Documentation ¶
Overview ¶
Package filters implements an ethereum filtering system for block, transactions and log events.
Index ¶
- Variables
- type Backend
- type EventSystem
- type Filter
- type FilterCriteria
- type Log
- type PublicFilterAPI
- func (api *PublicFilterAPI) GetFilterChanges(id rpc.ID) (interface{}, error)
- func (api *PublicFilterAPI) GetFilterLogs(ctx context.Context, id rpc.ID) ([]Log, error)
- func (api *PublicFilterAPI) GetLogs(ctx context.Context, crit FilterCriteria) ([]Log, error)
- func (api *PublicFilterAPI) Logs(ctx context.Context, crit FilterCriteria) (*rpc.Subscription, error)
- func (api *PublicFilterAPI) NewBlockFilter() rpc.ID
- func (api *PublicFilterAPI) NewFilter(crit FilterCriteria) (rpc.ID, error)
- func (api *PublicFilterAPI) NewHeads(ctx context.Context) (*rpc.Subscription, error)
- func (api *PublicFilterAPI) NewPendingTransactionFilter() rpc.ID
- func (api *PublicFilterAPI) NewPendingTransactions(ctx context.Context) (*rpc.Subscription, error)
- func (api *PublicFilterAPI) UninstallFilter(id rpc.ID) bool
- type Subscription
- type Type
Constants ¶
This section is empty.
Variables ¶
var (
ErrInvalidSubscriptionID = errors.New("invalid id")
)
Functions ¶
This section is empty.
Types ¶
type EventSystem ¶
type EventSystem struct {
// contains filtered or unexported fields
}
EventSystem creates subscriptions, processes events and broadcasts them to the subscription which match the subscription criteria.
func NewEventSystem ¶
func NewEventSystem(mux *event.TypeMux, backend Backend, lightMode bool) *EventSystem
NewEventSystem creates a new manager that listens for event on the given mux, parses and filters them. It uses the all map to retrieve filter changes. The work loop holds its own index that is used to forward events to filters.
The returned manager has a loop that needs to be stopped with the Stop function or by stopping the given mux.
func (*EventSystem) SubscribeLogs ¶
func (es *EventSystem) SubscribeLogs(crit FilterCriteria, logs chan []Log) (*Subscription, error)
SubscribeLogs creates a subscription that will write all logs matching the given criteria to the given logs channel. Default value for the from and to block is "latest". If the fromBlock > toBlock an error is returned.
func (*EventSystem) SubscribeNewHeads ¶
func (es *EventSystem) SubscribeNewHeads(headers chan *types.Header) *Subscription
SubscribeNewHeads creates a subscription that writes the header of a block that is imported in the chain.
func (*EventSystem) SubscribePendingTxEvents ¶
func (es *EventSystem) SubscribePendingTxEvents(hashes chan common.Hash) *Subscription
SubscribePendingTxEvents creates a subscription that writes transaction hashes for transactions that enter the transaction pool.
type Filter ¶
type Filter struct {
// contains filtered or unexported fields
}
Filter can be used to retrieve and filter logs
func New ¶
New creates a new filter which uses a bloom filter on blocks to figure out whether a particular block is interesting or not.
func (*Filter) SetAddresses ¶
SetAddresses matches only logs that are generated from addresses that are included in the given addresses.
func (*Filter) SetBeginBlock ¶
SetBeginBlock sets the earliest block for filtering. -1 = latest block (i.e., the current block) hash = particular hash from-to
func (*Filter) SetEndBlock ¶
SetEndBlock sets the latest block for filtering.
type FilterCriteria ¶
type FilterCriteria struct { FromBlock *big.Int ToBlock *big.Int Addresses []common.Address Topics [][]common.Hash }
FilterCriteria represents a request to create a new filter.
func (*FilterCriteria) UnmarshalJSON ¶
func (args *FilterCriteria) UnmarshalJSON(data []byte) error
UnmarshalJSON sets *args fields with given data.
type Log ¶
Log is a helper that can hold additional information about vm.Log necessary for the RPC interface.
func (*Log) MarshalJSON ¶
MarshalJSON returns *l as the JSON encoding of l.
type PublicFilterAPI ¶
type PublicFilterAPI struct {
// contains filtered or unexported fields
}
PublicFilterAPI offers support to create and manage filters. This will allow external clients to retrieve various information related to the Ethereum protocol such als blocks, transactions and logs.
func NewPublicFilterAPI ¶
func NewPublicFilterAPI(backend Backend, lightMode bool) *PublicFilterAPI
NewPublicFilterAPI returns a new PublicFilterAPI instance.
func (*PublicFilterAPI) GetFilterChanges ¶
func (api *PublicFilterAPI) GetFilterChanges(id rpc.ID) (interface{}, error)
GetFilterChanges returns the logs for the filter with the given id since last time is was called. This can be used for polling.
For pending transaction and block filters the result is []common.Hash. (pending)Log filters return []Log.
https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getfilterchanges
func (*PublicFilterAPI) GetFilterLogs ¶
GetFilterLogs returns the logs for the filter with the given id. If the filter could not be found an empty array of logs is returned.
https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getfilterlogs
func (*PublicFilterAPI) GetLogs ¶
func (api *PublicFilterAPI) GetLogs(ctx context.Context, crit FilterCriteria) ([]Log, error)
GetLogs returns logs matching the given argument that are stored within the state.
func (*PublicFilterAPI) Logs ¶
func (api *PublicFilterAPI) Logs(ctx context.Context, crit FilterCriteria) (*rpc.Subscription, error)
Logs creates a subscription that fires for all new log that match the given filter criteria.
func (*PublicFilterAPI) NewBlockFilter ¶
func (api *PublicFilterAPI) NewBlockFilter() rpc.ID
NewBlockFilter creates a filter that fetches blocks that are imported into the chain. It is part of the filter package since polling goes with eth_getFilterChanges.
https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_newblockfilter
func (*PublicFilterAPI) NewFilter ¶
func (api *PublicFilterAPI) NewFilter(crit FilterCriteria) (rpc.ID, error)
NewFilter creates a new filter and returns the filter id. It can be used to retrieve logs when the state changes. This method cannot be used to fetch logs that are already stored in the state.
Default criteria for the from and to block are "latest". Using "latest" as block number will return logs for mined blocks. Using "pending" as block number returns logs for not yet mined (pending) blocks. In case logs are removed (chain reorg) previously returned logs are returned again but with the removed property set to true.
In case "fromBlock" > "toBlock" an error is returned.
https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_newfilter
func (*PublicFilterAPI) NewHeads ¶
func (api *PublicFilterAPI) NewHeads(ctx context.Context) (*rpc.Subscription, error)
NewHeads send a notification each time a new (header) block is appended to the chain.
func (*PublicFilterAPI) NewPendingTransactionFilter ¶
func (api *PublicFilterAPI) NewPendingTransactionFilter() rpc.ID
NewPendingTransactionFilter creates a filter that fetches pending transaction hashes as transactions enter the pending state.
It is part of the filter package because this filter can be used throug the `eth_getFilterChanges` polling method that is also used for log filters.
https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_newpendingtransactionfilter
func (*PublicFilterAPI) NewPendingTransactions ¶
func (api *PublicFilterAPI) NewPendingTransactions(ctx context.Context) (*rpc.Subscription, error)
NewPendingTransactions creates a subscription that is triggered each time a transaction enters the transaction pool and was signed from one of the transactions this nodes manages.
func (*PublicFilterAPI) UninstallFilter ¶
func (api *PublicFilterAPI) UninstallFilter(id rpc.ID) bool
UninstallFilter removes the filter with the given filter id.
https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_uninstallfilter
type Subscription ¶
Subscription is created when the client registers itself for a particular event.
func (*Subscription) Err ¶
func (sub *Subscription) Err() <-chan error
Err returns a channel that is closed when unsubscribed.
func (*Subscription) Unsubscribe ¶
func (sub *Subscription) Unsubscribe()
Unsubscribe uninstalls the subscription from the event broadcast loop.
type Type ¶
type Type byte
Type determines the kind of filter and is used to put the filter in to the correct bucket when added.
const ( // UnknownSubscription indicates an unkown subscription type UnknownSubscription Type = iota // LogsSubscription queries for new or removed (chain reorg) logs LogsSubscription // PendingLogsSubscription queries for logs in pending blocks PendingLogsSubscription // MinedAndPendingLogsSubscription queries for logs in mined and pending blocks. MinedAndPendingLogsSubscription // PendingTransactionsSubscription queries tx hashes for pending // transactions entering the pending state PendingTransactionsSubscription // BlocksSubscription queries hashes for blocks that are imported BlocksSubscription // LastSubscription keeps track of the last index LastIndexSubscription )