hello all,
Apache Camel is an interesting, huge tech stack / framework.
Recently, as I'm learning the ropes of Apache Camel, I tried making a
web based pdf renderer which I called it 'camel print'.
I got into quite a lot of bummers and finally made a working version.
In a gist, the route is like:
|context.addRoutes(new RouteBuilder() {||
||||
|| @Override||
|| public void configure() throws Exception {||
||from("seda:print.jobs?concurrentConsumers=5&waitForTaskToComplete=IfReplyExpected")
||
|| .choice()||
|| .when(header("outputType").isEqualTo("xml"))||
|| .marshal().jaxb(jaxbctxpath).stop()||
|| .when(header("outputType").isEqualTo("xslt"))||
|| .marshal().jaxb(jaxbctxpath)||
|| .toD("xslt:${header.xsltTemplate}").stop()||
|| .otherwise()||
|| .marshal().jaxb(jaxbctxpath)||
|| .toD("xslt:${header.xsltTemplate}")||
|| .process("foToPdfProcessor").stop();||
|| }||
||});
|
I tried doing this in xml using xml-io-dsl
https://camel.apache.org/components/4.18.x/others/java-xml-io-dsl.html
It actually worked very well, until I got stuck as I wanted to
'dynamically' pass that '|jaxbctxpath'| for the jaxb context path.
I couldn't figure out how to pass 'variables' during route build phase
with xml, and finally resorted to just doing java dsl.
'printing' or rendering is like
| ProducerTemplate template = camelmgr.getProducerTemplate(); ||
|| Exchange pdfResp = template.request("seda:print.jobs", exchange -> {||
|| exchange.getIn().setBody(jaxbObject);||
|| exchange.getIn().setHeader("xsltTemplate", xsltemplate);||||||
|| });||
||||
|| byte[] pdf = pdfResp.getMessage().getBody(byte[].class);||
|
The stack is kind of 'huge' it apparently pulled in a good number of
camel dependencies, I'm not sure if I'd be able to make that 'thinner'.
The other 'non-camel' dependencies are like Apache FOP, jetty etc.
Hope to hear your comments
Cheers :)
Andrew
||
