feat: validate hash length

Author: jason-aelf

src/RandomContract.cs

@@ -6,7 +6,7 @@
 
 namespace AElf.Contracts.RandomContract;
 
-public class RandomContract : RandomContractContainer.RandomContractBase
+public partial class RandomContract : RandomContractContainer.RandomContractBase
 {
     // Initializes the contract
     public override Empty Initialize(InitializeInput input)
@@ -61,6 +61,8 @@ public override Empty GenerateRandomNumber(GenerateRandomNumberInput input)
     {
         // Check if the random number is already generated
         Assert(State.RandomNumbers[input.Hash] == null, "Random number already generated.");
+        // Check if the hash length is valid
+        Assert(input.Hash.Length <= MaxHashLength, "Invalid hash length.");
         // Check if the maxValue is valid
         Assert(input.MaxValue > 0 && input.MaxValue <= State.MaxValueLimit.Value, "Invalid max value.");
         // Check if the random number count is valid

src/RandomContractConstants.cs

@@ -0,0 +1,6 @@
+namespace AElf.Contracts.RandomContract;
+
+public partial class RandomContract
+{
+    private const long MaxHashLength = 100;
+}

test/RandomContractTests.cs

@@ -224,6 +224,17 @@ public async Task GenerateRandomNumberTest()
         result.TransactionResult.Status.ShouldBe(TransactionResultStatus.Failed);
         result.TransactionResult.Error.ShouldContain("Random number already generated");
 
+        var invalidHash = "cdd6b38b763d929355c47fb6f7be5107cdd6b38b763d929355c47fb6f7be5107cdd6b38b763d929355c47fb6f7be510712345";
+        // Generate random number with invalid hash length and expect an exception
+        result = await RandomContractStub.GenerateRandomNumber.SendWithExceptionAsync(new GenerateRandomNumberInput
+        {
+            Hash = invalidHash,
+            RandomNumberCount = randomNumberCount,
+            MaxValue = maxValue
+        });
+        result.TransactionResult.Status.ShouldBe(TransactionResultStatus.Failed);
+        result.TransactionResult.Error.ShouldContain("Invalid hash length");
+        
         hash = "OtherHash";
         // Generate random number with invalid max value and expect an exception
         result = await RandomContractStub.GenerateRandomNumber.SendWithExceptionAsync(new GenerateRandomNumberInput