Ethereum Block Explorer

Block explorer tool for given range of block inputs.

Functional Requirements:

1. Given a range of blocks OR a user inputed number of blocks to visit from, query the blockchain.
2. Return the following information:

• Total ether transfered from block range given.
• Which addresses sent/received and how much sent/receieved total?
• Total count of how many addresses are contract addresses.

3. OPTIONAL FEATURE

• What percentage of transactions were contract transactions?

Format: Command line interface

Tech Stack: NodeJs, Javascript

Challenges: How would you solve slow queries over large block ranges?

In order to arrive at a solution, one must have full scope of the problem. Why is it that slow queries occur over large block ranges to begin with?

Assuming the following reasons:

1. Newer blocks on the network contain more transactions, and are therefore larger blocks and have larger read/write time.
2. Depending on whether or not your ethereum node is fully synced, and its read/write time.
3. All blocks need to be validated by the network, so if you are syncing while querying, that could be a cause of slower queries.
4. Blocks are sequential and could need to be called or traversed to retreive the query (think of a linked list run time here!

Design Goals:

• User (top priority): Is everything clear and understandable for the user? Is it easy to use?
• Requirements: Are all functional requirements completed?
• Readability: Is code clear, well defined and declared, and commented when needed? Intuitive?
• Documentation: Is there documentation that explains how to run the code, code architecture, testing?
• Tests: Are there automated tests? Do these test edge cases and functionality?

How Do I Run Locally?

Prereqs:

1. NodeJs
2. Local Ethereum Node or Ganache Testnet

Dependencies:
In root project directory:

npm install

How To Package:

npm link

Run (packaged):

explorer

Run (unpackaged):
In root project directory:

./explorer.js

Tests:

npm test