Filter

getFilterChanges

caver.klay.getFilterChanges(filterId [, callback])

Polling method for a filter, which returns an array of logs since the last poll.

Parameters

Name	Type	Description
filterId	String	The filter id.
callback	Function	(optional) Optional callback, returns an error object as the first parameter and the result as the second.

Return Value

Promise returns Array - Array of log objects, or an empty array if nothing has changed since last poll.

The structure of the returned log Object in the Array looks as follows:

Name	Type	Description
address	20-byte DATA	Address from which this log originated.
topics	Array of DATA	Array of 0 to 4 32-byte DATA of indexed log arguments. (In Solidity: The first topic is the hash of the signature of the event (e.g., Deposit(address,bytes32,uint256)), except you declared the event with the anonymous specifier.).
data	DATA	Contains the non-indexed arguments of the log.
blockNumber	QUANTITY	The block number where this log was in. null when pending.
transactionHash	32-byte DATA	Hash of the transaction that this log was created from. null when pending, an edge case when the transaction has been executed, but the block has not been confirmed.
transactionIndex	QUANTITY	Integer. The index of the transaction that this log was created from. null when pending.
blockHash	32-byte DATA	Hash of the block where this log was in. null when pending.
logIndex	QUANTITY	Integer of the log index position in the block. null when it is a pending log.
id	String	A log identifier. It is made by concatenating "log_" string with keccak256(blockHash + transactionHash + logIndex).substr(0, 8)

Example

> caver.klay.getFilterChanges('0xafb8e49bbcba9d61a3c616a3a312533e').then(console.log);

[

{

address: '0x71e503935b7816757AA0314d4E7354dab9D39162',

topics: [ '0xe8451a9161f9159bc887328b634789768bd596360ef07c5a5cbfb927c44051f9' ],

data: '0x0000000000000000000000000000000000000000000000000000000000000001',

blockNumber: 3525,

transactionHash: '0x1b28e2c723e45a0d8978890598903f36a74397c9cea8531dc9762c39483e417f',

transactionIndex: 0,

blockHash: '0xb7f0bdaba93d3baaa01a5c24517da443207f774e0202f02c298e8e997a540b3d',

logIndex: 0,

id: 'log_c1ea867d'

}

]

getFilterLogs

caver.klay.getFilterLogs(filterId [, callback])

Returns an array of all logs matching the filter with the given id. The filter object should be obtained using newFilter.
Note that filter ids returned by other filter creation functions, such as newBlockFilter or newPendingTransactionFilter, cannot be used with this function.

Parameters

Name	Type	Description
filterId	String	The filter id.
callback	Function	(optional) Optional callback, returns an error object as the first parameter and the result as the second.

Return Value

See getFilterChanges

Example

> caver.klay.getFilterLogs('0xcac08a7fc32fc625a519644187e9f690').then(console.log);

[

{

address: '0x55384B52a9E5091B6012717197887dd3B5779Df3',

topics: [ '0xe8451a9161f9159bc887328b634789768bd596360ef07c5a5cbfb927c44051f9' ],

data: '0x0000000000000000000000000000000000000000000000000000000000000001',

blockNumber: 7217,

transactionHash: '0xa7436c54e47dafbce696de65f6e890c96ac22c236f50ca1be28b9b568034c3b3',

transactionIndex: 0,

blockHash: '0xe4f27c524dacfaaccb36735deccee69b3d6c315e969779784c36bb8e14b89e01',

logIndex: 0,

id: 'log_2dd695a8'

}

]

getPastLogs

caver.klay.getPastLogs(options [, callback])

Gets past logs, matching the given options.

Parameters

Name	Type	Description
options	Object	The filter options.
options.fromBlock	Number | String	(optional) The number of the earliest block to get the logs. ("latest" means the most recent block.) The default value is "latest".
options.toBlock	Number | String	(optional) The number of the last block to get the logs. ("latest" means the most recent block.). The default value is "latest".
options.address	String | Array	(optional) An address or a list of addresses. Only the logs related to the particular account(s) will be returned.
options.topics	Array	(optional) An array of values that must appear in the log entries. The order is important. If you want to leave topics out, use null, e.g., [null, '0x12...']. You can also pass an array for each topic with options for that topic, e.g., [null, ['option1', 'option2']].
callback	Function	(optional) Optional callback, returns an error object as the first parameter and the result as the second.

Return Value

Promise returns Array - Array of log objects.

The structure of the returned event Object in the Array looks as follows:

Name	Type	Description
address	String	From which this event originated from.
data	String	The data containing non-indexed log parameter.
topics	Array	An array with max 4 32-byte topics, topic 1-3 contains indexed parameters of the log.
logIndex	Number	Integer of the event index position in the block.
transactionIndex	Number	Integer of the transaction's index position, the event was created in.
transactionHash	32-byte String	Hash of the transaction this event was created in.
blockHash	32-byte String	Hash of the block where this event was created in. null when its still pending.
blockNumber	Number	The block number where this log was created in. null when still pending.
id	String	A log identifier. It is made through concatenating "log_" string with keccak256(blockHash + transactionHash + logIndex).substr(0, 8)

Example

> caver.klay.getPastLogs({

address: "0x11f4d0A3c12e86B4b5F39B213F7E19D048276DAe",

topics: ["0x033456732123ffff2342342dd12342434324234234fd234fd23fd4f23d4234"]

})

.then(console.log);

[{

data: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',

topics: ['0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7', '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385']

logIndex: 0,

transactionIndex: 0,

transactionHash: '0x7f9fade1c0d57a7af66ab4ead79fade1c0d57a7af66ab4ead7c2c2eb7b11a91385',

blockHash: '0xfd43ade1c09fade1c0d57a7af66ab4ead7c2c2eb7b11a91ffdd57a7af66ab4ead7',

blockNumber: 1234,

address: '0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe',

id: 'log_124d61bc',

},{...}]

newBlockFilter

caver.klay.newBlockFilter([callback])

Creates a filter in the node to receive the information about new block arrival. To check if the state has changed, call getFilterChanges.

Parameters

Name	Type	Description
callback	Function	(optional) Optional callback. The callback is fired with an error object as its first parameter and the result as the second.

Return Value

Promise returns String - A filter id.

Example

> caver.klay.newBlockFilter().then(console.log);

0x9ca049dc8b0788ee05724e45fc4137f1

newFilter

caver.klay.newFilter(options [, callback])

Creates a filter object using the given filter options, to receive the specific state changes (logs).

• To check if the state has changed, call getFilterChanges.
• To obtain all logs matching the filter created by newFilter, call getFilterLogs.

For detailed information about topic filters, please see Klaytn Platform API - klay_newFilter.

Parameters

Name	Type	Description
options	Object	The filter options.
options.fromBlock	Number | String	(optional) The number of the earliest block height to query the events. (There are special tags, "latest" means the most recent block). The default value is "latest".
options.toBlock	Number | String	(optional) The number of the last block height to query the events (There are special tags,"latest" means the most recent confirmed block). The default value is "latest".
options.address	String | Array	(optional) An address or a list of addresses to get logs generated inside the given contract(s).
options.topics	Array	(optional) An array of values to search for in the log entries. The order is important. If you want to match everything in the given position, use null, e.g., [null, '0x12...']. You can also pass an array to match one of them. e.g., [null, ['option1', 'option2']].
callback	Function	(optional) Optional callback, returns an error object as the first parameter and the result as the second.

Return Value

Promise returns String - A filter id.

Example

> caver.klay.newFilter({}).then(console.log);

0x40d40cb9758c6f0d99d9c2ce9c0f823

> caver.klay.newFilter({address: "0x55384B52a9E5091B6012717197887dd3B5779Df3"}).then(console.log);

0xd165cbf31b9d60346aada33dbefe01b

newPendingTransactionFilter

caver.klay.newPendingTransactionFilter([callback])

Creates a filter in the node, to receive the information about new pending transactions arrival. To check if the state has changed, call getFilterChanges.

Parameters

Name	Type	Description
callback	Function	(optional) Optional callback, returns an error object as the first parameter and the result as the second.

Return Value

Promise returns String - A filter id.

Example

> caver.klay.newPendingTransactionFilter().then(console.log);

0x1426438ffdae5abf43edf4159c5b013b

uninstallFilter

caver.klay.uninstallFilter(filterId [, callback])

Removes the filter with the given id. It is strongly recommended to immediately remove the filter if monitoring is no longer needed. A filter will be removed if the filter has not been invoked through getFilterChanges for more than the timeout value set in the node. The default configuration is 5 minutes.

Parameters

Name	Type	Description
filterId	String	The filter id.
callback	Function	(optional) Optional callback, returns an error object as the first parameter and the result as the second.

Return Value

Promise returns Boolean - true if the filter was successfully uninstalled, otherwise false.

Example

> caver.klay.uninstallFilter('0x1426438ffdae5abf43edf4159c5b013b').then(console.log);

true