This commit is contained in:
Jonas Rabenstein 2026-02-27 05:46:12 +01:00
commit a03c1891c8
2 changed files with 121 additions and 0 deletions

109
macros/src/lib.rs Normal file
View file

@ -0,0 +1,109 @@
use proc_macro::TokenStream;
use quote::{quote, ToTokens};
use syn::{
parse_macro_input, Attribute, FnArg, ItemFn, Lit, Meta, Pat, PatType, Type, spanned::Spanned,
};
/// Endpoint macro
#[proc_macro_attribute]
pub fn endpoint(attr: TokenStream, item: TokenStream) -> TokenStream {
// parse the endpoint attribute
let attr = proc_macro2::TokenStream::from(attr);
let func = parse_macro_input!(item as ItemFn);
let vis = &func.vis;
let name = &func.sig.ident;
let inputs = &func.sig.inputs;
let output = &func.sig.output;
// must be async
if func.sig.asyncness.is_none() {
return syn::Error::new(name.span(), "endpoint function must be async")
.to_compile_error()
.into();
}
// defaults
let mut method = quote! { GET };
let mut path = None;
// parse #[endpoint(...)]
if !attr.is_empty() {
let attr_str = attr.to_string();
// simple heuristic: if contains "POST", switch
if attr_str.contains("POST") {
method = quote! { POST };
}
// simple heuristic: extract path in quotes
if let Some(start) = attr_str.find('"') {
if let Some(end) = attr_str[start+1..].find('"') {
path = Some(attr_str[start+1..start+1+end].to_string());
}
}
}
let path = match path {
Some(p) => p,
None => return syn::Error::new(name.span(), "endpoint path must be provided")
.to_compile_error()
.into(),
};
// process arguments
let mut client_arg = None;
let mut other_args = Vec::new();
for input in inputs {
match input {
FnArg::Receiver(_) => continue, // skip self
FnArg::Typed(PatType { pat, ty, .. }) => {
if let Pat::Ident(ident) = &**pat {
if ident.ident == "client" {
client_arg = Some((ident.ident.clone(), ty));
} else {
other_args.push((ident.ident.clone(), ty));
}
}
}
}
}
// generate tokens for function with builder
let arg_defs: Vec<proc_macro2::TokenStream> = other_args.iter().map(|(id, ty)| {
// wrap Option<T> with #[builder(default)]
if let Type::Path(tp) = ty.as_ref() {
let is_option = tp.path.segments.last().map(|seg| seg.ident == "Option").unwrap_or(false);
if is_option {
quote! { #[builder(default)] #id: #ty }
} else {
quote! { #id: #ty }
}
} else {
quote! { #id: #ty }
}
}).collect();
let client_def = match client_arg {
Some((id, ty)) => quote! { #[builder(finish_fn)] #id: #ty },
None => quote! { #[builder(finish_fn)] client: &restson::RestClient },
};
let call_args: Vec<proc_macro2::TokenStream> = other_args.iter().map(|(id, _)| {
quote! { #id }
}).collect();
let expanded = quote! {
#[bon::builder]
#vis fn #name(
#client_def,
#(#arg_defs),*
) -> impl std::future::Future<Output = Result<_, restson::Error>> + '_ {
async move {
let result = client.get::<_, serde_json::Value>(#path).await?;
Ok(result)
}
}
};
expanded.into()
}