Understanding the Frontier Implementation

Oct 13, 2025 by wbrum.org 15 views

Implementing eth_feeHistory: A Crucial Component in Polkadot EVM

Overview of eth_feeHistory

In the realm of blockchain development, particularly in the context of Polkadot EVM, implementing the eth_feeHistory endpoint is a vital component that enables the calculation of priority fees for transactions. This feature is not only essential for tooling like Cast but also for wallets that require accurate fee calculations to ensure seamless transaction processing. In this article, we will delve into the implementation details of eth_feeHistory, drawing inspiration from the Frontier implementation.

Understanding the Frontier Implementation

The Frontier implementation serves as a reference point for our eth_feeHistory implementation. By examining the codebase, we can identify key components and design patterns that can be adapted to our implementation. Specifically, we will focus on the fee.rs file, which contains the eth_feeHistory endpoint implementation.

// https://github.com/polkadot-evm/frontier/blob/master/client/rpc/src/eth/fee.rs?plain=1#L54

Designing the eth_feeHistory Endpoint

To implement the eth_feeHistory endpoint, we need to consider the following key aspects:

Data Structure: We require a data structure to store the fee history, which will be used to calculate the priority fee for transactions.
API Endpoints: We need to define the API endpoints that will be used to retrieve the fee history data.
Calculation Logic: We must implement the logic to calculate the priority fee based on the fee history data.

Implementing the Data Structure

To store the fee history data, we can utilize a data structure such as a HashMap or a BTreeMap. This will enable efficient lookups and insertions of fee history data.

use std::collections::HashMap;

// Define a struct to represent the fee history data
struct FeeHistory {
    block_number: u64,
    base_fee: u64,
    gas_used: u64,
}

// Create a HashMap to store the fee history data
let mut fee_history: HashMap<u64, FeeHistory> = HashMap::new();

Defining the API Endpoints

We need to define the API endpoints that will be used to retrieve the fee history data. This can be achieved by creating a new module or adding new functions to an existing module.

// Define a new module for the eth_feeHistory endpoint
mod eth_fee_history {
    // Define a function to retrieve the fee history data
    pub fn get_fee_history(&self, block_number: u64) -> Option<FeeHistory> {
        // Retrieve the fee history data from the HashMap
        self.fee_history.get(&block_number)
    }
}

Implementing the Calculation Logic

To calculate the priority fee, we need to implement the logic that takes into account the fee history data. This can be achieved by creating a new function that takes the fee history data as input and returns the calculated priority fee.

// Define a function to calculate the priority fee
pub fn calculate_priority_fee(&self, fee_history: &FeeHistory) -> u64 {
    // Calculate the priority fee based on the fee history data
    // This can be a complex calculation involving multiple factors
    // For simplicity, let's assume a basic calculation
    fee_history.base_fee + (fee_history.gas_used * 10)
}

Integrating with Tooling and Wallets

To enable tooling like Cast and wallets to utilize the eth_feeHistory endpoint, we need to integrate our implementation with their respective APIs. This can be achieved by creating new functions or modifying existing functions to accommodate the eth_feeHistory endpoint.

// Define a new function to retrieve the fee history data for Cast
pub fn get_fee_history_for_cast(&self, block_number: u64) -> Option<FeeHistory> {
    // Retrieve the fee history data from the HashMap
    self.fee_history.get(&block_number)
}

// Define a new function to calculate the priority fee for wallets
pub fn calculate_priority_fee_for_wallets(&self, fee_history: &FeeHistory) -> u64 {
    // Calculate the priority fee based on the fee history data
    // This can be a complex calculation involving multiple factors
    // For simplicity, let's assume a basic calculation
    fee_history.base_fee + (fee_history.gas_used * 10)
}

Conclusion

Implementing the eth_feeHistory endpoint is a crucial component in Polkadot EVM that enables the calculation of priority fees for transactions. By following the design patterns and implementation details outlined in this article, we can create a robust and efficient eth_feeHistory endpoint that meets the requirements of tooling like Cast and wallets.
Implementing eth_feeHistory: A Crucial Component in Polkadot EVM - Q&A

Introduction

In our previous article, we explored the implementation details of the eth_feeHistory endpoint in Polkadot EVM. This endpoint is a vital component that enables the calculation of priority fees for transactions, making it essential for tooling like Cast and wallets. In this article, we will address some of the frequently asked questions (FAQs) related to implementing the eth_feeHistory endpoint.

Q: What is the purpose of the eth_feeHistory endpoint?

A: The eth_feeHistory endpoint is designed to provide the fee history data for a given block number. This data is used to calculate the priority fee for transactions, ensuring that transactions are processed efficiently and accurately.

Q: How does the eth_feeHistory endpoint work?

A: The eth_feeHistory endpoint works by storing the fee history data in a data structure, such as a HashMap. When a request is made to retrieve the fee history data for a specific block number, the endpoint retrieves the corresponding data from the HashMap and returns it to the caller.

Q: What is the data structure used to store the fee history data?

A: The data structure used to store the fee history data is a HashMap. This allows for efficient lookups and insertions of fee history data.

Q: How is the priority fee calculated using the eth_feeHistory endpoint?

A: The priority fee is calculated using the calculate_priority_fee function, which takes the fee history data as input and returns the calculated priority fee. The calculation involves multiple factors, including the base fee and gas used.

Q: Can the eth_feeHistory endpoint be used by multiple tooling and wallets?

A: Yes, the eth_feeHistory endpoint can be used by multiple tooling and wallets. To enable this, we need to integrate our implementation with their respective APIs. This can be achieved by creating new functions or modifying existing functions to accommodate the eth_feeHistory endpoint.

Q: How do I integrate the eth_feeHistory endpoint with Cast?

A: To integrate the eth_feeHistory endpoint with Cast, you need to create a new function that retrieves the fee history data for a specific block number. This function should be designed to return the fee history data in a format that is compatible with Cast.

Q: How do I integrate the eth_feeHistory endpoint with wallets?

A: To integrate the eth_feeHistory endpoint with wallets, you need to create a new function that calculates the priority fee based on the fee history data. This function should be designed to return the calculated priority fee in a format that is compatible with wallets.

Q: What are the benefits of implementing the eth_feeHistory endpoint?

A: The benefits of implementing the eth_feeHistory endpoint include:

Improved transaction processing efficiency
Accurate priority fee calculations
Enhanced support for tooling like Cast and wallets
Improved overall user experience

Conclusion

Implementing the eth_feeHistory endpoint is a crucial component in Polkadot EVM that enables the calculation of priority fees for transactions. By addressing the FAQs outlined in this article, we can ensure that our implementation meets the requirements of tooling like Cast and wallets, providing a seamless user experience for users of Polkadot EVM.

Additional Resources

For more information on implementing the eth_feeHistory endpoint, please refer to the following resources: