Generic contract call: ABI encode → eth_call → ABI decode in one function.
Eliminates the 3-step with chain every consumer writes for contract reads.
Takes a contract address, function signature, params, and return type — returns
decoded values.
Error Format
Errors pass through from the underlying module that failed:
| Source | Error Shape |
|---|---|
Onchain.Address.validate/1 | {:error, {:invalid_address, input}} |
Onchain.ABI.encode_call/2 | {:error, {:encode_error, reason}} |
Onchain.RPC.eth_call/3 | {:error, {:rpc_error, map}} |
Onchain.ABI.decode_response/2 | {:error, {:decode_error, reason}} |
Functions
| Function | Purpose |
|---|---|
call/5 | Generic contract read → decoded values list |
call!/5 | Same, raises on error |
API Functions
| Function | Arity | Description | Param Kinds |
|---|---|---|---|
call! | 5 | Execute a read-only contract call. Raises on error. | address: value, signature: value, params: value, return_type: value, opts: value |
call | 5 | Execute a read-only contract call: encode → eth_call → decode. | address: value, signature: value, params: value, return_type: value, opts: value |
Summary
Functions
Execute a read-only contract call: encode → eth_call → decode.
Execute a read-only contract call. Raises on error.
Functions
@spec call(String.t() | binary(), String.t(), list(), String.t(), keyword()) :: {:ok, list()} | {:error, term()}
Execute a read-only contract call: encode → eth_call → decode.
Parameters
address- Contract address as 0x hex string or 20-byte binary (value)signature- Function signature, e.g. "balanceOf(address)" (value)params- List of parameter values matching the signature (value)return_type- Tuple type signature for decoding, e.g. "(uint256)" or "(uint256,bool)" (value)opts- Options: :rpc_url, :timeout, :block (default:[], value)
Returns
List of decoded return values from the contract call ({:ok, [decoded_values]} | {:error, term()})
# descripex:contract
%{
params: %{
opts: %{
default: [],
description: "Options: :rpc_url, :timeout, :block",
kind: :value
},
address: %{
description: "Contract address as 0x hex string or 20-byte binary",
kind: :value
},
signature: %{
description: "Function signature, e.g. \"balanceOf(address)\"",
kind: :value
},
params: %{
description: "List of parameter values matching the signature",
kind: :value
},
return_type: %{
description: "Tuple type signature for decoding, e.g. \"(uint256)\" or \"(uint256,bool)\"",
kind: :value
}
},
returns: %{
type: "{:ok, [decoded_values]} | {:error, term()}",
description: "List of decoded return values from the contract call",
example: "{:ok, [1000000]}"
}
}Execute a read-only contract call. Raises on error.
Parameters
address- Contract address as 0x hex string or 20-byte binary (value)signature- Function signature, e.g. "balanceOf(address)" (value)params- List of parameter values matching the signature (value)return_type- Tuple type signature for decoding, e.g. "(uint256)" (value)opts- Options: :rpc_url, :timeout, :block (default:[], value)
Returns
List of decoded return values from the contract call ([decoded_values])
# descripex:contract
%{
params: %{
opts: %{
default: [],
description: "Options: :rpc_url, :timeout, :block",
kind: :value
},
address: %{
description: "Contract address as 0x hex string or 20-byte binary",
kind: :value
},
signature: %{
description: "Function signature, e.g. \"balanceOf(address)\"",
kind: :value
},
params: %{
description: "List of parameter values matching the signature",
kind: :value
},
return_type: %{
description: "Tuple type signature for decoding, e.g. \"(uint256)\"",
kind: :value
}
},
returns: %{
type: "[decoded_values]",
description: "List of decoded return values from the contract call"
}
}