Storage Contract

The Storage contract sets up a simple scenario to store and retrieve a string value. This contract demonstrates basic data storage and retrieval functionality within a blockchain environment.

from backend.node.genvm.icontract import IContract
 
class Storage(IContract):
    def __init__(self, initial_storage: str):
        self.storage = initial_storage
 
    def get_storage(self) -> str:
        return self.storage
 
    def update_storage(self, new_storage: str) -> None:
        self.storage = new_storage

Code Explanation

• Initialization: The Storage class initializes the contract with an initial_storage value. This value is stored in the self.storage attribute.
• Read Method: The get_storage() method is a read-only function that returns the current value stored in self.storage.
• Write Method: The update_storage(new_storage) method allows updating the stored value with a new string.

Deploying the Contract

To deploy the Storage contract, you need to initialize the contract state correctly. This setup will determine the initial value stored in the contract.

1. Set Initial Storage: Provide the initial storage value. The initial_storage constructor parameter is detected from the code. For example, you might set initial_storage to "Hello, World!".
2. Deploy the Contract: Once the initial storage is set, deploy the contract to make it ready for interaction.

Checking the Contract State

After deploying the contract, its address is displayed and you can check its state in the Read Methods section. Use the get_storage() function to see the current value stored in the contract.

Executing Transactions

To interact with the deployed contract, go to the Write Methods section. Here, you can call the update_storage method to change the stored value. This triggers the contract's logic to update the storage with the new value.

Analyzing the Contract's Behavior

When the update_storage method is executed:

• The contract updates the self.storage attribute with the new value provided.
• You can then use the get_storage() method to verify that the value has been updated.

Handling Different Scenarios

• Initial State: When the contract is first deployed, the get_storage() method will return the initial value set during deployment.
• After Update: After calling update_storage, the get_storage() method will return the newly set value.
• Multiple Updates: You can update the storage multiple times, and each time the most recent value will be stored and returned by get_storage().

You can view the logs to see detailed information about the contract interaction, including the values being stored and retrieved.

This Storage contract provides a simple example of how data can be stored and retrieved on a blockchain, demonstrating basic state management within a smart contract.