SmartContractInteraction.md

Interaction with Smart Contracts

Basic Workflow

1. Write a smart contract in Rust and compile it to Wasm.
   • Make sure to use wasm-strip on the .wasm file as described.
2. Deploy the smart contract module on the chain:

concordium-client module deploy <module-name>.wasm [--name <name>]

• If successful, the module reference is printed, which should be used in next step.
• The --name flag can be used to give the module a name that is easy to remember.

3. Initialise an instance of the contract:

concordium-client contract init <module-tbd> --energy <max-energy> [--func <init-name>] [--params <binary-file>] [--path] [--name <name>]

• The <module-tbd> should be one of three things:
  • if the --path flag is used:
    • the path to a module file (of which the reference then is calculated using hashing)
  • otherwise:
    • a module reference,
    • or a module name (fx specified with the --name during module deployment)
• The maximum energy should be specified manually with the --energy flag.
• By default the "init" function is used, but a different init function can be specified using the --func flag.
• If the init function takes parameters, they should be specified in a binary file with little endian encoding and provided with the --params flag.
  • Simple parameter files can be create by hand, fx a u64 with value 1: printf "\x01\x00\x00\x00\x00\x00\x00\x00" > <binary_file>
• The --name flag can be used to give the contract a name that is easy to remember.

4. View the state of an contract:

concordium-client contract show <index-or-name> [--subindex <address-subindex>]

• <index-or-name> can be either an index or a contract name.
• Currently, we just use the index, so the subindex defaults to 0.

5. Update a contract, i.e. call a receive function:

concordium-client update <index-or-name> --energy <max-energy> [--func <receive-name>] [--params <binary-file>] [--subindex <address-subindex>]

• <index-or-name> can be either an index or a contract name.
• Similar to init, it takes an optional --func flag, which defaults to "receive".
• Parameters work in the same way as with init.

Additional Commands

For Modules

List all modules on chain:

concordium-client module list

Get binary source of module:

concordium-client show <reference-or-name> --out <out-file>

• <reference-or-name> should be either a module reference or a module name.
• <out-file> is the file to output the source code to (use - for stdout).

Add a local name to a module:

concordium-client module name <module-or-ref> --name <name> 

• <module-or-ref> should be a module reference or a path to the module file.

For Contracts

List all contracts (instances) on chain:

concordium-client contract list

Add a local name to a contract:

concordium-client contract name <index> --name <name> [--subindex <address-subindex>]