Multiple Set-Cookie Headers: same-name headers

errodr

April 27, 2018 21:09

My origin is returning a response with multiple Set-Cookie headers:

set-cookie: cookie_one=value1; expires=Sat, 27-Apr-2019 20:34:33 GMT; Max-Age=31536000; path=/; domain=.mydomain.com
set-cookie: cookie_two=value2; expires=Sat, 27-Apr-2019 20:34:33 GMT; Max-Age=31536000; path=/; domain=.mydomain.com

I have tried several methods for getting the ENTIRE header (value, expires, Max-Age, etc):

I am able to get the VALUES of both set-cookie headers by using: setcookie.get_value_by_name(beresp, “<cookie_name>”). I have been unable to get the entire header for the second Set-Cookie header and I’ve tried regular expressions and beresp.http.Set-Cookie:<cookie_name> (https://docs.fastly.com/guides/vcl/isolating-header-values-without-regular-expressions).

Does Fastly not support manipulation of the second same-name header? I can see from this post: Having multiple Set-Cookie that as of 03/2015 it was not supported via the interface but is there a way to do this in VCL?

Thanks

Comments

3 comments

Hiro

February 08, 2019 03:06

Edited
Understood - one approach you could take is to collect all cookies, store it as a variable, and add it to the response header after separating it. This can be handled in the vcl_deliver.

Declare a custom variable in VCL.
```
declare local var.cookies STRING;
```
Read and collect all cookies separated by the pipe

(Assuming the cookie doesn't contain the pipe, and the origin returns two Set-Cookie headers).
```
std.collect(resp.http.Set-Cookie, "|");
```
Store it as a variable and unset the original one.
```
set var.cookies = resp.http.Set-Cookie;
unset resp.http.Set-Cookie;
```
Regex logic to grab the cookie separated by the pipe.

Add cookie everything before the pipe, and after the pipe.
```
if (var.cookies ~ "([^|]*)") { 
  add resp.http.Set-Cookie = re.group.1;

  #You can access/store the specific value from the First cookie by calling resp.http.Set-Cookie:<cookie-name> here
} 

if (var.cookies ~ "\| ([^|]*)") { 
  add resp.http.Set-Cookie = re.group.1;

  #You can access/store the specific value from the Second cookie by calling resp.http.Set-Cookie:<cookie-name> here
}

unset resp.http.Set-Cookie;

#Then you can build a new Set-Cookie header if necessary 
```
This will add two separate cookies that include the whole information to the response header. You can see the sample test here:

https://fiddle.fastlydemo.net/fiddle/690a8047 (click run) Hope this will help to work around.
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Hiro

April 28, 2018 00:10
Hi Eric,

Thanks for reaching out. Unfortunately, beresp.http.Set-Cookie will read/write the value of the first Set-Cookie header sent by your origin at this moment.

If you are looking to log multiple Set-Cookie headers, there is no way to architect a logging statement for subsequent Set-Cookies other than logging the value of the first one.

However, if you are looking to deliver the response with multiple Set-Cookie headers to the client, you can achieve it at the Fastly edge. You'll need to enable custom VCL and add the following line in the vcl_deliver subroutine:

add resp.http.Set-Cookie = <your_secod_cookie_value>;

Best, Hiro
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errodr

April 28, 2018 00:43
Yes, thank you. I have already done that but I need to get the extra information out of the second set-cookie header. I not only need the value but also the expires, domain, max-age, path and any other information from the set-cookie header.

Is there any way to do this?
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