Expand codegen to allow specify guards and async

actix-web-codegen/src/route.rs

@@ -0,0 +1,159 @@
+extern crate proc_macro;
+
+use std::fmt;
+
+use proc_macro::TokenStream;
+use quote::{quote};
+
+enum ResourceType {
+    Async,
+    Sync,
+}
+
+impl fmt::Display for ResourceType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            &ResourceType::Async => write!(f, "to_async"),
+            &ResourceType::Sync => write!(f, "to"),
+        }
+    }
+}
+
+#[derive(PartialEq)]
+pub enum GuardType {
+    Get,
+    Post,
+    Put,
+    Delete,
+}
+
+impl fmt::Display for GuardType {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            &GuardType::Get => write!(f, "Get"),
+            &GuardType::Post => write!(f, "Post"),
+            &GuardType::Put => write!(f, "Put"),
+            &GuardType::Delete => write!(f, "Delete"),
+        }
+    }
+}
+
+pub struct Args {
+    name: syn::Ident,
+    path: String,
+    ast: syn::ItemFn,
+    resource_type: ResourceType,
+    pub guard: GuardType,
+    pub extra_guards: Vec<String>,
+}
+
+impl fmt::Display for Args {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let ast = &self.ast;
+        let guards = format!(".guard(actix_web::guard::{}())", self.guard);
+        let guards = self.extra_guards.iter().fold(guards, |acc, val| format!("{}.guard(actix_web::guard::fn_guard({}))", acc, val));
+
+        write!(f, "
+#[allow(non_camel_case_types)]
+pub struct {name};
+
+impl<P: 'static> actix_web::dev::HttpServiceFactory<P> for {name} {{
+    fn register(self, config: &mut actix_web::dev::ServiceConfig<P>) {{
+        {ast}
+
+        let resource = actix_web::Resource::new(\"{path}\"){guards}.{to}({name});
+
+        actix_web::dev::HttpServiceFactory::register(resource, config)
+    }}
+}}", name=self.name, ast=quote!(#ast), path=self.path, guards=guards, to=self.resource_type)
+    }
+}
+
+fn guess_resource_type(typ: &syn::Type) -> ResourceType {
+    let mut guess = ResourceType::Sync;
+
+    match typ {
+        syn::Type::ImplTrait(typ) => for bound in typ.bounds.iter() {
+            match bound {
+                syn::TypeParamBound::Trait(bound) => {
+                    for bound in bound.path.segments.iter() {
+                        if bound.ident == "Future" {
+                            guess = ResourceType::Async;
+                            break;
+                        } else if bound.ident == "Responder" {
+                            guess = ResourceType::Sync;
+                            break;
+                        }
+                    }
+                },
+                _ => (),
+            }
+        },
+        _ => (),
+    }
+
+    guess
+
+}
+
+impl Args {
+    pub fn new(args: &Vec<syn::NestedMeta>, input: TokenStream, guard: GuardType) -> Self {
+        if args.is_empty() {
+            panic!("invalid server definition, expected: #[{}(\"some path\")]", guard);
+        }
+
+        let ast: syn::ItemFn = syn::parse(input).expect("Parse input as function");
+        let name = ast.ident.clone();
+
+        let mut extra_guards = Vec::new();
+        let mut path = None;
+        for arg in args {
+            match arg {
+                syn::NestedMeta::Literal(syn::Lit::Str(ref fname)) => {
+                    if path.is_some() {
+                        panic!("Multiple paths specified! Should be only one!")
+                    }
+                    let fname = quote!(#fname).to_string();
+                    path = Some(fname.as_str()[1..fname.len() - 1].to_owned())
+                },
+                syn::NestedMeta::Meta(syn::Meta::NameValue(ident)) => match ident.ident.to_string().to_lowercase().as_str() {
+                    "guard" => match ident.lit {
+                        syn::Lit::Str(ref text) => extra_guards.push(text.value()),
+                        _ => panic!("Attribute guard expects literal string!"),
+                    },
+                    attr => panic!("Unknown attribute key is specified: {}. Allowed: guard", attr)
+                },
+                attr => panic!("Unknown attribute{:?}", attr)
+            }
+        }
+
+        let resource_type = if ast.asyncness.is_some() {
+            ResourceType::Async
+        } else {
+            match ast.decl.output {
+                syn::ReturnType::Default => panic!("Function {} has no return type. Cannot be used as handler"),
+                syn::ReturnType::Type(_, ref typ) => guess_resource_type(typ.as_ref()),
+            }
+        };
+
+        let path = path.unwrap();
+
+        Self {
+            name,
+            path,
+            ast,
+            resource_type,
+            guard,
+            extra_guards,
+        }
+    }
+
+    pub fn generate(&self) -> TokenStream {
+        let text = self.to_string();
+
+        match text.parse() {
+            Ok(res) => res,
+            Err(error) => panic!("Error: {:?}\nGenerated code: {}", error, text)
+        }
+    }
+}