Add Cors for setting CORS headers (#112)

* Add `Cors` for settings CORS headers

* Pass layer along so config isn't lost

* Support allowing origin via closure

* Check for `Access-Control-Request-Method`

* Use `None` as default for `Max-Age`

* Add example for allowing multiple headers

* Fix wrong method check

* Also check for any

* Restrictive config by default, with "permissive" helper

* Change status for prelight response

* Make setting origin with predicate more consistent

* Merge clauses

* Use `WILDCARD` constant

* typo

* Conditionally set `allow-credentials`

* Add note to `Access-Control-Allow-Headers`

* minor docs tweaks

* Make `Any` constructor private and expose `any()` function

tower-http/CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 # Unreleased
 
+- New middleware: Add `Cors` for setting [CORS] headers ([#112])
 - New middleware: Add `AsyncRequireAuthorization` ([#118])
 - `Compression`: Don't recompress HTTP responses ([#140])
 - `Compression` and `Decompression`: Pass configuration from layer into middleware ([#132])
@@ -17,6 +18,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `ServeDir`: Return `404 Not Found` on requests to directories if
   `append_index_html_on_directories` is set to `false` ([#122])
 
+[#112]: https://github.com/tower-rs/tower-http/pull/112
 [#118]: https://github.com/tower-rs/tower-http/pull/118
 [#140]: https://github.com/tower-rs/tower-http/pull/140
 [#132]: https://github.com/tower-rs/tower-http/pull/132
@@ -52,3 +54,5 @@ None.
 # 0.1.0 (May 27, 2021)
 
 - Initial release.
+
+[CORS]: https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS

tower-http/Cargo.toml

@@ -52,6 +52,7 @@ full = [
     "auth",
     "compression",
     "compression-full",
+    "cors",
     "decompression-full",
     "follow-redirect",
     "fs",
@@ -67,6 +68,7 @@ full = [
 
 add-extension = []
 auth = ["base64"]
+cors = []
 follow-redirect = ["iri-string", "tower/util"]
 fs = ["tokio/fs", "tokio-util/io", "mime_guess", "mime", "percent-encoding"]
 map-request-body = []