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ICON SDK for Python |
ICON SDK for Python is a collection of libraries which allow you to interact with a local or remote Loopchain node, using an HTTP connection. The following documentation will guide you through installing and running ICON SDK for Python as well as providing an API reference documentation examples. It is reference to ICON JSON-RPC API v3.
- Quick Start
- Querying API Methods
- Loading a Wallet and Storing the Keystore
- API Methods of KeyWallet
- Signing and Sending Transaction
- Estimating step
ICON SDK for Python development and execution requires following environments.
- Python
- Version: Python 3.6+
- IDE: Pycharm is recommended.
1.0.9 beta
At first, you need to get ICON SDK for Python into your project. It can be installed using pip as follows:
$ pip install iconsdkAfter that, you need to create an IconService instance and set a provider.
-
The IconService class contains a set of API methods. It accepts a HTTPProvider which serves the purpose of connecting to HTTP and HTTPS based JSON-RPC servers.
-
A provider defines how the IconService connects to Loopchain.
-
The HTTPProvider takes the full URI where the server can be found. For local development, this would be something like http://localhost:9000.
Here is an example of calling a simple API method to get a block by its height :
from iconsdk.icon_service import IconService
from iconsdk.providers.http_provider import HTTPProvider
# Creates an IconService instance using the HTTP provider and set a provider.
icon_service = IconService(HTTPProvider("http://localhost:9000", 3))
# Gets a block by a given block height.
block = icon_service.get_block(1209)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)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(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
- Function A
- value : Integer of a block height
- Function B
- value : Hash of a block prefixed with '0x'
- Function C
- value : 'latest'
Block data
Example of a returned block data
- DataTypeException : Data type is invalid.
- JSONRPCException : JSON-RPC Response is error.
# 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(address: str)Returns the ICX balance of the given EOA or SCORE
Delegates to icx_getBalance RPC method
address : An address of EOA or SCORE
Number of ICX coins
- AddressException : Address is invalid.
- DataTypeException : Data type is invalid.
- JSONRPCException : JSON-RPC Response is error.
# Returns the ICX balance of the given EOA or SCORE
balance = icon_service.get_balance("hx000...1")get_score_api(address: str)Returns SCORE's external API list
Delegates to icx_getScoreApi RPC method
address : A SCORE address to be examined
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
- AddressException : Address is invalid.
- DataTypeException : Data type is invalid.
- JSONRPCException : JSON-RPC Response is error.
# Returns SCORE's external API list
score_apis = icon_service.get_score_api("cx000...1")get_total_supply()Returns total ICX coin supply that has been issued
Delegates to icx_getTotalSupply RPC method
None
Total number of ICX coins issued
- DataTypeException : Data type is invalid.
- JSONRPCException : JSON-RPC Response is error.
# Returns total ICX coin supply that has been issued
total_supply = icon_service.get_total_supply()get_transaction(tx_hash: str)Returns the transaction information requested by transaction hash
Delegates to icx_getTransactionByHash RPC method
tx_hash : Transaction hash prefixed with '0x'
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
- DataTypeException : Data type is invalid.
- JSONRPCException : JSON-RPC Response is error.
# Returns the transaction information requested by transaction hash
tx = icon_service.get_transaction("0x000...000")get_transaction_result(tx_hash: str)Returns the transaction result requested by transaction hash
Delegates to icx_getTransactionResult RPC method
tx_hash : Hash of a transaction prefixed with '0x'
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
- DataTypeException : Data type is invalid.
- JSONRPCException : JSON-RPC Response is error.
# Returns the transaction result requested by transaction hash
tx_result = icon_service.get_transaction_result("0x000...000")call(call: Call)Calls SCORE's external function which is read-only without creating a transaction on Loopchain
Delegates to icx_call RPC method
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.
Values returned by the executed SCORE function
- DataTypeException : Data type is invalid.
- JSONRPCException : JSON-RPC Response is error.
# 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)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.
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')create()Generates an instance of Wallet without a specific private key
None
An instance of Wallet class
# Generates a wallet
wallet = KeyWallet.create()load(private_key: bytes)Loads a wallet from bytes of the private key and generates an instance of Wallet
private_key : Bytes of the private key
An instance of Wallet class
- DataTypeException : Private key is invalid.
# Loads a wallet from bytes of the private key
wallet = KeyWallet.load(b'-B\x99...xedy')load(file_path, password)Loads a wallet from a keystore file with your password and generates an instance of Wallet
-
file_path : File path of the keystore file
-
password : Password for the keystore file. Password must include alphabet character, number, and special character
An instance of Wallet class
- KeyStoreException: Key store file is invalid.
# Loads a wallet from a keystore file
wallet = KeyWallet.load("./keystore", "password")store(file_path, password)Stores data of an instance of a derived wallet class on the file path with your password
-
file_path : File path of the keystore file
-
password : Password for the keystore file. Password must include alphabet character, number, and special character
None
- KeyStoreException: Key store file is invalid.
# Stores a keystore file on the file path
wallet.store("./keystore", "password") # throw exception if having an error.get_address()Returns an EOA address
The format of your account (which is generated from your public key) is hxfd7e4560ba363f5aabd32caac7317feeee70ea57.
None
An EOA address
# Returns an EOA address
wallet.get_address()get_private_key()Returns hex string of the private key of the wallet
None
Hex string of the private key
# Returns the private key
wallet.get_private_key()sign(data: bytes)Returns bytes of the ECDSA-SHA256 signature made from the data
data : bytes of the transaction
Bytes of the signature
- DataTypeException : Data type is invalid.
# Signs the transaction
signature = wallet.sign(b'D8\xe9...\xfc')After then, you should create an instance of the transaction using different types of transaction builders as follows.
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.
Finally, you can send a transaction with the signed transaction object as follows.
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 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("0x74657374")\
.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)Builder for a Transaction object
- 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
A transaction object
# 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()Builder for DeployTransaction object
- 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
A deploy transaction object
# 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()Builder for CallTransaction object
- 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
A call transaction object
# 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()Builder for MessageTransaction object
- 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 lowercase hex string prefixed with '0x'.
- 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
A message transaction object
# 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("0x74657374")\
.build()SignedTransaction(transaction: Transaction, wallet: Wallet)Returns the signed transaction object having a signature
- transaction : A transaction object not having a signature field yet
- wallet : A wallet object
The signed transaction object having a signature field finally
- DataTypeException : Data type is invalid.
# Returns the signed transaction object having a signature
signed_transaction = SignedTransaction(transaction, wallet)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.
signed_transaction : A signed transaction object
Transaction hash prefixed with '0x'
- DataTypeException : Data type is invalid.
- JSONRPCException : JSON-RPC Response is error.
# Sends the transaction
tx_hash = icon_service.send_transaction(signed_transaction)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 make a SignedTransaction with the step_limit based on the estimation.
# 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
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, estimate_step)
# 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(transaction: Transaction)Returns an estimated step of how much step is necessary to allow the transaction to complete
Delegates to debug_estimateStep RPC method
transaction : An Transaction object made by TransactionBuilder
Number of an estimated step
- DataTypeException : Data type is invalid.
- JSONRPCException : JSON-RPC Response is error.
# 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)