commit the first version of my httpd.lua demo - probably most advanced one so far.

ncat/scripts/httpd.lua

@@ -0,0 +1,118 @@
+input = io.stdin:read("*line")
+
+server_headers = {
+    ["Server"] = "Ncat --lua-exec httpd.lua",
+    ["Connection"] = "close",
+}
+
+function make_reply(params)
+
+    if params["status"] then
+        print(params["status"].."\r")
+    else
+        print("HTTP/1.1 200 OK")
+    end
+
+    --Not sure if it's exactly RFC RFC 1123 - no idea how Lua handles locales
+    --and what happens if the day is one-digit. TODO: check it.
+    print("Date: "..os.date("!%a, %d %b %Y %H:%M:%S GMT").."\r")
+
+    for key, value in pairs(server_headers) do
+        print(string.format("%s: %s\r", key, value))
+    end
+
+    if params["headers"] then
+        for key, value in pairs(params["headers"]) do
+            print(string.format("%s: %s\r", key, value))
+        end
+    end
+
+    if params["data"] then
+        print("Content-length: "..string.len(params["data"].."\r"))
+        print("\r")
+        print(params["data"])
+    else
+        print("\r")
+    end
+    os.exit(1)
+end
+
+function do_400()
+    make_reply({
+        ["status"] = "HTTP/1.1 400 Bad Request\r",
+        ["headers"] = {["Content-type"] = "text/html"},
+        ["data"] = "<h1>Bad request.</h1>",
+    })
+end
+
+function do_403()
+    make_reply({
+        ["status"] = "HTTP/1.1 403 Forbidden\r",
+        ["headers"] = {["Content-type"] = "text/html"},
+        ["data"] = "<h1>Forbidden.</h1>",
+    })
+end
+
+function do_404()
+    make_reply({
+        ["status"] = "HTTP/1.1 404 Not Found\r",
+        ["headers"] = {["Content-type"] = "text/html"},
+        ["data"] = "<h1>Not Found.</h1>",
+    })
+end
+
+
+
+--We assume that:
+-- * a method is alphanumeric uppercase,
+-- * resource may contain anything that's not a space,
+-- * protocol version is followed by a single space.
+pattern = "([A-Z]+ )([^ ]+) ?(.*)"
+method, resource, protocol = string.match(input, pattern)
+
+headers = {}
+while true do
+
+    input = io.stdin:read("*line")
+    if not input or input ~= "\r" then
+        break
+    end
+
+    --header line is anything before the colon (at least one character),
+    --then there's space, and the value is anything that is left,
+    --again - at least one character.
+    key, value = string.match(input, "(.+): (.+)")
+
+    if key == nil then
+        do_400()
+    end
+
+    headers[key] = value
+end
+
+--make sure that the resource starts with a slash.
+if string.sub(resource, 0, 1) ~= '/' then
+        do_400() --could probably use a fancier error here.
+end
+
+--now, remove the beginning slash
+resource = string.sub(resource, 2, string.len(resource))
+
+--if the resource was made of a slash only, let's make it index.html.
+if resource == "" then
+    resource = "index.html"
+end
+
+--if it starts with a dot, forbid any acccess to it.
+if string.sub(resource, 0, 1) == "." then
+    do_403() --no hidden Unix files or simple directory traversal, sorry!
+end
+
+--try to open the file...
+f = io.open(resource, "r")
+if not f then
+    do_404() --opening file failed, throw a 404.
+end
+
+--and output it all.
+print(f:read("*all"))