# CGI Library and core of a web server
#
# Juergen Kahrs, [email protected]
# with Arnold Robbins, [email protected]
# September 2000

# Global arrays
# GETARG --- arguments to CGI GET command
# MENU --- menu items (path names)
# PARAM --- parameters of form x=y

# Optional variable MyHost contains host address
# Optional variable MyPort contains port number
# Needs TopHeader, TopDoc, TopFooter
# Sets MyPrefix, HttpService, Status, Reason

BEGIN {
if (MyHost == "") {
"uname -n" | getline MyHost
close("uname -n")
}
if (MyPort == 0) MyPort = 8080
HttpService = "/inet/tcp/" MyPort "/0/0"
MyPrefix = "http://" MyHost ":" MyPort
SetUpServer()
while ("awk" != "complex") {
# header lines are terminated this way
RS = ORS = "\r\n"
Status = 200 # this means OK
Reason = "OK"
Header = TopHeader
Document = TopDoc
Footer = TopFooter
if (GETARG["Method"] == "GET") {
HandleGET()
} else if (GETARG["Method"] == "HEAD") {
# not yet implemented
} else if (GETARG["Method"] != "") {
print "bad method", GETARG["Method"]
}
Prompt = Header Document Footer
print "HTTP/1.0", Status, Reason |& HttpService
print "Connection: Close" |& HttpService
print "Pragma: no-cache" |& HttpService
len = length(Prompt) + length(ORS)
print "Content-length:", len |& HttpService
print ORS Prompt |& HttpService
# ignore all the header lines
while ((HttpService |& getline) > 0)
continue
# stop talking to this client
close(HttpService)
# wait for new client request
HttpService |& getline
# do some logging
print systime(), strftime(), $0
CGI_setup($1, $2, $3)
}
}

function CGI_setup( method, uri, version, i)
{
delete GETARG
delete MENU
delete PARAM
GETARG["Method"] = method
GETARG["URI"] = uri
GETARG["Version"] = version

i = index(uri, "?")
if (i > 0) { # is there a "?" indicating a CGI request?
split(substr(uri, 1, i-1), MENU, "[/:]")
split(substr(uri, i+1), PARAM, "&")
for (i in PARAM) {
PARAM[i] = _CGI_decode(PARAM[i])
j = index(PARAM[i], "=")
GETARG[substr(PARAM[i], 1, j-1)] = \
substr(PARAM[i], j+1)
}
} else { # there is no "?", no need for splitting PARAMs
split(uri, MENU, "[/:]")
}
for (i in MENU) # decode characters in path
if (i > 4) # but not those in host name
MENU[i] = _CGI_decode(MENU[i])
}
function _CGI_decode(str, hexdigs, i, pre, code1, code2,
val, result)
{
hexdigs = "123456789abcdef"

i = index(str, "%")
if (i == 0) # no work to do
return str

do {
pre = substr(str, 1, i-1) # part before %xx
code1 = substr(str, i+1, 1) # first hex digit
code2 = substr(str, i+2, 1) # second hex digit
str = substr(str, i+3) # rest of string

code1 = tolower(code1)
code2 = tolower(code2)
val = index(hexdigs, code1) * 16 \
+ index(hexdigs, code2)

result = result pre sprintf("%c", val)
i = index(str, "%")
} while (i != 0)
if (length(str) > 0)
result = result str
return result
}