Implement Web Client Nonce Retrieval with Enhanced Reliability

agent-framework/prometheus_swarm/clients/web_client_nonce.py

@@ -0,0 +1,60 @@
+import random
+import string
+from typing import Optional
+
+class WebClientNonceManager:
+    """
+    A utility class for generating and managing web client nonces.
+
+    Nonces (number used once) are random, unique tokens used to prevent 
+    replay attacks and ensure request uniqueness.
+    """
+
+    @staticmethod
+    def generate_nonce(length: int = 32) -> str:
+        """
+        Generate a cryptographically secure random nonce.
+
+        Args:
+            length (int, optional): Length of the nonce. Defaults to 32.
+
+        Returns:
+            str: A randomly generated nonce string.
+
+        Raises:
+            ValueError: If length is less than 16.
+        """
+        if length < 16:
+            raise ValueError("Nonce length must be at least 16 characters")
+
+        # Use a combination of uppercase, lowercase, and digits
+        characters = string.ascii_letters + string.digits
+
+        # Use SystemRandom for cryptographically secure random generation
+        secure_random = random.SystemRandom()
+
+        nonce = ''.join(secure_random.choice(characters) for _ in range(length))
+        return nonce
+
+    @staticmethod
+    def validate_nonce(nonce: Optional[str], min_length: int = 16, max_length: int = 64) -> bool:
+        """
+        Validate a nonce's format and characteristics.
+
+        Args:
+            nonce (Optional[str]): The nonce to validate.
+            min_length (int, optional): Minimum acceptable nonce length. Defaults to 16.
+            max_length (int, optional): Maximum acceptable nonce length. Defaults to 64.
+
+        Returns:
+            bool: True if nonce is valid, False otherwise.
+        """
+        if nonce is None:
+            return False
+
+        # Check length constraints
+        if not (min_length <= len(nonce) <= max_length):
+            return False
+
+        # Ensure nonce contains only valid characters
+        return all(char in string.ascii_letters + string.digits for char in nonce)

agent-framework/tests/unit/test_web_client_nonce.py

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+import pytest
+from prometheus_swarm.clients.web_client_nonce import WebClientNonceManager
+
+def test_generate_nonce_default_length():
+    """Test nonce generation with default length."""
+    nonce = WebClientNonceManager.generate_nonce()
+    assert len(nonce) == 32
+    assert WebClientNonceManager.validate_nonce(nonce)
+
+def test_generate_nonce_custom_length():
+    """Test nonce generation with custom length."""
+    for length in [16, 24, 48, 64]:
+        nonce = WebClientNonceManager.generate_nonce(length)
+        assert len(nonce) == length
+        assert WebClientNonceManager.validate_nonce(nonce)
+
+def test_generate_nonce_invalid_length():
+    """Test nonce generation fails for too short nonces."""
+    with pytest.raises(ValueError):
+        WebClientNonceManager.generate_nonce(15)
+
+def test_nonce_uniqueness():
+    """Verify generated nonces are unique."""
+    nonces = set(WebClientNonceManager.generate_nonce() for _ in range(100))
+    assert len(nonces) == 100
+
+def test_nonce_validation():
+    """Test nonce validation with various inputs."""
+    # Valid nonces
+    valid_cases = [
+        WebClientNonceManager.generate_nonce(),
+        WebClientNonceManager.generate_nonce(16),
+        WebClientNonceManager.generate_nonce(64)
+    ]
+
+    # Invalid nonces
+    invalid_cases = [
+        None,
+        "",  # Empty string
+        "short",  # Too short
+        "x" * 65,  # Too long
+        "invalid-nonce!",  # Special characters
+        "UPPERCASE_ONLY",  # Case sensitivity
+        "   spaces   "
+    ]
+
+    for nonce in valid_cases:
+        assert WebClientNonceManager.validate_nonce(nonce), f"Failed to validate: {nonce}"
+
+    for nonce in invalid_cases:
+        assert not WebClientNonceManager.validate_nonce(nonce), f"Incorrectly validated: {nonce}"