apigate_macros/
lib.rs

1mod codegen;
2mod expand;
3mod parse;
4mod route;
5mod service;
6mod template;
7
8use proc_macro::TokenStream;
9use proc_macro2::{Span, TokenStream as TokenStream2};
10use quote::quote;
11use syn::{Item, ItemMod, parse_macro_input};
12
13use expand::expand_fn_params;
14use route::expand_route_from_fn;
15use service::ServiceArgs;
16
17#[proc_macro_attribute]
18pub fn service(args: TokenStream, input: TokenStream) -> TokenStream {
19    expand_service(args, input)
20        .unwrap_or_else(syn::Error::into_compile_error)
21        .into()
22}
23
24/// Expands `#[apigate::service(name = "...", prefix = "...")]` on a module:
25/// iterates functions, expands routes, and injects a `routes()` entrypoint.
26fn expand_service(args: TokenStream, input: TokenStream) -> syn::Result<TokenStream2> {
27    let args = syn::parse::<ServiceArgs>(args)?;
28    let ServiceArgs {
29        name,
30        prefix,
31        policy,
32    } = args;
33
34    let mut module = syn::parse::<ItemMod>(input)?;
35    let apigate_path = apigate_crate_path()?;
36
37    let Some((_, items)) = module.content.as_mut() else {
38        return Err(syn::Error::new_spanned(
39            &module,
40            "#[apigate::service] requires an inline module body: `mod x { ... }`",
41        ));
42    };
43
44    let mut route_defs = Vec::new();
45    let mut generated_items = Vec::new();
46
47    for item in items.iter_mut() {
48        if let Item::Fn(f) = item {
49            if let Some(extracted) = expand_route_from_fn(&apigate_path, f)? {
50                route_defs.push(extracted.route_def);
51                generated_items.extend(extracted.generated_items);
52            }
53        }
54    }
55
56    // NOTE: We intentionally generate a hidden const with all routes,
57    // so it can be referenced without recomputing at runtime
58    let routes_ident = syn::Ident::new("__APIGATE_ROUTES", Span::call_site());
59
60    let service_policy = match &policy {
61        None => quote!(None),
62        Some(p) => quote!(Some(#p)),
63    };
64
65    items.extend(generated_items);
66    items.push(syn::parse_quote! {
67        #[doc(hidden)]
68        pub const #routes_ident: &'static [#apigate_path::RouteDef] = &[
69            #(#route_defs),*
70        ];
71    });
72
73    items.push(syn::parse_quote! {
74        pub fn routes() -> #apigate_path::Routes {
75            #apigate_path::Routes {
76                service: #name,
77                prefix: #prefix,
78                policy: #service_policy,
79                routes: #routes_ident,
80            }
81        }
82    });
83
84    Ok(quote!(#module))
85}
86
87#[proc_macro_attribute]
88pub fn hook(_args: TokenStream, input: TokenStream) -> TokenStream {
89    expand_fn_params(input, "hook", false)
90        .unwrap_or_else(syn::Error::into_compile_error)
91        .into()
92}
93
94#[proc_macro_attribute]
95pub fn map(_args: TokenStream, input: TokenStream) -> TokenStream {
96    expand_fn_params(input, "map", true)
97        .unwrap_or_else(syn::Error::into_compile_error)
98        .into()
99}
100
101/// Resolves the path to the `apigate` crate for use in generated code.
102pub(crate) fn apigate_crate_path() -> Result<TokenStream2, syn::Error> {
103    use proc_macro_crate::{FoundCrate, crate_name};
104
105    match crate_name("apigate") {
106        Ok(FoundCrate::Itself) => Ok(quote!(::apigate)),
107        Ok(FoundCrate::Name(n)) => {
108            let ident = syn::Ident::new(&n, Span::call_site());
109            Ok(quote!(::#ident))
110        }
111        Err(_) => Ok(quote!(::apigate)),
112    }
113}
114
115macro_rules! route_stub {
116    ($name:ident) => {
117        #[proc_macro_attribute]
118        pub fn $name(_args: TokenStream, input: TokenStream) -> TokenStream {
119            let item = parse_macro_input!(input as syn::Item);
120            syn::Error::new_spanned(
121                item,
122                concat!(
123                    "`#[apigate::",
124                    stringify!($name),
125                    "]` must be used inside a `#[apigate::service] mod ... {}` module"
126                ),
127            )
128            .to_compile_error()
129            .into()
130        }
131    };
132}
133
134route_stub!(get);
135route_stub!(post);
136route_stub!(put);
137route_stub!(delete);
138route_stub!(patch);
139route_stub!(head);
140route_stub!(options);
apigate_macros/lib.rs

apigate_macros/
lib.rs
