# Skipping the proxy cache based on a cookie?

**URL:** <https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066>\
**Category:** NGINX\
**Created:** [December 29, 2010, 3:16pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066 "2010-12-29T15:16:54Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**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:** [December 29, 2010, 3:16pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/1 "2010-12-29T15:16:54Z")

</div>

Hi everyone,  
I’m looking into setting up nginx as a proxy cache. I was wondering if  
someone can elaborate a bit about ways to bypass the cache  
in certain requests. For example, I’d like every new user to go to the  
backend server once in order for some cookies to be written.  
On further requests I’d like to serve the user with a cached copy of the  
site.  
How can I set a mechanism that bypasses the cache if a cookie with a  
certain name does/does not exist?

Thanks!

Posted at Nginx Forum:

> **[Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,161969#msg-161969)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [December 30, 2010, 2:28pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/2 "2010-12-30T14:28:49Z")

</div>

I’ve dug a bit deeper into the documentation and it seems like  
proxy\_no\_cache and proxy\_cache\_bypass should somehow do the trick, but I  
can get things to work with my exact scenario.  
Here’s the flow I’d like to create:

1. when a new user reaches the site, it is forwarded to the backend and  
receives a few cookies back.  
A “new user” is identified by a lack of a certain cookie, which  
is something I couldn’t figure out how to implement (seems like it only  
supports bypassing/no caching if a cookie exists, but not if it  
doesn’t).

This request should not be taken from the cache, but the response can be  
stored in cache as long as further requests will not be sent the cookies  
this request produced.

1. Returning visitors can be served from the cache, unless they are  
logged in (in which case they should be sent to the backend and the  
response should not be stored). This is simple enough to do with the  
regular bypass/no\_cache combination based on a cookie that is created  
when a user logs in.

* * *

It doesn’t seem like a complicated scenario, but I can’t get it to work  
just right.  
Any help would be appreciated 🙂

Posted at Nginx Forum:

> **[Re: Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,162238#msg-162238)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 2, 2011, 1:29pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/3 "2011-01-02T13:29:48Z")

</div>

Hmmm…  
Is there any chance that such functionality will ever make it into  
production?

Posted at Nginx Forum:

> **[Re: Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,162844#msg-162844)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 18, 2011, 10:35pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/4 "2011-01-18T22:35:52Z")

</div>

Just came back to this as I have hit this wall and it would be very  
useful if the roxy no cache and proxy bypass could be triggered based on  
the absence of a cookie.

I need to pass first time visitors to the backend and I need to make  
sure the content they get is not cached. As they are first time  
visitors, I can’t rely on the presence of a cookie to tell this and the  
only way I can think off is to check for the absence of a cookie.

Any chance of implementing …

```auto
proxy_cache_bypass_empty $cookie_COOKIE;
proxy_no_cache_empty $cookie_COOKIE;
```

… which would do the same as the standard modes except that they would  
be triggered if the cookie or header is absent or empty.

Thanks

Posted at Nginx Forum:

> **[Re: Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,167367#msg-167367)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 18, 2011, 10:58pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/5 "2011-01-18T22:58:29Z")

</div>

On 18 Jan 2011 21h34 WET, [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Any chance of implementing …
> 
> ```auto
> proxy_cache_bypass_empty $cookie_COOKIE;
> proxy_no_cache_empty $cookie_COOKIE;
> ```

If I understand your question, wouldn’t this do the trick?

if ($cookie\_COOKIE = “”) {  
set $cookie\_no\_cache true;  
}

Now it works as “usual”.  
— appa

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 18, 2011, 11:19pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/6 "2011-01-18T23:19:51Z")

</div>

Hmmm. That might work. I’ll give it a shot.

Posted at Nginx Forum:

> **[Re: Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,167382#msg-167382)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 7:46pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/7 "2011-01-19T19:46:20Z")

</div>

Hi all

I doesn’t seem that “if ($cookie\_COOKIE = “”) {” is a valid test for the  
presence of a cookie as the code in the if statement does not seem to be  
run.

I am using …

```auto
if ($cookie_COOKIE = "") {
add_header Set-Cookie: "hits = 1";
}
```

… but no joy. (I tried the original suggestion first)

Open to further suggestions

Thanks

Posted at Nginx Forum:

> **[Re: Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,167639#msg-167639)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 7:46pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/8 "2011-01-19T19:46:57Z")

</div>

ps I did change “$cookie\_COOKIE” to match my cookie name.

Thanks

Posted at Nginx Forum:

> **[Re: Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,167640#msg-167640)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 8:07pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/9 "2011-01-19T20:07:42Z")

</div>

## Dayo Wrote:

> if ($cookie\_COOKIE = “”) {  
> add\_header Set-Cookie: “hits = 1”;  
> }
> 
> … but no joy. (I tried the original suggestion  
> first)
> 
> Open to further suggestions
> 
> Thanks

OK managed to find out that it should be along the lines of …

```auto
if ($http_cookie ~* 'COOKIE = ""') {
```

… but will not appreciate some advice on why my add header is not  
working

Thanks

Posted at Nginx Forum:  
[http://forum.nginx.org/read.php?2,161969,167646#msg-167646](http://forum.nginx.org/read.php?2,161969,167646#msg-167646)

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 8:08pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/10 "2011-01-19T20:08:19Z")

</div>

Dayo Wrote:

> … but will not appreciate some advice on why my  
> add header is not working  
> “Will now …” that is!

Posted at Nginx Forum:  
[http://forum.nginx.org/read.php?2,161969,167647#msg-167647](http://forum.nginx.org/read.php?2,161969,167647#msg-167647)

---

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**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 8:59pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/11 "2011-01-19T20:59:51Z")

</div>

I think I am getting closer and hope someone can nudge me across the  
line.

My set up is now …

```auto
if ($http_cookie !~* "mycookie=0") {
  add_header Cookie: "mycookie=1";
}
```

The idea being that if mycookie is not 0 (which should cover it not  
being set), it is set to 1. I then added cookie\_MYCOOKIE to the bypass  
and no cache parameters so that if it is set to 1, they are triggered.

The backend sets mycookie to 0 if it is 1 so that on subsequent  
requests, the resource is served from the cache.

However unfortunately, the “add\_header Cookie: “mycookie=1”;” line does  
not seem to be called at all.

Thanks

Posted at Nginx Forum:

> **[Re: Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,167669#msg-167669)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 9:16pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/12 "2011-01-19T21:16:48Z")

</div>

On 19 Jan 2011 19h58 WET, [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> I think I am getting closer and hope someone can nudge me across the  
> line.
> 
> My set up is now …
> 
> ```auto
> if ($http_cookie !~* "mycookie=0") {
> add_header Cookie: "mycookie=1";
> }
> ```

IIRC you _want_ to bust the proxy cache. Right? So,

> **[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

If you want a header do as describe, this if you don’t want to cache  
the response. If not use a cache busting variable, to force a refresh.

— appa

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 9:44pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/13 "2011-01-19T21:44:26Z")

</div>

## António P. P. Almeida Wrote:

> > if ($http\_cookie !~\* “mycookie=0”) {  
> > don’t want to cache  
> > the response. If not use a cache busting variable,  
> > to force a refresh.
> 
> — appa
> 
> * * *
> 
> nginx mailing list  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [mailman.nginx.org archive](http://nginx.org/mailman/listinfo/nginx)

Hi

Thanks for the stopping by.

i am already using proxy\_cache\_bypass and proxy\_no\_cache.

What I am trying to do is as follows

1. User requests page and Nginx checks for cookie and if not present,  
sets cookie value to 1. Default cookie value is 0.
2. Cookie is evaluated against proxy\_cache\_bypass and proxy\_no\_cache so  
that if value is 1, user gets passed to backend and response is not  
cached
3. Backend checks for cookie and if value is 1, sets value to 0 and  
serves specific additional content
4. User requests another page and this time cookie is present with 0  
value so Step 1 is skipped
5. Cookie is evaluated against proxy\_cache\_bypass and proxy\_no\_cache and  
since value is 0, user gets served from cache or if cache is stale, from  
backend
6. If user is passed to backend, backend checks for cookie and since  
value is 0, serves normal content

I have Steps 2 onwards basically setup but Step 1 is where it is falling  
down. I can’t get Nginx to set that cookie.

Thanks again

Posted at Nginx Forum:  
[http://forum.nginx.org/read.php?2,161969,167684#msg-167684](http://forum.nginx.org/read.php?2,161969,167684#msg-167684)

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 10:08pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/14 "2011-01-19T22:08:57Z")

</div>

On 19 Jan 2011 20h43 WET, removed\_email\_address@domain.invalid wrote:

add\_header Cookie “mycookie=1”;

should do the trick.

Don’t use the colon when specifying the header name.

— appa

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 10:24pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/15 "2011-01-19T22:24:05Z")

</div>

I have actually already tried that with no success.

Taking a look at the 3rd party headers more module to see if it will  
help.

Posted at Nginx Forum:

> **[Re: Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,167699#msg-167699)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 10:28pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/16 "2011-01-19T22:28:29Z")

</div>

Hi,

On 19/01/2011 23:22, Dayo wrote:

> I have actually already tried that with no success.  
> Do you have multiple if blocks and have you read the if-is-evil stuff?

> **[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

It sounds like a different block is being processed.

Marcus.

---

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**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 10:34pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/17 "2011-01-19T22:34:09Z")

</div>

On 19 Jan 2011 21h22 WET, [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> I have actually already tried that with no success.
> 
> Taking a look at the 3rd party headers more module to see if it will  
> help.

There’s no need for that the Headers module does what is needed.

It works for me. So I guess that you’ve got something in your  
setup/config that breaks it.

HTTP/1.1 200 OK  
Server: nginx  
Date: Wed, 19 Jan 2011 21:27:05 GMT  
Content-Type: application/octet-stream  
Content-Length: 0  
Connection: keep-alive  
Keep-Alive: timeout=10  
Cookie: mycookie=1

— appa

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 11:21pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/18 "2011-01-19T23:21:13Z")

</div>

I throw my hands up in surrender as I just can’t get it to return the  
cookie.

I have tried a plain vanilla build with no joy.

v0.8.54

The relevant location code is …

```auto
  location /folder/ {
    if ($http_cookie !~* "COOKIEX=0") {
      add_header Cookie "COOKIEX=1; domain=domain.com; path=/folder/";
    }

    # BEGIN Url Rewrites
                   ...
    # END Url Rewrites

    try_files $uri $uri/ @proxy;
  }
```

Posted at Nginx Forum:

> **[Re: Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,167714#msg-167714)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 19, 2011, 10:51pm UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/19 "2011-01-19T22:51:07Z")

</div>

Probably … headers more isn’t working as well.

Maybe a third party module is breaking it…

Posted at Nginx Forum:

> **[Re: Skipping the proxy cache based on a cookie?](https://forum.nginx.org/read.php?2,161969,167709#msg-167709)**
>
> Hi everyone, I'm looking into setting up nginx as a proxy cache. I was wondering if someone can elaborate a bit about ways to bypass the cache in certain requests. For example, I'd like every new user to go to the backend server once in order for...

---

<div class="post-metadata">

**Author:** ![ehudros2](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/76d3ee/32.png) [@ehudros2](https://www.ruby-forum.com/u/ehudros2)\
**Post date:** [January 20, 2011, 2:26am UTC](https://www.ruby-forum.com/t/skipping-the-proxy-cache-based-on-a-cookie/201066/20 "2011-01-20T02:26:57Z")

</div>

On 19 Jan 2011 22h19 WET, [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> I throw my hands up in surrender as I just can’t get it to return  
> the cookie.
> 
> I have tried a plain vanilla build with no joy.
> 
> v0.8.54
> 
> The relevant location code is …

Like Marcus said before. You’re likely to have some implicit location  
(if) that it isn’t working.

> location /folder/ {  
> if ($http\_cookie !~\* “COOKIEX=0”) {  
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
> have you checked using the debug flag in the error log  
> that this if (implicit location) is entered?

Read this explanation by Maxim in another thread:  
[http://forum.nginx.org/read.php?2,156552,156552](http://forum.nginx.org/read.php?2,156552,156552)

> ```
> add_header Cookie "COOKIEX=1;
> domain=domain.com; path=/folder/";
> }
> 
> # BEGIN Url Rewrites
> 
> ```
> 
> …  
> # END Url Rewrites
> 
> ```
> try_files $uri $uri/ @proxy;
> 
> ```
> 
> }

— appa

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