docs/developers/ocean.py/technical-details.md

description
Technical details about most used ocean.py functions

Technical Details

At the beginning of most flows, we create an ocean object, which is an instance of class Ocean. It exposes useful information, including the following.

Ocean instance

Ocean class:

Ocean - The Ocean class is the entry point into Ocean Protocol.

In order to initialize a Ocean object, you must provide config_dict which is a Dictionary instance and optionally a DataServiceProvider instance.

Here is the source code.

{% code overflow="wrap" %}

class Ocean:
    """The Ocean class is the entry point into Ocean Protocol."""

    @enforce_types
    def __init__(self, config_dict: Dict, data_provider: Optional[Type] = None) -> None:
        """Initialize Ocean class.

        Usage: Make a new Ocean instance

        `ocean = Ocean({...})`

        This class provides the main top-level functions in ocean protocol:
        1. Publish assets metadata and associated services
            - Each asset is assigned a unique DID and a DID Document (DDO)
            - The DDO contains the asset's services including the metadata
            - The DID is registered on-chain with a URL of the metadata store
              to retrieve the DDO from

            `ddo = ocean.assets.create(metadata, publisher_wallet)`

        2. Discover/Search ddos via the current configured metadata store (Aquarius)

            - Usage:
            `ddos_list = ocean.assets.search('search text')`

        An instance of Ocean is parameterized by a `Config` instance.

        :param config_dict: variable definitions
        :param data_provider: `DataServiceProvider` instance
        """
        config_errors = {}
        for key, value in config_defaults.items():
            if key not in config_dict:
                config_errors[key] = "required"
                continue

            if not isinstance(config_dict[key], type(value)):
                config_errors[key] = f"must be {type(value).__name__}"

        if config_errors:
            raise Exception(json.dumps(config_errors))

        self.config_dict = config_dict

        network_name = config_dict["NETWORK_NAME"]
        check_network(network_name)

        if not data_provider:
            data_provider = DataServiceProvider

        self.assets = OceanAssets(self.config_dict, data_provider)
        self.compute = OceanCompute(self.config_dict, data_provider)

        logger.debug("Ocean instance initialized: ")

{% endcode %}

Config dict attribute:

ocean.config_dict or ocean.config -> dict

It is a helper method for retrieving the user's configuration for ocean.py.
It can be called only by Ocean object and returns a python dictionary.

    @property
    @enforce_types
    def config(self) -> dict:  # alias for config_dict
        return self.config_dict

OCEAN token:

ocean.OCEAN_address -> str

It is a helper method for retrieving the OCEAN's token address.
It can be called only by Ocean object and returns the address as a string.

 @property
    @enforce_types
    def OCEAN_address(self) -> str:
        return get_ocean_token_address(self.config)

get_ocean_token_address function is an utilitary function which gets the address from address.json file

{% code overflow="wrap" %}

@enforce_types
def get_ocean_token_address(config_dict: dict) -> str:
    """Returns the Ocean token address for given network or web3 instance
    Requires either network name or web3 instance.
    """
    addresses = get_contracts_addresses(config_dict)

    return Web3.toChecksumAddress(addresses.get("Ocean").lower()) if addresses else None

{% endcode %}

ocean.OCEAN_token or ocean.OCEAN -> Datatoken

It is a helper method for retrieving the OCEAN token object (Datatoken class).
It can be called within Ocean class and returns the OCEAN Datatoken.

    @property
    @enforce_types
    def OCEAN_token(self) -> DatatokenBase:
        return DatatokenBase.get_typed(self.config, self.OCEAN_address)

    @property
    @enforce_types
    def OCEAN(self):  # alias for OCEAN_token
        return self.OCEAN_token

Ocean smart contracts:

ocean.data_nft_factory -> DataNFTFactoryContract

It is a property for getting Data NFT Factory object for the singleton smart contract.
It can be called within Ocean class and returns the DataNFTFactoryContract instance.

{% code overflow="wrap" %}

@property
    @enforce_types
    def data_nft_factory(self) -> DataNFTFactoryContract:
        return DataNFTFactoryContract(self.config, self._addr("ERC721Factory"))

{% endcode %}

ocean.dispenser -> Dispenser

Dispenser is represented by a faucet for free data.
It is a property for getting Dispenser object for the singleton smart contract.
It can be called within Ocean class and returns the Dispenser instance.

    @property
    @enforce_types
    def dispenser(self) -> Dispenser:
        return Dispenser(self.config, self._addr("Dispenser"))

ocean.fixed_rate_exchange -> FixedRateExchange

Exchange is used for priced data.
It is a property for getting FixedRateExchange object for the singleton smart contract.
It can be called within Ocean class and returns the FixedRateExchange instance.

 @property
    @enforce_types
    def fixed_rate_exchange(self) -> FixedRateExchange:
        return FixedRateExchange(self.config, self._addr("FixedPrice"))

Simple getters:

ocean.get_nft_token(self, token_address: str) -> DataNFT

It is a getter for a specific data NFT object based on its checksumed address.
It can be called within Ocean class with a string token_address as parameter which returns the DataNFT instance.

    @enforce_types
    def get_nft_token(self, token_address: str) -> DataNFT:
        """
        :param token_address: Token contract address, str
        :return: `DataNFT` instance
        """
        return DataNFT(self.config, token_address)

ocean.get_datatoken(self, token_address: str) -> DatatokenBase

It is a getter for a specific datatoken object based on its checksumed address.
It can be called within Ocean class with a string token_address as parameter which returns the DatatokenBase instance depending on datatoken's template index.

@enforce_types
    def get_datatoken(self, token_address: str) -> DatatokenBase:
        """
        :param token_address: Token contract address, str
        :return: `Datatoken1` or `Datatoken2` instance
        """
        return DatatokenBase.get_typed(self.config, token_address)

ocean.get_user_orders(self, address: str, datatoken: str)

Returns the list of orders that were made by a certain user on a specific datatoken.

As parameters:

1. address - ETH wallet address of that user
2. datatoken - datatoken address

It can be called within Ocean class.

{% code overflow="wrap" %}

    @enforce_types
    def get_user_orders(self, address: str, datatoken: str) -> List[AttributeDict]:
        """
        :return: List of orders `[Order]`
        """
        dt = DatatokenBase.get_typed(self.config_dict, datatoken)
        _orders = []
        for log in dt.get_start_order_logs(address):
            a = dict(log.args.items())
            a["amount"] = int(log.args.amount)
            a["address"] = log.address
            a["transactionHash"] = log.transactionHash
            a = AttributeDict(a.items())

            _orders.append(a)

        return _orders

{% endcode %}

Provider fees:

ocean.retrieve_provider_fees( self, ddo: DDO, access_service: Service, publisher_wallet ) -> dict:

Calls Provider to compute provider fees as dictionary for access service.

As parameters:

1. ddo - the data asset which has the DDO object
2. access_service - Service instance for the service that needs the provider fees
3. publisher_wallet - Wallet instance of the user that wants to retrieve the provider fees

{% code overflow="wrap" %}

 @enforce_types
    def retrieve_provider_fees(
        self, ddo: DDO, access_service: Service, publisher_wallet
    ) -> dict:

        initialize_response = DataServiceProvider.initialize(
            ddo.did, access_service, consumer_address=publisher_wallet.address
        )
        initialize_data = initialize_response.json()
        provider_fees = initialize_data["providerFee"]

        return provider_fees

{% endcode %}

ocean.retrieve_provider_fees_for_compute( self, datasets: List[ComputeInput], algorithm_data: Union[ComputeInput, AlgorithmMetadata], consumer_address: str, compute_environment: str, valid_until: int, ) -> dict:

Calls Provider to generate provider fees as dictionary for compute service.

As parameters:

1. datasets - list of ComputeInput which contains the data assets
2. algorithm_data - necessary data for algorithm and it can be either a ComputeInput object, either just the algorithm metadata, AlgorithmMetadata
3. consumer_address - address of the compute consumer wallet which is requesting the provider fees
4. compute_environment - id provided from the compute environment as string
5. valid_until - timestamp in UNIX miliseconds for the duration of provider fees for the compute service.

{% code overflow="wrap" %}

@enforce_types
    def retrieve_provider_fees_for_compute(
        self,
        datasets: List[ComputeInput],
        algorithm_data: Union[ComputeInput, AlgorithmMetadata],
        consumer_address: str,
        compute_environment: str,
        valid_until: int,
    ) -> dict:

        initialize_compute_response = DataServiceProvider.initialize_compute(
            [x.as_dictionary() for x in datasets],
            algorithm_data.as_dictionary(),
            datasets[0].service.service_endpoint,
            consumer_address,
            compute_environment,
            valid_until,
        )

        return initialize_compute_response.json()

{% endcode %}

Ocean Assets

Datatoken Interface

datatoken.create_dispenser(self, tx_dict: dict, max_tokens: Optional[Union[int, str]] = None, max_balance: Optional[Union[int, str]] = None, with_mint: Optional[bool] = True)

Through datatoken, you can deploy a new dispenser schema which is used for creating free assets, because its behaviour is similar with a faucet. ⛲

It is implemented in DatatokenBase, inherited by Datatoken2, so it can be called within both instances.

Each parameter has the following meaning:

1. tx_dict - is the configuration for that specific transaction. Usually for development we include just the from wallet, but for remote networks, you can provide gas fees, required confirmations for that block etc. For more info, check Brownie docs.
2. max_tokens - maximum amount of tokens to dispense in wei
3. max_balance - maximum balance of requester in wei
4. with_mint - boolean, true if we want to allow the dispenser to be a minter as default value

Return value is a hex string which denotes the transaction hash of dispenser deployment.

@enforce_types
    def create_dispenser(
        self,
        tx_dict: dict,
        max_tokens: Optional[Union[int, str]] = None,
        max_balance: Optional[Union[int, str]] = None,
        with_mint: Optional[bool] = True,
    ):
        """
        For this datataken, create a dispenser faucet for free tokens.

        This wraps the smart contract method Datatoken.createDispenser()
          with a simpler interface.

        :param: max_tokens - max # tokens to dispense, in wei
        :param: max_balance - max balance of requester
        :tx_dict: e.g. {"from": alice_wallet}
        :return: tx
        """
        # already created, so nothing to do
        if self.dispenser_status().active:
            return

        # set max_tokens, max_balance if needed
        max_tokens = max_tokens or MAX_UINT256
        max_balance = max_balance or MAX_UINT256

        # args for contract tx
        dispenser_addr = get_address_of_type(self.config_dict, "Dispenser")
        with_mint = with_mint  # True -> can always mint more
        allowed_swapper = ZERO_ADDRESS  # 0 -> so anyone can call dispense

        # do contract tx
        tx = self.createDispenser(
            dispenser_addr,
            max_tokens,
            max_balance,
            with_mint,
            allowed_swapper,
            tx_dict,
        )
        return tx

datatoken.dispense(self, amount: Union[int, str], tx_dict: dict)

This function is used to retrieve funds or datatokens for an user who wants to access an asset.

It is implemented in DatatokenBase, so it can be called within Datatoken class.

Each parameter has the following meaning:

1. amount - amount of datatokens to be dispensed in wei (int or string format)
2. tx_dict - is the configuration for that specific transaction. Usually for development we include just the from wallet, but for remote networks, you can provide gas fees, required confirmations for that block etc. For more info, check Brownie docs.

Return value is a hex string which denotes the transaction hash of dispensed datatokens, like a proof.

    @enforce_types
    def dispense(self, amount: Union[int, str], tx_dict: dict):
        """
        Dispense free tokens via the dispenser faucet.

        :param: amount - number of tokens to dispense, in wei
        :tx_dict: e.g. {"from": alice_wallet}
        :return: tx
        """
        # args for contract tx
        datatoken_addr = self.address
        from_addr = (
            tx_dict["from"].address
            if hasattr(tx_dict["from"], "address")
            else tx_dict["from"]
        )

        # do contract tx
        tx = self._ocean_dispenser().dispense(
            datatoken_addr, amount, from_addr, tx_dict
        )
        return tx

datatoken.dispense_and_order(self, consumer: str, service_index: int, provider_fees: dict, transaction_parameters: dict, consume_market_fees=None)

This function is used to retrieve funds or datatokens for an user who wants to access an asset.

It is implemented in Datatoken2, so it can be called within Datatoken2 class (using the enterprise template).

Each parameter has the following meaning:

1. amount - amount of datatokens to be dispensed in wei (int or string format)
2. tx_dict - is the configuration for that specific transaction. Usually for development we include just the from wallet, but for remote networks, you can provide gas fees, required confirmations for that block etc. For more info, check Brownie docs.

Return value is a hex string which denotes the transaction hash of dispensed datatokens, like a proof.

Fixed Rate Exchange

Dispenser