Add webfinger predicate

examples/resolver.rs

@@ -1,5 +1,5 @@
 use actix_web::{server, App};
-use actix_webfinger::{Resolver, Webfinger};
+use actix_webfinger::{Resolver, Webfinger, WebfingerPredicate};
 use futures::{future::IntoFuture, Future};
 
 #[derive(Clone, Debug)]
@@ -33,7 +33,9 @@ fn main() {
             domain: "asonix.dog".to_owned(),
         })
         .resource("/.well-known/webfinger", |r| {
-            r.with(<MyResolver as Resolver<MyState>>::endpoint)
+            r.route()
+                .filter(WebfingerPredicate)
+                .with(<MyResolver as Resolver<MyState>>::endpoint)
         })
     })
     .bind("127.0.0.1:8000")

src/lib.rs

@@ -2,12 +2,40 @@ use actix::Addr;
 use actix_web::{
     client::{self, ClientConnector},
     error::ResponseError,
-    HttpMessage, HttpResponse, Query, State,
+    http::Method,
+    pred::Predicate,
+    HttpMessage, HttpResponse, Query, Request, State,
 };
 use failure::Fail;
 use futures::{future::IntoFuture, Future};
 use serde_derive::{Deserialize, Serialize};
 
+pub struct WebfingerPredicate;
+
+impl<S> Predicate<S> for WebfingerPredicate {
+    fn check(&self, req: &Request, _: &S) -> bool {
+        if let Some(val) = req.headers().get("Accept") {
+            if let Ok(s) = val.to_str() {
+                return s.split(",").any(|v| {
+                    let v = if let Some(index) = v.find(';') {
+                        v.split_at(index).0
+                    } else {
+                        v
+                    };
+                    let trimmed = v.trim();
+
+                    trimmed == "application/jrd+json"
+                        || trimmed == "application/json"
+                        || trimmed == "application/*"
+                        || trimmed == "*/*"
+                }) && req.method() == Method::GET;
+            }
+        }
+
+        false
+    }
+}
+
 #[derive(Clone, Debug, Fail)]
 #[fail(display = "Resource {} is invalid", _0)]
 pub struct InvalidResource(String);
@@ -239,17 +267,14 @@ impl Webfinger {
     ) -> Box<dyn Future<Item = Self, Error = actix_web::Error>> {
         let url = format!(
             "{}://{}/.well-known/webfinger?resource=acct:{}",
-            if https {
-                "https"
-            } else {
-                "http"
-            },
-            domain, user
+            if https { "https" } else { "http" },
+            domain,
+            user
         );
 
         let fut = client::get(url)
             .with_connector(conn)
-            .header("Accept", "application/json")
+            .header("Accept", "application/jrd+json")
             .finish()
             .into_future()
             .and_then(|r| {