Module vars set inside if's are not set

[Mark Maunder]

Awesome, thanks for the fix and insight! If a module writer's wiki 
exists this should be added.

agentzh wrote:
> On Tue, Nov 24, 2009 at 12:38 PM, Mark Maunder <mark at feedjit.com> wrote:
>> The variable is set fine outside an 'if' statement but when the if evaluates
>> to true, the variable is not set.
>>
> 
> Behind the scene, the if directive's "block" is implemented as a
> dynamic location (of type LIF, not LOC). It's very different from the
> if statements' blocks one usually finds in an everyday programming
> language :)
> 
>> I have duplicated this behaviour with the echo module as follows:
>> This will print "No":
>> location ^~ /echo/ {
>>        set $myText "No";
>>        if ($remote_addr ~* '000'){
>>                set $myText "Yes";
>>        }
>>        echo $myText;
>> }
>>
> 
> Tests have shown that if the "if" condition succeeds here, nginx will
> return a 404 error page because of the lack of content handler in that
> anonymous location corresponding to the "if" block :)
> 
> I've just released "echo" module v0.22 to allow you to use "echo"
> directly in "if" blocks and the following should work as expected:
> 
>     location ^~ /if {
>         set $res miss;
>         if ($arg_val ~* '^a') {
>             set $res hit;
>             echo $res;
>         }
>         echo $res;
>     }
> 
> GET /if?val=abc yields the "hit" output while GET /if?val=bcd yields "miss" :)
> 
> It seems that the standard proxy_pass directive also works in if blocks (yay!):
> 
>     location ^~ /if {
>         set $res miss;
>         if ($arg_val ~* '^a') {
>             set $res hit;
>             proxy_pass $scheme://127.0.0.1:$server_port/foo?res=$res;
>         }
>         proxy_pass $scheme://127.0.0.1:$server_port/foo?res=$res;
>     }
>     location /foo {
>         echo "res = $arg_res";
>     }
> 
> You will get the expected behavior :)
> 
> Feel free to take a look at more related (passing) test cases that
> I've included in the "echo" module's test suite:
> 
>   http://github.com/agentzh/echo-nginx-module/blob/master/test/t/if.t
> 
> Have fun with "if" and "echo"!
> 
> Regards,
> -agentzh
> 
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