Unable to change $args in accordance with agentzh tutorial at http://openresty.org/download/agentzh-nginx-tutorials-en.html

rvsw

Hello

I am attempting to do the following:

Client sends a GET /?abc=string

nginx is acting as a proxy and changes the request to GET /?abc=new_string.

The server should thus see the request as GET /?abc=new_string

This should be possible in accordance with the tutorial at http://openresty.org/download/agentzh-nginx-tutorials-en.html (Section : Nginx Variables (03)).

Specifically the server at 8081 should see different args

server {
    listen 8080;

    location /test {
        set $args "foo=1&bar=2";
        proxy_pass http://127.0.0.1:8081/args;
    }
}

server {
    listen 8081;

    location /args {
        echo "args: $args";
    }
}

However, in my case I see that server is still getting the same arguments even though $args is changed. The logs clearly indicate that the original args are sent. After sending the original args, the logs indicate that nginx now attempts to send an upstream request with the new args. The upstream request is not served and an error is indicated.

Here are the (edited)logs: (See the Resource temporarily unavailable when nginx tries to send an upstream request). Is there any other ocnfiguration that I need to achieve what is there in the example

[debug] 35149#0: *1 post rewrite phase: 5

[debug] 35149#0: *1 generic phase: 6

[debug] 35149#0: *1 generic phase: 7

[debug] 35149#0: *1 generic phase: 8

[debug] 35149#0: *1 generic phase: 9

[debug] 35149#0: *1 generic phase: 10

[debug] 35149#0: *1 access phase: 11

[debug] 35149#0: *1 access phase: 12

[debug] 35149#0: *1 access phase: 13

[debug] 35149#0: *1 access phase: 14

[debug] 35149#0: *1 post access phase: 15

[debug] 35149#0: *1 pagespeed phase: 16

[debug] 35149#0: *1 http init upstream, client timer: 0

[debug] 35149#0: *1 epoll add event: fd:3 op:3 ev:80000005

[debug] 35149#0: *1 http script copy: "Host: "

[debug] 35149#0: *1 http script var: "127.0.0.1:8080"

[debug] 35149#0: *1 http script copy: "

[debug] 35149#0: *1 http script copy: "Connection: close

[debug] 35149#0: *1 http script copy: ""

[debug] 35149#0: *1 http proxy header: "User-Agent: Wget/1.13.4 (linux-gnu)"

[debug] 35149#0: *1 http proxy header: "Accept: */*"

[debug] 35149#0: *1 http proxy header:

"GET /?abc=string HTTP/1.0

Host: 127.0.0.1:8080

Connection: close

User-Agent: Wget/1.13.4 (linux-gnu)

Accept: */*

[debug] 35149#0: *1 http cleanup add: 00000000021D86A0

[debug] 35149#0: *1 get rr peer, try: 1

[debug] 35149#0: *1 socket 13

[debug] 35149#0: *1 epoll add connection: fd:13 ev:80000005

[debug] 35149#0: *1 connect to 127.0.0.1:8080, fd:13 #2

[debug] 35149#0: *1 http upstream connect: -2

[debug] 35149#0: *1 posix_memalign: 00000000021CD0F0:128 @16

[debug] 35149#0: *1 event timer add: 13: 60000:1390503445096

[debug] 35149#0: *1 http finalize request: -4, "/?abc=newstring" a:1, c:2

[debug] 35149#0: *1 http request count:2 blk:0

[debug] 35149#0: *1 http run request: "/?abc=newstring"

[debug] 35149#0: *1 http upstream check client, write event:1, "/"

[debug] 35149#0: *1 http upstream recv(): -1 (11: Resource temporarily unavailable)

[debug] 35149#0: *1 http upstream request: "/?abc=newstring"

[debug] 35149#0: *1 http upstream send request handler

[debug] 35149#0: *1 http upstream send request

agentzh

Hello!

On Thu, Jan 23, 2014 at 11:16 AM, rvsw wrote:
> Hello
> I am attempting to do the following:
> Client sends a GET /?abc=string
> nginx is acting as a proxy and changes the request to GET /?abc=new_string.
> The server should thus see the request as GET /?abc=new_string
> This should be possible in accordance with the tutorial at
> http://openresty.org/download/agentzh-nginx-tutorials-en.html

Yeah, this is a bug in the (standard) nginx core. I've submitted a
patch to the nginx-devel mailing list to fix this issue:

    http://mailman.nginx.org/pipermail/nginx-devel/2014-January/004884.html

This patch will get included in the next release of ngx_openresty
regardless the inclusion of this patch in the nginx mainstream.

Thank you for the report!

Best regards,
-agentzh

rvsw

Thanks agentzh. I tested the patch posted on the nginx mailing list and it works well. Pretty awesome. Saved me several hours of work. Thanks a lot

On Friday, January 24, 2014 1:49:53 AM UTC+5:30, agentzh wrote:

Hello!

On Thu, Jan 23, 2014 at 11:16 AM, rvsw wrote:
> Hello
> I am attempting to do the following:
> Client sends a GET /?abc=string
> nginx is acting as a proxy and changes the request to GET /?abc=new_string.
> The server should thus see the request as GET /?abc=new_string
> This should be possible in accordance with the tutorial at
> http://openresty.org/download/agentzh-nginx-tutorials-en.html

Yeah, this is a bug in the (standard) nginx core. I've submitted a
patch to the nginx-devel mailing list to fix this issue:

http://mailman.nginx.org/pipermail/nginx-devel/2014-January/004884.html

This patch will get included in the next release of ngx_openresty
regardless the inclusion of this patch in the nginx mainstream.

Thank you for the report!

Best regards,
-agentzh