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From: Servalan eq <servalaneq@hotmail.com>
To: <users@trafficserver.apache.org>
Subject: RE: Calling an arbitrary http entpoint for advice in a remap plugin
Date: Thu, 5 Apr 2012 20:12:49 +1000
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> On 4/4/12 6:36 AM=2C Servalan eq wrote:> > I am writing a remap plugin to=
 do a hybrid reverse proxy / redirection task.In some circumstances I want =
to call out to a seperate http server (not related to the requests) do deci=
de how to handle the requests.> > I've coded this up using libcurl=2C which=
 works but seems very slow - creating and destroying a curl_easy_init objec=
t per call. Is there a way to call an HTTP GET during a plugin's process=2C=
 just passing some request parameters and headers using the internal ATSfun=
ctionality?=A0> > It seems TSFetchRespGet or TSFetchURL might work=2C but I=
 can't see any way to make a new tsapi_httptxn with my call in it.> > thank=
s very much=2C> >=A0>=A0> Yeah=2C none of this will work (well) in a remap =
plugin. You need to=A0> rewrite this as e.g. a read-request-header hook=2C =
and then use=A0> TSHttpConnect() (most likely) to fetch the content. This a=
lso implies=A0> you have to yield and reschedule your continuation while wa=
iting and=A0> processing the response. If not (and as you probably have not=
iced with=A0> your remap plugin)=2C you will block the net-thread for the d=
uration of=A0> the request. This is very bad=2C because all clients on that=
 thread are=A0> now stalled until your (curl) request finishes.>=A0> -- Lei=
f

Thanks Leif=2C this mostly makes sense - I am looking at the basic authoriz=
ation plugin example (basic-auth.c) and I think I understand it.=A0It is in=
tercepting calls and terminating some of them by not calling=A0TSHttpTxnRee=
nable(txnp=2C TS_EVENT_HTTP_CONTINUE)=3B=A0in the cases where the authoriza=
tion isn't found (as I understand it).

I think I can add a hook to TS_HTTP_READ_REQUEST_HDR_HOOK and then have a c=
ontinuation called back after a TSHttpConnect call.
Can I then (based on the response) achieve the same results of remapping or=
 forwarding the response as I am doing in my remap plugin?TSUrlHostSet(...T=
SUrlPathSet (...TSUrlHttpQuerySet (...(sometimes) rri->redirect =3D 1=3B
and then=A0return TSREMAP_DID_REMAP
thanks very much=2CServalan
 		 	   		  =