Metadata-Version: 2.1
Name: canoser
Version: 0.7.3
Summary: A python implementation of the LCS(Libra Canonical Serialization) for the Libra network.
Home-page: https://github.com/yuan-xy/canoser-python.git
Author: yuan xinyu
Author-email: yuan_xin_yu@hotmail.com
License: UNKNOWN
Description: A python implementation of the canonical serialization for the Libra network.
        
        Canonical serialization guarantees byte consistency when serializing an in-memory
        data structure. It is useful for situations where two parties want to efficiently compare
        data structures they independently maintain. It happens in consensus where
        independent validators need to agree on the state they independently compute. A cryptographic
        hash of the serialized data structure is what ultimately gets compared. In order for
        this to work, the serialization of the same data structures must be identical when computed
        by independent validators potentially running different implementations
        of the same spec in different languages.
        
        ## Installation
        
        Require python 3.6 or above installed.
        
        ```sh
        $ python3 -m pip install canoser
        ```
        
        
        ## Usage
        
        First define a data structure with Canoser, that is, write a class that inherits from "canoser.Struct", and then define the fields owned by the structure through the "\_fields" array. This structure naturally has the ability to canonical serialize and deserialize types. For example, the following AccountResource defines a data structure of the same name in the Libra code：
        ```python
          #python code，define canoser data structure
        from canoser import Struct, Uint8, Uint64
        class AccountResource(Struct):
            _fields = [
                ('authentication_key', [Uint8]),
                ('balance', Uint64),
                ('delegated_withdrawal_capability', bool),
                ('received_events', EventHandle),
                ('sent_events', EventHandle),
                ('sequence_number', Uint64)
            ]
        ```
        
        Here is the code that defines this data structure and serialization in Libra code:
        ```rust
        // rust code in Libra
        // define the data structure
        pub struct AccountResource {
            balance: u64,
            sequence_number: u64,
            authentication_key: ByteArray,
            sent_events: EventHandle,
            received_events: EventHandle,
            delegated_withdrawal_capability: bool,
        }
        // serialization
        impl CanonicalSerialize for AccountResource {
            fn serialize(&self, serializer: &mut impl CanonicalSerializer) -> Result<()> {
                serializer
                    .encode_struct(&self.authentication_key)?
                    .encode_u64(self.balance)?
                    .encode_bool(self.delegated_withdrawal_capability)?
                    .encode_struct(self.received_events)?
                    .encode_struct(self.sent_events)?
                    .encode_u64(self.sequence_number)?;
                Ok(())
            }
        }
        ```
        ~~In the rust language used by Libra, it is necessary to manually write code to serialize/deserialize the data structure, and the order of the fields in the data structure and the order of serialization are not necessarily the same.~~
        
        In Canoser, after defining the data structure, you don't need to write code to implement serialization and deserialization. Note that the order of the data structures in Canoser is defined in the order in which they are serialized in Libra.
        
        ### Supported field types
        
        | field type | optionl sub type | description |
        | ------ | ------ | ------ |
        | canoser.Uint8 |  | Unsigned 8-bit integer |
        | canoser.Uint16 |  | Unsigned 16-bit integer|
        | canoser.Uint32 |  | Unsigned 32-bit integer |
        | canoser.Uint64 |  | Unsigned 64-bit integer |
        | canoser.Uint128 |  | Unsigned 128-bit integer |
        | canoser.Int8 |  | Signed 8-bit integer |
        | canoser.Int16 |  | Signed 16-bit integer|
        | canoser.Int32 |  | Signed 32-bit integer |
        | canoser.Int64 |  | Signed 64-bit integer |
        | canoser.Int128 |  | Signed 128-bit integer |
        | bool |  | Boolean |
        | str |  | String |
        | bytes |  | Binary String |
        | [] | supported | Array Type |
        | {} | supported |  Map Type |
        | () | supported |  Tuple Type |
        | canoser.Struct |  | Another structure nested (cannot be recycled) |
        | RustEnum |  | Enum type |
        | RustOptional |  | Optional type |
        
        ### About Array Type
        The default data type (if not defined) in the array is Uint8. The following two definitions are equivalent:
        ```python
          class Arr1(Struct):
              _fields = [(addr, [])]
        
        
          class Arr2(Struct):
              _fields = [(addr, [Uint8])]
        
        ```
        Arrays can also define lengths to represent fixed length data. For example, the address in Libra is 256 bits, which is 32 bytes, so it can be defined as follows:
        ```python
          class Address(Struct):
              _fields = [(addr, [Uint8, 32])]
        ```
        When the fixed length data is serialized, you can skip the length information written to the output. For example, following code will generate 32 bytes without writing the length of the addr during serialization.
        
        ```python
          class Address(Struct):
              _fields = [(addr, [Uint8, 32, False])]
        ```
        
        
        ### About map type
        The default data type (if not defined) in the map is an array of Uint8 in Libra, both of key and value.
        But the python language dosn't support the array data type to be the key of a dict, so we change the key type from array of Uint8 to bytes in python, the type of value is unchanged.
        The following two definitions are equivalent:
        ```python
          class Map1(Struct):
            _fields = [(addr, {})]
        
        
          class Map2(Struct):
            _fields = [(addr, {bytes : [Uint8] })]
        
        ```
        
        ### About enum type
        In python and C, enum is just enumerated constants. But in Libra(Rust), a enum has a type constant and a optional Value. A rust enumeration is typically represented as:
        
        ```
        enum SomeDataType {
          type0(u32),
          type1(u64),
          type2
        }
        ```
        
        To define a enum with Canoser, first write a class that inherits from "canoser.RustEnum", and then define the types owned by the enum through the "\_enums" array.
        For example, the following TransactionArgument defines a data structure of the same name in the Libra code. The argument of a transaction can be one of the four types: Uint64 or Address or String or IntArray.：
        
        ```python
        class TransactionArgument(RustEnum):
            _enums = [
                ('U64', Uint64),
                ('Address', [Uint8, ADDRESS_LENGTH]),
                ('String', str),
                ('ByteArray', [Uint8])
            ]
        ```
        You can instantiate an enum obj and call its method and properties like this:
        
        ```python
            arg2 = TransactionArgument('String', 'abc')
            assert arg2.index == 2
            assert arg2.value == 'abc'
            assert arg2.String == True
            assert arg2.U64 == False
        ```
        
        Every RustEnum object has an `index` property and a `value` property. After instantiated, the `index` can't be modified. You can only modify the `value` of an enum with correct data type.
        
        For example, the following code is valid:
        
        ```python
            arg2 = TransactionArgument('String', 'abc')
            arg2.value == 'Bcd'
        ```
        
        For example, the following code is invalid:
        ```python
            arg2.index = 0      #raise an exception
            arg2.value = [3]    #raise an exception
        ```
        
        The RustEnum can have a enum without value type, which represented by `None`.
        
        ```python
        class Enum1(RustEnum):
            _enums = [('opt1', [Uint8]), ('opt2', None)]
        
        e2 = Enum1('opt2', None)
        #or
        e2 = Enum1('opt2')
        ```
        
        You can also instantiate a RustEnum object by index and value.
        
        ```python
        e1 = Enum1.new(0, [5])
        # which is equivalent to
        e1 = Enum1('opt1', [5])
        ```
        
        ### About optional type
        An optional type in libra is a nullable data either exists in its full representation or does not. For example,
        
        ```
        optional_data: Option(uint8); // Rust/Libra
        uint8 *optional_data; // C
        ```
        It has similar semantics meaning with the following enum type:
        ```
        enum Option<uint8> {
            Some(uint8),
            None,
        }
        ```
        
        To define a optional with Canoser, first write a class that inherits from "canoser.RustOptional", and then define the types owned by RustOptional through the "\_type" field. For example,
        
        ```python
        class OptionUInt(RustOptional):
            _type = Uint8
        
        null = OptionUInt(None)
        obj = OptionUInt(8)
        assert obj.value == 8
        ```
        
        Here's a complete example:
        
        ```python
        class OptionStr(RustOptional):
            _type = str
        
        class OptionTest(Struct):
            _fields = [
                ('message', OptionStr)
            ]
        
            def __init__(self, msg=None):
                if msg is not None:
                    self.message = OptionStr(msg)
                else:
                    self.message = OptionStr(None)
        
        test = OptionTest('test_str')
        assert test.message.value == 'test_str'
        ```
        
        
        The RustOptional type in canoser is similar to `typing.Optional` in python. Note that this is not the same concept as an optional argument, which is one that has a default.
        
        
        ### Nested data structure
        The following is a complex example with three data structures:
        ```python
        class Addr(Struct):
            _fields = [('addr', [Uint8, 32])]
        
        
        class Bar(Struct):
            _fields = [
                ('a', Uint64),
                ('b', [Uint8]),
                ('c', Addr),
                ('d', Uint32),
            ]
        
        class Foo(Struct):
            _fields = [
                ('a', Uint64),
                ('b', [Uint8]),
                ('c', Bar),
                ('d', bool),
                ('e', {}),
            ]
        ```
        This example refers to the test code from canonical serialization in libra.
        
        
        ### Serialization and deserialization
        After defining canoser.Struct, you don't need to implement serialization and deserialization code yourself, you can directly call the default implementation of the base class. Take the AccountResource structure as an example:
        
        ```python
        # serialize an object
        obj = AccountResource(authentication_key=...,...)
        bbytes = obj.serialize()
        
        # deserialize an object from bytes
        obj = AccountResource.deserialize(bbytes)
        ```
        
        ### Json pretty print
        
        For any canoser `Struct`, you can call the `to_json` method to get a formatted json string:
        
        ```python
        # serialize an object
        print(obj.to_json())
        
        ```
        
        ### Get field value from object
        
        For all fields defined by the "\_fields", the value of this field of an object can be obtained via field_name. such as:
        ```python
        obj.authentication_key
        ```
        
        
        ## Rust Type Alias
        For simple type alias in rust, such as:
        ```rust
        // in rust
        pub type Round = u64;
        ```
        
        We can define the alias like this:
        
        ```python
        # in python
        Round = Uint64
        ```
        
        
        ## Rust Tuple Struct
        
        Struct like Address and ByteArray has no fields:
        
        ```rust
        pub struct Address([u8; ADDRESS_LENGTH]);
        pub struct ByteArray(Vec<u8>);
        ```
        
        These struct called `tuple struct` in `Rust` programming language. Tuple struct is like `typedef` other than struct in `C` like programming languages.
        
        You can just define them as a direct type, no struct. Just code like this:
        ```python
        class TransactionArgument(RustEnum):
            _enums = [
                ...
                ('Address', [Uint8, ADDRESS_LENGTH]),
                ...
            ]
        ```
        
        Or you can define an `Address` class which inherit from `canoser.DelegateT` and has a `delegate_type` field with type `[Uint8, ADDRESS_LENGTH]`:
        
        ```python
        class Address(DelegateT):
            delegate_type = [Uint8, ADDRESS_LENGTH]
        
        
        class TransactionArgument(RustEnum):
            _enums = [
                ...
                ('Address', Address),
                ...
            ]
        ```
        
        Do not instantiate a `canoser.DelegateT` type in assaignment, for example:
        
        ```python
        transactionArgument.address = [...] #ok
        transactionArgument.address = Address([...])  #error
        ```
        
        
        ## Notice
        
        ### Must define canoser struct by serialized fields and sequence, not the definition in the rust struct.
        
        For example, the SignedTransaction in Libra is defined as following code:
        
        ```rust
        pub struct SignedTransaction {
            raw_txn: RawTransaction,
            public_key: Ed25519PublicKey,
            signature: Ed25519Signature,
            transaction_length: usize,
        }
        ```
        But field `transaction_length` doesn't write to the output.
        
        ```rust
        impl CanonicalSerialize for SignedTransaction {
            fn serialize(&self, serializer: &mut impl CanonicalSerializer) -> Result<()> {
                serializer
                    .encode_struct(&self.raw_txn)?
                    .encode_bytes(&self.public_key.to_bytes())?
                    .encode_bytes(&self.signature.to_bytes())?;
                Ok(())
            }
        }
        ```
        
        So we define SignedTransaction in canoser as following code:
        ```python
        class SignedTransaction(canoser.Struct):
            _fields = [
                ('raw_txn', RawTransaction),
                ('public_key', [Uint8, ED25519_PUBLIC_KEY_LENGTH]),
                ('signature', [Uint8, ED25519_SIGNATURE_LENGTH])
            ]
        ```
        
        Here is another example. The definition sequence and serialize sequence is opposite in  `WriteOp`
        
        ```rust
        pub enum WriteOp {
            Value(Vec<u8>),
            Deletion,
        }
        
        enum WriteOpType {
            Deletion = 0,
            Value = 1,
        }
        
        impl CanonicalSerialize for WriteOp {
            fn serialize(&self, serializer: &mut impl CanonicalSerializer) -> Result<()> {
                match self {
                    WriteOp::Deletion => serializer.encode_u32(WriteOpType::Deletion as u32)?,
                    WriteOp::Value(value) => {
                        serializer.encode_u32(WriteOpType::Value as u32)?;
                        serializer.encode_vec(value)?
                    }
                };
                Ok(())
            }
        }
        ```
        
        So, we define `WriteOp` as follow:
        ```python
        class WriteOp(RustEnum):
            _enums = [
                ('Deletion', None),
                ('Value', [Uint8])
            ]
        
        ```
        
        ## Related Projects
        
        [MoveOnLibra OpenAPI: make writing libra wallet & move program easier](https://www.MoveOnLibra.com)
        
        [A Ruby implementation of the LCS(Libra Canonical Serialization)](https://github.com/yuan-xy/canoser-ruby)
        
        [A Python implementation of client APIs and command-line tools for the Libra network](https://github.com/yuan-xy/libra-client)
        
        
        
        ## License
        
        The package is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).
        
        
Platform: UNKNOWN
Classifier: Programming Language :: Python :: 3
Classifier: License :: OSI Approved :: MIT License
Classifier: Operating System :: OS Independent
Requires-Python: >=3.6
Description-Content-Type: text/markdown
