Add ContractCaller and depraction decorator for ConciseContract

tests/core/contracts/test_concise_contract.py

@@ -8,7 +8,7 @@
 )
 
 from web3.contract import (
-    CONCISE_NORMALIZERS,
+    CALLER_NORMALIZERS,
     ConciseContract,
     ConciseMethod,
 )
@@ -109,7 +109,7 @@ def test_conciscecontract_keeps_custom_normalizers_on_base(web3):
 
     # check that concise contract includes the new normalizers
     concise_normalizers_size = len(concise._classic_contract._return_data_normalizers)
-    assert concise_normalizers_size == new_normalizers_size + len(CONCISE_NORMALIZERS)
+    assert concise_normalizers_size == new_normalizers_size + len(CALLER_NORMALIZERS)
     assert concise._classic_contract._return_data_normalizers[0] is None
 
 

web3/contract.py

@@ -789,6 +789,7 @@ def mk_collision_prop(fn_name):
     def collision_fn():
         msg = "Namespace collision for function name {0} with ConciseContract API.".format(fn_name)
         raise AttributeError(msg)
+
     collision_fn.__name__ = fn_name
     return collision_fn
 
@@ -797,6 +798,7 @@ class ContractConstructor:
     """
     Class for contract constructor API.
     """
+
     def __init__(self, web3, abi, bytecode, *args, **kwargs):
         self.web3 = web3
         self.abi = abi
@@ -882,6 +884,79 @@ def check_forbidden_keys_in_transaction(transaction, forbidden_keys=None):
             raise ValueError("Cannot set {} in transaction".format(', '.join(keys_found)))
 
 
+def _none_addr(datatype, data):
+    if datatype == 'address' and int(data, base=16) == 0:
+        return (datatype, None)
+    else:
+        return (datatype, data)
+
+
+CALLER_NORMALIZERS = (
+    _none_addr,
+)
+
+
+class CallerMethod:
+    ALLOWED_MODIFIERS = {'call'}
+
+    def __init__(self, function, normalizers=None):
+        self._function = function
+        self._function._return_data_normalizers = normalizers
+
+    def __call__(self, *args, **kwargs):
+        return self.__prepared_function(*args, **kwargs)
+
+    def __prepared_function(self, *args, **kwargs):
+        if not kwargs:
+            modifier, modifier_dict = 'call', {}
+        elif len(kwargs) == 1:
+            modifier, modifier_dict = kwargs.popitem()
+            if modifier not in self.ALLOWED_MODIFIERS:
+                raise TypeError(
+                    "The only allowed keyword arguments are: %s" % self.ALLOWED_MODIFIERS)
+        else:
+            raise TypeError("Use up to one keyword argument, one of: %s" % self.ALLOWED_MODIFIERS)
+
+        return getattr(self._function(*args), modifier)(modifier_dict)
+
+
+class ContractCaller:
+    """
+    An alternative Contract Factory which invokes all methods as `call()`,
+    unless you add a keyword argument. The keyword argument assigns the prep method.
+    """
+
+    def __init__(self, classic_contract, method_class=CallerMethod):
+
+        classic_contract._return_data_normalizers += CALLER_NORMALIZERS
+        self._classic_contract = classic_contract
+        self.address = self._classic_contract.address
+
+        protected_fn_names = [fn for fn in dir(self) if not fn.endswith('__')]
+
+        for fn_name in self._classic_contract.functions:
+
+            # Override namespace collisions
+            if fn_name in protected_fn_names:
+                _reader_method = mk_collision_prop(fn_name)
+
+            else:
+                _classic_method = getattr(
+                    self._classic_contract.functions,
+                    fn_name)
+
+                _reader_method = method_class(
+                    _classic_method,
+                    self._classic_contract._return_data_normalizers
+                )
+
+            setattr(self, fn_name, _reader_method)
+
+    @classmethod
+    def factory(cls, *args, **kwargs):
+        return compose(cls, Contract.factory(*args, **kwargs))
+
+
 class ConciseMethod:
     ALLOWED_MODIFIERS = {'call', 'estimateGas', 'transact', 'buildTransaction'}
 
@@ -906,6 +981,7 @@ def __prepared_function(self, *args, **kwargs):
         return getattr(self._function(*args), modifier)(modifier_dict)
 
 
+@deprecated_for("contract.ContractCaller")
 class ConciseContract:
     '''
     An alternative Contract Factory which invokes all methods as `call()`,
@@ -919,9 +995,10 @@ class ConciseContract:
 
     > contract.functions.withdraw(amount).transact({'from': eth.accounts[1], 'gas': 100000, ...})
     '''
+
     def __init__(self, classic_contract, method_class=ConciseMethod):
 
-        classic_contract._return_data_normalizers += CONCISE_NORMALIZERS
+        classic_contract._return_data_normalizers += CALLER_NORMALIZERS
         self._classic_contract = classic_contract
         self.address = self._classic_contract.address
 
@@ -950,18 +1027,6 @@ def factory(cls, *args, **kwargs):
         return compose(cls, Contract.factory(*args, **kwargs))
 
 
-def _none_addr(datatype, data):
-    if datatype == 'address' and int(data, base=16) == 0:
-        return (datatype, None)
-    else:
-        return (datatype, data)
-
-
-CONCISE_NORMALIZERS = (
-    _none_addr,
-)
-
-
 class ImplicitMethod(ConciseMethod):
     def __call_by_default(self, args):
         function_abi = find_matching_fn_abi(self._function.contract_abi,
@@ -978,6 +1043,7 @@ def __call__(self, *args, **kwargs):
             return super().__call__(*args, **kwargs)
 
 
+@deprecated_for("contract.ContractCaller")
 class ImplicitContract(ConciseContract):
     '''
     ImplicitContract class is similar to the ConciseContract class
@@ -994,6 +1060,7 @@ class ImplicitContract(ConciseContract):
 
     > contract.functions.withdraw(amount).transact({})
     '''
+
     def __init__(self, classic_contract, method_class=ImplicitMethod):
         super().__init__(classic_contract, method_class=method_class)
 
@@ -1379,8 +1446,8 @@ def call_contract_function(
         # Provide a more helpful error message than the one provided by
         # eth-abi-utils
         is_missing_code_error = (
-            return_data in ACCEPTABLE_EMPTY_STRINGS and
-            web3.eth.getCode(address) in ACCEPTABLE_EMPTY_STRINGS
+            return_data in ACCEPTABLE_EMPTY_STRINGS and web3.eth.getCode(address)
+            in ACCEPTABLE_EMPTY_STRINGS
         )
         if is_missing_code_error:
             msg = (