1 files changed, 51 insertions, 0 deletions
diff --git a/ncat/scripts/conditional.lua b/ncat/scripts/conditional.lua
new file mode 100644
index 0000000..76817b2
--- /dev/null
+++ b/ncat/scripts/conditional.lua
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+--This is another --lua-exec demo. It displays a menu to a user, waits for her
+--input and makes a decision according to what the user entered. All happens
+--in an infinite loop.
+
+--This function reads a line of at most 8096 bytes (or whatever the first
+--parameter says) from standard input. Returns the string and a boolean value
+--that is true if we hit the newline (defined as "\n") or false if the line had
+--to be truncated. This is here because io.stdin:read("*line") could lead to
+--memory exhaustion if we received gigabytes of characters with no newline.
+function read_line(max_len)
+    local ret = ""
+    for i = 1, (max_len or 8096) do
+        local chr = io.read(1)
+        if chr == "\n" then
+            return ret, true
+        end
+        ret = ret .. chr
+    end
+
+    return ret, false
+end
+
+while true do
+
+  print "Here's a menu for you: "
+  print "1. Repeat the menu."
+  print "0. Exit."
+
+  io.write "Please enter your choice: "
+  io.flush(io.stdout)
+  i = read_line()
+
+  --WARNING! Without this line, the script will go into an infinite loop
+  --that keeps consuming system resources when the connection gets broken.
+  --Ncat's subprocesses are NOT killed in this case!
+  if i == nil then
+    break
+  end
+
+  print("You wrote: ", i, ".")
+
+  if i == "0" then
+    break
+  elseif i == "1" then
+    print "As you wish."
+  else
+    print "No idea what you meant. Please try again."
+  end
+
+  print() --print a newline
+end