flatbuffers 试用
安装cli 编译器
brew install flatbuffers
cli 命令
flatc: error: unknown commandline argument: --help
Usage: flatc [OPTION]
--binary -b Generate wire format binaries for any data definitions.
--json -t Generate text output for any data definitions.
--cpp -c Generate C++ headers for tables/structs.
--go -g Generate Go files for tables/structs.
--java -j Generate Java classes for tables/structs.
--js -s Generate JavaScript code for tables/structs.
--dart -d Generate Dart classes for tables/structs.
--ts -T Generate TypeScript code for tables/structs.
--csharp -n Generate C# classes for tables/structs.
--python -p Generate Python files for tables/structs.
--lobster Generate Lobster files for tables/structs.
--lua -l Generate Lua files for tables/structs.
--rust -r Generate Rust files for tables/structs.
--php Generate PHP files for tables/structs.
--kotlin Generate Kotlin classes for tables/structs.
--jsonschema Generate Json schema.
--swift Generate Swift files for tables/structs.
-o PATH Prefix PATH to all generated files.
-I PATH Search for includes in the specified path.
-M Print make rules for generated files.
--version Print the version number of flatc and exit.
--strict-json Strict JSON: field names must be / will be quoted,
no trailing commas in tables/vectors.
--allow-non-utf8 Pass non-UTF-8 input through parser and emit nonstandard
\x escapes in JSON. (Default is to raise parse error on
non-UTF-8 input.)
--natural-utf8 Output strings with UTF-8 as human-readable strings.
By default, UTF-8 characters are printed as \uXXXX escapes.
--defaults-json Output fields whose value is the default when
writing JSON
--unknown-json Allow fields in JSON that are not defined in the
schema. These fields will be discared when generating
binaries.
--no-prefix Don't prefix enum values with the enum type in C++.
--scoped-enums Use C++11 style scoped and strongly typed enums.
also implies --no-prefix.
--gen-includes (deprecated), this is the default behavior.
If the original behavior is required (no include
statements) use --no-includes.
--no-includes Don't generate include statements for included
schemas the generated file depends on (C++ / Python).
--gen-mutable Generate accessors that can mutate buffers in-place.
--gen-onefile Generate single output file for C# and Go.
--gen-name-strings Generate type name functions for C++ and Rust.
--gen-object-api Generate an additional object-based API.
--gen-compare Generate operator== for object-based API types.
--gen-nullable Add Clang _Nullable for C++ pointer. or @Nullable for Java
--java-checkerframe work Add @Pure for Java.
--gen-generated Add @Generated annotation for Java
--gen-all Generate not just code for the current schema files,
but for all files it includes as well.
If the language uses a single file for output (by default
the case for C++ and JS), all code will end up in this one
file.
--cpp-include Adds an #include in generated file.
--cpp-ptr-type T Set object API pointer type (default std::unique_ptr).
--cpp-str-type T Set object API string type (default std::string).
T::c_str(), T::length() and T::empty() must be supported.
The custom type also needs to be constructible from std::string
(see the --cpp-str-flex-ctor option to change this behavior).
--cpp-str-flex-ctor Don't construct custom string types by passing std::string
from Flatbuffers, but (char* + length).
--cpp-std CPP_STD Generate a C++ code using features of selected C++ standard.
Supported CPP_STD values:
* 'c++0x' - generate code compatible with old compilers;
* 'c++11' - use C++11 code generator (default);
* 'c++17' - use C++17 features in generated code (experimental).
--object-prefix Customise class prefix for C++ object-based API.
--object-suffix Customise class suffix for C++ object-based API.
Default value is "T".
--no-js-exports Removes Node.js style export lines in JS.
--goog-js-export Uses goog.exports* for closure compiler exporting in JS.
--es6-js-export Uses ECMAScript 6 export style lines in JS.
--go-namespace Generate the overrided namespace in Golang.
--go-import Generate the overrided import for flatbuffers in Golang
(default is "github.com/google/flatbuffers/go").
--raw-binary Allow binaries without file_indentifier to be read.
This may crash flatc given a mismatched schema.
--size-prefixed Input binaries are size prefixed buffers.
--proto Input is a .proto, translate to .fbs.
--proto-namespace-suffix Add this namespace to any flatbuffers generated
SUFFIX from protobufs.
--oneof-union Translate .proto oneofs to flatbuffer unions.
--grpc Generate GRPC interfaces for the specified languages.
--schema Serialize schemas instead of JSON (use with -b).
--bfbs-comments Add doc comments to the binary schema files.
--bfbs-builtins Add builtin attributes to the binary schema files.
--bfbs-gen-embed Generate code to embed the bfbs schema to the source.
--conform FILE Specify a schema the following schemas should be
an evolution of. Gives errors if not.
--conform-includes Include path for the schema given with --conform PATH
--filename-suffix The suffix appended to the generated file names.
Default is '_generated'.
--filename-ext The extension appended to the generated file names.
Default is language-specific (e.g., '.h' for C++)
--include-prefix Prefix this path to any generated include statements.
PATH
--keep-prefix Keep original prefix of schema include statement.
--no-fb-import Don't include flatbuffers import statement for TypeScript.
--no-ts-reexport Don't re-export imported dependencies for TypeScript.
--short-names Use short function names for JS and TypeScript.
--reflect-types Add minimal type reflection to code generation.
--reflect-names Add minimal type/name reflection.
--root-type T Select or override the default root_type
--force-defaults Emit default values in binary output from JSON
--force-empty When serializing from object API representation,
force strings and vectors to empty rather than null.
--force-empty-vectors When serializing from object API representation,
force vectors to empty rather than null.
--flexbuffers Used with "binary" and "json" options, it generates
data using schema-less FlexBuffers.
FILEs may be schemas (must end in .fbs), binary schemas (must end in .bfbs),
or JSON files (conforming to preceding schema). FILEs after the -- must be
binary flatbuffer format files.
Output files are named using the base file name of the input,
and written to the current directory or the path given by -o.
example: flatc -c -b schema1.fbs schema2.fbs data.json
编写一个schema
http_message.fbs
union HttpCommand {
HttpQuery,
HttpResultSet,
HttpError
}
table HttpMessage {
message_id: uint;
command: HttpCommand;
}
table HttpQuery {
query: string;
}
table HttpError {
error: string;
}
table HttpResultSet {
columns: [string];
rows: [HttpRow];
}
table HttpRow {
values: [HttpColumnValue];
}
table HttpColumnValue {
string_value: string;
}
root_type HttpMessage;
生成代码
flatc --js ./http_message.fbs
代码效果
参考资料
https://formulae.brew.sh/formula/flatbuffers
https://github.com/google/flatbuffers
https://www.npmjs.com/package/flatbuffers
