Fix eval() security risk, input validation, and symbol typos in Converter

Converter/converter.py

@@ -1,19 +1,19 @@
-from converter_values import *  # import required files
+from converter_values import options, CATEGORIES
 
 def main():
     print(options["help"])  # prints help menu
     res = input("Response: ")
 
     while res.lower() != "q":  # program loop
         try:
-            res = res.strip().split(" ")
+            tokens = res.strip().split(" ")
 
-            if len(res) == 1:
-                display_help(res[0])  # display help menu
-            elif len(res) == 4:
-                perform_conversion(res)  # perform unit conversion
+            if len(tokens) == 1:
+                display_help(tokens[0])  # display help menu
+            elif len(tokens) == 4:
+                perform_conversion(tokens)  # perform unit conversion
             else:
-                print("Invalid command")
+                print("Invalid command. Format: <Category> <Unit> <Value> <TargetUnits>")
 
         except Exception as e:
             print("Error:", e)
@@ -22,15 +22,44 @@ def main():
 
 def display_help(command):
     """Display help menu."""
-    print(options[command])
+    if command in options:
+        print(options[command])
+    else:
+        print(f"Unknown command '{command}'. Type 'help' or 'symbols'.")
 
 def perform_conversion(res):
-    """Perform unit conversion."""
-    for i in res[3].split(','):
-        value = round(eval("{} * {}['{}'] / {}['{}']".format(res[2], res[0], i, res[0], res[1])), 6)  # calculating
-        print("{} \t : {}".format(i, value))  # displaying
+    """Perform unit conversion cleanly without unsafe eval."""
+    category_code = res[0].upper()
+    src_unit = res[1]
+
+    if category_code not in CATEGORIES:
+        print(f"Invalid category '{res[0]}'. Valid categories: {', '.join(CATEGORIES.keys())}")
+        return
+
+    unit_dict = CATEGORIES[category_code]
+
+    if src_unit not in unit_dict:
+        print(f"Invalid source unit '{src_unit}' for category '{category_code}'.")
+        return
+
+    try:
+        raw_val = float(res[2])
+    except ValueError:
+        print(f"Invalid numeric value '{res[2]}'.")
+        return
+
+    target_units = [u.strip() for u in res[3].split(',')]
+    for target in target_units:
+        if target not in unit_dict:
+            print(f"Invalid target unit '{target}' for category '{category_code}'.")
+            continue
+
+        # Calculation: val * unit_dict[target] / unit_dict[src_unit]
+        calc_value = round((raw_val * unit_dict[target]) / unit_dict[src_unit], 6)
+        print("{} \t : {}".format(target, calc_value))
 
 if __name__ == "__main__":
     main()
 
 
+

Converter/converter_values.py

@@ -7,7 +7,7 @@
 inch : in
 kilometer : km
 meter : m
-micrometer ; um
+micrometer : um
 mile : mi
 millimeter : mm
 nanometer : nm
@@ -21,7 +21,7 @@
 sq inch : in2
 sq km : km2
 sq m : m2
-sq mile : mi
+sq mile : mi2
 sq yard : yd2
 
 VOLUME : V ----------------------------------------------------------------
@@ -115,3 +115,12 @@
     "min":1440  ,
     "sec":86400 }
 
+CATEGORIES = {
+    "L": L,
+    "A": A,
+    "V": V,
+    "M": M,
+    "T": T
+}
+
+