c526cb640b
This commit significantly improves the developer experience for the Python Object-Based API by overhauling the generated `__init__` method for `T`-suffixed classes.
Previously, `T` objects had to be instantiated with an empty constructor, and their fields had to be populated manually one by one. This was verbose and not idiomatic Python.
This change modifies the Python code generator (`GenInitialize`) to produce `__init__` methods that are:
1. **Keyword-Argument-Friendly**: The constructor now accepts all table/struct fields as keyword arguments, allowing for concise, single-line object creation.
2. **Fully Typed**: The signature of the `__init__` method is now annotated with Python type hints. This provides immediate benefits for static analysis tools (like Mypy) and IDEs, enabling better autocompletion and type checking.
3. **Correctly Optional**: The generator now correctly wraps types in `Optional[...]` if their default value is `None`. This applies to strings, vectors, and other nullable fields, ensuring strict type safety.
The new approach remains **fully backward-compatible**, as all arguments have default values. Existing code that uses the empty constructor will continue to work without modification.
#### Example of a Generated `__init__`
**Before:**
```python
class KeyValueT(object):
def __init__(self):
self.key = None # type: str
self.value = None # type: str
```
**After:**
```python
class KeyValueT(object):
def __init__(self, key: Optional[str] = None, value: Optional[str] = None):
self.key = key
self.value = value
```
#### Example of User Code
**Before:**
```python
# Old, verbose way
kv = KeyValueT()
kv.key = "instrument"
kv.value = "EUR/USD"
```
**After:**
```python
# New, Pythonic way
kv = KeyValueT(key="instrument", value="EUR/USD")
```
FlatBuffers
FlatBuffers is a cross platform serialization library architected for maximum memory efficiency. It allows you to directly access serialized data without parsing/unpacking it first, while still having great forwards/backwards compatibility.
Quick Start
-
Build the compiler for flatbuffers (
flatc)Use
cmaketo create the build files for your platform and then perform the compilation (Linux example).cmake -G "Unix Makefiles" make -j -
Define your flatbuffer schema (
.fbs)Write the schema to define the data you want to serialize. See monster.fbs for an example.
-
Generate code for your language(s)
Use the
flatccompiler to take your schema and generate language-specific code:./flatc --cpp --rust monster.fbsWhich generates
monster_generated.handmonster_generated.rsfiles. -
Serialize data
Use the generated code, as well as the
FlatBufferBuilderto construct your serialized buffer. (C++example) -
Transmit/store/save Buffer
Use your serialized buffer however you want. Send it to someone, save it for later, etc...
-
Read the data
Use the generated accessors to read the data from the serialized buffer.
It doesn't need to be the same language/schema version, FlatBuffers ensures the data is readable across languages and schema versions. See the
Rustexample reading the data written byC++.
Documentation
Go to our landing page to browse our documentation.
Supported operating systems
- Windows
- macOS
- Linux
- Android
- And any others with a recent C++ compiler (C++ 11 and newer)
Supported programming languages
Code generation and runtime libraries for many popular languages.
- C
- C++ - snapcraft.io
- C# - nuget.org
- Dart - pub.dev
- Go - go.dev
- Java - Maven
- JavaScript - NPM
- Kotlin
- Lobster
- Lua
- PHP
- Python - PyPI
- Rust - crates.io
- Swift - swiftpackageindex
- TypeScript - NPM
- Nim
Versioning
FlatBuffers does not follow traditional SemVer versioning (see rationale) but rather uses a format of the date of the release.
Contribution
- FlatBuffers Issues Tracker to submit an issue.
- stackoverflow.com with
flatbufferstag for any questions regarding FlatBuffers.
To contribute to this project, see CONTRIBUTING.
Community
Security
Please see our Security Policy for reporting vulnerabilities.
Licensing
Flatbuffers is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.