[Apiman-user] Is it possible blocking request after request body parsing?

[Marc Savy]

Thanks. I'll check it out and report back.

On 26 April 2018 at 12:26, Eric Wittmann <eric.wittmann at redhat.com> wrote:
> Yes that is the UI option I was referring to.
>
> If the request payload is being parsed without that option being set, then
> there is a bug in the Apiman gateway.  I will write up a bug report for that
> so that @marcsavy can have a look. :)
>
> -Eric
>
>
> On Thu, Apr 26, 2018 at 4:36 AM, 林 柏廷 <btlin1025 at hotmail.com> wrote:
>>
>> Dear Eric
>>
>> Thanks for your helpful information.
>> I can get request body with IPolicyContext object.
>> Besides, you also mentioned enable this on a per-API basis in the apiman
>> UI.
>> Is It "Enable stateful request payload insepction" in API implementation
>> tab?
>> I'm wondering because I didn't enable this option but can still get the
>> request body in doApply() with IPolicyContext.
>> What is the difference if I enable this option?
>> Thanks
>>
>> Regards
>>
>> ________________________________
>> 寄件者: Eric Wittmann <eric.wittmann at redhat.com>
>> 寄件日期: 2018年4月25日 下午 08:15
>> 收件者: 林 柏廷
>> 副本: apiman-user at lists.jboss.org
>> 主旨: Re: [Apiman-user] Is it possible blocking request after request body
>> parsing?
>>
>> Yes there is a feature where apiman will parse the request BEFORE applying
>> the policies.  This will make the HTTP request body available to all
>> policies in the chain, should they need them.
>>
>> You can enable this on a per-API basis in the apiman UI.
>>
>> When this feature is enabled, your custom policy can access the request
>> body as an object found in the IPolicyContext object.  For example:
>>
>> Object payload = context.getAttribute("apiman.request-payload");
>>
>> The type of thing that you get depends on the API's endpoint type.  The
>> endpoint type might be JSON, XML, or SOAP.  I think it might be possible to
>> have some other kind of endpoint type, but those three are handled by the
>> request body parser feature.
>>
>> Here is what you'll get as that payload object, depending on endpoint
>> type:
>>
>> JSON - Java Map object as a result of parsing the JSON data using Jackson
>> XML - org.w3c.dom.Document
>> Soap - javax.xml.soap.SOAPEnvelope
>> Anything Else - byte[]
>>
>> So for example, if your endpoint type is XML, then you could do this in
>> your policy implementation (in the doApply() method):
>>
>> org.w3c.dom.Document requestBody = (org.w3c.dom.Document)
>> context.gettAttribute("apiman.request-payload");
>>
>> And then you could make some decision using the request data and e.g. call
>> doFailure().
>>
>> Also note - you can *change* the request body at this point as well.  For
>> example you could apply a XML Transformation to the w3c Document, resulting
>> in a new w3c Document object, which you could store in the Policy Context
>> (at the same key, obviously).  That new document would then get serialized
>> and sent as the request body to the backing API impl.  There may be some
>> Content-Length issues if you do that, I can't remember...
>>
>> -Eric
>>
>>
>> On Wed, Apr 25, 2018 at 1:29 AM, 林 柏廷 <btlin1025 at hotmail.com> wrote:
>>
>> Hi all,
>> I would like to customize a policy, which parses the request body and
>> blocks the request in case.
>> in http://www.apiman.io/latest/developer-guide.html 4.2.1.2 IData policy,
>> it describes:
>> The request or response body will not begin streaming before the
>> corresponding doApply has been called, however, it is still possible to
>> interrupt the conversation during the streaming phase by signalling
>> doFailure or doError.
>> When I trace the transformation-policy source code, doApply() executes
>> before getRequestDataHandler() which matches the description.
>> In doApply() I can blocks the request via chain.doFailure() however I have
>> no idea how to interrupt/block request in getRequestDataHandler().
>> Besides, I found following mail group which is similar to my question.
>> Eric also points it's possible to parse the body before apply in request:
>>
>> On Thu, Feb 2, 2017 at 10:31 PM, Eric Wittmann <
>> eric.wittmann at redhat.com> wrote:
>>
>>  The bottom line here is that you cannot return a Policy Failure (or
>>  customize it) based on information in the response body.  The response is
>>  streamed from the back-end to the client, and at the time streaming
>> begins,
>>  the response code and HTTP headers have already been sent.
>>
>>  It sounds to me like you're asking for a feature where you can parse
>>  the response body *before* the policy's "apply" method is invoked.  we
>> have
>>  such a feature for requests, but not for responses.  I suspect core
>> changes
>>  to apiman would be required to enable that.  It seems like a reasonable
>>  request to me, as long as users of the feature understand the performance
>>  and memory requirements of enabling it.
>>
>>  -Eric
>>
>> Thanks for any comments in advance.
>> Kind Regards
>> BT
>>
>>
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>>
>
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