handle header with spaces before value

src/header.rs

@@ -94,6 +94,16 @@ impl FromStr for Header {
             return Err(Error::BadHeader);
         }
 
+        // https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
+        // The field value MAY be preceded by any amount of LWS, though a single SP is preferred.
+        let value_from = &s[index..];
+        let voff = match value_from.find(|c: char| !c.is_whitespace()) {
+            Some(n) => n,
+            None => 0,
+        };
+
+        let index = index + voff;
+
         Ok(Header { line, index })
     }
 }

src/test/simple.rs

@@ -151,3 +151,16 @@ pub fn no_status_text() {
     assert!(resp.ok());
     assert_eq!(resp.status(), 200);
 }
+
+#[test]
+pub fn header_with_spaces_before_value() {
+    test::set_handler("/space_before_value", |unit| {
+        assert!(unit.has("X-Test"));
+        assert_eq!(unit.header("X-Test").unwrap(), "value");
+        test::make_response(200, "OK", vec![], vec![])
+    });
+    let resp = get("test://host/space_before_value")
+        .set("X-Test", "     value")
+        .call();
+    assert_eq!(resp.status(), 200);
+}