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, LitStr, 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    let prefix = prefix.unwrap_or_else(|| LitStr::new("", Span::call_site()));
34
35    let mut module = syn::parse::<ItemMod>(input)?;
36    let apigate_path = apigate_crate_path()?;
37
38    let Some((_, items)) = module.content.as_mut() else {
39        return Err(syn::Error::new_spanned(
40            &module,
41            "#[apigate::service] requires an inline module body: `mod x { ... }`",
42        ));
43    };
44
45    let mut route_defs = Vec::new();
46    let mut generated_items = Vec::new();
47
48    for item in items.iter_mut() {
49        if let Item::Fn(f) = item {
50            if let Some(extracted) = expand_route_from_fn(&apigate_path, f)? {
51                route_defs.push(extracted.route_def);
52                generated_items.extend(extracted.generated_items);
53            }
54        }
55    }
56
57    // NOTE: We intentionally generate a hidden const with all routes,
58    // so it can be referenced without recomputing at runtime
59    let routes_ident = syn::Ident::new("__APIGATE_ROUTES", Span::call_site());
60
61    let service_policy = match &policy {
62        None => quote!(None),
63        Some(p) => quote!(Some(#p)),
64    };
65
66    items.extend(generated_items);
67    items.push(syn::parse_quote! {
68        #[doc(hidden)]
69        pub const #routes_ident: &'static [#apigate_path::RouteDef] = &[
70            #(#route_defs),*
71        ];
72    });
73
74    items.push(syn::parse_quote! {
75        pub fn routes() -> #apigate_path::Routes {
76            #apigate_path::Routes {
77                service: #name,
78                prefix: #prefix,
79                policy: #service_policy,
80                routes: #routes_ident,
81            }
82        }
83    });
84
85    Ok(quote!(#module))
86}
87
88#[proc_macro_attribute]
89pub fn hook(_args: TokenStream, input: TokenStream) -> TokenStream {
90    expand_fn_params(input, "hook", false)
91        .unwrap_or_else(syn::Error::into_compile_error)
92        .into()
93}
94
95#[proc_macro_attribute]
96pub fn map(_args: TokenStream, input: TokenStream) -> TokenStream {
97    expand_fn_params(input, "map", true)
98        .unwrap_or_else(syn::Error::into_compile_error)
99        .into()
100}
101
102/// Resolves the path to the `apigate` crate for use in generated code.
103pub(crate) fn apigate_crate_path() -> Result<TokenStream2, syn::Error> {
104    use proc_macro_crate::{FoundCrate, crate_name};
105
106    match crate_name("apigate") {
107        Ok(FoundCrate::Itself) => Ok(quote!(::apigate)),
108        Ok(FoundCrate::Name(n)) => {
109            let ident = syn::Ident::new(&n, Span::call_site());
110            Ok(quote!(::#ident))
111        }
112        Err(_) => Ok(quote!(::apigate)),
113    }
114}
115
116macro_rules! route_stub {
117    ($name:ident) => {
118        #[proc_macro_attribute]
119        pub fn $name(_args: TokenStream, input: TokenStream) -> TokenStream {
120            let item = parse_macro_input!(input as syn::Item);
121            syn::Error::new_spanned(
122                item,
123                concat!(
124                    "`#[apigate::",
125                    stringify!($name),
126                    "]` must be used inside a `#[apigate::service] mod ... {}` module"
127                ),
128            )
129            .to_compile_error()
130            .into()
131        }
132    };
133}
134
135route_stub!(get);
136route_stub!(post);
137route_stub!(put);
138route_stub!(delete);
139route_stub!(patch);
140route_stub!(head);
141route_stub!(options);
apigate_macros/lib.rs

apigate_macros/
lib.rs
