Python abstraction for ERC190 packages.
Project description
parse and validate packages.
given a web3 instance provide access to contract factory classes
given a web3 instance provide access to all of the deployed contract instances for the chain that web3 is connected to.
validate package bytecode matches compilation output.
validate deployed bytecode matches compilation output
access to packages dependencies
construct new packages
Web3
The Package object will function much like the Contract class provided by web3. Rather than instantiating the base class provided by ethpm, you will instead use a classmethod which generates a new Package class for a given package.
OwnedPackage = BasePackage.factory('/path/to/owned-v1.0.0.json')Then, the OwnedPackage can be instantiated with any web3 intance.
owned_package = OwnedPackage(web3)A Package class can only be directly constructed from the parsed package JSON. It can also be initialized with the package’s URI or the local filesystem path to a package by using Package.from_file(path).
Contract Factories
Contract factories should be accessible from the package class but you must also provide a web3 instance.
Owned = OwnedPackage.get_contract_factory(web3, 'owned')From a package instance, they are also available as properties.
Owned = owned_package.contract_factories.ownedIn cases where a contract uses a library, the contract factory will have unlinked bytecode. The ethpm package ships with its own subclass of web3.contract.Contract with a few extra methods and properties related to bytecode linking
>>> math = owned_package.contract_factories.math
>>> math.has_linkable_bytecode
True
>>> math.is_bytecode_linked
False
>>> linked_math = math.link_bytecode({'MathLib': '0x1234...'})
>>> linked_math.is_bytecode_linked
TrueNote: the actual format of the link data is not clear since library names aren’t a one-size-fits all solution. We need the ability to specify specific link references in the code.
Deployed Contracts
Deployed contracts are only available from package instances. The package instance will filter the deployments based on the chain that web3 is connected to.
Accessing deployments is done with property access
package.deployed_contracts.GreeterIPFS
We’ll need a pluggable backend system for IPFS access. A built-in default one that defaults to using infura should be enough to get off the ground.
Lower priority but important will be ensuring that a user can configure connecting to their own IPFS node.
Verifying Things
The Package class should verify all of the following things.
Package json matches EthPM V2 Manifest Specification
Included bytecode matches compilation output
Deployed bytecode matches compilation output
Dependencies
The Package class should provide access to the full dependency tree.
>>> owned_package.build_dependencies['zeppelin']
<ZeppelinPackage>Testing Strategy
Load and validate packages from disk.
Access package data.
Access contract factories.
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