Same URL: Don't cache with store response header, but cache when it's not there
Maninder Singh
mandys at gmail.com
Wed Jan 23 04:53:53 UTC 2019
Thank you Guillaume for your suggestions.
This seemed to have worked.
I am now using the following vcl config.
>> I understand where you are coming from with the std.log debugging, but
that info is actually super redundant with what's in the log.
I know. But, varnishlog has lot of info and this was done so that I could
just do varnishlog | grep "vtglog" to see the flow as per my liking :-)
This has now been removed.
This should now keep 2 copies of the same url - one for Safari and one for
the rest - right ?
Question:
What's a good way to check how many cache copies are present for a url ?
Once again thank you for your help!
- Mandy.
vcl 4.0;
# Default backend definition. Set this to point to your content server.
backend default {
.host = "127.0.0.1";
.port = "8080";
}
sub vcl_recv {
if (req.http.User-Agent ~ "Safari") {
if (req.http.User-Agent ~ "Chrome") {
set req.http.browser = "other";
} else {
set req.http.browser = "safari";
}
} else {
set req.http.browser = "other";
}
# Only cache GET or HEAD requests. This makes sure the POST requests
are always passed.
if (req.method != "GET" && req.method != "HEAD") {
return (pass);
}
if(req.http.host == "sqa03.mydomain.com" && req.url ~ "/app/profile"){
unset req.http.cookie;
} else{
return(pass);
}
if (req.http.Authorization) {
# Not cacheable by default
return (pass);
}
}
sub vcl_backend_response {
# Happens after we have read the response headers from the backend.
#
# Here you clean the response headers, removing silly Set-Cookie headers
# and other mistakes your backend does.
if (bereq.http.host == "sqa03.mydomain.com" && bereq.url ~
"/app/profile") {
set beresp.ttl = 180 s;
if ( beresp.http.Set-Cookie ) {
unset beresp.http.Set-Cookie;
}
}
if (beresp.status == 301 || beresp.status == 302) {
set beresp.http.Location = regsub(beresp.http.Location, ":[0-9]+",
"");
}
# Don't cache 50x responses
if (beresp.status == 500 || beresp.status == 502 || beresp.status ==
503 || beresp.status == 504) {
return (abandon);
}
}
sub vcl_hash {
hash_data(req.http.browser);
}
sub vcl_deliver {
# Happens when we have all the pieces we need, and are about to send the
# response to the client.
#
# You can do accounting or modifying the final object here.
if (obj.hits > 0) {
# Add debug header to see if it's a HIT/MISS and the number of hits,
disable when not needed
set resp.http.X-Cache = "HIT";
} else {
set resp.http.X-Cache = "MISS";
}
set resp.http.X-Cache-Hits = obj.hits;
}
On Mon, 21 Jan 2019 at 09:09, Guillaume Quintard <
guillaume at varnish-software.com> wrote:
> Hi,
>
> > Is it because I have one url -
> > - that can return 2 responses based on browser
>
> That's the one, you need to tell varnish to care about the browser. You
> have two ways to do that: either put that in in the hash key directly, or
> put it in in a header, and tell that to varnish via the vary header.
>
> First option looks like this:
>
> sub vcl_recv {
> if (SOME_TEST_TO_CHECK_ITS_SAFARI) {
> set req.http.browser = "safari";
> } else {
> set req.http.browser = "somethingelse";
> }
> }
>
> sub vcl_hash {
> hash_data(req.http.browser);
> # do NOT return, let the built-in vcl run
> }
>
> The pro is that you don't need to change the backend, the con is that if
> you purge, you have to purge twice because they are two different objects.
>
> The second option is to tell varnish that the browser is important, but
> just a variant of the same object:
>
> sub vcl_recv {
> if (SOME_TEST_TO_CHECK_ITS_SAFARI) {
> set req.http.browser = "safari";
> } else {
> set req.http.browser = "somethingelse";
> }
> }
>
> sub vcl_backend_response {
> set beresp.http.vary = beresp.http.vary + ",browser";
> }
>
> Note that you can also have the backend return the vary header for you
> directly
>
> There are a couple of cleaner versions, but they are a bit more involved,
> so let's start with that.
>
> Side note: I understand where you are coming from with the std.log
> debugging, but that info is actually super redundant with what's in the log.
>
> --
> Guillaume Quintard
>
>
> On Sun, Jan 20, 2019 at 4:14 AM Maninder Singh <mandys at gmail.com> wrote:
>
>> Hi Everyone,
>>
>> I am unable to get caching to work in a particular scenario.
>>
>> I need to cache the url eg: /app/profile/GDPR1?hostingUrl=http%3A%2F%
>> 2Fitvidffya.blogspot.com%2F2019%2F01%2Fvar-nish-issue-fix.html
>>
>> However, this is embedded in a 3rd party site (www.anotherdomain.com
>> calls mydomain.com in iframe ) so on Apple Safari we can't drop cookies
>> ( as 3rd party cookies are blocked by default ).
>>
>> As a result, for Apple Safari, when this url is hit, our backend returns
>> top.location.href='someurlonoursite_to_set_cookie' which is fired in
>> context of 3rd party site since they embed using our javascript.
>>
>> This way a cookie is dropped on our domain and user gets back to the url
>> inside the iframe.
>>
>> Now, when I hit this url in chrome, it always picks up
>> top.location.href='....' as it got cached by safari.
>>
>> But, chrome was supposed to get the actual page content since it's not
>> blocking 3rd party cookies.
>>
>> So, I went ahead and added a custom header, "store" for cases of apple
>> safari in our backend.
>> I skip unsetting cookie (hence varnish cache) for this url in this case.
>>
>> But, it still doesn't cache on chrome in subsequent hits.
>>
>> Always goes to backend, never goes to the cache.
>>
>> Is it because I have one url -
>> - that can return 2 responses based on browser
>> - I told it to not cache first time when store header was there, but when
>> store header is not there i ask it to cache it.
>>
>> Still doesn't work.
>>
>> Config
>>
>> sub vcl_recv {
>> std.log("vtglog: in vcl_recv " + req.url);
>> # Only cache GET or HEAD requests. This makes sure the POST requests
>> are always passed.
>> if (req.method != "GET" && req.method != "HEAD") {
>> return (pass);
>> }
>>
>> if(req.http.host == "sqa03.mydomain.com" && req.url ~
>> "/app/profile"){
>> std.log("vtglog: unsetting cookies");
>> unset req.http.cookie;
>> } else{
>> return(pass);
>> }
>>
>> if (req.http.Authorization) {
>> # Not cacheable by default
>> return (pass);
>> }
>> }
>>
>> sub vcl_backend_response {
>> std.log("vtglog: vcl_backend_response" + bereq.url) ;
>> # Happens after we have read the response headers from the backend.
>> #
>> # Here you clean the response headers, removing silly Set-Cookie
>> headers
>> # and other mistakes your backend does.
>> if (bereq.http.host == "sqa03.mydomain.com" && bereq.url ~
>> "/app/profile") {
>> std.log("vtglog: inside condition in backend response");
>> std.log("vtglog: store header value is " + beresp.http.store);
>> if ( beresp.http.Set-Cookie ) {
>> if ( !beresp.http.store ) {
>> std.log("vtglog: since no store headers, cache it by
>> unsetting cookies");
>> unset beresp.http.Set-Cookie;
>> } else {
>> std.log("vtglog: store header found, dont cache");
>> }
>> }
>> }
>>
>> if (beresp.status == 301 || beresp.status == 302) {
>> set beresp.http.Location = regsub(beresp.http.Location,
>> ":[0-9]+", "");
>> }
>>
>> # Don't cache 50x responses
>> if (beresp.status == 500 || beresp.status == 502 || beresp.status ==
>> 503 || beresp.status == 504) {
>> return (abandon);
>> }
>> }
>> _______________________________________________
>> varnish-misc mailing list
>> varnish-misc at varnish-cache.org
>> https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
>>
>
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