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The bomboni_prost crate provides advanced protobuf code generation capabilities, building on top of prost with additional helper functions and utilities for working with protobuf messages and enums.

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compile

Compiles protobuf files using the provided configuration. This function reads the file descriptor set, processes all protobuf files, and generates Rust code with additional helper functions and utilities.
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config
CompileConfig
required
Configuration for the compilation process

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Returns

  • Success: Ok(()) when compilation completes successfully
  • Error: Returns Box<dyn Error> if:
    • The file descriptor set cannot be read
    • Protobuf compilation fails
    • File I/O operations fail
    • Code generation encounters invalid protobuf definitions

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Example

use bomboni_prost::{compile, config::CompileConfig, ApiConfig, path_map::PathMap};

let config = CompileConfig {
    file_descriptor_set_path: "descriptor.bin".into(),
    output_path: "src/generated".into(),
    format: true,
    api: ApiConfig::default(),
    external_paths: PathMap::default(),
};

compile(config)?;

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CompileConfig

Configuration struct for compiling protobuf files.
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file_descriptor_set_path
PathBuf
required
Path to the file descriptor set binary file.This file contains the compiled protobuf descriptors and is typically generated by protoc --descriptor_set_out.
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output_path
PathBuf
required
Output directory for generated Rust files.All generated Rust code will be written to this directory.
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format
bool
required
Whether to format the generated code.When set to true, the generated Rust code will be formatted using rustfmt before being written to files.
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api
ApiConfig
required
API-specific configuration options.Controls generation of API-related helper functions and utilities.
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external_paths
PathMap
required
External path mappings for custom type handling.Maps protobuf type paths to custom Rust types for integration with external libraries or custom implementations.

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Default Configuration

The default configuration uses:
  • File descriptor set path: $OUT_DIR/fd.pb
  • Output path: $OUT_DIR
  • Format: true
  • API config: Default ApiConfig
  • External paths: Empty PathMap

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ApiConfig

Configuration for API-specific code generation.
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names
bool
default:"true"
Generate name helper functions.When set to true, generates functions for getting the name of messages and enums, useful for debugging and logging.
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field_names
bool
default:"true"
Generate field name helper functions.When set to true, generates functions for getting the names of fields within messages, useful for reflection and debugging.
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type_url
bool
default:"true"
Generate type URL helper functions.When set to true, generates functions for getting the type URL of messages, useful for Google APIs and Any type handling.
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oneof_utility
bool
default:"true"
Generate oneof utility functions.When set to true, generates utility functions for working with oneof fields, including getters and setters.
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domain
Option<String>
default:"None"
Optional domain prefix for generated types.When specified, adds the given domain prefix to generated type names, useful for avoiding name conflicts in multi-domain APIs.
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serde
bool
default:"true"
Generate serde serialization support.When set to true, generates Serialize and Deserialize implementations for all protobuf messages and enums.
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helpers_mod
Option<String>
default:"None"
Optional name for the helpers module.When specified, creates a module with the given name containing all generated helper functions. If None, helpers are placed in the same module as the message.

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PathMap

Maps fully-qualified protobuf type names to Rust types or paths.

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Methods

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insert

Inserts a new matcher-value pair into the path map.
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matcher
impl ToString
required
The protobuf type path pattern to match (e.g., .google.protobuf.Timestamp)
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value
impl ToString
required
The corresponding Rust type or mapping (e.g., chrono::DateTime<chrono::Utc>)
Example: 
use bomboni_prost::path_map::PathMap;

let mut map = PathMap::default();
map.insert(".google.protobuf.Timestamp", "chrono::DateTime<chrono::Utc>");
map.insert(".myapi.User", "crate::models::User");

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get_first

Gets the first matching value for a given protobuf path.
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path
&str
required
The protobuf type path to match against
Returns: Option<(&str, &str)> - A tuple of (matcher, value) if a match is found, or None otherwise. Searches for the most specific matcher that matches the given path. Exact matches take precedence over prefix matches. Example: 
let map = PathMap::from([(".a", "A"), (".a.b", "B")]);
assert_eq!(map.get_first(".a").unwrap().1, "A");  // Exact match
assert_eq!(map.get_first(".a.b").unwrap().1, "B");  // More specific
assert_eq!(map.get_first(".a.c").unwrap().1, "A");  // Prefix match

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get_first_field

Gets the first matching value for a specific field within a type.
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path
&str
required
The protobuf type path
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field
&str
required
The field name within the type
Returns: Option<(&str, &str)> - A tuple of (matcher, value) if a match is found, or None otherwise. Example: 
let map = PathMap::from([(".myapi.User", "crate::User")]);
assert_eq!(map.get_first_field(".myapi.User", "name").unwrap().1, "crate::User");

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Helper Generation

The bomboni_prost crate generates various helper functions based on the ApiConfig settings:

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Name Helpers

When names is enabled, generates functions for getting message and enum names.

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Field Name Helpers

When field_names is enabled, generates constants for field names (e.g., FIELD_NAME_FIELD_NAME).

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Type URL Helpers

When type_url is enabled, generates functions for getting type URLs compatible with google.protobuf.Any.

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Oneof Utilities

When oneof_utility is enabled, generates utility functions for working with oneof fields.

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Serde Support

When serde is enabled, generates serde helper modules for enum serialization (e.g., enum_name_serde).

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