diff --git a/docs/manual/howto/http2.html.en b/docs/manual/howto/http2.html.en index 2437b128b9..d9f0a3cb42 100644 --- a/docs/manual/howto/http2.html.en +++ b/docs/manual/howto/http2.html.en @@ -41,6 +41,7 @@
  • Clients
  • Useful tools to debug HTTP/2
  • Server Push
    • +
  • Early Hints

    • See also

    top
    @@ -261,6 +262,48 @@ is the Accept-Push-Policy Header Field where a client can, for each request, define what kind of PUSHes it accepts.

    +

    + PUSH might not always trigger the request/response/performance that one expects or + hopes for. There are various studies on this topic to be found on the web that explain + benefits and weaknesses and how different features of client and network influence + the outcome. For example: just because the server PUSHes a resource does not mean + a browser will actually use the data.

    +

    The major thing that influences the response being PUSHed is the request that was + simulated. The request URL for a PUSH is given by the application, but where do the + request headers come from? For example, will the PUSH request a accept-language + header and if yes with what value?

    +

    Apache will look at the original request (the one that triggered the PUSH) and copy the + following headers over to PUSH requests: user-agent, accept, + accept-encoding, accept-language, cache-control.

    +

    All other headers are ignored. Cookies will also not be copied over. PUSHing resources + that require a cookie to be present will not work. This can be a matter of debate. But + unless this is more clearly discussed with browser, let's err on the side of caution and + not expose cookie where they might oridinarily not be visible.

    +
    top
    +
    +

    Early Hints

    + +

    An alternative to PUSHing resources is to send Link headers to the + client before the response is even ready. This uses the HTTP feature called "Early Hints" and + is described in RFC 8297.

    +

    In order to use this, you need to explicitly enable it on the server via

    + 
    H2EarlyHints on
    + +

    (It is not enabled by default since some older browser tripped on such responses.)

    +

    If this feature is on, you can the directive H2PushResource to + trigger early hints and resource PUSHes:

    + 
    <Location /xxx.html>
+    H2PushResource /xxx.css
+    H2PushResource /xxx.js
+</Location>
    + +

    This will send out a "103 Early Hints" response to a client as soon + as the server starts processing the request. This may be much early than + the time the first response headers have been determined, depending on your web + application.

    +

    If H2Push is enabled, this will also start the PUSH right after the + 103 response. If H2Push is disabled however, the 103 response will be send + nevertheless to the client.

    Available Languages:  en  | diff --git a/docs/manual/howto/http2.xml.es b/docs/manual/howto/http2.xml.es index 6c4fce52c4..fa765c3474 100644 --- a/docs/manual/howto/http2.xml.es +++ b/docs/manual/howto/http2.xml.es @@ -1,7 +1,7 @@ - + diff --git a/docs/manual/howto/http2.xml.fr b/docs/manual/howto/http2.xml.fr index 19dbb09f95..306829ffa2 100644 --- a/docs/manual/howto/http2.xml.fr +++ b/docs/manual/howto/http2.xml.fr @@ -1,7 +1,7 @@ - + diff --git a/docs/manual/howto/http2.xml.meta b/docs/manual/howto/http2.xml.meta index 368861be37..9b93a6fba0 100644 --- a/docs/manual/howto/http2.xml.meta +++ b/docs/manual/howto/http2.xml.meta @@ -8,7 +8,7 @@ en - es - fr + es + fr diff --git a/docs/manual/mod/mod_proxy_http2.html.en b/docs/manual/mod/mod_proxy_http2.html.en index e7b2a2ecca..b3cc55651b 100644 --- a/docs/manual/mod/mod_proxy_http2.html.en +++ b/docs/manual/mod/mod_proxy_http2.html.en @@ -51,7 +51,7 @@ to the same backend are sent over a single TCP connection whenever possible (namely when the connection can be re-used).

    -

    Caveat: there will be no attemp to consolidate multiple HTTP/1.1 +

    Caveat: there will be no attempt to consolidate multiple HTTP/1.1 frontend requests (configured to be proxied to the same backend) into HTTP/2 streams belonging to the same HTTP/2 request. Each HTTP/1.1 frontend request will be proxied to the backend using @@ -78,6 +78,7 @@

    Directives

    This module provides no directives.

    @@ -123,6 +124,19 @@ ProxyPassReverse "/app" "http://app.example.com"
    proxy-status
    The HTTP/2 status received from the backend server.
    +
    top
    +
    +

    HTTP/2 PUSH

    +

    The module does not support the HTTP/2 feature PUSH. Backend servers + that would like to advertise preload resources should send the appropriate + Link headers.

    +

    If available, they may do so using the "103 Early Hints" + intermediate responses as specified in + RFC 8297. This will give + the best performance. If the client is talking HTTP/2 as well, this may + then result in a PUSH from Apache to the client or just in forwarding + the 103 response.

    +
    diff --git a/docs/manual/mod/mod_proxy_http2.xml.fr b/docs/manual/mod/mod_proxy_http2.xml.fr index 1520e8e51a..e936cf5c65 100644 --- a/docs/manual/mod/mod_proxy_http2.xml.fr +++ b/docs/manual/mod/mod_proxy_http2.xml.fr @@ -1,7 +1,7 @@ - + diff --git a/docs/manual/mod/mod_proxy_http2.xml.meta b/docs/manual/mod/mod_proxy_http2.xml.meta index 071a546512..38e9951f9e 100644 --- a/docs/manual/mod/mod_proxy_http2.xml.meta +++ b/docs/manual/mod/mod_proxy_http2.xml.meta @@ -8,6 +8,6 @@ en - fr + fr