3 Replies Latest reply on Jul 1, 2014 1:54 PM by jorgemoralespou_2

simple http proxy service

jorgemoralespou_2 Jun 16, 2014 8:43 AM

I have been doing a simple Http proxy service (REST and HTTP bindings) and I have struggle with some problems. I think this use case should be very straightforward, as it is a typical use case of "Man in the middle" type of services.

I will summarize my findings, and hope that some SwitchYard masters will throw some light here if I'm wrong.

Service binding has to be fixed, although services will be invoked even for longer URIs than the requested. (https://github.com/jboss-switchyard/release/blob/master/jboss-as7/extension/src/main/java/org/switchyard/as7/extension/http/JBossWebEndpointPublisher.java#L80)

To get original request information, you need to access the Context as the request info is copied there.

        HttpRequestInfo requestInfo = msgContext.getPropertyValue(HttpComposition.HTTP_REQUEST_INFO);
        LOGGER.info("********************************************************************************");
        LOGGER.info("method      = {}", requestInfo.getMethod());
        LOGGER.info("pathInfo    = {}", requestInfo.getPathInfo());
        LOGGER.info("queryString = {}", requestInfo.getQueryString());
        LOGGER.info("content     = {}", content);
        LOGGER.info("********************************************************************************");

To set destination HTTP method, uri or query can be set using the Invoker's context (You can not use a plain reference, but rather a ReferenceInvoker):

        Context context = referenceInvoker.newInvocation().getMessage().getContext();

        context.setProperty(org.apache.camel.Exchange.HTTP_METHOD, requestInfo.getMethod());
        context.setProperty(org.apache.camel.Exchange.HTTP_URI, REFERENCE_BASE_URL + requestInfo.getPathInfo());
        context.setProperty(org.apache.camel.Exchange.HTTP_QUERY, requestInfo.getQueryString());

Error codes should be set in custom MessageComposer (although it doesn't work very well in some scenarios).

                        exchange.getContext()
                                        .setProperty(HttpContextMapper.HTTP_RESPONSE_STATUS, 404)
                                        .addLabels(new String[] { EndpointLabel.HTTP.label() });

HTTP Headers must be set in the composer to be regex copied:

<http:contextMapper includes="http.*"/>

I think there should be a simple proxy service for HTTP, Rest and SOAP services as quickstarts as this is fairly easy to do with some other products, and it is a very used type of service.

Please, comment on what I have wrong, and I will try to create this quickstarts for the project.

1. Re: simple http proxy service

mageshbk Jun 23, 2014 12:35 AM (in response to jorgemoralespou_2)
Hi Jorge,

The service binding fix is not required. The mapping is done only for that context path. release/jboss-as7/extension/src/main/java/org/switchyard/as7/extension/http/JBossWebEndpointPublisher.java at master · j…
That is correct.
You can set the HTTP method in configuration for reference bindings. You can include the query string in your address parameter, does this not work? See HTTP - SwitchYard - Project Documentation Editor
True, for custom error codes. Could you please elaborate in which scenarios it does not work?
By default not all headers are copied. Only those included in contextMapper configuration are copied. Yes you can use regular expressions or individual header names.

Most of the quickstarts are showcased with service-reference binding pairs, that pretty much is like a proxy. Have a look at http-binding, rest-binding, camel-soap-proxy and the soap-* QS.
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2. Re: simple http proxy service

jorgemoralespou_2 Jun 23, 2014 4:57 AM (in response to mageshbk)

Hi Magesh,
Thank you for clarification.
As you comment, most quickstarts are service-reference pairs, but they do not act as proxy (as in http, rest, soap) as they usually create a whole different request to the reference than the one received at the service. I have seen many questions here, as well as for my customers on how to create a pure proxy service (one that can get anything in a service binding url) and pass everything to the reference (copying url path, method, parameters, body/payload) but doing some logic in between (in a component). There is no quickstart like this.

As for the 3, the thing is not to tied the reference to an endpoint, rather making it dynamic, so I can have one proxy servicing many inbound operations.

I'll try to create it and whenever I encounter errors, will post them here for your help. So far, main problem is with propagating back errors to clients, as well as creating custom errors, as RESTEasy service and ExceptionMapper and other posts states. Errors in authorization should throw back a 401, resources not found a 404, and so forth.

As I say, I'll post here my findings.

Thanks,
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3. Re: simple http proxy service

jorgemoralespou_2 Jul 1, 2014 1:54 PM (in response to jorgemoralespou_2)
Hi,
Following this discussion, I have done a deep analysis of how http message composition works in order to be able to create this basic scenario.
So far, I have found terrible difficult to create a simple proxy service.
So far, I've seen there are many JIRAs that prevent this feature:
[SWITCHYARD-1916] Allow HTTP reference binding to accept HTTP method, request URI, query string, etc. dynamically - JBos…
[SWITCHYARD-1997] Dynamic "per message" endpoint - JBoss Issue Tracker
[SWITCHYARD-1375] Allow URL path to be set as part of composer - JBoss Issue Tracker

With this we end up with:
We need to use camel-http reference invocation instead of SwitchYard HTTP, otherwise endpoint, method, queryString, etc... can not be set. Only http headers.
All headers are lowercased (This should be no problem, as per the http specification this should be fine). But it has to be taken into account.
To copy all headers from incoming request to outgoing call, we need to specify all the headers as a list, or create custom mappers
With usage of camel-http invocation it is needed to copy context from the Message to the beanComponent to the Message of the Invocation
Mapping of errors from backed service is cumbersome, as has to be done in several points and copying properties with specific labels, which is not very documented

I have created a document at: fsw-documentation/switchyard/internals/http_messagecomposition.adoc at master · jorgemoralespou/fsw-documentation · GitH… for those who want to have some insight. I might be wrong in some of the points, so I somebody corrects me, I'll fix it. There is an accompanying project.
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