diff --git a/src/lib.rs b/src/lib.rs index 5c37c17..515430f 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -654,6 +654,21 @@ impl Options { /// A CORS Response which wraps another struct which implements `Responder`. You will typically /// use [`Options`] instead to verify and build the response instead of this directly. /// See module level documentation for usage examples. +/// +/// If the wrapped `Responder` already has the `Access-Control-Allow-Origin` header set, +/// this responder will leave the response untouched. +/// This allows for chaining of several CORS responders. +/// +/// Otherwise, the following headers may be set for the final Rocket `Response`, overwriting any +/// existing headers defined: +/// +/// - `Access-Control-Allow-Origin` +/// - `Access-Control-Expose-Headers` +/// - `Access-Control-Max-Age` +/// - `Access-Control-Allow-Credentials` +/// - `Access-Control-Allow-Methods` +/// - `Access-Control-Allow-Headers` +/// - `Vary` pub struct Response { responder: R, allow_origin: Option>, @@ -808,26 +823,23 @@ impl<'r, R: Responder<'r>> Response { ), ) } -} -impl<'r, R: Responder<'r>> Responder<'r> for Response { + /// Builds a `rocket::Response` from this struct containing only the CORS headers. #[allow(unused_results)] - fn respond_to(self, request: &Request) -> response::Result<'r> { - use std::borrow::Cow; - - let mut builder = response::Response::build_from(self.responder.respond_to(request)?); + fn build(&self) -> response::Response<'r> { + let mut builder = response::Response::build(); let origin = match self.allow_origin { None => { // This is not a CORS response - return Ok(builder.finalize()); + return builder.finalize(); } - Some(origin) => origin, + Some(ref origin) => origin, }; - let origin: Cow = match origin { - AllOrSome::All => Into::into("*"), - AllOrSome::Some(origin) => Into::into(origin), + let origin = match *origin { + AllOrSome::All => "*".to_string(), + AllOrSome::Some(ref origin) => origin.to_string(), }; builder.raw_header("Access-Control-Allow-Origin", origin); @@ -838,7 +850,7 @@ impl<'r, R: Responder<'r>> Responder<'r> for Response { if !self.expose_headers.is_empty() { let headers: Vec = self.expose_headers - .into_iter() + .iter() .map(|s| s.deref().to_string()) .collect(); let headers = headers.join(", "); @@ -848,7 +860,7 @@ impl<'r, R: Responder<'r>> Responder<'r> for Response { if !self.allow_headers.is_empty() { let headers: Vec = self.allow_headers - .into_iter() + .iter() .map(|s| s.deref().to_string()) .collect(); let headers = headers.join(", "); @@ -858,7 +870,7 @@ impl<'r, R: Responder<'r>> Responder<'r> for Response { if !self.allow_methods.is_empty() { - let methods: Vec<_> = self.allow_methods.into_iter().map(|m| m.as_str()).collect(); + let methods: Vec<_> = self.allow_methods.iter().map(|m| m.as_str()).collect(); let methods = methods.join(", "); builder.raw_header("Access-Control-Allow-Methods", methods); @@ -873,7 +885,57 @@ impl<'r, R: Responder<'r>> Responder<'r> for Response { builder.raw_header("Vary", "Origin"); } - Ok(builder.finalize()) + builder.finalize() + } + + /// Merge a `wrapped` Response with a `cors` response + /// + /// If the `wrapped` response has the `Access-Control-Allow-Origin` header already defined, + /// it will be left untouched. This allows for chaining of several CORS responders. + /// + /// Otherwise, the merging will be done according to the rules of `rocket::Response::merge`. + fn merge( + mut wrapped: response::Response<'r>, + cors: response::Response<'r>, + ) -> response::Response<'r> { + + let existing_cors = { + wrapped.headers().get("Access-Control-Allow-Origin").next() == None + }; + + if existing_cors { + wrapped.merge(cors); + } + + wrapped + } + + /// Finalize the Response by merging the CORS header with the wrapped `Responder + /// + /// If the original response has the `Access-Control-Allow-Origin` header already defined, + /// it will be left untouched.This allows for chaining of several CORS responders. + /// + /// Otherwise, the following headers may be set for the final Rocket `Response`, overwriting any + /// existing headers defined: + /// + /// - `Access-Control-Allow-Origin` + /// - `Access-Control-Expose-Headers` + /// - `Access-Control-Max-Age` + /// - `Access-Control-Allow-Credentials` + /// - `Access-Control-Allow-Methods` + /// - `Access-Control-Allow-Headers` + /// - `Vary` + fn finalize(self, request: &Request) -> response::Result<'r> { + let cors_response = self.build(); + let original_response = self.responder.respond_to(request)?; + + Ok(Self::merge(original_response, cors_response)) + } +} + +impl<'r, R: Responder<'r>> Responder<'r> for Response { + fn respond_to(self, request: &Request) -> response::Result<'r> { + self.finalize(request) } }