Cairo Smart contracts

Smart contracts written in cairo1.0

Important Commands

Install rust

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Check rust version

rustc --version

Install scarb

curl --proto '=https' --tlsv1.2 -sSf https://docs.swmansion.com/scarb/install.sh | sh

Check scarb version

scarb --version

Install starkli

curl https://get.starkli.sh | sh
starkliup

Check starkli version

starkli --version

Local Deployment With Katana

Install Katana

git clone https://github.com/dojoengine/dojo
cd dojo
cargo install --path ./crates/katana --locked --force

How to Generate a keystore and account descriptor for Local development

1. Start katana with katana command. You should see a list of accounts with Account Address, Private Key, and Public Key and see similar message 👇

🚀 JSON-RPC server started: http://0.0.0.0:5050

2. Create a keystore file by running

starkli signer keystore from-key ~/.starkli-wallets/deployer/my_local_account_1_key.json

Note: If you see folder not found or similar error, create .starkli-wallets/deployer folder with mkdir

Now, you should see a prompt asking for a Private Key. copy first account private key from katana output. Now. you see a prompt asking for a password. remember to enter something you can remember easily 😀 that's it, now we have our keystore file.

3. Create account descriptor file

touch ~/.starkli-wallets/deployer/my_local_account_1.json

Open the newly created my_local_account_1.json file and paste following content

{
  "version": 1,
  "variant": {
        "type": "open_zeppelin",
        "version": 1,
        "public_key": "<SMART_WALLET_PUBLIC_KEY>"
  },
    "deployment": {
        "status": "deployed",
        "class_hash": "<SMART_WALLET_CLASS_HASH>",
        "address": "<SMART_WALLET_ADDRESS>"
  }
}

• here replace <SMART_WALLET_PUBLIC_KEY> and <SMART_WALLET_ADDRESS> with respected values that you have from katana command output.

• to get a class hash for wallet run, replace SMART_WALLET_ADDRESS with respected value.

starkli class-hash-at  <SMART_WALLET_ADDRESS> --rpc http://0.0.0.0:5050

You will get class hash as the output, put that value in my_local_account_1.json file.

How to setup Katana wallet and rpc file path.

Replace respected file path in local.env file and then run source local.env on terminal. you can verify if values are set correctly using

echo ${STARKNET_ACCOUNT}

Testnet deployment with Goerli Network and Braavos Wallet

1. Copy your Braavos wallet private key from Privacy and Security section

2. Create a keystore file for starkli

starkli signer keystore from-key ~/.starkli-wallets/deployer/my_testnet_account_1_key.json

Note: If you see folder not found or similar error, create .starkli-wallets/deployer folder with mkdir

3. Create a account descriptor

account fetch <SMART_WALLET_ADDRESS> --output ~/.starkli-wallets/deployer/my_testnet_account_1.json

Here Replace <SMART_WALLET_ADDRESS> with your Braavos wallet address. You Should see a message similar to

WARNING: no valid provider option found. Falling back to using the sequencer gateway for the goerli-1 network. Doing this is discouraged. See https://book.starkli.rs/providers for more details.
Account contract type identified as: Braavos
Description: Braavos official proxy account
Downloaded new account config file: ~/.starkli-wallets/deployer/my_testnet_account_1.json

Note: If you get unknown class hash error, checkout Issues section.

4. Create a new env file testnet.env and copy sample.testnet.env content. You can replace values if you are using different RPC or path for keys is different.

5. run source testnet.env to export env variables to your terminal. you can verify if values are set correctly using

echo ${STARKNET_ACCOUNT}

How to declare contract

starkli declare target/dev/<CONTRACT_NAME>.sierra.json --compiler-version 2.1.0

How to deploy contract

starkli deploy <CLASS_HASH> <CONSTRUCTOR_ARGS>

How to call contract methods

1. To call view functions, use call keyword, for example

starkli call 0x03d568de0f4e151ed97a196e7585cae03be68b8d01c3d5af2e19c7aa4bb07202 get

2. To call writable functions, use invoke keyword, for example

 starkli invoke 0x03d568de0f4e151ed97a196e7585cae03be68b8d01c3d5af2e19c7aa4bb07202 set 7

Important Facts

• In Cairo, a string is a collection of characters stored in a felt252. Strings can have a maximum length of 31 characters.
• field elements are integers in the range between 0 <= x < P, where P is a very large prime number, currently P = 2^{251} + 17 * 2^{192} + 1

Known-Issues

1. Unknown Classhash error: If you get an unknown classhash error while creating account descriptor for your braavos account, you can create a account file manually. create a file ~/.starkli-wallets/deployer/my_testnet_account1.json with following content

{
  "version": 1,
  "variant": {
        "type": "open_zeppelin",
        "version": 1,
        "public_key": "<PUBLIC_KEY>"
  },
    "deployment": {
        "status": "deployed",
        "class_hash": "<CLASS_HASH>",
        "address": "<WALLET_ADDRESS>"
  }
}

• Get <PUBLIC_KEY>, from Privacy and Security section in Braavos
• To get classhash, open https://testnet.starkscan.co/contract/<WALLET_ADDRESS> link in browser. you should be able to see classhash for your account.

Starknet foundry commands

Declare a contract

sncast --profile <profile-name> declare --contract-name 
<contract-name>

Deploy a contract

sncast --profile testnet1 deploy --class-hash <class-hash> --constructor-calldata 10000000000  0 0x032aee2a95f251a984a391fb2919757a9074065f3c12b010a142c9fd939e933

Other Useful commands

1. Run scarb --offline build to build a project without updating dependencies.

Important Links

• Braavos google play store link
• Starknet Goerli network faucet
• Starscan
• Voyager
• Starknet Documentation
• Starknet Book
• Cairo Book
• Starknet Foundry book
• Starknet Ecosystem
• Run Starknet Locally with Katana
• Starknet By Example Voyager book
• Starknet Converter Utility
• Starknet docs