $mimetype
            dict set w3 $name.content $content
          } elseif {[regexp {name="(.*)"} $hdr hr name]
                    && [regexp {^[a-z][a-z0-9]*$} $name]} {
            dict set wapp $name $content
            dict set w3 $name $content
          }
        }
      }
    }
  }
}

# Invoke application-supplied methods to generate a reply to
# a single HTTP request.
#
# This routine uses the global variable ::wapp and so must not be nested.
# This routine uses the global variable ::w3 and so must not be nested.
# It must run to completion before the next instance runs.  If a recursive
# instances of this routine starts while another is running, the the
# recursive instance is added to a queue to be invoked after the current
# instance finishes.  Yes, this means that WAPP IS SINGLE THREADED.  Only
# instance finishes.  Yes, this means that W3 IS SINGLE THREADED.  Only
# a single page rendering instance my be running at a time.  There can
# be multiple HTTP requests inbound at once, but only one my be processed
# at a time once the request is full read and parsed.
#
set wappIntPending {}
set wappIntLock 0
proc wappInt-handle-request {chan} {
  global wappIntPending wappIntLock
set w3IntPending {}
set w3IntLock 0
proc w3Int-handle-request {chan} {
  global w3IntPending w3IntLock
  fileevent $chan readable {}
  if {$wappIntLock} {
  if {$w3IntLock} {
    # Another instance of request is already running, so defer this one
    lappend wappIntPending [list wappInt-handle-request $chan]
    lappend w3IntPending [list w3Int-handle-request $chan]
    return
  }
  set wappIntLock 1
  catch [list wappInt-handle-request-unsafe $chan]
  set wappIntLock 0
  if {[llength $wappIntPending]>0} {
  set w3IntLock 1
  catch [list w3Int-handle-request-unsafe $chan]
  set w3IntLock 0
  if {[llength $w3IntPending]>0} {
    # If there are deferred requests, then launch the oldest one
    after idle [lindex $wappIntPending 0]
    set wappIntPending [lrange $wappIntPending 1 end]
    after idle [lindex $w3IntPending 0]
    set w3IntPending [lrange $w3IntPending 1 end]
  }
}
proc wappInt-handle-request-unsafe {chan} {
  global wapp
  dict set wapp .reply {}
  dict set wapp .mimetype {text/html; charset=utf-8}
  dict set wapp .reply-code {200 Ok}
  dict set wapp .csp {default-src 'self'}
proc w3Int-handle-request-unsafe {chan} {
  global w3
  dict set w3 .reply {}
  dict set w3 .mimetype {text/html; charset=utf-8}
  dict set w3 .reply-code {200 Ok}
  dict set w3 .csp {default-src 'self'}

  # 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]
  if {![dict exists $w3 HTTP_HOST]} {
    dict set w3 BASE_URL {}
  } elseif {[dict exists $w3 HTTPS]} {
    dict set w3 BASE_URL https://[dict get $w3 HTTP_HOST]
  } else {
    dict set wapp BASE_URL http://[dict get $wapp HTTP_HOST]
    dict set w3 BASE_URL http://[dict get $w3 HTTP_HOST]
  }
  if {![dict exists $wapp REQUEST_URI]} {
    dict set wapp REQUEST_URI /
  if {![dict exists $w3 REQUEST_URI]} {
    dict set w3 REQUEST_URI /
  }
  if {[dict exists $wapp SCRIPT_NAME]} {
    dict append wapp BASE_URL [dict get $wapp SCRIPT_NAME]
  if {[dict exists $w3 SCRIPT_NAME]} {
    dict append w3 BASE_URL [dict get $w3 SCRIPT_NAME]
  } else {
    dict set wapp SCRIPT_NAME {}
    dict set w3 SCRIPT_NAME {}
  }
  if {![dict exists $wapp PATH_INFO]} {
  if {![dict exists $w3 PATH_INFO]} {
    # If PATH_INFO is missing (ex: nginx) then construct it
    set URI [dict get $wapp REQUEST_URI]
    set URI [dict get $w3 REQUEST_URI]
    regsub {\?.*} $URI {} URI
    set skip [string length [dict get $wapp SCRIPT_NAME]]
    dict set wapp PATH_INFO [string range $URI $skip end]
    set skip [string length [dict get $w3 SCRIPT_NAME]]
    dict set w3 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 $tail /]
  if {[regexp {^/([^/]+)(.*)$} [dict get $w3 PATH_INFO] all head tail]} {
    dict set w3 PATH_HEAD $head
    dict set w3 PATH_TAIL [string trimleft $tail /]
  } else {
    dict set wapp PATH_INFO {}
    dict set wapp PATH_HEAD {}
    dict set wapp PATH_TAIL {}
    dict set w3 PATH_INFO {}
    dict set w3 PATH_HEAD {}
    dict set w3 PATH_TAIL {}
  }
  dict set wapp SELF_URL [dict get $wapp BASE_URL]/[dict get $wapp PATH_HEAD]
  dict set w3 SELF_URL [dict get $w3 BASE_URL]/[dict get $w3 PATH_HEAD]

  # Parse query parameters from the query string, the cookies, and
  # POST data
  #
  if {[dict exists $wapp HTTP_COOKIE]} {
    foreach qterm [split [dict get $wapp HTTP_COOKIE] {;}] {
  if {[dict exists $w3 HTTP_COOKIE]} {
    foreach qterm [split [dict get $w3 HTTP_COOKIE] {;}] {
      set qsplit [split [string trim $qterm] =]
      set nm [lindex $qsplit 0]
      if {[regexp {^[a-z][-a-z0-9_]*$} $nm]} {
        dict set wapp $nm [wappInt-decode-url [lindex $qsplit 1]]
        dict set w3 $nm [w3Int-decode-url [lindex $qsplit 1]]
      }
    }
  }
  set same_origin 0
  if {[dict exists $wapp HTTP_REFERER]} {
    set referer [dict get $wapp HTTP_REFERER]
    set base [dict get $wapp BASE_URL]
  if {[dict exists $w3 HTTP_REFERER]} {
    set referer [dict get $w3 HTTP_REFERER]
    set base [dict get $w3 BASE_URL]
    if {$referer==$base || [string match $base/* $referer]} {
      set same_origin 1
    }
  }
  dict set wapp SAME_ORIGIN $same_origin
  dict set w3 SAME_ORIGIN $same_origin
  if {$same_origin} {
    wappInt-decode-query-params
    w3Int-decode-query-params
  }

  # Invoke the application-defined handler procedure for this page
  # request.  If an error occurs while running that procedure, generate
  # an HTTP reply that contains the error message.
  #
  wapp-before-dispatch-hook
  wappInt-trace
  set mname [dict get $wapp PATH_HEAD]
  w3-before-dispatch-hook
  w3Int-trace
  set mname [dict get $w3 PATH_HEAD]
  if {[catch {
    if {$mname!="" && [llength [info command wapp-page-$mname]]>0} {
      wapp-page-$mname
    if {$mname!="" && [llength [info command w3-page-$mname]]>0} {
      w3-page-$mname
    } else {
      wapp-default
      w3-default
    }
  } msg]} {
    if {[wapp-param WAPP_MODE]=="local" || [wapp-param WAPP_MODE]=="server"} {
    if {[w3-param W3_MODE]=="local" || [w3-param W3_MODE]=="server"} {
      puts "ERROR: $::errorInfo"
    }
    wapp-reset
    wapp-reply-code "500 Internal Server Error"
    wapp-mimetype text/html
    wapp-trim {
      <h1>Wapp Application Error</h1>
    w3-reset
    w3-reply-code "500 Internal Server Error"
    w3-mimetype text/html
    w3-trim {
      <h1>W3 Application Error</h1>
      <pre>%html($::errorInfo)</pre>
    }
    dict unset wapp .new-cookies
    dict unset w3 .new-cookies
  }
  wapp-before-reply-hook
  w3-before-reply-hook

  # Transmit the HTTP reply
  #
  set rc [dict get $wapp .reply-code]
  set rc [dict get $w3 .reply-code]
  if {$rc=="ABORT"} {
    # If the page handler invokes "wapp-reply-code ABORT" then close the
    # If the page handler invokes "w3-reply-code ABORT" then close the
    # TCP/IP connection without sending any reply
    wappInt-close-channel $chan
    w3Int-close-channel $chan
    return
  } elseif {$chan=="stdout"} {
    puts $chan "Status: $rc\r"
  } else {
    puts $chan "HTTP/1.1 $rc\r"
    puts $chan "Server: wapp\r"
    puts $chan "Server: w3\r"
    puts $chan "Connection: close\r"
  }
  if {[dict exists $wapp .reply-extra]} {
    foreach {name value} [dict get $wapp .reply-extra] {
  if {[dict exists $w3 .reply-extra]} {
    foreach {name value} [dict get $w3 .reply-extra] {
      puts $chan "$name: $value\r"
    }
  }
  if {[dict exists $wapp .csp]} {
    puts $chan "Content-Security-Policy: [dict get $wapp .csp]\r"
  if {[dict exists $w3 .csp]} {
    puts $chan "Content-Security-Policy: [dict get $w3 .csp]\r"
  }
  set mimetype [dict get $wapp .mimetype]
  set mimetype [dict get $w3 .mimetype]
  puts $chan "Content-Type: $mimetype\r"
  if {[dict exists $wapp .new-cookies]} {
    foreach {nm val} [dict get $wapp .new-cookies] {
  if {[dict exists $w3 .new-cookies]} {
    foreach {nm val} [dict get $w3 .new-cookies] {
      if {[regexp {^[a-z][-a-z0-9_]*$} $nm]} {
        if {$val==""} {
          puts $chan "Set-Cookie: $nm=; HttpOnly; Path=/; Max-Age=1\r"
        } else {
          set val [wappInt-enc-url $val]
          set val [w3Int-enc-url $val]
          puts $chan "Set-Cookie: $nm=$val; HttpOnly; Path=/\r"
        }
      }
    }
  }
  if {[string match text/* $mimetype]} {
    set reply [encoding convertto utf-8 [dict get $wapp .reply]]
    if {[regexp {\ygzip\y} [wapp-param HTTP_ACCEPT_ENCODING]]} {
      catch {wappInt-gzip-reply reply chan}
    set reply [encoding convertto utf-8 [dict get $w3 .reply]]
    if {[regexp {\ygzip\y} [w3-param HTTP_ACCEPT_ENCODING]]} {
      catch {w3Int-gzip-reply reply chan}
    }
  } else {
    set reply [dict get $wapp .reply]
    set reply [dict get $w3 .reply]
  }
  puts $chan "Content-Length: [string length $reply]\r"
  puts $chan \r
  puts -nonewline $chan $reply
  flush $chan
  wappInt-close-channel $chan
  w3Int-close-channel $chan
}

# Compress the reply content
#
proc wappInt-gzip-reply {replyVar chanVar} {
proc w3Int-gzip-reply {replyVar chanVar} {
  upvar $replyVar reply $chanVar chan
  set x [zlib gzip $reply]
  set reply $x
  puts $chan "Content-Encoding: gzip\r"
}

# This routine runs just prior to request-handler dispatch.  The
# default implementation is a no-op, but applications can override
# to do additional transformations or checks.
#
proc wapp-before-dispatch-hook {} {return}
proc w3-before-dispatch-hook {} {return}

# This routine runs after the request-handler dispatch and just
# before the reply is generated.  The default implementation is
# a no-op, but applications can override to do validation and security
# checks on the reply, such as verifying that no sensitive information
# such as an API key or password is accidentally included in the
# reply text.
#
proc wapp-before-reply-hook {} {return}
proc w3-before-reply-hook {} {return}

# Process a single CGI request
#
proc wappInt-handle-cgi-request {} {
  global wapp env
  foreach key [array names env {[A-Z]*}] {dict set wapp $key $env($key)}
proc w3Int-handle-cgi-request {} {
  global w3 env
  foreach key [array names env {[A-Z]*}] {dict set w3 $key $env($key)}
  set len 0
  if {[dict exists $wapp CONTENT_LENGTH]} {
    set len [dict get $wapp CONTENT_LENGTH]
  if {[dict exists $w3 CONTENT_LENGTH]} {
    set len [dict get $w3 CONTENT_LENGTH]
  }
  if {$len>0} {
    fconfigure stdin -translation binary
    dict set wapp CONTENT [read stdin $len]
    dict set w3 CONTENT [read stdin $len]
  }
  dict set wapp WAPP_MODE cgi
  dict set w3 W3_MODE cgi
  fconfigure stdout -translation binary
  wappInt-handle-request-unsafe stdout
  w3Int-handle-request-unsafe stdout
}

# Process new text received on an inbound SCGI request
#
proc wappInt-scgi-readable {chan} {
  if {[catch [list wappInt-scgi-readable-unsafe $chan] msg]} {
proc w3Int-scgi-readable {chan} {
  if {[catch [list w3Int-scgi-readable-unsafe $chan] msg]} {
    puts stderr "$msg\n$::errorInfo"
    wappInt-close-channel $chan
    w3Int-close-channel $chan
  }
}
proc wappInt-scgi-readable-unsafe {chan} {
  upvar #0 wappInt-$chan W wapp wapp
proc w3Int-scgi-readable-unsafe {chan} {
  upvar #0 w3Int-$chan W w3 w3
  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.
    #

    }
    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
      set w3 $W
      w3Int-handle-request $chan
    }
  } 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
      set w3 $W
      w3Int-handle-request $chan
    }
  }
}

# Start up the wapp framework.  Parameters are a list passed as the
# Start up the w3 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

#                         after all event handlers are established.
#
#    -trace               "puts" each request URL as it is handled, for
#                         debugging
#
#    -debug               Disable content compression
#
#    -lint                Run wapp-safety-check on the application instead
#    -lint                Run w3-safety-check on the application instead
#                         of running the application itself
#
#    -Dvar=value          Set TCL global variable "var" to "value"
#
#
proc wapp-start {arglist} {
proc w3-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} {

        incr i
        set fromip [lindex $arglist $i]
      }
      -nowait {
        set nowait 1
      }
      -debug {
        proc wappInt-gzip-reply {a b} {return}
        proc w3Int-gzip-reply {a b} {return}
      }
      -trace {
        proc wappInt-trace {} {
          set q [wapp-param QUERY_STRING]
          set uri [wapp-param BASE_URL][wapp-param PATH_INFO]
        proc w3Int-trace {} {
          set q [w3-param QUERY_STRING]
          set uri [w3-param BASE_URL][w3-param PATH_INFO]
          if {$q!=""} {append uri ?$q}
          puts $uri
        }
      }
      -lint {
        set res [wapp-safety-check]
        set res [w3-safety-check]
        if {$res!=""} {
          puts "Potential problems in this code:"
          puts $res
          exit 1
        } else {
          exit
        }

        && [string match CGI/1.* $env(GATEWAY_INTERFACE)]} {
      set mode cgi
    } else {
      set mode local
    }
  }
  if {$mode=="cgi"} {
    wappInt-handle-cgi-request
    w3Int-handle-cgi-request
  } else {
    wappInt-start-listener $port $mode $fromip
    w3Int-start-listener $port $mode $fromip
    if {!$nowait} {
      vwait ::forever
    }
  }
}

# Call this version 1.0
package provide wapp 1.0
package provide w3 1.0