docs/components/modules/ROOT/pages/tarfile-dataformat.adoc

[[tarfile-dataformat]]
= Tar File DataFormat
:page-source: components/camel-tarfile/src/main/docs/tarfile-dataformat.adoc

*Available as of Camel version 2.16*

The Tar File Data Format is a message compression
and de-compression format. Messages can be marshalled (compressed) to
Tar Files containing a single entry, and Tar Files containing a single
entry can be unmarshalled (decompressed) to the original file contents.

There is also a aggregation strategy that can
aggregate multiple messages into a single Tar File.

== TarFile Options


// dataformat options: START
The Tar File dataformat supports 4 options, which are listed below.



[width="100%",cols="2s,1m,1m,6",options="header"]
|===
| Name | Default | Java Type | Description
| usingIterator | false | Boolean | If the tar file has more then one entry, the setting this option to true, allows to work with the splitter EIP, to split the data using an iterator in a streaming mode.
| allowEmptyDirectory | false | Boolean | If the tar file has more then one entry, setting this option to true, allows to get the iterator even if the directory is empty
| preservePathElements | false | Boolean | If the file name contains path elements, setting this option to true, allows the path to be maintained in the tar file.
| contentTypeHeader | false | Boolean | Whether the data format should set the Content-Type header with the type from the data format if the data format is capable of doing so. For example application/xml for data formats marshalling to XML, or application/json for data formats marshalling to JSon etc.
|===
// dataformat options: END
// spring-boot-auto-configure options: START
== Spring Boot Auto-Configuration

When using Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

[source,xml]
----
<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-tarfile-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>
----


The component supports 5 options, which are listed below.



[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *camel.dataformat.tarfile.allow-empty-directory* | If the tar file has more then one entry, setting this option to true, allows to get the iterator even if the directory is empty | false | Boolean
| *camel.dataformat.tarfile.content-type-header* | Whether the data format should set the Content-Type header with the type from the data format if the data format is capable of doing so. For example application/xml for data formats marshalling to XML, or application/json for data formats marshalling to JSon etc. | false | Boolean
| *camel.dataformat.tarfile.enabled* | Enable tarfile dataformat | true | Boolean
| *camel.dataformat.tarfile.preserve-path-elements* | If the file name contains path elements, setting this option to true, allows the path to be maintained in the tar file. | false | Boolean
| *camel.dataformat.tarfile.using-iterator* | If the tar file has more then one entry, the setting this option to true, allows to work with the splitter EIP, to split the data using an iterator in a streaming mode. | false | Boolean
|===
// spring-boot-auto-configure options: END


== Marshal

In this example we marshal a regular text/XML payload to a compressed
payload using Tar File compression, and send it to an ActiveMQ queue
called MY_QUEUE.

[source,java]
-----------------------------------------------------------------------
from("direct:start").marshal().tarFile().to("activemq:queue:MY_QUEUE");
-----------------------------------------------------------------------

The name of the Tar entry inside the created Tar File is based on the
incoming `CamelFileName` message header, which is the standard message
header used by the file component. Additionally, the
outgoing `CamelFileName` message header is automatically set to the
value of the incoming `CamelFileName` message header, with the ".tar"
suffix. So for example, if the following route finds a file named
"test.txt" in the input directory, the output will be a Tar File named
"test.txt.tar" containing a single Tar entry named "test.txt":

[source,java]
-----------------------------------------------------------------------------------------------
from("file:input/directory?antInclude=*/.txt").marshal().tarFile().to("file:output/directory");
-----------------------------------------------------------------------------------------------

If there is no incoming `CamelFileName` message header (for example, if
the file component is not the consumer), then the
message ID is used by default, and since the message ID is normally a
unique generated ID, you will end up with filenames like
`ID-MACHINENAME-2443-1211718892437-1-0.tar`. If you want to override
this behavior, then you can set the value of the `CamelFileName` header
explicitly in your route:

[source,java]
---------------------------------------------------------------------------------------------------------------------------
from("direct:start").setHeader(Exchange.FILE_NAME, constant("report.txt")).marshal().tarFile().to("file:output/directory");
---------------------------------------------------------------------------------------------------------------------------

This route would result in a Tar File named "report.txt.tar" in the
output directory, containing a single Tar entry named "report.txt".

== Unmarshal

In this example we unmarshal a Tar File payload from an ActiveMQ queue
called MY_QUEUE to its original format, and forward it for processing to
the `UnTarpedMessageProcessor`.

[source,java]
-----------------------------------------------------------------------------------------------
from("activemq:queue:MY_QUEUE").unmarshal().tarFile().process(new UnTarpedMessageProcessor()); 
-----------------------------------------------------------------------------------------------

If the Tar File has more then one entry, the usingIterator option of
TarFileDataFormat to be true, and you can use splitter to do the further
work.

[source,java]
----------------------------------------------------------------------------------------------------
  TarFileDataFormat tarFile = new TarFileDataFormat();
  tarFile.setUsingIterator(true);
  from("file:src/test/resources/org/apache/camel/dataformat/tarfile/?delay=1000&noop=true")
    .unmarshal(tarFile)
    .split(body(Iterator.class))
        .streaming()
          .process(new UnTarpedMessageProcessor())
    .end();
----------------------------------------------------------------------------------------------------

Or you can use the TarSplitter as an expression for splitter directly
like this

[source,java]
----------------------------------------------------------------------------------------------------
   from("file:src/test/resources/org/apache/camel/dataformat/tarfile?delay=1000&noop=true")
     .split(new TarSplitter())
        .streaming()
        .process(new UnTarpedMessageProcessor())
     .end();
----------------------------------------------------------------------------------------------------


== Aggregate

NOTE: Please note that this aggregation strategy requires eager completion
check to work properly.

In this example we aggregate all text files found in the input directory
into a single Tar File that is stored in the output directory. 

[source,java]
-------------------------------------------------
   from("file:input/directory?antInclude=*/.txt")
     .aggregate(new TarAggregationStrategy())
       .constant(true)
       .completionFromBatchConsumer()
       .eagerCheckCompletion()
   .to("file:output/directory");
-------------------------------------------------

The outgoing `CamelFileName` message header is created using
java.io.File.createTempFile, with the ".tar" suffix. If you want to
override this behavior, then you can set the value of
the `CamelFileName` header explicitly in your route:

[source,java]
------------------------------------------------------------
   from("file:input/directory?antInclude=*/.txt")
     .aggregate(new TarAggregationStrategy())
       .constant(true)
       .completionFromBatchConsumer()
       .eagerCheckCompletion()
     .setHeader(Exchange.FILE_NAME, constant("reports.tar"))
   .to("file:output/directory");
------------------------------------------------------------

== Dependencies

To use Tar Files in your camel routes you need to add a dependency on
*camel-tarfile* which implements this data format.

If you use Maven you can just add the following to your `pom.xml`,
substituting the version number for the latest & greatest release (see
the download page for the latest versions).

[source,xml]
----------------------------------------------------------
<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-tarfile</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>
----------------------------------------------------------