| [resending as the original reply bounced]
At Feb 19, 2015, 1:07:14 AM, Sudheer Vinukonda wrote:Yeah, there's really no
hook named "READ_REQUEST_HOOK", so, it probably becomes a no-op (adding the
correct hook name READ_REQUEST_HDR_HOOK will cause it not to work, since the
read request state is not available on a remap mode). To avoid confusion, I
would simply remove that line.
As for the logic, yes you are absolutely correct. The rules basically are two
fold. One to check for the necessary Query param and add a header in the client
request and the second check for that specific client request header to add the
required header in the outgoing client response. One little neat thing to note
here is that the header added to the client request is an @ header, which means
it never goes out to the origin. It is only added internally within ATS
(Without the @ prefix the header QueryPresent in the client request will
actually go out to the origin as well, which is unnecessary).
Thanks,
Sudheer
At Feb 19, 2015, 12:42:44 AM, Ezequiel Foncubierta wrote:Hi,
It works even with the READ_REQUEST_HOOK! Kudos to you sir. Just to understand
what is going on as there is not much documentation about this.
1. We are adding a header in the client request header if the query parameter
is present.
cond %{QUERY} /(^|&)a=true(&|$)/
add-header @QueryPresent TRUE [L]
2. Check wether the flag (@QueryPresent) exists in the client request header.
cond %{SEND_RESPONSE_HDR_HOOK} [AND]cond %{CLIENT-HEADER:@QueryPresent}
=TRUEadd-header TestHeader 1234 [L]
is that correct?
Thank you so much!
Best regards.
On 18 Feb 2015, at 20:17, Sudheer Vinukonda [email protected]> wrote:
Sorry, the hook name READ_REQUEST_HOOK is incorrect - the below config is
sufficient (as this is being added on a remap hook anyway).
% cat rules.config
cond %{QUERY} /(^|&)a=true(&|$)/
add-header @QueryPresent TRUE [L]cond %{SEND_RESPONSE_HDR_HOOK} [AND]cond
%{CLIENT-HEADER:@QueryPresent} =TRUEadd-header TestHeader 1234 [L]
%cat remap.configmap http://cache.server:8080 http://web.server:8080
@plugin=header_rewrite.so @pparam=rules.config From: Sudheer Vinukonda
[email protected]>
To: "[email protected]" [email protected]>
Sent: Wednesday, February 18, 2015 10:50 AM
Subject: Re: Header rewrite rule based on query string
The below config seems to do what you need:
% cat rules.config cond %{READ_REQUEST_HOOK} [AND]cond %{QUERY}
/(^|&)a=true(&|$)/add-header @QueryPresent TRUE [L]cond
%{SEND_RESPONSE_HDR_HOOK} [AND]cond %{CLIENT-HEADER:@QueryPresent}
=TRUEadd-header TestHeader 1234 [L]
%cat remap.configmap http://cache.server:8080 http://web.server:8080
@plugin=header_rewrite.so @pparam=rules.config
Thanks,
Sudheer
From: Ezequiel Foncubierta [email protected]>
To: [email protected]
Sent: Wednesday, February 18, 2015 6:35 AM
Subject: Header rewrite rule based on query string
Hi,
I am trying to rewrite the response header using the header_rewrite.so plugin.
My remap.config file:
map http://cache.server:8080 http://web.server:8080 @plugin=header_rewrite.so
@pparam=rules.conf
reverse_map http://web.server:8080 http://cache.server:8080
My rules.conf file:
cond %{SEND_RESPONSE_HDR_HOOK}
cond %{QUERY} /(^|&)a=true(&|$)/
add-header TestHeader 1234
What I am expecting with this configuration so far is that if the request URL
has a query parameter "a=true”, then the TestHeader 1234 will be added to the
response header. However, I get the following message in the debug traces.
vagrant@cache:~/trafficserver$ sudo traffic_server -T"header"
traffic_server: using root directory '/usr/local'
traffic_server: using root directory '/usr/local'
[Feb 18 14:05:04.450] Server {0x7fd4f5454740} DIAG: (header_rewrite) Remap
plugin is successfully initialized
[Feb 18 14:05:04.451] Server {0x7fd4f5454740} DIAG: (header_rewrite)
Instantiating a new remap.config plugin rule
[Feb 18 14:05:04.451] Server {0x7fd4f5454740} DIAG: (header_rewrite) Loading
remap configuration file rules.conf
[Feb 18 14:05:04.451] Server {0x7fd4f5454740} DIAG: (header_rewrite) Adding
condition: %{QUERY} with arg: /(^|&)a=true(&|$)/
[Feb 18 14:05:04.452] Server {0x7fd4f5454740} DIAG: (header_rewrite) Regex
precompiled successfully
[Feb 18 14:05:04.452] Server {0x7fd4f5454740} DIAG: (header_rewrite) Adding
operator: add-header(TestHeader)
[Feb 18 14:05:04.452] Server {0x7fd4f5454740} DIAG: (header_rewrite)
Succesfully loaded remap config file rules.conf
[Feb 18 14:05:04.453] Server {0x7fd4f5454740} DIAG: (header_rewrite) Adding
remap ruleset to hook=TS_HTTP_SEND_RESPONSE_HDR_HOOK
[Feb 18 14:05:23.841] Server {0x7fd4f1819700} DIAG: (header_rewrite) Added
remapped TXN hook=TS_HTTP_SEND_RESPONSE_HDR_HOOK
[Feb 18 14:05:23.841] Server {0x7fd4f1819700} DIAG: (header_rewrite) Building
resources, hook=(null)
[Feb 18 14:05:23.841] Server {0x7fd4f1819700} DIAG: (header_rewrite) Adding TXN
client request header buffers
[Feb 18 14:05:23.841] Server {0x7fd4f1819700} DIAG: (header_rewrite) Adding TXN
client request header buffers for remap instance
[Feb 18 14:05:23.896] Server {0x7fd4f1819700} DIAG: (header_rewrite) Building
resources, hook=TS_HTTP_SEND_RESPONSE_HDR_HOOK
[Feb 18 14:05:23.896] Server {0x7fd4f1819700} DIAG: (header_rewrite) Adding TXN
client request header buffers
[Feb 18 14:05:23.896] Server {0x7fd4f1819700} DIAG: (header_rewrite) Adding TXN
client response header buffers
[Feb 18 14:05:23.896] Server {0x7fd4f1819700} DIAG: (header_rewrite) QUERY
requires remap initialization! Evaluating to false!
If I get rid of the SEND_RESPONSE_HDR_HOOK condition in rules.conf, I get the
following traces:
vagrant@cache:~/trafficserver$ sudo traffic_server -T"header"
traffic_server: using root directory '/usr/local'
traffic_server: using root directory '/usr/local'
[Feb 18 14:09:49.061] Server {0x7f7d6d42f740} DIAG: (header_rewrite) Remap
plugin is successfully initialized
[Feb 18 14:09:49.061] Server {0x7f7d6d42f740} DIAG: (header_rewrite)
Instantiating a new remap.config plugin rule
[Feb 18 14:09:49.061] Server {0x7f7d6d42f740} DIAG: (header_rewrite) Loading
remap configuration file rules.conf
[Feb 18 14:09:49.061] Server {0x7f7d6d42f740} DIAG: (header_rewrite) Adding
condition: %{QUERY} with arg: /(^|&)a=true(&|$)/
[Feb 18 14:09:49.061] Server {0x7f7d6d42f740} DIAG: (header_rewrite) Regex
precompiled successfully
[Feb 18 14:09:49.062] Server {0x7f7d6d42f740} DIAG: (header_rewrite) Adding
operator: add-header(TestHeader)
[Feb 18 14:09:49.062] Server {0x7f7d6d42f740} DIAG: (header_rewrite)
Succesfully loaded remap config file rules.conf
[Feb 18 14:09:55.967] Server {0x7f7d697f4700} DIAG: (header_rewrite) Building
resources, hook=(null)
[Feb 18 14:09:55.968] Server {0x7f7d697f4700} DIAG: (header_rewrite) Adding TXN
client request header buffers
[Feb 18 14:09:55.968] Server {0x7f7d697f4700} DIAG: (header_rewrite) Adding TXN
client request header buffers for remap instance
[Feb 18 14:09:55.968] Server {0x7f7d697f4700} DIAG: (header_rewrite) Appending
QUERY to evaluation value: a=true
[Feb 18 14:09:55.968] Server {0x7f7d697f4700} DIAG: (header_rewrite) Evaluating
QUERY - a=true
[Feb 18 14:09:55.968] Server {0x7f7d697f4700} DIAG: (header_rewrite) Test
regular expression (^|&)a=true(&|$) : a=true
[Feb 18 14:09:55.968] Server {0x7f7d697f4700} DIAG: (header_rewrite)
Successfully found regular expression match
[Feb 18 14:09:55.968] Server {0x7f7d697f4700} DIAG: (header_rewrite)
OperatorAddHeader::exec() invoked on header TestHeader: 1234
[Feb 18 14:09:55.968] Server {0x7f7d697f4700} DIAG: (header_rewrite) Adding
header TestHeader
The regular expression is working as it is expected for the QUERY condition
but, obviously, the TestHeader is added to the HTTP request from cache.server
to web.server instead of the HTTP response from cache.server to the client. On
the other hand, the PATH condition works nicely with the SEND_RESPONSE_HDR_HOOK
condition.
I have tried many different configuration with no luck (i.e. setting the plugin
in plugin.config). Any help would be really appreciated.
Thank you!
Best regards.
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