THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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h2. File Component
The File component provides access to file systems; allowing files to be processed by any other Camel [Components] or messages from other components can be saved to disk.
h3. URI format
{code}
file:directoryName[?options]
{code}
or
{code}
file://directoryName[?options]
{code}
Where *directoryName* represents the underlying file directory.
{tip:title=Only directories}
Camel 2.0 only support endpoints configured with a starting directory. So the *directoryName* must be a directory.
If you want to consume a single file only, you can use the *regexPattern* option to only select your filename, eg by just setting {{regexPattern=thefilename}}.
In Camel 1.x you could also configure a file and this caused more harm than good as it could lead to confusing situations.
{tip}
h3. URI Options
h4. Common
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|| Name || Default Value || Description ||
| autoCreate | true | If set to true Camel will create the directory to the file if the file path does not exists - Uses File#mkdirs()|
| bufferSize | 128kb | Write buffer sized in bytes. Camel uses a default of 128 * 1024 bytes. |
| fileName | null | Use [Expression] to dynamically set the filename. For consumers its used as a filename filter. For producers its used to evaluate the filename to write. If an expression is set it take precedents over the {{CamelFileName}} header. (*Note:* The header itself can also be an [Expression]). The expression options supports both String and Expression types. If the expression is a String type then its *always* evaluated using the [File Language]. If the expression is an Expression type then this type is of course used as it - this allows for instance also to use [OGNL] as expression. For the consumer, you can use it to filter filenames, so you can for instance consume todays file using the [File Language] syntax: {{mydata-$\{date:now:yyyyMMdd}.txt}}. |
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h4. Consumer only
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|| Name || Default Value || Description ||
| initialDelay | 1000 | milliseconds before polling the file/directory starts|
| delay | 500 | milliseconds before the next poll of the file/directory|
| useFixedDelay | false | true to use fixed delay between pools, otherwise fixed rate is used. See [ScheduledExecutorService|http://java.sun.com/j2se/1.5.0/docs/api/java/util/concurrent/ScheduledExecutorService.html] in JDK for details.|
| recursive | false| if a directory, will look for files in all the sub directories as well. |
| delete | false | If delete is true then the file will be deleted *after* it is processed |
| noop | false | If true then the file is not moved or deleted in any way. This option is good for read only data, or for [ETL] type requirements. If noop=true then Camel will set idempotent=true as well, avoiding consuming the same files over and over again. |
| preMove | null | Use [Expression] to dynamically set the filename when moving it *before* processing. For example to move in progress file into the _order_ directory set this value to {{order/$\{file:name}}} |
| move | .camel/$\{file:name} | Use [Expression] to dynamically set the filename when moving it *after* processing. For example to move processed files into the _done_ directory and use _.bak_ as extension set this value to {{done/$\{file:name.noext}.bak}} |
| include | null | Is used to include files if filename matches the regex pattern. |
| exclude | null | Is used to exclude files if filename matches the regex pattern. |
| idempotent | false | Option to use the [Idempotent Consumer] EIP pattern to let Camel skip already processed files. Will default use a memory based LRUCache that holds 1000 entries. If noop=true then idempotent will be enabled as well to avoid consuming the same files over and over again. |
| idempotentRepository | null | Pluggable repository as a [org.apache.camel.processor.idempotent.MessageIdRepository|http://camel.apache.org/maven/camel-core/apidocs/org/apache/camel/processor/idempotent/MessageIdRepository.html] class. Will default use MemoryMessageIdRepository if none is specified and idempotent is true. |
| filter | null | Pluggable filter as a {{org.apache.camel.component.file.GenericFileFilter}} class. Will skip files if filter returns false in its accept method. Camel also ships with an *ANT path matcher* filter in the camel-spring component. More details in section below. |
| sorter | null | Pluggable sorter as a [java.util.Comparator<org.apache.camel.component.file.GenericFile>|http://java.sun.com/j2se/1.5.0/docs/api/java/util/Comparator.html] class. |
| sortBy | null | Build in sort by using the [File Language]. Supports nested sorts so you can have a sort by file name and as a 2nd group sort by modified date. See sorting section below for details. |
| readLock | markerFile | Used by consumer, to only poll the files if it has exclusive read lock to the file (= the file is not in progress of being written). Camel will wait until the file lock is granted. This option provides the build in strategies: *fileLock*, *rename*, *markerFile* and *none*. fileLock is for using {{java.nio.channels.FileLock}}. rename is for using a try to rename the file as a test if we can get exclusive read lock. *markerFile* is the behaviour from Camel 1.x, where Camel will create a marker file and hold lock on the marker file. *none* is for no read locks at all. |
| readLockTimeout | 0 | Optional timeout in millis for the read lock, if supported by the read lock. If the read lock could not be granted and the timeout triggered then Camel will skip the file. At next poll Camel will try the file again, and this time maybe the read lock could be granted. |
| exclusiveReadLockStrategy | null | Pluggable read lock as a {{org.apache.camel.component.file.GenericFileExclusiveReadLockStrategy}} implementation. |
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h4. Producer only
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|| Name || Default Value || Description ||
| tempPrefix | null | This option is used to write the file using a temporary name, and then after the write is complete rename it to the real name. Can be used to identify files being written and also avoid consumers (not using exclusive read locks) reading in progress files. Is often used by [FTP|FTP2] when uploading big files. |
{div}
h3. Default behavior for file consumer
* By default the file is locked for the duration of the processing.
* After the route has completed they are moved into the _.camel_ subdirectory; so that they appear to be deleted.
* The File Consumer will always skip any file which name starts with a dot, such as {{".", ".camel", ".m2" or ".groovy"}}.
* Only files (not directories) is matched for valid filename if options such as: {{includeNamePrefix, includeNamePostfix, excludeNamePrefix, excludeNamePostfix, regexPattern}} is used.
h3. Move and Delete operations
Any move or delete operations is executed after (post command) the routing has completed. So during processing of the Exchange the file is still located in the inbox folder.
Lets illustrate this with an example:
{code:java}
from("file://inobox?move=done/${file:name}").to("bean:handleOrder");
{code}
When a file is dropped in the inbox folder the file consumer notices this and creates a new {{FileExchange}} that is routed to the handleOrder bean. The bean then processes the File. At this point in time the File is still located in the inbox folder. After the bean completes and thus the route is completed the file consumer will perform the move operation and move the file to the done sub folder.
By default Camel will move consumed files to the sub folder {{.camel}} relative where the file was consumed.
We have introduced a *pre* move operation to move files *before* they are processed. This allows you to mark which files has been scanned as they are moved to this sub folder before being processed.
{code:java}
from("file://inobox?preMove=inprogress/${file:name}").to("bean:handleOrder");
{code}
You can combine the *pre* move and the regular move:
{code:java}
from("file://inobox?preMove=inprogress/${file:name}&move=../done/${file:name}").to("bean:handleOrder");
{code}
So in this situation the file is in the inprogress folder when being processed, and after it's processed it's moved to the done folder.
h3. Message Headers
The following headers is supported by this component.
h4. File producer only
|| Header || Description ||
h4. File producer
| CamelFileName | Specifies the name of the file to write (relative to the endpoint directory). The name can be a String, a String with a [File Language] or [Simple] expression. Or an [Expression] object. If its *null* then Camel will auto generate a filename based on the message unique id. |
h4. File consumer only
|| Header || Description ||
| CamelFileName | Name of the consumed file as a relative file path with offset from the starting directory configured on the endpoint. |
| CamelFileNameOnly | Only the file name, is just the name with no leading paths. |
| CamelFileNameProduced | The actual absolute filepath (path + name) for the output file that was written. This header is set by Camel and its purpose is providing end-users the name of the file that was written. |
| CamelFileAbsolute | A boolean whether the consumed file denotes a absolute path or not. Should normally be false for relative paths. Absolute path should normally not be used but we added to the move option to allow moving files to absolute paths. But can be used elsewhere as well. |
| CamelFileAbsolutePath | The absolute path to the file. For relative files this path holds the relative path instead. |
| CamelFilePath | The file path. For relative files this is the starting directory + the relative filename. For absolute files this is the absolute path. |
| CamelFileRelativePath | The relative path. |
| CamelFileParent | The parent path. |
| CamelFileLength | A long containing the file size |
| CamelFileLastModified | A Date containing the last modified timestamp of the file. |
| CamelFileBatchSize | Total number of files being consumed in this batch. |
| CamelFileBatchIndex | Current index out of total number of files being consumed in this batch. |
h3. Common gotchas with folder and filenames
When Camel is producing files (writing files) there are a few gotchas how to set a filename of your choice. By default Camel will use the message id as the filename, and since the message id is normally a unique generated id you will end up with filenames such as: ID-MACHINENAME-2443-1211718892437-1-0. If such a filename is not desired, then a filename must be provided in the message header {{"CamelFileName"}}. The constant {{Exchange.FILE_NAME}} can also be used.
The sample code below produces files using the message id as the filename:
{code}
from("direct:report").to("file:target/reports");
{code}
To use report.txt as the filename you have to do:
{code}
from("direct:report").setHeader(Exchange.FILE_NAME, constant("report.txt")).to( "file:target/reports");
{code}
... the same as above, but with "CamelFileName":
{code}
from("direct:report").setHeader("CamelFileName", constant("report.txt")).to( "file:target/reports");
{code}
And a syntax where we set the filename on the endpoint with the *fileName* URI option.
{code}
from("direct:report").to("file:target/reports/?fileName=report.txt");
{code}
h3. Filename Expression
Filename can be set either using the *expression* option or as a string based [File Language] expression in the {{CamelFileName}} header. See the [File Language] for syntax and samples.
h3. Samples
h4. Read from a directory and write to another directory
{code:java}
from("file://inputdir/?delete=true").to("file://outputdir")
{code}
Listen on a directory and create a message for each file dropped there. Copy the contents to the outputdir and delete the file in the inputdir.
h4. Read from a directory and process the message in java
{code}
from("file://inputdir/").process(new Processor() {
public void process(Exchange exchange) throws Exception {
Object body = exchange.getIn().getBody();
// do some business logic with the input body
}
});
{code}
Body will be File object pointing to the file that was just dropped to the inputdir directory.
h4. Read files from a directory and send the content to a jms queue
{code}
from("file://inputdir/").convertBodyTo(String.class).to("jms:test.queue")
{code}
By default the file endpoint sends a FileMessage which contains a File as body. If you send this directly to the jms component the jms message will only contain the File object but not the content. By converting the File to a String the message will contain the file contents what is probably what you want to do.
The route above using Spring DSL:
{code:xml}
<route>
<from uri="file://inputdir/"/>
<convertBodyTo type="java.lang.String"/>
<to uri="jms:test.queue"/>
</route>
{code}
h4. Writing to files
Camel is of course also able to write files, eg. producing files. In the sample below we receive some reports on the SEDA queue that we processes before they are written to a directory.
{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/component/file/ToFileRouteTest.java}
h4. Write to subdirectory using {{Exchange.FILE_NAME}}
Using a single route, it is possible to write a file to any number of subdirectories. If you have a route setup as such:
{code}
<route>
<from uri="bean:myBean"/>
<to uri="file:/rootDirectory"/>
</route>
{code}
You can have {{myBean}} set the header {{Exchange.FILE_NAME}} to values such as:
{code}
Exchange.FILE_NAME = hello.txt => /rootDirectory/hello.txt
Exchange.FILE_NAME = foo/bye.txt => /rootDirectory/foo/bye.txt
{code}
This allows you to have a single route to write files to multiple destinations.
h4. Using expression for filenames
In this sample we want to move consumed files to a backup folder using todays date as a sub foldername:
{code:java}
from("file://inbox?move=backup/${date:now:yyyyMMdd}/${file:name}").to("...");
{code}
See [File Language] for more samples.
h3. Avoiding reading the same file more than once (idempotent consumer)
Camel supports [Idempotent Consumer] directly within the component so it will skip already processed files. This feature can be enabled by setting the {{idempotent=true}} option.
{code:java}
from("file://inbox?idempotent=true").to("...");
{code}
By default Camel uses a in memory based store for keeping track of consumed files, it uses a least recently used cache storing holding up to 1000 entries. You can plugin your own implementation of this store by using the {{idempotentRepository}} option using the # sign in the value to indicate it's a referring to a bean in the [Registry] with this id.
{code:xml}
<!-- define our store as a plain spring bean -->
<bean id="myStore" class="com.mycompany.MyIdempotentStore"/>
<route>
<from uri="file://inbox?idempotent=true&idempotentRepository=#myStore"/>
<to uri="bean:processInbox"/>
</route>
{code}
Camel will log at {{DEBUG}} level if it skips a file because it has been consumed before:
{code}
DEBUG FileConsumer is idempotent and the file has been consumed before. Will skip this file: target\idempotent\report.txt
{code}
h4. Using a File based idempotent repository
In this section we will use the file based idempotent repository {{org.apache.camel.processor.idempotent.FileIdempotentRepository}} instead of the in memory based that is used as default.
This repository uses a 1st level cache to avoid reading the file repository. It will only use the file repository to store the content of the 1st level cache. Thereby the repository can survive server restarts. It will load the content of the file into the 1st level cache upon startup. The file structure is very simple as it store the key in separate lines in the file. By default the file store has a size limit of 1mb when the file grew larger Camel will truncate the file store be rebuilding the content by flushing the 1st level cache in a fresh empty file.
We configure our repository using Spring XML creating our file idempotent repository and define our file consumer to use our repository with the {{idempotentRepository}} using # sign to indicate [Registry] lookup:
{snippet:id=example|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/processor/idempotent/fileConsumerIdempotentTest.xml}
h4. Using a JPA based idempotent repository
In this section we will use the JPA based idempotent repository instead of the in memory based that is used as default.
First we need a persistence-unit in {{META-INF/persistence.xml}} where we need to use the class {{org.apache.camel.processor.idempotent.jpa.MessageProcessed}} as model.
{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-jpa/src/test/resources/META-INF/persistence.xml}
Then we need to setup a Spring jpaTemplate in the spring XML file:
{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-jpa/src/test/resources/org/apache/camel/processor/jpa/spring.xml}
And finally we can create our JPA idempotent repository in the spring XML file as well:
{snippet:id=jpaStore|lang=xml|url=camel/trunk/components/camel-jpa/src/test/resources/org/apache/camel/processor/jpa/fileConsumerJpaIdempotentTest-config.xml}
And yes then we just need to refer to the *jpaStore* bean in the file consumer endpoint using the [[idempotentRepository}} using the # syntax option:
{code:xml}
<route>
<from uri="file://inbox?idempotent=true&idempotentRepository=#jpaStore"/>
<to uri="bean:processInbox"/>
</route>
{code}
h3. Filter using org.apache.camel.component.file.GenericFileFilter
Camel supports pluggable filtering strategies. You can then configure the endpoint with such a filter to skip certain files being processed.
In the sample we have build our own filter that skips files starting with skip in the filename:
{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/component/file/FileConsumerFileFilterTest.java}
And then we can configure our route using the *filter* attribute to reference our filter (using # notation) that we have defines in the spring XML file:
{code:xml}
<!-- define our sorter as a plain spring bean -->
<bean id="myFilter" class="com.mycompany.MyFileSorter"/>
<route>
<from uri="file://inbox?filter=#myFilter"/>
<to uri="bean:processInbox"/>
</route>
{code}
h4. Filtering using ANT path matcher
The ANT path matcher is shipped out-of-the-box in the *camel-spring* jar. So you need to depend on *camel-spring* if you are using Maven.
The reasons is that we leverage Spring's [AntPathMatcher|http://static.springframework.org/spring/docs/2.5.x/api/org/springframework/util/AntPathMatcher.html] to do the actual matching.
The file paths is matched with the following rules:
- {{?}} matches one character
- {{*}} matches zero or more characters
- {{**}} matches zero or more directories in a path
The sample below demonstrates how to use it:
{snippet:id=example|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/file/SpringFileAntPathMatcherFileFilterTest-context.xml}
h3. Sorting using Comparator
Camel supports pluggable sorting strategies. This strategy it to use the build in java.util.Comparator in Java. You can then configure the endpoint with such a comparator and have Camel sort the files before being processed.
In the sample we have build our own comparator that just sorts by file name:
{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/component/file/FileSorterRefTest.java}
And then we can configure our route using the *sorter* option to reference to our sorter (mySorter) we have defined in the spring XML file:
{code:xml}
<!-- define our sorter as a plain spring bean -->
<bean id="mySorter" class="com.mycompany.MyFileSorter"/>
<route>
<from uri="file://inbox?sorter=#mySorter"/>
<to uri="bean:processInbox"/>
</route>
{code}
{tip:title=URI options can reference beans using the # syntax}
In the Spring DSL route about notice that we can refer to beans in the [Registry] by prefixing the id with #. So writing {{sorter=#mySorter}}, will instruct Camel to go look in the [Registry] for a bean with the id mySorter.
{tip}
h3. Sorting using sortBy
Camel supports pluggable sorting strategies. This strategy it to use the [File Language] to configure the sorting. The sortBy is configured as:
{code}
sortBy=group 1;group 2;group 3;...
{code}
Where each group is separated with semi colon. In the simple situations you just use one group, so a simple example could be:
{code}
sortBy=file:name
{code}
This will sort by file name, you can reverse the order by prefixing {{reverse:}} to the group, so the sorting is now Z..A:
{code}
sortBy=reverse:file:name
{code}
As we have the full power of [File Language] we can use some of the other parameters, so if we want to sort by file size we do:
{code}
sortBy=file:size
{code}
You can configure to ignore the case, using {{ignoreCase:}} for string comparison, so if you want to use file name sorting but to ignore the case then we do:
{code}
sortBy=ignoreCase:file:name
{code}
You can combine ignore case and reverse, however reverse must be specified first:
{code}
sortBy=reverse:ignoreCase:file:name
{code}
In the sample below we want to sort by last modified file, so we do:
{code}
sortBy=file:modifed
{code}
And then we want to group by name as a 2nd option so files with same modifcation is sorted by name:
{code}
sortBy=file:modifed;file:name
{code}
Now there is an issue here, can you spot it? Well the modified timestamp of the file is too fine as it will be in millis, but what if we want to sort by date only and then sub group by name?
Well as we have the true power of [File Language] we can use the its date command that supports patterns. So this can be solved as:
{code}
sortBy=date:file:yyyyMMdd;file:name
{code}
Yeah that is pretty powerful, oh by the way you can also use reverse per group so we could reverse the file names:
{code}
sortBy=date:file:yyyyMMdd;reverse:file:name
{code}
h3. Debug logging
This component has log level *TRACE* that can be helpful if you have problems.
{include:Endpoint See Also}
- [File Language]
- [FTP2] |