We already have project which received request on REST EndPoint and by
using FINITE STATE Machine evaluate next action with Transition and
call action class accordingly.
I am assigned to evaluate possibility to migrate this part to apache camel.
But i am not seeing any value addition as in camel we already defined
routes and we can also use dynamic routing for evaluating next
endpoint.
I googled but couldnt find any Apache Camel example using FSM.
I need comments any use case where we can use FSM in Apache Camel or
we dont require due to nature of Camel.
if anyone found any links for google please share it to.
https://dzone.com/articles/why-developers-never-use-state
Regards,
Related
The version of Apache Camel is 2.18.1
In documentation for 2.x, https://camel.apache.org/components/2.x/http4-component.html, getWithBody and deleteWithBody options as query parameters are provided.
deleteWithBody (producer) : Whether the HTTP DELETE should include the message body or not. By default HTTP DELETE do not include any HTTP body. However in some rare cases users may need to be able to include the message body. Default: false
getWithBody (producer) : Whether the HTTP GET should include the message body or not. By default HTTP GET do not include any HTTP body. However in some rare cases users may need to be able to include the message body. Default false
But when I concatenate one of these 2 parameters at the end of the endpoint URI, it's not recognized as an option. Instead, it's passed to the endpoint as an ordinary query parameter, while other query parameter options are treated as component options and not forwarded to the endpoint.
When I inspect the source code, I see that options are recognized by matching with the fields and methods of HttpEndpoint (org.apache.camel.component.http4) and HttpCommonEndpoint (org.apache.camel.http.common) classes. getWithBody and deleteWithBody fields doesn't exist in these classes while other options can be found among the fields of these classes.
Can I assume that the documentation is wrong? If so, how can I achieve to send body with HttpComponent(Http4Component) of Camel while the http method is GET or DELETE?
Option deleteWithBody was introduced in Apache Camel 2.19.0. See CAMEL-10916.
Option getWithBody was introduced in Apache Camel 3.0.0 and backported to 2.25.0. See CAMEL-14118.
For such old version use docs archived on github, it is not published on website - https://github.com/apache/camel/blob/camel-2.18.x/components/camel-http4/src/main/docs/http4-component.adoc
You need to update to newer version or implement custom component overriding some methods from HTTP4 component. There is no option to enable this OOTB in 2.18.1.
i agree with the answer given by #Bedla.
to add something additional this is what we did .
We checked the code and debugged - this allowed us to realize that at a point were camel interacts it drops the body if a GET Call has a one. it will be send as a normal GET Request because Camel version 3.x.x only supports it.
we tried different ways to forcefully add the body. that was also failed because what ever we add will be discarded by camel.
we were using camel v2.22.1 at the time. going to a higher version such as camel 3.x.x will be a big leap since there are multiple changes that will be included , so lucky for us camel team back ported this ability to send the GET Request with the Body (from here on getWithBody) to camel v2.25.0
coding level changes :
Append getWithBody=true to the Request URL
Updated camel Modules
camel-core-2.25.0.jar
camel-cxf-transport-2.25.0.jar
camel-cxf-2.25.0.jar
camel-core-xml-2.25.0.jar
camel-http-common-2.25.0.jar
camel-jaxb-2.25.0.jar
camel-spring-2.25.0.jar
camel-soap-2.25.0.jar
camel-cdi-2.25.0.jar
camel-jdbc-2.25.0.jar
camel-http4-2.25.0.jar
****special note ****
Note that under each folder location, there is a modules.xml file. You need yo open that and change the jar file version number to the one you want to use. in this case 2.25.0
That’s it and Happy Coding !
Does the Apache Camel framework offer support the Process Manager Pattern?
(http://www.enterpriseintegrationpatterns.com/ProcessManager.html)
Yeah you can use the dynamic router
http://camel.apache.org/dynamic-router.html
And then keep state on the exchange which the dynamic router accesses to determine the next step.
When you are done then the next step should be evaluated as null.
I am new to the concepts of Camel and I would like someone to confirm my findings so far.
Please correct if wrong
The way I see it, Camel has Components, which can have several communication interfaces called Endpoints. A Component can communicate with another component by sending a message to on of its Endpoints, which then will use a Processor to deliver it to the destination. I also read about Routes but I am not sure what they are used for because they seem to overlap in function with Processors (aka, they seem to be the same thing?)
Camel Routes and Endpoints
http://java.dzone.com/articles/open-source-integration-apache
Please confirm if correct
So far I believe that a Component (C1) in machine A can use an Endpoint (E1) to communicate with another component (C2) using its endpoint (E2) in machine B, by using websockets:
http://camel.apache.org/how-do-i-configure-endpoints.html
I would be grateful if someone could enlighten me in the first question or confirm my second one. Also, is there a better way to communicate between machines that doesn't involve using webscokets?
Thanks in advance, Pedro.
A Route is what connects endpoints and processors together. When you define a route in Camel it starts with a Component that exposes a communication Endpoint, invokes processors that implement the business logic of the route, and then can output the Exchange (the message being processed) to another Endpoint that is exposed by another Component.
Certain components allow Camel routes to communicate with endpoints in different machines. For example, the JMS component can be used to communicate with other machines via JMS messages. However, some components are limited to communicating with endpoints within the same VM like the SEDA component.
Camel provides many different ways to send data between machines (Here is a list of a few of them off the top of my head):
AMQP
JMS
Amazon SQS
HTTP
Mina
Netty
Take a look at the Camel Components page for a complete list: http://camel.apache.org/components.html
In a route (that exposes a REST service) i need to get the local host address/domain (so as I can build links to be included in a response body)
Is there a way to get the local host address from within camel ?
PS : running camel inside servicemix
there isn't a Camel specific way (that I know of), I'd just use an external property file to configure environment specific settings like this...you can then use camel properties to pull this in, etc.
A good idea when posting questions is to provide more details.
Which camel component do you use for REST. And which version of SMX/Camel do you use etc.
As you question assume that the rest component in Camel will expose a hostname information.
This questions is not Camel specific per see, as you can use the regular Java API to get the hostname.
First of all thanks to folks who are currently involved in the development of Camel, I am grateful for all the hard work they have put in.
I am looking for some design advice.
The architecture is something like this:
I have a bunch of Java classes which when instantiated are required to connect to each other and send messages using Apache Camel. The design constraints require me to create a framework such that all routing information, producers, consumers, endpoints etc should be a part of the camel-context.xml.
An individual should have the capability to modify such a file and completely change the existing route without having the Java code available to him.(The Java code would not be provided, only the compiled Jar would be)
For example in One setup,
Bean A ->Bean B->Bean C->file->email.
in another
Bean B->Bean A->Bean C->ftp->file->email
We have tried various approached, but if the originating bean is not implemented as a Java DSL, the messages rate is very high because camel constantly invokes Bean A in the first example and Bean B in the second(they being the source).
Bean A and Bean B originate messages and are event driven. In case the required event occurs, the beans send out a notification message.
My transformations are very simple and I do not require the power of Java DSL at all.
To summarize, I have the following questions:
1) Considering the above constraints, I do I ensure all routing information, including destination addresses, everything is a part of the camel context file?
2) Are there example I can look at for keeping the routing information completely independent of the java code?
3) How do I ensure Camel does not constantly invoke the originating bean?
4) Does Camel constantly invoke just the originating bean or any bean it sends & messages to irrespective of the position of the bean in the entire messaging queue?
I have run out of options trying various ways to set this up. Any help would be appreciated.
Read about hiding the middleware on the Camel wiki pages. This allows you to let clients use an interface to send/receive messages but totally unaware of Camel (no Camel API used at all).
Even better consider buying the Camel in Action book and read chapter 14 which talks about this.
http://www.manning.com/ibsen/
Save 41% on Manning books: Camel in Action or ActiveMQ in Action. Use code s2941. Expires 6th oct. http://www.manning.com/ibsen/
If you consider using ServiceMix of FuseESB, you might want to separate your routes in two parts.
First part would be the Event-driver bean that trigger the route. It could push messages to the ServiceNMR (see http://camel.apache.org/nmr.html).
The other part would be left to the framework users, using Spring DSL. It would just listen to message on the NMR (push by the other route) and do whatever they want with it.
Of course endpoint definition could be propertized using servicemix configuration service (see http://camel.apache.org/properties.html#Properties-UsingBlueprintpropertyplaceholderwithCamelroutes)