On Nov 30, 2007 2:09 PM, ant elder <[EMAIL PROTECTED]> wrote: > On Nov 30, 2007 1:52 PM, Simon Laws <[EMAIL PROTECTED]> wrote: > > > We have discussed this behaviour before and I was sort of convinced last > > time but now I'm playing with the store sample I'm not so sure. This > > features comes about because of the store composite, for example, > > > > <component name="Store"> > > <t:implementation.widget location="uiservices/store.html"/> > > <service name="Widget"> > > <t:binding.http uri="http://localhost:8101/ui"/> > > </service> > > <reference name="catalog" target="Catalog"> > > <t:binding.jsonrpc/> > > </reference> > > <reference name="shoppingCart" target="ShoppingCart/Cart"> > > <t:binding.atom/> > > </reference> > > <reference name="shoppingTotal" target="ShoppingCart/Total"> > > <t:binding.jsonrpc/> > > </reference> > > </component> > > > > To keep the composite tidy many of the URIs are omitted and they rely on > > the > > default value. However the URI for one of the bindings is provided so > that > > the node will detect this and use this as the default for all service > > bindings (where this kind of URI is applicable). All the bindings must > be > > the same here as store.html relies on the services being accessible from > > the > > same root. > > > > There are several places that the default port for the servlet host > comes > > from when setting up the SCA runtime. > > > > 1. The web app container. In this case no matter how you configure SCA > you > > will get whatever the web app container gives you > > 2. Node URI. This is used to tell what endpoints SCA should use by > default > > and also as a unique ID for the node. When running inside a web app this > > must be the host/port you expect the web app to expose your services on. > > Otherwise SCA can't tell what values the web app container is going to > use > > and hence can't register services with the domain. In the case that SCA > > starts Tomcat/Jetty itself then the Node URI is just the default value > > that > > will be used if a URI is not provided explicitly on a binding. > > 3. Binding uri attribute. If SCA is running inside a web app container > > this > > value is ignored and Node URI is used (see 2). If SCA has started > > Tomcat/Jetty itself this value will be used to configure the endpoint of > > the > > service. If no value is provided then the default value is used (see 1 > > and > > 2). > > > > So what's the drawback of using > > > > <component name="Store"> > > <t:implementation.widget location="uiservices/store.html"/> > > <service name="Widget"> > > <t:binding.http uri="/ui"/> > > </service> > > <reference name="catalog" target="Catalog"> > > <t:binding.jsonrpc/> > > </reference> > > <reference name="shoppingCart" target="ShoppingCart/Cart"> > > <t:binding.atom/> > > </reference> > > <reference name="shoppingTotal" target="ShoppingCart/Total"> > > <t:binding.jsonrpc/> > > </reference> > > </component> > > > > And setting Node URI = http://localhost:8101 > > > > I'm uncomfortable about the current feature because I could easily > include > > a > > component in front of the existing component, e.g. > > > > <component name"SomeComponent" > > <implementation .../> > > <service name="SomeService"> > > <binding.ws url="http://localhost:8100/SomeService"/> > > </service> > > </component> > > > > > > <component name="Store"> > > <t:implementation.widget location="uiservices/store.html"/> > > <service name="Widget"> > > <t:binding.http uri="http://localhost:8101/ui"/> > > </service> > > <reference name="catalog" target="Catalog"> > > <t:binding.jsonrpc/> > > </reference> > > <reference name="shoppingCart" target="ShoppingCart/Cart"> > > <t:binding.atom/> > > </reference> > > <reference name="shoppingTotal" target="ShoppingCart/Total"> > > <t:binding.jsonrpc/> > > </reference> > > </component> > > > > And mess it up as now the majority services in the composite are at 8100 > > and > > not 8101 where store.html expects them to be. > > > > Regards > > > > Simon > > > > I agree. We've never come up with a very consistent story about default > URLs > that works well everywhere, would be great if we could as its always > causing > problems with getting all the runtimes and nodes and service endpoints > working consistently everywhere. > > Can we change so that the ServletHost implementation controls the default > base URL and have everything tries to use relative URLs with that? > > ...ant > I think we can be relatively consistent using the three sources of endpoint information I put in the original mail.Now I think about it there is a number 4 that I didn't include so the list would be.
1. The web app container. In this case no matter how you configure SCA you will get whatever the web app container gives you 2. Node URI. This is used to tell what endpoints SCA should use by default and also as a unique ID for the node. When running inside a web app this must be the host/port you expect the web app to expose your services on. Otherwise SCA can't tell what values the web app container is going to use and hence can't register services with the domain. In the case that SCA starts Tomcat/Jetty itself then the Node URI is just the default value that will be used if a URI is not provided explicitly on a binding. 3. Binding uri attribute. If SCA is running inside a web app container this value is ignored and Node URI is used (see 2). If SCA has started Tomcat/Jetty itself this value will be used to configure the endpoint of the service. If no value is provided then the default value is used (see 1 and 2). 4. Free port. If not running inside a web app container and no Node URI is provided then a free port is selected automatically as the default port The default is set into the servlet host when the node starts and the bindings which use servlet host tend to use the servlet host interface to calculate their endpoint. So we are pretty close to what you suggest but we need to check that it is applied everywhere. I tried to represent the algorithm in psuedo code ( http://cwiki.apache.org/confluence/display/TUSCANYWIKI/Binding+URI+Construction) is this correct? Simon
