Decodes Ethereum event log data into Solidity-typed arguments.
Splits the topic list (indexed parameters) from the data blob (non-indexed
parameters) per the ABI specification, and optionally verifies that
topics[0] matches the keccak256 hash of the event signature.
Summary
Functions
Returns the canonical form of this event topic. Pass in indexed: true
to include "indexed" keywords.
Decodes an event, including handling parsing out data from topics.
Returns the signature of an event, i.e. the first item that appears in an Ethereum log for this event.
Functions
@spec canonical( ABI.FunctionSelector.t(), keyword() ) :: String.t()
Returns the canonical form of this event topic. Pass in indexed: true
to include "indexed" keywords.
Examples
iex> ABI.Event.canonical(
...> %ABI.FunctionSelector{
...> function: "Transfer",
...> types: [
...> %{type: :address, name: "from", indexed: true},
...> %{type: :address, name: "to", indexed: true},
...> %{type: {:uint, 256}, name: "amount"},
...> ]
...> }
...> )
"Transfer(address,address,uint256)"
iex> ABI.Event.canonical(
...> %ABI.FunctionSelector{
...> function: "Transfer",
...> types: [
...> %{type: :address, name: "from", indexed: true},
...> %{type: :address, name: "to", indexed: true},
...> %{type: {:uint, 256}, name: "amount"},
...> ]
...> },
...> names: true
...> )
"Transfer(address from,address to,uint256 amount)"
iex> ABI.Event.canonical(
...> %ABI.FunctionSelector{
...> function: "Transfer",
...> types: [
...> %{type: :address, name: "from", indexed: true},
...> %{type: :address, name: "to", indexed: true},
...> %{type: {:uint, 256}, name: "amount"},
...> ]
...> },
...> indexed: true
...> )
"Transfer(address indexed,address indexed,uint256)"
iex> ABI.Event.canonical(
...> %ABI.FunctionSelector{
...> function: "Transfer",
...> types: [
...> %{type: :address, name: "from", indexed: true},
...> %{type: :address, name: "to", indexed: true},
...> %{type: {:uint, 256}, name: "amount"},
...> ]
...> },
...> indexed: true,
...> names: true
...> )
"Transfer(address indexed from,address indexed to,uint256 amount)"@spec decode_event(binary(), [binary()], ABI.FunctionSelector.t(), keyword()) :: {:ok, String.t() | nil, map()} | {:error, String.t()}
Decodes an event, including handling parsing out data from topics.
Examples
iex> ABI.Event.decode_event(
...> ~h[0x00000000000000000000000000000000000000000000000000000004a817c800],
...> [
...> ~h[0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef],
...> ~h[0x000000000000000000000000b2b7c1795f19fbc28fda77a95e59edbb8b3709c8],
...> ~h[0x0000000000000000000000007795126b3ae468f44c901287de98594198ce38ea]
...> ],
...> %ABI.FunctionSelector{
...> function: "Transfer",
...> types: [
...> %{type: :address, name: "from", indexed: true},
...> %{type: :address, name: "to", indexed: true},
...> %{type: {:uint, 256}, name: "amount"},
...> ]
...> })
{:ok,
"Transfer", %{
"amount" => 20000000000,
"from" => ~h[0xb2b7c1795f19fbc28fda77a95e59edbb8b3709c8],
"to" => ~h[0x7795126b3ae468f44c901287de98594198ce38ea]
}}
iex> ABI.Event.decode_event(
...> ~h[0x00000000000000000000000000000000000000000000000000000004a817c800],
...> [
...> ~h[0x0000000000000000000000000000000000000000000000000000000000000001],
...> ~h[0x000000000000000000000000b2b7c1795f19fbc28fda77a95e59edbb8b3709c8],
...> ~h[0x0000000000000000000000007795126b3ae468f44c901287de98594198ce38ea]
...> ],
...> %ABI.FunctionSelector{
...> function: "Transfer",
...> types: [
...> %{type: :address, name: "from", indexed: true},
...> %{type: :address, name: "to", indexed: true},
...> %{type: {:uint, 256}, name: "amount"},
...> ]
...> })
{:error, "Mismatched event signature topic[0], expected=DDF252AD1BE2C89B69C2B068FC378DAA952BA7F163C4A11628F55A4DF523B3EF, got=0000000000000000000000000000000000000000000000000000000000000001"}
iex> ABI.Event.decode_event(
...> ~h[0x00000000000000000000000000000000000000000000000000000004a817c800],
...> [
...> ~h[0x000000000000000000000000b2b7c1795f19fbc28fda77a95e59edbb8b3709c8],
...> ~h[0x0000000000000000000000007795126b3ae468f44c901287de98594198ce38ea]
...> ],
...> %ABI.FunctionSelector{
...> function: "Transfer",
...> types: [
...> %{type: :address, name: "from", indexed: true},
...> %{type: :address, name: "to", indexed: true},
...> %{type: {:uint, 256}, name: "amount"},
...> ]
...> })
{:error, "Invalid topics length (got=2, expected=3), consider toggling `check_event_signature`"}
iex> ABI.Event.decode_event(
...> ~h[0x00000000000000000000000000000000000000000000000000000004a817c800],
...> [
...> ~h[0x000000000000000000000000b2b7c1795f19fbc28fda77a95e59edbb8b3709c8],
...> ~h[0x0000000000000000000000007795126b3ae468f44c901287de98594198ce38ea]
...> ],
...> %ABI.FunctionSelector{
...> function: "Transfer",
...> types: [
...> %{type: :address, name: "from", indexed: true},
...> %{type: :address, name: "to", indexed: true},
...> %{type: {:uint, 256}, name: "amount"},
...> ]
...> },
...> check_event_signature: false
...> )
{:ok,
"Transfer", %{
"amount" => 20000000000,
"from" => ~h[0xb2b7c1795f19fbc28fda77a95e59edbb8b3709c8],
"to" => ~h[0x7795126b3ae468f44c901287de98594198ce38ea]
}}@spec event_signature(ABI.FunctionSelector.t()) :: binary()
Returns the signature of an event, i.e. the first item that appears in an Ethereum log for this event.
Examples
iex> ABI.Event.event_signature(
...> %ABI.FunctionSelector{
...> function: "Transfer",
...> types: [
...> %{type: :address, name: "from", indexed: true},
...> %{type: :address, name: "to", indexed: true},
...> %{type: {:uint, 256}, name: "amount"},
...> ]
...> }
...> )
...> |> to_hex()
"0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"