ESB: Extract email attachment with cProcessor and CAMEL code
Hi there,
My scenario is the following:
Fetch email on POP3 every 10 seconds. If email, split into separate Message for every attachment. Save attachment locally.
I'm using the following recommendation from CAMEL:
Consuming mails with attachment sample
In this sample we poll a mailbox and store all attachments from the mails as files. First, we define a route to poll the mailbox. As this sample is based on google mail, it uses the same route as shown in the SSL sample:
Instead of logging the mail we use a processor where we can process the mail from java code:
public void process(Exchange exchange) throws Exception { // the API is a bit clunky so we need to loop Map<String, DataHandler> attachments = exchange.getIn().getAttachments(); if (attachments.size() > 0) { for (String name : attachments.keySet()) { DataHandler dh = attachments.get(name); // get the file name String filename = dh.getName(); // get the content and convert it to byte[] byte[] data = exchange.getContext().getTypeConverter() .convertTo(byte[].class, dh.getInputStream()); // write the data to a file FileOutputStream out = new FileOutputStream(filename); out.write(data); out.flush(); out.close(); } } }
As you can see the API to handle attachments is a bit clunky but it's there so you can get thejavax.activation.DataHandlerso you can handle the attachments using standard API.
How to split a mail message with attachments
In this example we consume mail messages which may have a number of attachments. What we want to do is to use theSplitterEIP per individual attachment, to process the attachments separately. For example if the mail message has 5 attachments, we want theSplitterto process five messages, each having a single attachment. To do this we need to provide a customExpressionto theSplitterwhere we provide a List<Message> that contains the five messages with the single attachment.
The code is provided out of the box in Camel 2.10 onwards in thecamel-mailcomponent. The code is in the class:org.apache.camel.component.mail.SplitAttachmentsExpression, which you can find the source codehere
In the Camel route you then need to use thisExpressionin the route as shown below:{snippet:id=e1|lang=java|url=camel/trunk/components/camel-mail/src/test/java/org/apache/camel/component/mail/MailSplitAttachmentsTest.java}If you use XML DSL then you need to declare a method call expression in theSplitteras shown below
From Camel 2.16 onwards you can also split the attachments as byte[] to be stored as the message body. This is done by creating the expression with boolean true
And then use the expression with the splitter eip.
Putting the code in my cProcessor make my route unusable (Java Error). Does anyone already do this on his system? I don't want to make a job, really want a route.
