My HW5

Scott_Submissions/HW5.py

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+# 5. What does this do? print("\007") Can you figure out why?
+
+    # It is a ASCII Bell character.
+    # It generates a beep sound or a system alert depending on the platform and environment where the code is executed.
+    # It is often used to trigger attention or alert the user in certain situations or as a way to generate a simple sound signal in text-based interfaces.
+
+    # BUT NOTHING HAPPENED ON MAC.
+
+
+
+# 6. What does this do? print("abcdefg\rhijklmnop") Can you figure out why?
+
+    # '\r' is a carriage return character
+    # When the string is printed, the carriage return character '\r' causes the cursor to return to the beginning of the line. 
+    # So when "hijklmnop" is printed, the cursor moves back to the start of the line, and the subsequent text "abcdefg" overwrites the initial characters.
+
+    # The output is gonna be 'hijklmnop'.
+
+
+
+# 7. To shut down the HTTP server afterward, using Ctrl + C to interrupt the execution of the Python program.
+
+import http.server
+import socketserver
+from urllib.parse import urlparse, parse_qs
+
+class MyRequestHandler(http.server.SimpleHTTPRequestHandler):
+    def do_GET(self):
+        self.send_response(200)
+        self.send_header('Content-type', 'text/plain')
+        self.end_headers()
+        output_string = "abcdefg\rhijklmnop"
+        self.wfile.write(output_string.encode())
+
+PORT = 8000
+Handler = MyRequestHandler
+httpd = socketserver.TCPServer(("", PORT), Handler)
+print(f"Serving on port {PORT}")
+
+httpd.serve_forever()
+
+    # The HTTP server sends the response over the network to the client, which is typically a web browser.
+    # In this function, the server sends an HTTP response with a status code of 200 and a content type of "text/plain". 
+    # The response body is set to the string "abcdefg\rhijklmnop" encoded as bytes.
+    # When the client receives this response, it interprets the \r character as a normal character and displays the entire string "abcdefg\rhijklmnop" as it is.
+
+    # The '\r' character is a carriage return character, which is a control character used to return the cursor to the beginning of the current line.
+    # The behavior of the carriage return character '\r' can depend on the platform and how the output is handled.
+
+    # For example:
+    # In Safari and Chrome, the "http://localhost:8000" shows:
+        # abcdefg
+        # hijklmnop
+    # In Macbook Terminal, the "curl http://localhost:8000" shows:
+        # hijklmnop%    
+
+
+
+# 8. Think of a way someone might try to commit a crime or hide an embezzlement scheme using the answers to the above two questions.
+
+    # The key is by manipulating or altering the output displayed on a web page versus what is actually happening in the system.
+
+    # Case 1:
+        # Show the false financial transactions to earn the cut.
+    # Case 2:
+        # Delivey the heist planning details and hide any suspicious activity.
+    # Case 3:
+        # Overwrite the previously displayed information for the false testimony purpose.
+
+
+
+# 9. Think of how you would do input validation to prevent such a crime. Replace the code REPLACE ME here so the tests pass:
+
+def validate(input_str):
+    if '\r' in input_str or '\n' in input_str:
+        raise ValueError("Crime detected!")
+
+try:
+    validate("abcdefg")
+    print("✅ test1 pass!")
+except ValueError:
+    print("❌ test1 fail!")
+
+try:
+    validate("abcdefg\rhijklmnop")
+    print("❌ test2 fail!")
+except ValueError:
+    print("✅ test2 pass!")
+
+    # Test 1 pass means there is no ValueError
+    # Test 2 pass means the ValueError has been detected