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ICON is a scalable smart contract enabled blockchain platform with a long-term goal of interoperability between enterprise and public blockchains. Our goal is to Hyperconnect the World, and by combining groundbreaking technology, a strong community, and relentless growth strategies we believe this goal is reachable.

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Python API Reference

The source code is found on GitHub at https://github.com/icon-project/icon-sdk-python

Querying API Methods

Examples

from iconsdk.builder.call_builder import CallBuilder

# Returns block information by block height
block = icon_service.get_block(1000)             

# Returns block information by block hash
block = icon_service.get_block("0x000...000")

# Returns the last block information
block = icon_service.get_block("latest")        

# Returns the balance of the account of given address
balance = icon_service.get_balance("hx000...1")

# Returns a list of the SCORE APIs
score_apis = icon_service.get_score_api("cx000...1")

# Returns the total supply of ICX
total_supply = icon_service.get_total_supply()

# Returns information about a transaction requested by transaction hash
tx = icon_service.get_transaction("0x000...000")

# Returns the result of a transaction by transaction hash
tx_result = icon_service.get_transaction_result("0x000...000")

# Generates a call instance using the CallBuilder
call = CallBuilder().from_(wallet.get_address())\
                    .to("cx000...1")\
                    .method("balance_of")\
                    .params({"address": "hx000...1"})\
                    .build()

# Executes a call method to call a read-only API method on the SCORE immediately without creating a transaction on Loopchain
result = icon_service.call(call)

Error Cases

There are different types of error cases as below. The exception is raised with the specific message. You can get more information about the exception from the message.

  • KeyStoreException
    • It is raised when making or loading a key store file.
    • Error code for the exception is 1.
  • AddressException
    • It is raised when the address is invalid.
    • Error code for the exception is 2.
  • BalanceException
    • It is raised when the balance is invalid.
    • Error code for the exception is 3.
  • DataTypeException
    • It is raised when the data type is invalid.
    • Error code for the exception is 4.
  • JSONRPCException
    • It is raised when JSON-RPC response is an error.
    • Error code for the exception is 5.
  • ZipException
    • It is raised while writing zip in memory.
    • Error code for the exception is 6.

get_block

get_block(value)
  • Function A
    • Returns block information by block height
    • Delegates to icx_getBlockByHeight RPC method
  • Function B
    • Returns block information by block hash
    • Delegates to icx_getBlockByHash RPC method
  • Function C
    • Returns the last block information
    • Delegates to icx_getLastBlock RPC method

Parameters

  • Function A
    • value : Integer of a block height
  • Function B
    • value : Hash of a block prefixed with '0x'
  • Function C
    • value : 'latest'

Returns

Block data

Example of a returned block data

Error Cases

  • DataTypeException : Data type is invalid.
  • JSONRPCException : JSON-RPC Response is error.

Example

# Returns block information by block height
block = icon_service.get_block(1000)             

# Returns block information by block hash
block = icon_service.get_block("0x000...000")

# Returns the last block information
block = icon_service.get_block("latest")

get_balance

get_balance(address: str)

Returns the ICX balance of the given EOA or SCORE

Delegates to icx_getBalance RPC method

Parameters

address : An address of EOA or SCORE

Returns

Number of ICX coins

Error Cases

  • AddressException : Address is invalid.
  • DataTypeException : Data type is invalid.
  • JSONRPCException : JSON-RPC Response is error.

Example

# Returns the ICX balance of the given EOA or SCORE
balance = icon_service.get_balance("hx000...1")

get_score_api

get_score_api(address: str)

Returns SCORE's external API list

Delegates to icx_getScoreApi RPC method

Parameters

address : A SCORE address to be examined

Returns

A list of API methods of the SCORE and its information

Fields :

  • type : Method type; function, fallback, or eventlog
  • name : Function name on the SCORE
  • inputs : A list of information of parameters
    • name : Parameter name
    • type : Parameter type ; int, str, bytes, bool, Address
    • indexed : In the case of eventlog, tells if the parameter is indexed.
  • outputs : Return value
    • type : Return value type ; int, str, bytes, bool, Address
  • Readonly : External (readonly=True)
  • Payable: Payable

Error Cases

  • AddressException : Address is invalid.
  • DataTypeException : Data type is invalid.
  • JSONRPCException : JSON-RPC Response is error.

Example

# Returns SCORE's external API list
score_apis = icon_service.get_score_api("cx000...1")

get_total_supply

get_total_supply()

Returns total ICX coin supply that has been issued

Delegates to icx_getTotalSupply RPC method

Parameters

None

Returns

Total number of ICX coins issued

Error Cases

  • DataTypeException : Data type is invalid.
  • JSONRPCException : JSON-RPC Response is error.

Example

# Returns total ICX coin supply that has been issued
total_supply = icon_service.get_total_supply()

get_transaction

get_transaction(tx_hash: str)

Returns the transaction information requested by transaction hash

Delegates to icx_getTransactionByHash RPC method

Parameters

tx_hash : Transaction hash prefixed with '0x'

Returns

Information about a transaction

Fields :

  • version : Protocol version (3 for V3)
  • from : An EOA address that created the transaction
  • to : An EOA address to receive coins, or SCORE address to execute the transaction
  • value : Amount of ICX coins in loop to transfer. When omitted, assumes 0. (1 icx = 10 ^ 18 loop)
  • stepLimit : Maximum step allowance that can be used by the transaction
  • timestamp : Transaction creation time. Timestamp is in microseconds.
  • nid : Network ID (1 for Main net, etc)
  • nonce : An arbitrary number used to prevent transaction hash collision
  • txHash : Transaction hash
  • txIndex : Transaction index in a block. Null when it is pending.
  • blockHeight : Block height including the transaction. Null when it is pending
  • blockHash : Block hash including the transaction. Null when it is pending.
  • signature : Signature of the transaction
  • dataType : Data type; call, deploy, message
  • data : Contains various type of data depending on the dataType

Error Cases

  • DataTypeException : Data type is invalid.
  • JSONRPCException : JSON-RPC Response is error.

Example

# Returns the transaction information requested by transaction hash
tx = icon_service.get_transaction("0x000...000")

get_transaction_result

get_transaction_result(tx_hash: str)

Returns the transaction result requested by transaction hash

Delegates to icx_getTransactionResult RPC method

Parameters

tx_hash : Hash of a transaction prefixed with '0x'

Returns

A transaction result object

Field :

  • status : 1 on success, 0 on failure
  • to : Recipient address of the transaction
  • failure : This field exists when status is 0. Contains code(str) and message(str)
  • txHash : Transaction hash
  • txIndex : Transaction index in the block
  • blockHeight : Block height including the transaction
  • blockHash : Block hash including the transaction
  • cumulativeStepUsed : Sum of stepUsed by this transaction and all preceding transactions in the same block
  • stepUsed : The amount of step used by this transaction
  • stepPrice: The step price used by this transaction
  • scoreAddress : A SCORE address if the transaction created a new SCORE. (optional)
  • eventLogs : Array of eventlogs generated by this transaction
  • logsBloom : Bloom filter to quickly retrieve related eventlogs

Error Cases

  • DataTypeException : Data type is invalid.
  • JSONRPCException : JSON-RPC Response is error.

Example

# Returns the transaction result requested by transaction hash
tx_result = icon_service.get_transaction_result("0x000...000")

call

call(call: Call)

Calls SCORE's external function which is read-only without creating a transaction on Loopchain

Delegates to icx_call RPC method

Parameters

Call object made by CallBuilder

Fields :

  • from : Message sender's address
  • to : A SCORE address that will handle the message
  • method : name of an external function
  • params : Parameters to be passed to the function (optional). A data type of params should be dict.

Returns

Values returned by the executed SCORE function

Error Cases

  • DataTypeException : Data type is invalid.
  • JSONRPCException : JSON-RPC Response is error.

Example

# Generates a call instance using the CallBuilder
call = CallBuilder().from_(wallet.get_address())\
                    .to("cx000...1")\
                    .method("balance_of")\
                    .params({"address": "hx000...1"})\
                    .build()

# Calls SCORE's external function which is read-only without creating a transaction on Loopchain
result = icon_service.call(call)

Loading a Wallet and Storing the Keystore

To send transactions, first, you should make an instance of your wallet.

You can make an instance of the wallet using bytes of the private key or from a keystore file.

Examples

from iconsdk.wallet.wallet import KeyWallet

# Generates a wallet
wallet = KeyWallet.create()

# Loads a wallet from bytes of the private key
wallet = KeyWallet.load(b'-B\x99...xedy')

# Loads a wallet from a keystore file
wallet = KeyWallet.load("./keystore", "password")

# Stores a keystore file on the file path
wallet.store("./keystore", "password") # throw exception if having an error.

# Returns an Address
wallet.get_address()

# Returns a private key
wallet.get_private_key()

# Signs the transaction
signature = wallet.sign(b'D8\xe9...\xfc')

API Methods of KeyWallet

create

create()

Generates an instance of Wallet without a specific private key

Parameters

None

Returns

An instance of Wallet class

Example

# Generates a wallet
wallet = KeyWallet.create()

load

load(private_key: bytes)

Loads a wallet from bytes of the private key and generates an instance of Wallet

Parameters

private_key : Bytes of the private key

Returns

An instance of Wallet class

Error Cases

  • DataTypeException : Private key is invalid.

Example

# Loads a wallet from a private key in bytes
wallet = KeyWallet.load(b'-B\x99...xedy')

load

load(file_path, password)

Loads a wallet from a keystore file with your password and generates an instance of Wallet

Parameters

  • file_path : File path of the keystore file
  • password : Password for the keystore file. Password must include alphabet character, number, and special character

Returns

An instance of Wallet class

Error Cases

  • KeyStoreException: Key store file is invalid.

Example

# Loads a wallet from a keystore file
wallet = KeyWallet.load("./keystore", "password")

store

store(file_path, password)

Stores data of an instance of a derived wallet class on the file path with your password

Parameters

  • file_path : File path of the keystore file
  • password : Password for the keystore file. Password must include alphabet character, number, and special character

Returns

None

Error Cases

  • KeyStoreException: Key store file is invalid.

Example

# Stores a keystore file on the file path
wallet.store("./keystore", "password") # throw exception if having an error.

get_address

get_address()

Returns an EOA address

The format of your account (which is generated from your public key) is hxfd7e4560ba363f5aabd32caac7317feeee70ea57.

Parameters

None

Returns

An EOA address

Example

# Returns an EOA address
wallet.get_address()

get_private_key

get_private_key()

Returns hex string of the private key of the wallet

Parameters

None

Returns

Hex string of the private key

Example

# Returns the private key
wallet.get_private_key()

sign

sign(data: bytes)

Returns bytes of the ECDSA-SHA256 signature made from the data

Parameters

data : bytes of the transaction

Returns

Bytes of the signature

Error Cases

  • DataTypeException : Data type is invalid.

Example

# Signs the transaction
signature = wallet.sign(b'D8\xe9...\xfc')

Signing and Sending Transaction

Generating a Transaction

After then, you should create an instance of the transaction using different types of transaction builders as follows.

Signing a Transaction

Before sending a transaction, the transaction should be signed by using SignedTransaction class. The SignedTransaction class is used to sign the transaction by returning an instance of the signed transaction as demonstrated in the example below. The instance of the signed transaction has the property of a signature.

Sending a Transaction

Finally, you can send a transaction with the signed transaction object as follows.

Examples

from iconsdk.builder.transaction_builder import (
    TransactionBuilder,
    DeployTransactionBuilder,
    CallTransactionBuilder,
    MessageTransactionBuilder
)
from iconsdk.signed_transaction import SignedTransaction

# Generates an instance of transaction for sending icx.
transaction = TransactionBuilder()\
    .from_(wallet.get_address())\
    .to("cx00...02")\
    .value(150000000)\
    .step_limit(1000000)\
    .nid(3)\
    .nonce(100)\
    .build()

# Generates an instance of transaction for deploying SCORE.
transaction = DeployTransactionBuilder()\
    .from_(wallet.get_address())\
    .to("cx00...02")\
    .step_limit(1000000)\
    .nid(3)\
    .nonce(100)\
    .content_type("application/zip")\
    .content(b'D8\xe9...\xfc')\
    .params(params)\
    .build()

# Generates an instance of transaction for the calling method in SCORE.
transaction = CallTransactionBuilder()\
    .from_(wallet.get_address())\
    .to("cx00...02")\
    .step_limit(1000000)\
    .nid(3)\
    .nonce(100)\
    .method("transfer")\
    .params(params)\
    .build()

# Generates an instance of transaction for sending a message.
transaction = MessageTransactionBuilder()\
    .from_(wallet.get_address())\
    .to("cx00...02")\
    .step_limit(1000000)\
    .nid(3)\
    .nonce(100)\
    .data("test")\
    .build()

# Returns the signed transaction object having a signature
signed_transaction = SignedTransaction(transaction, wallet)

# Sends the transaction
tx_hash = icon_service.send_transaction(signed_transaction)

TransactionBuilder

Builder for a Transaction object

Methods

  • from_ : The wallet address making a transaction. The default address is your account address.
  • to : The wallet address to receive coin or SCORE address to receive a transaction.
  • value : The amount of ICX to be sent. (Optional)
  • step_limit : The maximum step value for processing a transaction.
  • nid : Network ID. Default nid is 1 if you didn't set the value. (1 for Main net, etc)
  • nonce : An arbitrary number used to prevent transaction hash collision. (Optional)
  • version : Protocol version (3 for V3). The default version is 3 if you didn't set the value.
  • timestamp : Transaction creation time. Timestamp is in microseconds. Default timestamp is set, if you didn't set the value.
  • build : Returns an ICX transaction object

Returns

A transaction object

Example

# Generates an instance of transaction for sending icx.
transaction = TransactionBuilder()\
    .from_(wallet.get_address())\
    .to("cx00...02")\
    .value(150000000)\
    .step_limit(1000000)\
    .nid(3)\
    .nonce(100)\
    .build()

DeployTransactionBuilder

Builder for DeployTransaction object

Methods

  • from_ : The wallet address making a transaction. The default address is your account address.
  • to : The wallet address to receive coin or SCORE address to receive a transaction
  • step_limit : The maximum step value for processing a transaction
  • nid : Network ID. Default nid is 1 if you didn't set the value. (1 for Main net, etc)
  • nonce : An arbitrary number used to prevent transaction hash collision
  • content_type : Content's MIME type
  • content : Binary data of the SCORE
  • params : Parameters passed on the SCORE methods ; on_install (), on_update (). Data type of the params should be dict. (optional)
  • version : Protocol version (3 for V3). The default version is 3 if you didn't set the value.
  • timestamp : Transaction creation time. Timestamp is in microseconds. Default timestamp is set, if you didn't set the value.
  • build : Returns a deploy transaction object

Returns

A deploy transaction object

Example

# Generates an instance of transaction for deploying SCORE.
transaction = DeployTransactionBuilder()\
    .from_(wallet.get_address())\
    .to("cx00...02")\
    .step_limit(1000000)\
    .nid(3)\
    .nonce(100)\
    .content_type("application/zip")\
    .content(b'D8\xe9...\xfc')\
    .params(params)\
    .build()

CallTransactionBuilder

Builder for CallTransaction object

Methods

  • from_ : The wallet address making a transaction. The default address is your account address.
  • to : The wallet address to receive coin or SCORE address to receive a transaction
  • step_limit : The maximum step value for processing a transaction
  • nid : Network ID. Default nid is 1 if you didn't set the value. (1 for Main net, etc)
  • nonce : An arbitrary number used to prevent transaction hash collision
  • method : Methods in the SCORE
  • params : Parameters passed on the SCORE methods. Data type of the params should be dict. (optional)
  • version : Protocol version (3 for V3). The default version is 3 if you didn't set the value.
  • timestamp : Transaction creation time. Timestamp is in microseconds. Default timestamp is set, if you didn't set the value.
  • Build : Returns a call transaction object

Returns

A call transaction object

Example

# Generates an instance of transaction for calling method in SCORE.
transaction = CallTransactionBuilder()\
    .from_(wallet.get_address())\
    .to("cx00...02")\
    .step_limit(1000000)\
    .nid(3)\
    .nonce(100)\
    .method("transfer")\
    .params(params)\
    .build()

MessageTransactionBuilder

Builder for MessageTransaction object

Methods

  • from_ : The wallet address making a transaction. The default address is your account address.
  • to : The wallet address to receive coin or SCORE address to receive a transaction
  • stepLimit : The maximum step value for processing a transaction
  • nid : Network ID. Default nid is 1 if you didn't set the value. (1 for Main net, etc)
  • nonce : An arbitrary number used to prevent transaction hash collision
  • data : Data by the dataType. Data type of the data should be string.
  • version : Protocol version (3 for V3). The default version is 3 if you didn't set the value.
  • timestamp : Transaction creation time. Timestamp is in microseconds. Default timestamp is set, if you didn't set the value.
  • build : Returns a message transaction object

Returns

A message transaction object

Example

# Generates an instance of transaction for sending a message.
transaction = MessageTransactionBuilder()\
    .from_(wallet.get_address())\
    .to("cx00...02")\
    .step_limit(1000000)\
    .nid(3)\
    .nonce(100)\
    .data("test")\
    .build()

SignedTransaction

SignedTransaction(transaction: Transaction, wallet: Wallet)

Returns the signed transaction object having a signature

Parameters

  • transaction : A transaction object not having a signature field yet
  • wallet : A wallet object

Returns

The signed transaction object having a signature field finally

Error Cases

  • DataTypeException : Data type is invalid.

Example

# Returns the signed transaction object having a signature
signed_transaction = SignedTransaction(transaction, wallet)

send_transaction

send_transaction(signed_transaction: SignedTransaction)

Sends the transaction

Delegates to icx_sendTransaction RPC method

Need to wait for a while after sending the transaction. Because it takes time to make a consensus among nodes. We recommend 0.3 second at least.

Parameters

signed_transaction : A signed transaction object

Returns

Transaction hash prefixed with '0x'

Error Cases

  • DataTypeException : Data type is invalid.
  • JSONRPCException : JSON-RPC Response is error.

Example

# Sends the transaction
tx_hash = icon_service.send_transaction(signed_transaction)

Estimating Step

It is important to set a proper step_limit value in your transaction to make the submitted transaction executed successfully.

estimate_step API provides a way to estimate the Step usage of a given transaction. Using the method, you can get an estimated Step usage before sending your transaction, then based on the estimation, decide the optimal step_limit in your SignedTransaction.

Note: You’ll need to have iconsdk 1.0.9 or later on your local development machine to use 'estimate_step' API.

Examples

# Generates a raw transaction without the stepLimit
transaction = TransactionBuilder()\
    .from_(wallet.get_address())\
    .to("cx00...02")\
    .value(150000000)\
    .nid(3)\
    .nonce(100)\
    .build()

# Returns an estimated step value
estimate_step = icon_service.estimate_step(transaction)
# Adds some margin to the estimated step 
step_limit = estimate_step + 10000
# Returns the signed transaction object having a signature with the same raw transaction and the estimated step
signed_transaction = SignedTransaction(transaction, wallet, step_limit)
# Sends the transaction
tx_hash = icon_service.send_transaction(signed_transaction)

Note that the estimation can be smaller or larger than the actual amount of step to be used by the transaction, so it is recommended to add some margin to the estimation when you set the step_limit of the SignedTransaction.

estimate_step

estimate_step(transaction: Transaction)

Returns an estimated step of how much step is necessary to allow the transaction to complete

Delegates to debug_estimateStep RPC method

Parameters

transaction : An Transaction object made by TransactionBuilder

Returns

Number of an estimated step

Error Cases

  • DataTypeException : Data type is invalid.
  • JSONRPCException : JSON-RPC Response is error.

Example

# Generates a raw transaction without the stepLimit
transaction = TransactionBuilder()\
    .from_(wallet.get_address())\
    .to("cx00...02")\
    .value(150000000)\
    .nid(3)\
    .nonce(100)\
    .build()

# Returns an estimated step value
estimate_step = icon_service.estimate_step(transaction)

Reference

Updated 6 months ago

Python API Reference


The source code is found on GitHub at https://github.com/icon-project/icon-sdk-python

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