Chapter 3 of the NEAR crossword tutorial

How to play with this contract

1. Clone the repo.

git clone https://github.com/near-examples/crossword-tutorial-chapter-3
cd crossword-tutorial-chapter-3

2. Next, make sure you have NEAR CLI by running:

near --version

If you need to install near-cli:

npm install near-cli -g

3. Build the smart contract

cd contract
./build.sh

4. Run near dev-deploy to deploy the contract to testnet.

5. Create a crossword, let's say that the answer to your crossword is "many clever words"

6. Answer for your crossword from now on will be a seed phrase! Let's generate key pair out of it.

   near generate-key randomAccountId.testnet --seedPhrase='many clever words'

   Now this key pair will be store on your machine under ~/.near-credentials/testnet/randomAccountId.json

7. We should add your puzzle to our contract. To do that run

   near call <contract-account-id> new_puzzle '{"answer_pk":"<generated-pk>"}' --accountId=<signer-acc-id> --deposit=10

   Where:

   • contract-account-id - Account on which contract is stored. If you have used near dev-deploy in the first step it was autogenerated for you. It should look like dev-<random-numbers>.
   • generate-pk - Public key from JSON generated in the step #4
   • accountId - your existing testnet accountId (you can create one at https://wallet.testnet.near.org/)
   • deposit - reword for the person who will solve this puzzle

   After this call your puzzle will be added to the NEAR Crossword contract. Share your Crossword with friends, the person who will be able to solve it will be able to generate the same key pair and get the reward. Let's do that in the following steps.

8. Pretend that we have solved the puzzle and generated the very same key pair. This time it should be stored at ~/.near-credentials/testnet/<contract-id>.json. We are using <contract-id> here because in the next step we will need to sign the transaction with this acc.

Attention! If you are using the same machine, your old key pair from <dev-acc> will be overwritten! Save it in some other place if you need it. Keys are stored in ~/.near-credentials/testnet/ folder.

To generate the new key:

near generate-key <crossword-contract-id> --seedPhrase='many clever words'

Also, we need to have another key that will be used later to get the reward. Let's generate it.

near generate-key keyToGetTheReward.testnet

7. Let's call submit_solution function to solve this puzzle.

near call <contract-id> submit_solution '{"solver_pk":"<PK from keyToGetTheReward.testnet>"}' --accountId=<contract-id>

Puzzle solved! Let's get our reward!

8. To get the reward we need to call the claim_reward function with the function call key that we have added in the previous step. Before that call we should prepare the keys:

cp ~/.near-credentials/testnet/keyToGetTheReward.testnet.json ~/.near-credentials/testnet/<contract-id>.json

And now we can claim our reward:

near call <contract-id> claim_reward '{"receiver_acc_id":"serhii.testnet", "crossword_pk":"<PK from randomAccountId account>", "memo":"Victory!"}' --accountId=<contract-id>

Quick Start

To run this project locally:

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.

Exploring The Code

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/index.html is a great place to start exploring. Note that it loads in /src/index.js, where you can learn how the frontend connects to the NEAR blockchain.
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.

Deploy

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

Step 0: Install near-cli (optional)

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)

Step 1: Create an account for the contract

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 crossword.your-name.testnet. Assuming you've already created an account on NEAR Wallet, here's how to create crossword.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 crossword.YOUR-NAME.testnet --masterAccount YOUR-NAME.testnet

Step 2: set contract name in code

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 || 'crossword.YOUR-NAME.testnet'

Step 3: deploy!

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.

Troubleshooting

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.