# Nginx parse var in if file exist statement error? **URL:** \ **Category:** NGINX\ **Created:** [November 2, 2011, 11:10am UTC](https://www.ruby-forum.com/t/nginx-parse-var-in-if-file-exist-statement-error/213444 "2011-11-02T11:10:33Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![luislavena](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/0ea827/32.png) [@luislavena](https://www.ruby-forum.com/u/luislavena)\ **Post date:** [November 2, 2011, 11:10am UTC](https://www.ruby-forum.com/t/nginx-parse-var-in-if-file-exist-statement-error/213444/1 "2011-11-02T11:10:33Z")
Hi guys, I found a stange bug in nginx 0.7.65, 0.8.54, and 1.0.6 Here is my setup of three machines $ nginx -V nginx version: nginx/0.7.65 TLS SNI support enabled configure arguments: --conf-path=/etc/nginx/nginx.conf –error-log-path=/var/log/nginx/error.log --pid-path=/var/run/nginx.pid –lock-path=/var/lock/nginx.lock –http-log-path=/var/log/nginx/access.log –http-client-body-temp-path=/var/lib/nginx/body –http-proxy-temp-path=/var/lib/nginx/proxy –http-fastcgi-temp-path=/var/lib/nginx/fastcgi --with-debug –with-http\_stub\_status\_module --with-http\_flv\_module –with-http\_ssl\_module --with-http\_dav\_module –with-http\_gzip\_static\_module --with-http\_realip\_module --with-mail –with-mail\_ssl\_module --with-ipv6 –add-module=/build/buildd/nginx-0.7.65/modules/nginx-upstream-fair $nginx -V nginx version: nginx/0.8.54 built by gcc 4.2.4 (Ubuntu 4.2.4-1ubuntu4) configure arguments: --user=www-data --group=www-data –prefix=/usr/local/nginx --with-http\_stub\_status\_module $ nginx -V nginx: nginx version: nginx/1.0.6 nginx: TLS SNI support enabled nginx: configure arguments: --prefix=/etc/nginx/ –sbin-path=/usr/sbin/nginx --conf-path=/etc/nginx/nginx.conf –error-log-path=/var/log/nginx/error.log –http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid –lock-path=/var/run/nginx.lock –http-client-body-temp-path=/var/cache/nginx/client\_temp –http-proxy-temp-path=/var/cache/nginx/proxy\_temp –http-fastcgi-temp-path=/var/cache/nginx/fastcgi\_temp –http-uwsgi-temp-path=/var/cache/nginx/uwcgi\_temp –http-scgi-temp-path=/var/cache/nginx/scgi\_temp --user=nginx –group=nginx --with-http\_ssl\_module --with-http\_realip\_module –with-http\_addition\_module --with-http\_sub\_module –with-http\_dav\_module --with-http\_flv\_module –with-http\_gzip\_static\_module --with-http\_random\_index\_module –with-http\_secure\_link\_module --with-http\_stub\_status\_module –with-mail --with-mail\_ssl\_module --with-file-aio --with-ipv6 So I have dir to store images, either jpg or png, the file name (image id) is unique. I want the URL to provide image id only, nginx to serve static jpg or png. the config snippet is something like this: server { listen 80; error\_log /var/log/nginx/error\_imglib.log debug; root /home/develop/image\_library; location ~\* ^/img/small/(\d+)/?$ { set $fext ‘jpg’; if (!-f ‘/home/develop/image\_library/dump/$1-s.jpg’){ set $fext png; } alias ‘/home/develop/image\_library/dump/$1-s.$fext’ ; } } When running curl it returls something like this $ curl “[http://127.0.0.1/img/small/1](http://127.0.0.1/img/small/1)” 404 Not Found # 404 Not Found * * * nginx/1.0.6 Now the bug: in three of my machines I set the error\_log level to “debug”, here is the output: 2011/11/02 14:01:09 [debug] 4194#0: \*24 http script capture: “1” 2011/11/02 14:01:09 [debug] 4194#0: \*24 http script copy: “-s.” 2011/11/02 14:01:09 [debug] 4194#0: \*24 http script var: “png” 2011/11/02 14:01:09 [debug] 4194#0: \*24 http filename: “/home/steve/image\_library/dump/1-s.png1 User-Agent” 2011/11/02 14:01:09 [debug] 4194#0: \*24 add cleanup: 0833B2F0 2011/11/02 14:01:09 [error] 4194#0: \*24 open() “/home/steve/image\_library/dump/1” failed (2: No such file or directory), client: 127.0.0.1, request: “GET /img/small/1 HTTP/1.1” 2011/11/01 23:00:53 [alert] 7793#0: \*38 “/home/develop/image\_library/dump/1-s.jpgindex.html” is not a directory, request: “GET /img/small/1 HTTP/1.1” 2011/11/02 02:30:18 [error] 7666#0: \*2491 open() “/home/develop/image\_library/dump/1-s.pn” failed (2: No such file or directory), client: 127.0.0.1, request: “GET /img/small/1 HTTP/1.1” 2011/11/01 22:47:45 [error] 6740#0: \*24 “/home/develop/image\_library/dump/1-s.jpgTP/1.1 Hostindex.html” is not found (2: No such file or directory), request: “GET /img/small/1 HTTP/1.1” So clearly somehow, nginx managed to mess HTTP headers into filename parser. Can anyone help me? This is the weirdest bug I have ever encountered with nginx. Posted at Nginx Forum: > **[nginx parse var in if file exist statement error?](https://forum.nginx.org/read.php?2,217683,217683#msg-217683)** > > Hi guys, I found a stange bug in nginx 0.7.65, 0.8.54, and 1.0.6 Here is my setup of three machines $ nginx -V nginx version: nginx/0.7.65 TLS SNI support enabled configure arguments: --conf-path=/etc/nginx/nginx.conf --error- ---
**Author:** ![est](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/74df32/32.png) [@est](https://www.ruby-forum.com/u/est)\ **Post date:** [November 2, 2011, 2:35pm UTC](https://www.ruby-forum.com/t/nginx-parse-var-in-if-file-exist-statement-error/213444/2 "2011-11-02T14:35:23Z")
On Wednesday 02 November 2011 14:09:59 est wrote: […] > root /home/develop/image\_library; > > location ~\* ^/img/small/(\d+)/?$ { > set $fext ‘jpg’; > if (!-f ‘/home/develop/image\_library/dump/$1-s.jpg’){ > set $fext png; > } > alias ‘/home/develop/image\_library/dump/$1-s.$fext’ ; > } > } […] server { listen 80; error\_log /var/log/nginx/error\_imglib.log debug; root /home/develop/image\_library; location ~\* ^/img/small/(\d+)/?$ { try\_files /dump/$1-s.jpg /dump/$1-s.png =404 } } wbr, Valentin V. Bartenev ---
**Author:** ![est](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/74df32/32.png) [@est](https://www.ruby-forum.com/u/est)\ **Post date:** [November 3, 2011, 2:24am UTC](https://www.ruby-forum.com/t/nginx-parse-var-in-if-file-exist-statement-error/213444/3 "2011-11-03T02:24:58Z")
Oh thanks very much guys. try\_files worked well. I tried using try\_files before, but mistakenly wrote it as something like this try\_files dump/$1-s.jpg dump/$1-s.png 404; The correct working line should be like this try\_files /dump/$1-s.jpg /dump/$1-s.png =404; And I didn’t expect IF is evil. Suprise! Thanks again. Posted at Nginx Forum: > **[Re: nginx parse var in if file exist statement error?](https://forum.nginx.org/read.php?2,217683,217730#msg-217730)** > > Hi guys, I found a stange bug in nginx 0.7.65, 0.8.54, and 1.0.6 Here is my setup of three machines $ nginx -V nginx version: nginx/0.7.65 TLS SNI support enabled configure arguments: --conf-path=/etc/nginx/nginx.conf --error- ---
**Author:** ![est](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/74df32/32.png) [@est](https://www.ruby-forum.com/u/est)\ **Post date:** [November 2, 2011, 2:51pm UTC](https://www.ruby-forum.com/t/nginx-parse-var-in-if-file-exist-statement-error/213444/4 "2011-11-02T14:51:31Z")
Hello! On Wed, Nov 02, 2011 at 06:09:59AM -0400, est wrote: […] > So clearly somehow, nginx managed to mess HTTP headers into filename > parser. > > Can anyone help me? This is the weirdest bug I have ever encountered > with nginx. Valentin already replied how to do this properly. As for the bug itself, it’s documented here: > **[GitHub - nginxinc/nginx-wiki: ARCHIVED -- Source for the now archived NGINX Wiki...](https://github.com/nginxinc/nginx-wiki)** > > ARCHIVED -- Source for the now archived NGINX Wiki section of https://www.nginx.com Maxim D.