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Protobuf Schema Parser is a pure-Python library that parses and writes Protobuf schemas to and from an abstract syntax tree (AST).

The library usesproto_schema_parser.parser.Parser to parse theCST into an AST. Theproto_schema_parser.generator.Generator class converts the AST back into a CST (a Protobuf schema string).

The lexer and parser are autogenerated fromBuf's ANTLRlexer and parser grammar files.

• ✅ proto2 and proto3 support
• ✅ protobuf editions support (edition 2023, edition 2024)
• ✅ message, field, enum, optional, required, repeated
• ✅ import, package, oneof, map, and option
• ✅ group and extend (in proto2)
• ✅ service, rpc, and stream
• ✅ line and block comment preservation

Install the package via pip:

pip install proto-schema-parser

To parse a protobuf schema, create aParser object and call theparse method:

fromproto_schema_parser.parserimportParsertext="""syntax = "proto3";message SearchRequest {  string query = 1;  int32 page_number = 2;  int32 result_per_page = 3;}"""result=Parser().parse(text)

This will return an AST object (ast.File) representing the parsed protobuf schema.

File(syntax='proto3',file_elements=[Message(name='SearchRequest',elements=[Field(name='query',number=1,type='string',cardinality=None,options=[]),Field(name='page_number',number=2,type='int32',cardinality=None,options=[]),Field(name='result_per_page',number=3,type='int32',cardinality=None,options=[])])])

To write the AST back to a protobuf schema, create aGenerator object and call thegenerate method:

fromproto_schema_parser.generatorimportGeneratorproto=Generator().generate(result)

Theproto variable now contains the string:

syntax="proto3";messageSearchRequest {stringquery=1;int32page_number=2;int32result_per_page=3;}

The library also supportsprotobuf editions, which provide more flexibility than proto2/proto3 syntax:

fromproto_schema_parser.parserimportParserfromproto_schema_parser.generatorimportGenerator# Parse a protobuf file using edition syntaxtext="""edition = "2023";message SearchRequest {  string query = 1;  int32 page_number = 2;}"""result=Parser().parse(text)# result.edition will be "2023"# result.syntax will be None# Generate back to protobuf formatproto=Generator().generate(result)

Supported editions:

• edition = "2023"; -Edition 2023 spec
• edition = "2024"; -Edition 2024 spec

I welcome contributions!

• Submit a PR and I'll review it as soon as I can.
• Open an issue if you find a bug or have a feature request.

Protobuf Schema Parser is licensed under theMIT license.