Hi Maxim,
Thanks for your response. Youre right! Using the map did work (I thought
Id tried that, but must have been tired!).
So, now I have one other challenge, the value of $foo that you define
below is needed to identify whether to cache the response of not. The
only issue is that I have a number of other directives that I also need
to add into the mix - therefore I use the set_by_lua code to
nest/combine OR within an if statementcode below (Ive kept the variable
name as foo, so its clear which Im referring to):
map $upstream_http_x_no_cache $foo {
“” 0;
default 1;
}
set_by_lua $bypass_cache ’
local no_cache_dirs = tonumber(ngx.var.no_cache_dirs) or 0
local logged_in = tonumber(ngx.var.logged_in) or 0
local no_cache_header = tonumber(ngx.var.foo) or 0
if((no_cache_dirs == 1) or (no_cache_header == 1) or (logged_in == 1))
then
return 1;
end
return 0;
';
Now when I make the Lua local variable declaration in order to use it,
the value of $upstream_http_x_no_cache is reset to 0, even when it was
set as 1 originally. If I comment out the line declaring the local
variable within the Lua call, it returns to being a value of 1 again.
Am I getting the sequencing of events wrong again? Is there any way that
I can get the value of $upstream_http_x_no_cache into this Lua block, or
would I need to do it another way?
Thanks very much for your help so far Maxim.
Paul
Hello!
On Thu, Dec 12, 2013 at 07:19:56PM +0000, Paul T. wrote:
header, it disappears.
For example, if I was to perform a map on the custom header, try
to set an Nginx variable to the value of the header, or test
within an IF statement, any future call to this header is no
longer possible. Additionally any setting or testing of the
header fails.
Both “set” and “if” directives you mentioned are executed before
a request is sent to upstream, and at this point there is no
X-No-Cache header in the response. Due to this, using the
$sent_http_x_no_cache variable in “set” or “if” will result in an
empty value, and this value will be cached for later use.
It’s not clear what you are trying to do so I can’t advise any
further, but certainly using the $sent_http_x_no_cache variable in
“if” or “set” directives isn’t going to work, and this is what
causes behaviour you see.
Just a map{} should work fine though - as long as you don’t try to
call the map before the X-No-Cache header is actually available.
E.g., something like this should work fine:
map $sent_http_x_no_cache $foo {
"" empty;
default foo;
}
add_header X-Foo $foo;
It might be also a goo idea to use $upstream_http_x_no_cache
variable instead, see here:
http://nginx.org/en/docs/http/ngx_http_upstream_module.html#variables
