Merge pull request 'Resolve #1' (#3) from issue-1 into main

Reviewed-on: #3

tg_server/tg_server.lua

@@ -34,7 +34,28 @@ local function check_for_outdated_sessions()
           #clearances .. " active session(s) remain.")
 end
 
+local function validate_key(card_holder, card_clearance, random_chars)
+    local card_hash = hash(card_holder..','..card_clearance..','..random_chars)
+    local key_file = fs.open(dir..config.key_file, 'r')
+    local card_authentic = false
 
+    while true do
+        local trusted_hash = key_file.readLine()
+        if trusted_hash == card_hash then
+            print("Valid card "..card_hash)
+            card_authentic = true
+            return true, card_hash
+        end
+        if not line then break end -- Stop when EOF reached
+    end
+
+    key_file.close()
+    
+    if card_authentic == false then
+        print("Unknown card "..card_hash)
+        return false
+    end
+end
 
 rednet.open(config.modem_side)
 rednet.host('tg', config.name)
@@ -69,28 +90,29 @@ while true do
         print("Beginning transaction for authentication with "..id)
         local card_holder = msg_parts[2]
         local card_clearance = msg_parts[3]
-        local card_hash = hash(card_holder..','..card_clearance..','..msg_parts[4])
-        local key_file = fs.open(dir..config.key_file, 'r')
-        local card_authentic = false
 
-        while true do
-            local trusted_hash = key_file.readLine()
-            if trusted_hash == card_hash then
+        local is_authentic, card_hash = validate_key(card_holder, card_clearance, msg_parts[4])
+
+        if is_authentic then
                 table.insert(clearances, { computer_id = tonumber(id), clearance_level = tonumber(card_clearance), time_granted = os.clock() })
                 rednet.send(id, "authentication successful", "tg")
                 print("Granted card "..card_hash.." clearance level "..card_clearance)
-
-                card_authentic = true
-            end
-            if not line then break end -- Stop when EOF reached
-        end
-
-        key_file.close()
-        
-        if card_authentic == false then
+        else
             print("Unknown card "..card_hash)
             rednet.send(id, "authentication failed", "tg")
         end
         print("Transaction finished")
+    elseif msg_parts[1] == 'validate_key' then
+        print("Beginning transaction for single-validation with "..id)
+        local card_holder = msg_parts[2]
+        local card_clearance = msg_parts[3]
+        local minimum_clearance = msg_parts[5]
+
+        if validate_key(card_holder, card_clearance, msg_parts[4]) and tonumber(card_clearance) >= tonumber(minimum_clearance) then
+            rednet.send(id, "authentication successful", "tg")
+        else
+            rednet.send(id, "authentication failed", "tg")
+        end
+        print("Transaction finished")
     end
 end