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//! A prost toolkit to build protobuf with serde support. //! //! Usually when we define our protobuf messages, we hope some of the generated //! data structures have good serde support. Fortunately `serde-build` has that //! capability - you can create a config with `prost_build::Config::new()` and //! and then set proper attributes for type or field. For exmaple, you can add //! serde support for this structure by using: //! //! ```ignore //! config.type_attribute("package.RequestPing", "#[derive(serde::Serialize, serde::Deserialize)]"); //! config.type_attribute("package.RequestPing", "#[serde(default)]"); //! ``` //! //! and you will get this generated code: //! //! ```ignore //! #[derive(serde::Serialize, serde::Deserialize)] //! #[serde(default)] //! #[derive(Clone, PartialEq, ::prost::Message)] //! pub struct RequestPing { //! #[prost(string, tag = "1")] //! pub ping: ::prost::alloc::string::String, //! } //! ``` //! //! This crate helps to simplify this build script by using a predefined build configuration. //! //! # Getting started //! //! First of all, you shall create a JSON file which contains configuration for the builder. You can //! get a copy of a default JSON file from: https://github.com/tyrchen/prost-helper/prost-serde/default_build_config.json. //! Please add the proto files, proto includes, output dir, and the data structure or field you want //! to add the desired attributes. //! Then you could use it in: //! //! ```ignore //! use prost_serde::build_with_serde; //! //! fn main() { //! let json = include_str!("../examples/build_config.json"); //! build_with_serde(json); //! } //! ``` use serde::{Deserialize, Serialize}; use std::{fs, process::Command}; #[derive(Deserialize, Serialize, Debug, Default)] #[serde(default)] struct BuildConfig { /// protobuf include dirs includes: Vec<String>, /// protobuf files files: Vec<String>, /// dir for generated code output: String, /// build options for serde support opts: Vec<BuildOption>, } #[derive(Deserialize, Serialize, Debug, Default)] #[serde(default)] struct BuildOption { /// scope of the attribute scope: String, /// description of the option description: String, /// extra attribute to put on generated data structure, for example: `#[derive(Serialize, Deserialize)]` attr: String, /// a list of paths you want to add the attribute paths: Vec<String>, } /// Encodes the message to a buffer. /// /// An error will be returned if the buffer does not have sufficient capacity. pub fn build_with_serde(json: &str) { let build_config: BuildConfig = serde_json::from_str(json).unwrap(); let mut config = prost_build::Config::new(); for opt in build_config.opts.iter() { for path in opt.paths.iter() { match opt.scope.as_str() { "type" => config.type_attribute(path, opt.attr.as_str()), "field" => config.field_attribute(path, opt.attr.as_str()), v => panic!("Not supported type: {}", v), }; } } fs::create_dir_all(&build_config.output).unwrap(); config.out_dir(&build_config.output); config .compile_protos(&build_config.files, &build_config.includes) .unwrap_or_else(|e| panic!("Failed to compile proto files. Error: {:?}", e)); Command::new("cargo") .args(&["fmt"]) .status() .expect("cargo fmt failed"); } #[cfg(test)] mod tests { use super::*; #[test] fn generate_serde_supported_code() { let json = include_str!("../examples/build_config.json"); build_with_serde(json); } }