RE: Re: Re: Re: Dynamic Redirector
I haven't dug into this code, but I suspect you aren't manipulating
References properly. I advise printing out the intermediate steps of your
Reference computation to see where it goes wrong.
That's just it, I don't think it is even selecting my Redirector as the target
for the endpoint, b/c it is not even calling getTargetRef due to the child
endpoints. Is there something else on Redirector or in my attachment I should
be overriding so that it stops trying to match once it resolves the parent?
Also, the template argument to Redirector is ignored if you override
getTargetRef.
Hmm, that doesn't seem to be the case for me, since my code is almost an exact
copy the parent class.
--tim
On Sat, Apr 27, 2013 at 6:03 PM, Grant gsingers at apache dot org wrote:
I don't understand what you mean by the handling of the {rr} template.
The approach I suggested, overriding getTargetRef, ignores the template
argument entirely.
In my old code, I had:
URI = hardcoded URI to resource
Redirector redir = new Redirector(router.getContext(), URI + {rr},
Redirector.MODE_SERVER_OUTBOUND);
router.attach(, redir, Template.MODE_STARTS_WITH);
So, when I pass in http://foo:port/a/b/c, it redirects to URI/a/b/c
In my new code, I pass in the target template simply as {rr} and then iin
the getTargetRef, I do:
protected Reference getTargetRef(Request request, Response response) {
URI serviceURI = serviceLocator.getServiceURI(service); //THIS looks
up the location of the service
// Create the template
Template rt = new Template(this.targetTemplate);
rt.setLogger(getLogger());
// Return the formatted target URI
if (new Reference(this.targetTemplate).isRelative()) {
// Be sure to keep the resource's base reference.
//Reference baseRef = new Reference(serviceURI.uri);
if (log.isInfoEnabled()) {
log.info(dynRedir from {} to {}, request.getResourceRef(),
serviceURI.uri);
}
String format = rt.format(request,
response);
try {
return new Reference(new URI(serviceURI.uri.toString() + format));
} catch (URISyntaxException e) {
log.error(Exception, e);
throw new RuntimeException(e);
}
}
return new Reference(rt.format(request, response));
}
///
I attach my DynamicRedirector at, for example, /a. When I pass in
http://foo:port/a/b/c;, I want it to select my DynamicRedirector due to
the /a (I'm using STARTS_WITH mode) part and then redirect to the target
by passing along b/c (i.e. the {rr} part) such that the new URL would be
something like http://dynamicHost:port/b/c;, based on what my
serviceLocator returns. Like I said, it works great if I'm just matching
at /a, but it doesn't handle the /b/c part. AFAICT, the handle()
methods in Restlet are continuing to resolve down to the last endpoint
(i.e. b/c) even though it has a match at /a.
I will see if I can work up a standalone test example to demonstrate it.
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Re: Re: Re: Re: Dynamic Redirector
On Sun, Apr 28, 2013 at 11:42 AM, Grant gsing...@apache.org wrote:
I haven't dug into this code, but I suspect you aren't manipulating
References properly. I advise printing out the intermediate steps of your
Reference computation to see where it goes wrong.
That's just it, I don't think it is even selecting my Redirector as the
target for the endpoint, b/c it is not even calling getTargetRef due to the
child endpoints. Is there something else on Redirector or in my attachment
I should be overriding so that it stops trying to match once it resolves
the parent?
I don't know what you mean by parent or child endpoints.
If getTargetRef isn't being called, it's because the routing is wrong. If
you want the application or component to send *all* requests to the
redirector, use attachDefault:
router.attachDefault(new MyRedirector(getContext(), ... other args ...);
Also, the template argument to Redirector is ignored if you
override getTargetRef.
Hmm, that doesn't seem to be the case for me, since my code is almost an
exact copy the parent class.
The point of overriding getTargetRef is to give you the freedom to
determine the target in arbitrary ways, which can be independent of the
template. Here's the code for Redirector:
https://github.com/restlet/restlet-framework-java/blob/master/modules/org.restlet/src/org/restlet/routing/Redirector.java
You can see that the template is only used in getTargetRef. Your overridden
getTargetRef need not use that template. You can just do something like
this:
public class MyRedirector extends Redirector {
final FunctionReference, Reference targetMapper;
public MyRedirector(Context context, FunctionReference, Reference
targetMapper, int mode) {
super(context, ignored, mode);
this.targetMapper = targetMapper;
}
protected Reference getTargetRef(Request request, Response response) {
return targetMapper.apply(request.getOriginalRef());
}
}
I'm using Guava's Function type as a shorthand here, to illustrate how the
template can be made irrelevant to the redirection logic, but you can
obviously write this any way you want.
--tim
--
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RE: Re: Re: Re: Re: Dynamic Redirector
On Sun, Apr 28, 2013 at 11:42 AM, Grant gsingers at apache dot org wrote:
I haven't dug into this code, but I suspect you aren't manipulating
References properly. I advise printing out the intermediate steps of your
Reference computation to see where it goes wrong.
That's just it, I don't think it is even selecting my Redirector as the
target for the endpoint, b/c it is not even calling getTargetRef due to the
child endpoints. Is there something else on Redirector or in my attachment
I should be overriding so that it stops trying to match once it resolves
the parent?
I don't know what you mean by parent or child endpoints.
If getTargetRef isn't being called, it's because the routing is wrong. If
you want the application or component to send *all* requests to the
redirector, use attachDefault:
router.attachDefault(new MyRedirector(getContext(), ... other args ...);
Yes, this is my suspicion too. Here's what I mean by parent and child.
I am attaching my DynRedirector at:
http://foo:port/a
I am, at run time, making a call to http://foo:port/a/b. Thus, /b is my
child endpoint and /a is my parent endpoint (ie the one that _is_ the
Redirector). Not sure if this is the right nomenclature for Restlet, so please
correct me.
I can see that the Restlet that owns the DynRedirector is getting selected, but
then it is not able to find it's next route b/c /b was never officially
attached since it is (in my mind) supposed to be handled by the {rr} part. I
suspect my issue is in how I am handling the {rr} part when I am attaching the
DynamicRedirector to the owning Restlet.
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Re: Re: Re: Re: Re: Dynamic Redirector
On Sun, Apr 28, 2013 at 12:58 PM, Grant gsing...@apache.org wrote:
I am attaching my DynRedirector at:
http://foo:port/a
What's the code for this? It could be a Component level routing:
VirtualHost host = component.getDefaultHost();
host.attach(/a, new DynRedirector(... args ...));
or an Application level routing:
host.attach(/a, new MyApplication());
...
// In MyApplication.createInboundRoot:
router.attachDefault(new DynRedirector(... args ...));
If it doesn't fall into one of these two camps, it's a good bet that your
problem lies there.
I am, at run time, making a call to http://foo:port/a/b. Thus, /b is
my child endpoint and /a is my parent endpoint (ie the one that _is_
the Redirector). Not sure if this is the right nomenclature for Restlet,
so please correct me.
I would have said that you want all requests for resources at URIs with a
prefix of http://foo:port/a to be handled by an instance of DynRedirector.
I can see that the Restlet that owns the DynRedirector is getting selected,
but then it is not able to find it's next route b/c /b was never
officially attached since it is (in my mind) supposed to be handled by the
{rr} part. I suspect my issue is in how I am handling the {rr} part when I
am attaching the DynamicRedirector to the owning Restlet.
Again, if DynRedirector.getTargetRef isn't being called at all, then the
template argument passed to DynRedirector isn't being used, so handled by
the {rr} part doesn't mean anything.
I think you're confusing the path provided to attach, which can be a
template pattern, with the template pattern passed to the Redirector. The
former is used during routing, the latter is made available to getTargetRef
to be used in determining a target reference from values in the current
request and response.
--tim
--
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RE: Re: Dynamic Redirector
Hmm, digging in on this a bit more, I'm not sure it fully works for what I'm
trying to do. The issue seems to be in the handling of the {rr} template.
In other words, if I'm just redirecting a single URI to another (i.e.
http://foo/a to http://bar/b), this approach works, but if I want to redirect
all children URIs to the respective children URIs of the target.
That is, if I have I request
http://foo:port/a/b/c
and I want to attach at http://foo:port/a and redirect to http://bar:port/b/c
(by rewriting the target reference), it doesn't seem to work if I create a
MyRedirector (my derivation of Redirector) that has an attach point of
http://foo:port/a and a target template of {rr} whereas before in my static
redirector I was doing http://bar:port/{rr} and everything was good.
Thanks,
Grant
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Re: Re: Dynamic Redirector
I don't understand what you mean by the handling of the {rr} template.
The approach I suggested, overriding getTargetRef, ignores the template
argument entirely.
--tim
On Sat, Apr 27, 2013 at 2:54 PM, Grant gsing...@apache.org wrote:
Hmm, digging in on this a bit more, I'm not sure it fully works for what
I'm trying to do. The issue seems to be in the handling of the {rr}
template.
In other words, if I'm just redirecting a single URI to another (i.e.
http://foo/a to http://bar/b), this approach works, but if I want to
redirect all children URIs to the respective children URIs of the target.
That is, if I have I request
http://foo:port/a/b/c
and I want to attach at http://foo:port/a and redirect to http://bar:port/b/c
(by rewriting the target reference), it doesn't seem to work if I create a
MyRedirector (my derivation of Redirector) that has an attach point of
http://foo:port/a and a target template of {rr} whereas before in my
static redirector I was doing http://bar:port/{rr} and everything was
good.
Thanks,
Grant
--
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RE: Re: Re: Dynamic Redirector
I don't understand what you mean by the handling of the {rr} template.
The approach I suggested, overriding getTargetRef, ignores the template
argument entirely.
In my old code, I had:
URI = hardcoded URI to resource
Redirector redir = new Redirector(router.getContext(), URI + {rr},
Redirector.MODE_SERVER_OUTBOUND);
router.attach(, redir, Template.MODE_STARTS_WITH);
So, when I pass in http://foo:port/a/b/c, it redirects to URI/a/b/c
In my new code, I pass in the target template simply as {rr} and then iin the
getTargetRef, I do:
protected Reference getTargetRef(Request request, Response response) {
URI serviceURI = serviceLocator.getServiceURI(service); //THIS looks up the
location of the service
// Create the template
Template rt = new Template(this.targetTemplate);
rt.setLogger(getLogger());
// Return the formatted target URI
if (new Reference(this.targetTemplate).isRelative()) {
// Be sure to keep the resource's base reference.
//Reference baseRef = new Reference(serviceURI.uri);
if (log.isInfoEnabled()) {
log.info(dynRedir from {} to {}, request.getResourceRef(),
serviceURI.uri);
}
String format = rt.format(request,
response);
try {
return new Reference(new URI(serviceURI.uri.toString() + format));
} catch (URISyntaxException e) {
log.error(Exception, e);
throw new RuntimeException(e);
}
}
return new Reference(rt.format(request, response));
}
///
I attach my DynamicRedirector at, for example, /a. When I pass in
http://foo:port/a/b/c;, I want it to select my DynamicRedirector due to the
/a (I'm using STARTS_WITH mode) part and then redirect to the target by
passing along b/c (i.e. the {rr} part) such that the new URL would be
something like http://dynamicHost:port/b/c;, based on what my serviceLocator
returns. Like I said, it works great if I'm just matching at /a, but it
doesn't handle the /b/c part. AFAICT, the handle() methods in Restlet are
continuing to resolve down to the last endpoint (i.e. b/c) even though it has
a match at /a.
I will see if I can work up a standalone test example to demonstrate it.
--
http://restlet.tigris.org/ds/viewMessage.do?dsForumId=4447dsMessageId=3054458
Re: Re: Re: Dynamic Redirector
I haven't dug into this code, but I suspect you aren't manipulating
References properly. I advise printing out the intermediate steps of your
Reference computation to see where it goes wrong.
Also, the template argument to Redirector is ignored if you override
getTargetRef.
--tim
On Sat, Apr 27, 2013 at 6:03 PM, Grant gsing...@apache.org wrote:
I don't understand what you mean by the handling of the {rr} template.
The approach I suggested, overriding getTargetRef, ignores the template
argument entirely.
In my old code, I had:
URI = hardcoded URI to resource
Redirector redir = new Redirector(router.getContext(), URI + {rr},
Redirector.MODE_SERVER_OUTBOUND);
router.attach(, redir, Template.MODE_STARTS_WITH);
So, when I pass in http://foo:port/a/b/c, it redirects to URI/a/b/c
In my new code, I pass in the target template simply as {rr} and then iin
the getTargetRef, I do:
protected Reference getTargetRef(Request request, Response response) {
URI serviceURI = serviceLocator.getServiceURI(service); //THIS looks
up the location of the service
// Create the template
Template rt = new Template(this.targetTemplate);
rt.setLogger(getLogger());
// Return the formatted target URI
if (new Reference(this.targetTemplate).isRelative()) {
// Be sure to keep the resource's base reference.
//Reference baseRef = new Reference(serviceURI.uri);
if (log.isInfoEnabled()) {
log.info(dynRedir from {} to {}, request.getResourceRef(),
serviceURI.uri);
}
String format = rt.format(request,
response);
try {
return new Reference(new URI(serviceURI.uri.toString() + format));
} catch (URISyntaxException e) {
log.error(Exception, e);
throw new RuntimeException(e);
}
}
return new Reference(rt.format(request, response));
}
///
I attach my DynamicRedirector at, for example, /a. When I pass in
http://foo:port/a/b/c;, I want it to select my DynamicRedirector due to
the /a (I'm using STARTS_WITH mode) part and then redirect to the target
by passing along b/c (i.e. the {rr} part) such that the new URL would be
something like http://dynamicHost:port/b/c;, based on what my
serviceLocator returns. Like I said, it works great if I'm just matching
at /a, but it doesn't handle the /b/c part. AFAICT, the handle()
methods in Restlet are continuing to resolve down to the last endpoint
(i.e. b/c) even though it has a match at /a.
I will see if I can work up a standalone test example to demonstrate it.
--
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--
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Re: Dynamic Redirector
Subclass Redirector, overriding getTargetRef(Request, Response) to return a
Reference that you determine dynamically from the request and response
parameters.
--tim
On Mon, Apr 15, 2013 at 10:06 PM, Grant gsing...@apache.org wrote:
I have a front end API which I want to use to proxy/redirect requests to a
backend service. Up until now, I've been binding the APIs using the {rr}
technique described in the documentation, but the main issue I have is that
I am binding to the backend service's host/port at startup (in
createInboundRoot) and I want to be able to dynamically set the host/port
of the backend service at request time, as it is possible the service may
be down or I want to load balance it.
I'm on Restlet 2.1.5-RC1.
Thanks,
Grant
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RE: Re: Dynamic Redirector
That works beautifully, thank you! For the record, I used what was in getTargetRef almost as is, except I replaced the baseRef with a dynamically discovered one (that I get from Zookeeper). Thanks, Grant -- http://restlet.tigris.org/ds/viewMessage.do?dsForumId=4447dsMessageId=3053466
