Async eth_call (#2083)

* Async eth_call * Update docs for supported async middleware and methods
ethereum · Jul 23, 2021 · 8586a00 · 8586a00
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diff --git a/docs/middleware.rst b/docs/middleware.rst
@@ -58,16 +58,27 @@ Pythonic
 
 Gas Price Strategy
 ~~~~~~~~~~~~~~~~~~~~~~~~
-.. warning::
-    Gas price strategy is only supported for legacy transactions. The London fork
-    introduced ``maxFeePerGas`` and ``maxPriorityFeePerGas`` transaction parameters
-    which should be used over ``gasPrice`` whenever possible.
-
 
 .. py:method:: web3.middleware.gas_price_strategy_middleware
 
-    This adds a gasPrice to transactions if applicable and when a gas price strategy has
-    been set. See :ref:`Gas_Price` for information about how gas price is derived.
+  .. warning::
+
+      Gas price strategy is only supported for legacy transactions. The London fork
+      introduced ``maxFeePerGas`` and ``maxPriorityFeePerGas`` transaction parameters
+      which should be used over ``gasPrice`` whenever possible.
+
+  This adds a gasPrice to transactions if applicable and when a gas price strategy has
+  been set. See :ref:`Gas_Price` for information about how gas price is derived.
+
+Buffered Gas Estimate
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. py:method:: web3.middleware.buffered_gas_estimate_middleware
+
+    This adds a gas estimate to transactions if ``gas`` is not present in the transaction
+    parameters. Sets gas to:
+    ``min(w3.eth.estimate_gas + gas_buffer, gas_limit)``
+    where the gas_buffer default is 100,000 Wei
 
 HTTPRequestRetry
 ~~~~~~~~~~~~~~~~~~

diff --git a/docs/providers.rst b/docs/providers.rst
@@ -391,15 +391,31 @@ AsyncHTTPProvider
 Supported Methods
 ^^^^^^^^^^^^^^^^^
 
+Eth
+***
 - :meth:`web3.eth.block_number <web3.eth.Eth.block_number>`
 - :meth:`web3.eth.coinbase <web3.eth.Eth.coinbase>`
 - :meth:`web3.eth.gas_price <web3.eth.Eth.gas_price>`
+- :meth:`web3.eth.call() <web3.eth.Eth.call>`
 - :meth:`web3.eth.estimate_gas() <web3.eth.Eth.estimate_gas>`
 - :meth:`web3.eth.generate_gas_price() <web3.eth.Eth.generate_gas_price>`
+- :meth:`web3.eth.get_balance() <web3.eth.Eth.get_balance>`
 - :meth:`web3.eth.get_block() <web3.eth.Eth.get_block>`
+- :meth:`web3.eth.get_code() <web3.eth.Eth.get_code>`
+- :meth:`web3.eth.get_raw_transaction() <web3.eth.Eth.get_raw_transaction>`
 - :meth:`web3.eth.get_transaction() <web3.eth.Eth.get_transaction>`
+- :meth:`web3.eth.get_transaction_count() <web3.eth.Eth.get_transaction_count>`
 - :meth:`web3.eth.send_transaction() <web3.eth.Eth.send_transaction>`
 
+Net
+***
+- :meth:`web3.net.listening() <web3.net.listening>`
+- :meth:`web3.net.peer_count() <web3.net.peer_count>`
+- :meth:`web3.net.version() <web3.net.version>`
+
+
+
 Supported Middleware
 ^^^^^^^^^^^^^^^^^^^^
 - :meth:`Gas Price Strategy <web3.middleware.gas_price_strategy_middleware>`
+- :meth:`Buffered Gas Estimate Middleware <web3.middleware.buffered_gas_estimate_middleware>`
diff --git a/newsfragments/2083.feature.rst b/newsfragments/2083.feature.rst
@@ -0,0 +1 @@
+Add support for async ``w3.eth.call``.
diff --git a/web3/_utils/module_testing/eth_module.py b/web3/_utils/module_testing/eth_module.py
@@ -422,6 +422,94 @@ async def test_eth_get_transaction_count(
         assert is_integer(transaction_count)
         assert transaction_count >= 0
 
+    @pytest.mark.asyncio
+    async def test_eth_call(
+        self, async_w3: "Web3", math_contract: "Contract"
+    ) -> None:
+        coinbase = await async_w3.eth.coinbase  # type: ignore
+        txn_params = math_contract._prepare_transaction(
+            fn_name='add',
+            fn_args=(7, 11),
+            transaction={'from': coinbase, 'to': math_contract.address},
+        )
+        call_result = await async_w3.eth.call(txn_params)  # type: ignore
+        assert is_string(call_result)
+        result = async_w3.codec.decode_single('uint256', call_result)
+        assert result == 18
+
+    @pytest.mark.asyncio
+    async def test_eth_call_with_override(
+        self, async_w3: "Web3", revert_contract: "Contract"
+    ) -> None:
+        coinbase = await async_w3.eth.coinbase  # type: ignore
+        txn_params = revert_contract._prepare_transaction(
+            fn_name='normalFunction',
+            transaction={'from': coinbase, 'to': revert_contract.address},
+        )
+        call_result = await async_w3.eth.call(txn_params)  # type: ignore
+        result = async_w3.codec.decode_single('bool', call_result)
+        assert result is True
+
+        # override runtime bytecode: `normalFunction` returns `false`
+        override_code = '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'  # noqa: E501
+        call_result = await async_w3.eth.call(  # type: ignore
+            txn_params,
+            'latest',
+            {revert_contract.address: {'code': override_code}}
+        )
+        result = async_w3.codec.decode_single('bool', call_result)
+        assert result is False
+
+    @pytest.mark.asyncio
+    async def test_eth_call_with_0_result(
+        self, async_w3: "Web3", math_contract: "Contract"
+    ) -> None:
+        coinbase = await async_w3.eth.coinbase  # type: ignore
+        txn_params = math_contract._prepare_transaction(
+            fn_name='add',
+            fn_args=(0, 0),
+            transaction={'from': coinbase, 'to': math_contract.address},
+        )
+        call_result = await async_w3.eth.call(txn_params)  # type: ignore
+        assert is_string(call_result)
+        result = async_w3.codec.decode_single('uint256', call_result)
+        assert result == 0
+
+    @pytest.mark.asyncio
+    async def test_eth_call_revert_with_msg(
+        self,
+        async_w3: "Web3",
+        revert_contract: "Contract",
+        unlocked_account: ChecksumAddress,
+    ) -> None:
+        with pytest.raises(ContractLogicError,
+                           match='execution reverted: Function has been reverted'):
+            txn_params = revert_contract._prepare_transaction(
+                fn_name="revertWithMessage",
+                transaction={
+                    "from": unlocked_account,
+                    "to": revert_contract.address,
+                },
+            )
+            await async_w3.eth.call(txn_params)  # type: ignore
+
+    @pytest.mark.asyncio
+    async def test_eth_call_revert_without_msg(
+        self,
+        async_w3: "Web3",
+        revert_contract: "Contract",
+        unlocked_account: ChecksumAddress,
+    ) -> None:
+        with pytest.raises(ContractLogicError, match="execution reverted"):
+            txn_params = revert_contract._prepare_transaction(
+                fn_name="revertWithoutMessage",
+                transaction={
+                    "from": unlocked_account,
+                    "to": revert_contract.address,
+                },
+            )
+            await async_w3.eth.call(txn_params)  # type: ignore
+
 
 class EthModuleTest:
     def test_eth_protocol_version(self, web3: "Web3") -> None:

diff --git a/web3/eth.py b/web3/eth.py
@@ -213,6 +213,25 @@ def block_id_munger(
             block_identifier = self.default_block
         return (account, block_identifier)
 
+    def call_munger(
+        self,
+        transaction: TxParams,
+        block_identifier: Optional[BlockIdentifier] = None,
+        state_override: Optional[CallOverrideParams] = None,
+    ) -> Union[Tuple[TxParams, BlockIdentifier], Tuple[TxParams, BlockIdentifier, CallOverrideParams]]:  # noqa-E501
+        # TODO: move to middleware
+        if 'from' not in transaction and is_checksum_address(self.default_account):
+            transaction = assoc(transaction, 'from', self.default_account)
+
+        # TODO: move to middleware
+        if block_identifier is None:
+            block_identifier = self.default_block
+
+        if state_override is None:
+            return (transaction, block_identifier)
+        else:
+            return (transaction, block_identifier, state_override)
+
 
 class AsyncEth(BaseEth):
     is_async = True
@@ -299,6 +318,19 @@ async def get_transaction_count(
     ) -> Nonce:
         return await self._get_transaction_count(account, block_identifier)
 
+    _call: Method[Callable[..., Awaitable[Union[bytes, bytearray]]]] = Method(
+        RPC.eth_call,
+        mungers=[BaseEth.call_munger]
+    )
+
+    async def call(
+        self,
+        transaction: TxParams,
+        block_identifier: Optional[BlockIdentifier] = None,
+        state_override: Optional[CallOverrideParams] = None,
+    ) -> Union[bytes, bytearray]:
+        return await self._call(transaction, block_identifier, state_override)
+
 
 class Eth(BaseEth, Module):
     account = Account()
@@ -654,28 +686,9 @@ def sign_munger(
         mungers=[default_root_munger],
     )
 
-    def call_munger(
-        self,
-        transaction: TxParams,
-        block_identifier: Optional[BlockIdentifier] = None,
-        state_override: Optional[CallOverrideParams] = None,
-    ) -> Union[Tuple[TxParams, BlockIdentifier], Tuple[TxParams, BlockIdentifier, CallOverrideParams]]:  # noqa-E501
-        # TODO: move to middleware
-        if 'from' not in transaction and is_checksum_address(self.default_account):
-            transaction = assoc(transaction, 'from', self.default_account)
-
-        # TODO: move to middleware
-        if block_identifier is None:
-            block_identifier = self.default_block
-
-        if state_override is None:
-            return (transaction, block_identifier)
-        else:
-            return (transaction, block_identifier, state_override)
-
     call: Method[Callable[..., Union[bytes, bytearray]]] = Method(
         RPC.eth_call,
-        mungers=[call_munger]
+        mungers=[BaseEth.call_munger]
     )
 
     def estimate_gas(