Utrust

Utrust Challenge - Fullstack Developer solution

Approach

In order to solve the challenge, I opted to use a tech stack as close to what is in use at Utrust (React, Graphql, less Commanded) although I could have used Liveview.

In verifying transactions using Etherscan API, I found the following issues

Etherscan API Transactions endpoint (https://docs.etherscan.io/api-endpoints/stats#check-contract-execution-status) does not verify if a tx_hashis valid and returns successful response for randomly generated strings
It returns limited information about the transaction.

In the light of the above, I implemented transaction verification via the Etherscan API and also through scraping the Etherscan transactions webpage (https://etherscan.io/tx/0x7b6d0e8d812873260291c3f8a9fa99a61721a033a01e5c5af3ceb5e1dc9e7bd0 ) and exposed a graphql endpoint that allows a client to specify a verification channel.

Setting Up the Stack

Versioned dependencies

Following core dependencies in the Utrust stack are versioned in .tool-versions:

Erlang (OTP)
Elixir
NodeJS

In order to install these locally via asdf, just run:

asdf install

System libraries

Following system libraries are required:

Docker-Compose 1.29 (optional)

They need to be installed manually using means matching your specific platform.

Data storage

Following data storage dependencies are required:

PostgreSQL v13

It may be installed manually or started in Docker with:

docker-compose up -d

They may then be stopped with:

docker-compose down

Running the Server

To start your Phoenix server:

Install dependencies and setup database for all apps with mix setup
Install Node.js dependencies with npm inside the assets directory in the UtrustWeb app
Start Phoenix endpoint with mix phx.server

mix setup
cd apps/utrust_web/assets; npm install; cd -
mix phx.server

Now you can visit localhost:4000 from your browser. Below is a list of some test transactions.

0x7b6d0e8d812873260291c3f8a9fa99a61721a033a01e5c5af3ceb5e1dc9e7bd0
0x15f8e5ea1079d9a0bb04a4c58ae5fe7654b5b2b4463375ff7ffb490aa0032f3a
0x513c1ba0bebf66436b5fed86ab668452b7805593c05073eb2d51d3a52f480a76

Demo

Successful transaction

Failed transaction

badeyeye1/utrust