move typed headers and implement FromRequest (#2094)

Co-authored-by: Rob Ede <robjtede@icloud.com>

src/http/header/accept_language.rs

@@ -0,0 +1,69 @@
+use super::{QualityItem, ACCEPT_LANGUAGE};
+use language_tags::LanguageTag;
+
+crate::header! {
+    /// `Accept-Language` header, defined in
+    /// [RFC7231](http://tools.ietf.org/html/rfc7231#section-5.3.5)
+    ///
+    /// The `Accept-Language` header field can be used by user agents to
+    /// indicate the set of natural languages that are preferred in the
+    /// response.
+    ///
+    /// # ABNF
+    ///
+    /// ```text
+    /// Accept-Language = 1#( language-range [ weight ] )
+    /// language-range  = <language-range, see [RFC4647], Section 2.1>
+    /// ```
+    ///
+    /// # Example values
+    /// * `da, en-gb;q=0.8, en;q=0.7`
+    /// * `en-us;q=1.0, en;q=0.5, fr`
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use language_tags::langtag;
+    /// use actix_web::HttpResponse;
+    /// use actix_web::http::header::{AcceptLanguage, LanguageTag, qitem};
+    ///
+    /// let mut builder = HttpResponse::Ok();
+    /// let mut langtag: LanguageTag = Default::default();
+    /// langtag.language = Some("en".to_owned());
+    /// langtag.region = Some("US".to_owned());
+    /// builder.insert_header(
+    ///     AcceptLanguage(vec![
+    ///         qitem(langtag),
+    ///     ])
+    /// );
+    /// ```
+    ///
+    /// ```
+    /// use language_tags::langtag;
+    /// use actix_web::HttpResponse;
+    /// use actix_web::http::header::{AcceptLanguage, QualityItem, q, qitem};
+    ///
+    /// let mut builder = HttpResponse::Ok();
+    /// builder.insert_header(
+    ///     AcceptLanguage(vec![
+    ///         qitem(langtag!(da)),
+    ///         QualityItem::new(langtag!(en;;;GB), q(800)),
+    ///         QualityItem::new(langtag!(en), q(700)),
+    ///     ])
+    /// );
+    /// ```
+    (AcceptLanguage, ACCEPT_LANGUAGE) => (QualityItem<LanguageTag>)+
+
+    test_accept_language {
+        // From the RFC
+        test_header!(test1, vec![b"da, en-gb;q=0.8, en;q=0.7"]);
+        // Own test
+        test_header!(
+            test2, vec![b"en-US, en; q=0.5, fr"],
+            Some(AcceptLanguage(vec![
+                qitem("en-US".parse().unwrap()),
+                QualityItem::new("en".parse().unwrap(), q(500)),
+                qitem("fr".parse().unwrap()),
+        ])));
+    }
+}