As proposed by coffeezilla on YouTube, traders interacting with social media should provide profit-loss statements to prevent fraud and scams. I want to create a technical proposal for exchanges and brokers to enable algorithmic and non-algorithmic traders to issue trustless or even zero knowledge p&l statements for their social media followers to audit, written in Rust and deployable on the NEAR blockchain.

For now, this demo presents a possibility where every account on near could update their global PnL by posting trading results as percentages. Every Account can only update their own PnL by submitting statements, but every account can get every other accounts current PnL. Furthermore, by querying the blockchain for past transactions accocated to a specific account, past performance and history can be reviewed.

The smart contract written in Rust and stored in contract/src/lib.rs, has two callable functions:

1. add_statement(statement) enables every account on the blockchain to add a PnL statement to their balance
2. get_pnl(account_id) enables every account to query every other account for their overall PnL

This [React] app was initialized with create-near-app Namely, the exact command was:

npx create-near-app --contract rust --frontend react trustless-PnL-statement

If you are lazy like me, simply run docker-compose up -d --build after installing docker and docker-compose. For the installation you can use the following Ansible Project hosted on Github.

If you are not lazy, follow the manual deployment guide for testnet.

1. Prerequisites: Make sure you've installed Node.js ≥ 12
2. Install dependencies: yarn install
3. Run the local development server: yarn dev (see package.json for a full list of scripts you can run with yarn)

Now you'll have a local development environment backed by the NEAR TestNet!

Go ahead and play with the app and the code. As you make code changes, the app will automatically reload.

1. The "backend" code lives in the /contract folder. See the README there for more info.
2. The frontend code lives in the /src folder. /src/main.js is a great place to start exploring.
3. Tests: there are different kinds of tests for the frontend and the smart contract. See contract/README for info about how it's tested. The frontend code gets tested with jest. You can run both of these at once with yarn run test.

Every smart contract in NEAR has its own associated account. When you run yarn dev, your smart contract gets deployed to the live NEAR TestNet with a throwaway account. When you're ready to make it permanent, here's how.

near-cli is a command line interface (CLI) for interacting with the NEAR blockchain. It was installed to the local node_modules folder when you ran yarn install, but for best ergonomics you may want to install it globally:

yarn install --global near-cli

Or, if you'd rather use the locally-installed version, you can prefix all near commands with npx

Ensure that it's installed with near --version (or npx near --version)

Each account on NEAR can have at most one contract deployed to it. If you've already created an account such as your-name.testnet, you can deploy your contract to trustless-profit-loss-statement.your-name.testnet. Assuming you've already created an account on NEAR Wallet, here's how to create trustless-profit-loss-statement.your-name.testnet:

1. Authorize NEAR CLI, following the commands it gives you:

   near login

2. Create a subaccount (replace YOUR-NAME below with your actual account name):

   near create-account trustless-profit-loss-statement.YOUR-NAME.testnet --masterAccount YOUR-NAME.testnet

Modify the line in src/config.js that sets the account name of the contract. Set it to the account id you used above.

const CONTRACT_NAME = process.env.CONTRACT_NAME || 'trustless-profit-loss-statement.YOUR-NAME.testnet'

One command:

yarn deploy

As you can see in package.json, this does two things:

1. builds & deploys smart contract to NEAR TestNet
2. builds & deploys frontend code to GitHub using gh-pages. This will only work if the project already has a repository set up on GitHub. Feel free to modify the deploy script in package.json to deploy elsewhere.

On NEAR using storage is being payed for by staking NEAR coins for as long as the data is saved on the main network. Since algorithmic traders regularily exceed 10.000 trades per year, it is not plausibe to save every trades PnL statement on the blockchain for every user. Instead, the PnL statements are simply being added up and only the sum is saved on the blockchain. Anyhow, due to the nature of the blockchain of course it is possible to backtrace every single transaction and thus the history of the account can be calculated and presented by a blockchain analytics software or explorer.

On Windows, if you're seeing an error containing EPERM it may be related to spaces in your path. Please see this issue for more details.