Package: reef-interface
Python Reef InterfacePython Reef Interface LibraryDescriptionThis library specializes in interfacing with the Reef node, providing additional convenience methods to deal with
SCALE encoding/decoding (the default output and input format of the Substrate JSONRPC), metadata parsing, type registry
management and versioning of types.DocumentationInstallationpipinstallreef-interfaceInitializationThe following examples show how to initialize:fromreefinterfaceimportReefInterfacereef=ReefInterface(url="testnet")urlcan betestnet,mainnetor anws://<url>URL for custom node.FeaturesRetrieve extrinsics for a certain block# Set block_hash to None for chain tipblock_hash="0x51d15792ff3c5ee9c6b24ddccd95b377d5cccc759b8e76e5de9250cf58225087"# Retrieve extrinsics in blockresult=reef.get_block(block_hash=block_hash)forextrinsicinresult['extrinsics']:ifextrinsic.address:signed_by_address=extrinsic.address.valueelse:signed_by_address=Noneprint('\nPallet:{}\nCall:{}\nSigned by:{}'.format(extrinsic.call_module.name,extrinsic.call.name,signed_by_address))# Loop through call paramsforparaminextrinsic.params:ifparam['type']=='Compact<Balance>':param['value']='{}{}'.format(param['value']/10**18r.token_decimals,reef.token_symbol)print("Param '{}':{}".format(param['name'],param['value']))Subscribe to new block headersdefsubscription_handler(obj,update_nr,subscription_id):print(f"New block #{obj['header']['number']}produced by{obj['author']}")ifupdate_nr>10:return{'message':'Subscription will cancel when a value is returned','updates_processed':update_nr}result=reef.subscribe_block_headers(subscription_handler,include_author=True)Storage queriesThe modules and storage functions are provided in the metadata (seereef.get_metadata_storage_functions()),
parameters will be automatically converted to SCALE-bytes (also including decoding of SS58 addresses).Example:result=reef.query(module='System',storage_function='Account',params=['F4xQKRUagnSGjFqafyhajLs94e7Vvzvr8ebwYJceKpr8R7T'])print(result.value['nonce'])print(result.value['data']['free'])Or get the account info at a specific block hash:account_info=reef.query(module='System',storage_function='Account',params=['F4xQKRUagnSGjFqafyhajLs94e7Vvzvr8ebwYJceKpr8R7T'],block_hash='0x176e064454388fd78941a0bace38db424e71db9d5d5ed0272ead7003a02234fa')print(account_info.value['nonce'])#  7673print(account_info.value['data']['free'])# 637747267365404068Storage subscriptionsWhen a callable is passed as kwargsubscription_handler, there will be a subscription created for given storage query.
Updates will be pushed to the callable and will block execution until a final value is returned. This value will be returned
as a result of the query and finally automatically unsubscribed from further updates.defsubscription_handler(account_info_obj,update_nr,subscription_id):ifupdate_nr==0:print('Initial account data:',account_info_obj.value)ifupdate_nr>0:# Do something with the updateprint('Account data changed:',account_info_obj.value)# The execution will block until an arbitrary value is returned, which will be the result of the `query`ifupdate_nr>5:returnaccount_info_objresult=reef.query("System","Account",["5GNJqTPyNqANBkUVMN1LPPrxXnFouWXoe2wNSmmEoLctxiZY"],subscription_handler=subscription_handler)print(result)Query a mapped storage functionMapped storage functions can be iterated over all key/value pairs, for these type of storage functionsquery_mapcan be used.The result is aQueryMapResultobject, which is an iterator:# Retrieve the first 199 System.Account entriesresult=reef.query_map('System','Account',max_results=199)foraccount,account_infoinresult:print(f"Free balance of account '{account.value}':{account_info.value['data']['free']}")These results are transparently retrieved in batches capped by thepage_sizekwarg, currently the
maximumpage_sizerestricted by the RPC node is 1000# Retrieve all System.Account entries in batches of 200 (automatically appended by `QueryMapResult` iterator)result=reef.query_map('System','Account',page_size=200,max_results=400)foraccount,account_infoinresult:print(f"Free balance of account '{account.value}':{account_info.value['data']['free']}")Create and send signed extrinsicsThe following code snippet illustrates how to create a call, wrap it in a signed extrinsic and send it to the network:fromreefinterfaceimportReefInterface,Keypairfromreefinterface.exceptionsimportSubstrateRequestExceptionreef=ReefInterface(url="testnet")keypair=Keypair.create_from_mnemonic('episode together nose spoon dose oil faculty zoo ankle evoke admit walnut')call=reef.compose_call(call_module='Balances',call_function='transfer',call_params={'dest':'5E9oDs9PjpsBbxXxRE9uMaZZhnBAV38n2ouLB28oecBDdeQo','value':1*10**18})extrinsic=reef.create_signed_extrinsic(call=call,keypair=keypair)try:receipt=reef.submit_extrinsic(extrinsic,wait_for_inclusion=True)print("Extrinsic '{}' sent and included in block '{}'".format(receipt.extrinsic_hash,receipt.block_hash))exceptSubstrateRequestExceptionase:print("Failed to send:{}".format(e))Thewait_for_inclusionkeyword argument used in the example above will block giving the result until it gets
confirmation from the node that the extrinsic is succesfully included in a block. Thewait_for_finalizationkeyword
will wait until extrinsic is finalized. Note this feature is only available for websocket connections.Examining the ExtrinsicReceipt objectThereef.submit_extrinsicexample above returns anExtrinsicReceiptobject, which contains information about the on-chain
execution of the extrinsic. Because theblock_hashis necessary to retrieve the triggered events from storage, most
information is only available whenwait_for_inclusion=Trueorwait_for_finalization=Trueis used when submitting
an extrinsic.Examples:receipt=reef.submit_extrinsic(extrinsic,wait_for_inclusion=True)print(receipt.is_success)# Falseprint(receipt.weight)# 216625000print(receipt.total_fee_amount)# 2749998966print(receipt.error_message['name'])# 'LiquidityRestrictions'ExtrinsicReceiptobjects can also be created for all existing extrinsics on-chain:receipt=ExtrinsicReceipt(reef=reef,extrinsic_hash="0x56fea3010910bd8c0c97253ffe308dc13d1613b7e952e7e2028257d2b83c027a",block_hash="0x04fb003f8bc999eeb284aa8e74f2c6f63cf5bd5c00d0d0da4cd4d253a643e4c9")print(receipt.is_success)# Falseprint(receipt.extrinsic.call_module.name)# 'Identity'print(receipt.extrinsic.call.name)# 'remove_sub'print(receipt.weight)# 359262000print(receipt.total_fee_amount)# 2483332406print(receipt.error_message['docs'])# [' Sender is not a sub-account.']foreventinreceipt.triggered_events:print(f'*{event.value}')Create mortal extrinsicsBy default,immortalextrinsics are created, which means they have an indefinite lifetime for being included in a
block. However, it is recommended to use specify an expiry window, so you know after a certain amount of time if the
extrinsic is not included in a block, it will be invalidated.extrinsic=reef.create_signed_extrinsic(call=call,keypair=keypair,era={'period':64})Theperiodspecifies the number of blocks the extrinsic is valid counted from current head.Multi-signingIn the below example we see signing with Alice and Bob, who have a common Multisig account. The transfer will not be done until both of them sign the extrinsic. Other extrinsics are availablehere.# Multisig examplefromreefinterfaceimportKeypair,ReefInterface# Connect to nodetry:network="ws://127.0.0.1:9944"substrate=ReefInterface(url=network)exceptConnectionRefusedError:print("Reef node could not be reached.")exit()alice=Keypair.create_from_uri("//Alice")bob=Keypair.create_from_uri("//Bob")# Extrinsic to be multi-signedtransfer=substrate.compose_call(call_module="Balances",call_function="transfer",call_params={"dest":alice.ss58_address,"value":123*10**18},)extrinsic=substrate.create_unsigned_extrinsic(transfer)# First sign will be done with alicecall=substrate.compose_call(call_module="Multisig",call_function="approve_as_multi",call_params={"threshold":2,# number of signatures requires"other_signatories":[bob.ss58_address],# cannot be empty"maybe_timepoint":None,# must be None for the first approval"call_hash":"0x"+extrinsic.extrinsic_hash.hex(),"max_weight":215137000,},)call_extrinsic=substrate.create_signed_extrinsic(call,alice)receipt=substrate.submit_extrinsic(call_extrinsic,wait_for_inclusion=True)# Check the eventsforeventinreceipt.triggered_events:print(f"*{event.value}")# ----------- SIGNING WITH BOB -----------# First get the timepoint (block_number, extrinsic_index) for the first approval abovetimepoint={"height":substrate.get_block_number(receipt.block_hash),"index":receipt.extrinsic_idx,}# Compose call, extrinsic should match the one abovecall=substrate.compose_call(call_module="Multisig",call_function="as_multi",call_params={"threshold":2,"other_signatories":[alice.ss58_address],"maybe_timepoint":timepoint,"call":{"call_module":"Balances","call_function":"transfer","call_args":{"dest":alice.ss58_address,"value":123*10**18,},},"store_call":False,"max_weight":215137000,},)call_extrinsic=substrate.create_signed_extrinsic(call,bob)receipt=substrate.submit_extrinsic(call_extrinsic,wait_for_inclusion=True)# Check the eventsforeventinreceipt.triggered_events:print(f"*{event.value}")Keypair creation and signingmnemonic=Keypair.generate_mnemonic()keypair=Keypair.create_from_mnemonic(mnemonic)signature=keypair.sign("Test123")ifkeypair.verify("Test123",signature):print('Verified')By default, a keypair is using SR25519 cryptography, alternatively ED25519 can be explictly specified:keypair=Keypair.create_from_mnemonic(mnemonic,crypto_type=KeypairType.ED25519)Creating keypairs with soft and hard key derivation pathsmnemonic=Keypair.generate_mnemonic()keypair=Keypair.create_from_uri(mnemonic+'//hard/soft')By omitting the mnemonic the default development mnemonic is used:keypair=Keypair.create_from_uri('//Alice')Getting estimate of network fees for extrinsic in advancekeypair=Keypair(ss58_address="EaG2CRhJWPb7qmdcJvy3LiWdh26Jreu9Dx6R1rXxPmYXoDk")call=reef.compose_call(call_module='Balances',call_function='transfer',call_params={'dest':'EaG2CRhJWPb7qmdcJvy3LiWdh26Jreu9Dx6R1rXxPmYXoDk','value':1*10**18})payment_info=reef.get_payment_info(call=call,keypair=keypair)# {'class': 'normal', 'partialFee': 2499999066, 'weight': 216625000}Offline signing of extrinsicsThis example generates a signature payload which can be signed on another (offline) machine and later on sent to the
network with the generated signature.Generate signature payload on online machine:reef=ReefInterface(url="testnet")call=reef.compose_call(call_module='Balances',call_function='transfer',call_params={'dest':'5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY','value':1*10**18})era={'period':64,'current':22719}nonce=0signature_payload=reef.generate_signature_payload(call=call,era=era,nonce=nonce)Then on another (offline) machine generate the signature with givensignature_payload:keypair=Keypair.create_from_mnemonic("nature exchange gasp toy result bacon coin broccoli rule oyster believe lyrics")signature=keypair.sign(signature_payload)Finally on the online machine send the extrinsic with generated signature:keypair=Keypair(ss58_address="5EChUec3ZQhUvY1g52ZbfBVkqjUY9Kcr6mcEvQMbmd38shQL")extrinsic=reef.create_signed_extrinsic(call=call,keypair=keypair,era=era,nonce=nonce,signature=signature)result=reef.submit_extrinsic(extrinsic=extrinsic)print(result.extrinsic_hash)Accessing runtime constantsAll runtime constants are provided in the metadata (seereef.get_metadata_constants()),
to access these as a decodedScaleTypeyou can use the functionreef.get_constant():constant=reef.get_constant("Balances","ExistentialDeposit")print(constant.value)# 10000000000Batching callsBy usingUtilitypallet, we can submit multiple calls within a single call. In the below example we create 100 transfer calls of 10k REEF.fromreefinterfaceimportKeypair,ReefInterface# Connect to nodetry:network="ws://127.0.0.1:9944"substrate=ReefInterface(url=network)exceptConnectionRefusedError:print("Reef node could not be reached.")exit()alice=Keypair.create_from_uri("//Alice")bob=Keypair.create_from_uri("//Bob")# Transfer 1M REEF in 100 calls of 10kcall=substrate.compose_call(call_module="Utility",call_function="batch",call_params={"calls":[{"call_module":"Balances","call_function":"transfer","call_args":{"dest":bob.ss58_address,"value":10000*10**18},}]*100},)extrinsic=substrate.create_signed_extrinsic(call=call,keypair=alice,era={"period":64})receipt=substrate.submit_extrinsic(extrinsic,wait_for_inclusion=True)# Check the eventsforeventinreceipt.triggered_events:print(f"*{event.value}")Cleanup and context managerAt the end of the lifecycle of aReefInterfaceinstance, calling theclose()method will do all the necessary
cleanup, like closing the websocket connection.When using the context manager this will be done automatically:withReefInterface(url="testnet")asreef:events=reef.query("System","Events")# connection is now closedContact and SupportFor questions, please reach out to us on ourmatrixchat group:Reef Developer Chat.