Merge branch '4.1.x' into 4.2.x

docs/modules/ROOT/nav.adoc

@@ -109,6 +109,7 @@
 *** xref:spring-cloud-gateway-server-mvc/filters/requestsize.adoc[]
 *** xref:spring-cloud-gateway-server-mvc/filters/setrequesthostheader.adoc[]
 *** xref:spring-cloud-gateway-server-mvc/filters/tokenrelay.adoc[]
+** xref:spring-cloud-gateway-server-mvc/httpheadersfilters.adoc[]
 ** xref:spring-cloud-gateway-server-mvc/writing-custom-predicates-and-filters.adoc[]
 ** xref:spring-cloud-gateway-server-mvc/working-with-servlets-and-filters.adoc[]
 

docs/modules/ROOT/pages/spring-cloud-gateway-server-mvc/httpheadersfilters.adoc

@@ -0,0 +1,45 @@
+[[httpheadersfilters]]
+= HttpHeadersFilters
+
+HttpHeadersFilters are applied to the requests before sending them downstream, such as in the `NettyRoutingFilter`.
+
+[[forwarded-headers-filter]]
+== Forwarded Headers Filter
+The `Forwarded` Headers Filter creates a `Forwarded` header to send to the downstream service. It adds the `Host` header, scheme and port of the current request to any existing `Forwarded` header. To activate this filter set the `spring.cloud.gateway.mvc.trusted-proxies` property to a Java Regular Expression. This regular expression defines the proxies that are trusted when they appear in the `Forwarded` header.
+
+[[removehopbyhop-headers-filter]]
+== RemoveHopByHop Headers Filter
+The `RemoveHopByHop` Headers Filter removes headers from forwarded requests. The default list of headers that is removed comes from the https://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-7.1.3[IETF].
+
+.The default removed headers are:
+*  Connection
+*  Keep-Alive
+*  Proxy-Authenticate
+*  Proxy-Authorization
+*  TE
+*  Trailer
+*  Transfer-Encoding
+*  Upgrade
+
+//To change this, set the `spring.cloud.gateway.filter.remove-hop-by-hop.headers` property to the list of header names to remove.
+
+[[xforwarded-headers-filter]]
+== XForwarded Headers Filter
+The `XForwarded` Headers Filter creates various `X-Forwarded-*` headers to send to the downstream service. It uses the `Host` header, scheme, port and path of the current request to create the various headers.  To activate this filter set the `spring.cloud.gateway.mvc.trusted-proxies` property to a Java Regular Expression. This regular expression defines the proxies that are trusted when they appear in the `Forwarded` header.
+
+Creating of individual headers can be controlled by the following boolean properties (defaults to true):
+
+- `spring.cloud.gateway.x-forwarded.for-enabled`
+- `spring.cloud.gateway.x-forwarded.host-enabled`
+- `spring.cloud.gateway.x-forwarded.port-enabled`
+- `spring.cloud.gateway.x-forwarded.proto-enabled`
+- `spring.cloud.gateway.x-forwarded.prefix-enabled`
+
+Appending multiple headers can be controlled by the following boolean properties (defaults to true):
+
+- `spring.cloud.gateway.x-forwarded.for-append`
+- `spring.cloud.gateway.x-forwarded.host-append`
+- `spring.cloud.gateway.x-forwarded.port-append`
+- `spring.cloud.gateway.x-forwarded.proto-append`
+- `spring.cloud.gateway.x-forwarded.prefix-append`
+

docs/modules/ROOT/pages/spring-cloud-gateway/httpheadersfilters.adoc

@@ -5,7 +5,7 @@
 
 [[forwarded-headers-filter]]
 == Forwarded Headers Filter
-The `Forwarded` Headers Filter creates a `Forwarded` header to send to the downstream service. It adds the `Host` header, scheme and port of the current request to any existing `Forwarded` header.
+The `Forwarded` Headers Filter creates a `Forwarded` header to send to the downstream service. It adds the `Host` header, scheme and port of the current request to any existing `Forwarded` header. To activate this filter set the `spring.cloud.gateway.trusted-proxies` property to a Java Regular Expression. This regular expression defines the proxies that are trusted when they appear in the `Forwarded` header.
 
 [[removehopbyhop-headers-filter]]
 == RemoveHopByHop Headers Filter
@@ -25,7 +25,7 @@ To change this, set the `spring.cloud.gateway.filter.remove-hop-by-hop.headers`
 
 [[xforwarded-headers-filter]]
 == XForwarded Headers Filter
-The `XForwarded` Headers Filter creates various `X-Forwarded-*` headers to send to the downstream service. It uses the `Host` header, scheme, port and path of the current request to create the various headers.
+The `XForwarded` Headers Filter creates various `X-Forwarded-*` headers to send to the downstream service. It uses the `Host` header, scheme, port and path of the current request to create the various headers.  To activate this filter set the `spring.cloud.gateway.trusted-proxies` property to a Java Regular Expression. This regular expression defines the proxies that are trusted when they appear in the `Forwarded` header.
 
 Creating of individual headers can be controlled by the following boolean properties (defaults to true):