rs_web_host/
lib.rs

1extern crate proc_macro;
2
3use proc_macro::TokenStream;
4use quote::{quote, format_ident};
5use syn::{parse_macro_input, AttributeArgs, ItemFn, Lit, NestedMeta, Signature};
6
7#[proc_macro_attribute]
8pub fn get(args: TokenStream, input: TokenStream) -> TokenStream {
9    generate_route("GET", args, input, false)
10}
11
12#[proc_macro_attribute]
13pub fn post(args: TokenStream, input: TokenStream) -> TokenStream {
14    generate_route("POST", args, input, true)
15}
16
17fn generate_route(method: &str, args: TokenStream, input: TokenStream, has_body: bool) -> TokenStream {
18    let args = parse_macro_input!(args as AttributeArgs);
19    let input = parse_macro_input!(input as ItemFn);
20    let path = match args.get(0) {
21        Some(NestedMeta::Lit(Lit::Str(lit))) => lit.value(),
22        _ => panic!("Expected path as first argument"),
23    };
24
25    let name = &input.sig.ident;
26    let vis = &input.vis;
27    let block = &input.block;
28    let params = extract_params_from_signature(&input.sig);
29    let handler_name = format_ident!("{}_{}_handler", method.to_lowercase(), name);
30
31    let expanded = quote! {
32        #vis fn #handler_name(#params) -> String {
33            #block
34        }
35
36        inventory::submit! {
37            crate::Route {
38                method: #method.to_string(),
39                path: #path.to_string(),
40                handler: #handler_name,
41                has_body: #has_body,
42            }
43        }
44    };
45
46    expanded.into()
47}
48
49fn extract_params_from_signature(sig: &Signature) -> proc_macro2::TokenStream {
50    let params = sig.inputs.iter().map(|input| {
51        if let syn::FnArg::Typed(pat_type) = input {
52            let pat = &pat_type.pat;
53            let ty = &pat_type.ty;
54            quote! {
55                #pat: #ty
56            }
57        } else {
58            quote!()
59        }
60    });
61
62    quote! { #( #params ),* }
63}
rs_web_host/lib.rs

rs_web_host/
lib.rs
