[PATH] Variable: setting $args should invalidate unparsed uri.

[Yichun Zhang (agentzh)]

Hello!

A user of mine, rvsw, reported an issue in the $args builtin variable.
Setting $args does not change the r->valid_unparsed_uri flag so
modules like ngx_proxy might still use the unparsed URI even when the
$args has been assigned to a new value.

A minimal example that can reproduce this is as follows:

    server {
        listen 54123;

        location = /t {
            return 200 "args: $args";
        }
    }

    server {
        listen 8080;

        location = /t {
            set $args "foo=1&bar=2";
            proxy_pass http://127.0.0.1:54123;
        }
    }

Querying localhost:8080/t should give

    args: foo=1&bar=2

But we're getting

    args:

with the current nginx core.

The patch attached to this email fixes this issue.

Thanks!
-agentzh

# HG changeset patch
# User Yichun Zhang <agentzh at gmail.com>
# Date 1390506359 28800
# Node ID 17186b98c235c07e94c64e5853689f790f173756
# Parent  4b50d1f299d8a69f3e3f7975132e1490352642fe
Variable: setting $args should invalidate unparsed uri.

diff -r 4b50d1f299d8 -r 17186b98c235 src/http/ngx_http_variables.c
--- a/src/http/ngx_http_variables.c Fri Jan 10 11:22:14 2014 -0800
+++ b/src/http/ngx_http_variables.c Thu Jan 23 11:45:59 2014 -0800
@@ -15,6 +15,8 @@
     ngx_http_variable_value_t *v, uintptr_t data);
 static void ngx_http_variable_request_set(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
+static void ngx_http_variable_request_args_set(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data);
 static ngx_int_t ngx_http_variable_request_get_size(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data);
 static void ngx_http_variable_request_set_size(ngx_http_request_t *r,
@@ -218,7 +220,7 @@
       NGX_HTTP_VAR_NOCACHEABLE, 0 },

     { ngx_string("args"),
-      ngx_http_variable_request_set,
+      ngx_http_variable_request_args_set,
       ngx_http_variable_request,
       offsetof(ngx_http_request_t, args),
       NGX_HTTP_VAR_CHANGEABLE|NGX_HTTP_VAR_NOCACHEABLE, 0 },
@@ -647,6 +649,15 @@


 static void
+ngx_http_variable_request_args_set(ngx_http_request_t *r,
+    ngx_http_variable_value_t *v, uintptr_t data)
+{
+    r->valid_unparsed_uri = 0;
+    ngx_http_variable_request_set(r, v, data);
+}
+
+
+static void
 ngx_http_variable_request_set(ngx_http_request_t *r,
     ngx_http_variable_value_t *v, uintptr_t data)
 {
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