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From Servalan eq <servala...@hotmail.com>
Subject RE: Calling an arbitrary http entpoint for advice in a remap plugin
Date Thu, 05 Apr 2012 10:12:49 GMT


> On 4/4/12 6:36 AM, 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 decide how to handle the requests.> > I've coded
this up using libcurl, which works but seems very slow - creating and destroying a curl_easy_init
object per call. Is there a way to call an HTTP GET during a plugin's process, just passing
some request parameters and headers using the internal ATSfunctionality? > > It seems
TSFetchRespGet or TSFetchURL might work, but I can't see any way to make a new tsapi_httptxn
with my call in it.> > thanks very much,> > > > Yeah, none of this will
work (well) in a remap plugin. You need to > rewrite this as e.g. a read-request-header
hook, and then use > TSHttpConnect() (most likely) to fetch the content. This also implies >
you have to yield and reschedule your continuation while waiting and > processing the
response. If not (and as you probably have noticed with > your remap plugin), you will
block the net-thread for the duration of > the request. This is very bad, because all
clients on that thread are > now stalled until your (curl) request finishes.> >
-- Leif

Thanks Leif, this mostly makes sense - I am looking at the basic authorization plugin example
(basic-auth.c) and I think I understand it. It is intercepting calls and terminating some
of them by not calling TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE); in the cases where
the authorization 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 continuation 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(...TSUrlPathSet (...TSUrlHttpQuerySet
(...(sometimes) rri->redirect = 1;
and then return TSREMAP_DID_REMAP
thanks very much,Servalan
 		 	   		  
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