Chapter 49. File2

File Component - Apache Camel 2.0 onwards

The File component provides access to file systems, allowing files to be processed by any other Apache Camel Components or messages from other components to be saved to disk.

URI format

file:directoryName[?options]
or
file://directoryName[?options]
Where directoryName represents the underlying file directory.
You can append query options to the URI in the following format, ?option=value&option=value&...
Note
Apache Camel only supports 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 fileName option, e.g. by setting fileName=thefilename. Also, the starting directory must not contain dynamic expressions with ${ } placeholders. Again use the fileName option to specify the dynamic part of the filename.
Avoid reading files currently being written by another application
Beware the JDK File IO API is a bit limited in detecting whether another application is currently writing/copying a file. And the implementation can be different depending on OS platform as well. This could lead to that Apache Camel thinks the file is not locked by another process and start consuming it. Therefore you have to do your own investigation as to what suits your environment. To help with this, Apache Camel provides different readLock options and the doneFileName option that you can use. Also, see the section the section called “Consuming files from folders where others drop files directly”.

Camel on EAP deployment

This component is supported by the Camel on EAP (Wildfly Camel) framework, which offers a simplified deployment model on the Red Hat JBoss Enterprise Application Platform (JBoss EAP) container. For details of this model, see chapter "Apache Camel on JBoss EAP" in "Deploying into a Web Server".

URI Options

Name Default Value Description
autoCreate true Automatically create missing directories in the file's pathname. For the file consumer, that means creating the starting directory. For the file producer, it means the directory where the files should be written.
bufferSize 128kb Write buffer sized in bytes.
fileName null Use Expression such as File Language to dynamically set the filename. For consumers, it's used as a filename filter. For producers, it's used to evaluate the filename to write. If an expression is set, it take precedence over the CamelFileName header. (Note: The header itself can also be an Expression). The expression options support both String and Expression types. If the expression is a String type, it is always evaluated using the File Language. If the expression is an Expression type, the specified Expression type is used - this allows you, for instance, to use OGNL expressions. For the consumer, you can use it to filter filenames, so you can for instance consume today's file using the File Language syntax: mydata-${date:now:yyyyMMdd}.txt. From Camel 2.11 onwards the producers support the CamelOverruleFileName header which takes precedence over any existing CamelFileName header; the CamelOverruleFileName is a header that is used only once, and makes it easier as this avoids to temporary store CamelFileName and have to restore it afterwards.
flatten false Flatten is used to flatten the file name path to strip any leading paths, so it's just the file name. This allows you to consume recursively into sub-directories, but when you eg write the files to another directory they will be written in a single directory. Setting this to true on the producer enforces that any file name recived in CamelFileName header will be stripped for any leading paths.
charset null Camel 2.5: this option is used to specify the encoding of the file, and camel will set the Exchange property with Exchange.CHARSET_NAME with the value of this option.
copyAndDeleteOnRenameFail true Camel 2.9: whether to fallback and do a copy and delete file, in case the file could not be renamed directly. This option is not available for the FTP component.
renameUsingCopy false
Camel 2.13.1: Perform rename operations using a copy and delete strategy. This is primarily used in environments where the regular rename operation is unreliable (e.g. across different file systems or networks). This option takes precedence over the copyAndDeleteOnRenameFail parameter that will automatically fall back to the copy and delete strategy, but only after additional delays.

Consumer only

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 true Set to true to use fixed delay between pools, otherwise fixed rate is used. See ScheduledExecutorService in JDK for details.
runLoggingLevel TRACE Camel 2.8: The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.
recursive false If a directory, will look for files in all the sub-directories as well.
delete false If true, the file will be deleted after it is processed successfully.
noop false If true, the file is not moved or deleted in any way. This option is good for readonly data, or for ETL type requirements. If noop=true, Apache Camel will set idempotent=true as well, to avoid consuming the same files over and over again.
preMove null Use Expression such as File Language to dynamically set the filename when moving it before processing. For example to move in-progress files into the order directory set this value to order.
move .camel Use Expression such as File Language to dynamically set the filename when moving it after processing. To move files into a .done subdirectory just enter .done.
moveFailed null Use Expression such as File Language to dynamically set the filename when moving failed files after processing. To move files into a error subdirectory just enter error. Note: When moving the files to another location it can/will handle the error when you move it to another location so Apache Camel cannot pick up the file again.
include null Is used to include files, if filename matches the regex pattern (matching is case in-sensitive from Camel 2.17 onwards).
exclude null Is used to exclude files, if filename matches the regex pattern (matching is case in-sensitive from Camel 2.17 onwards).
antInclude null Camel 2.10: Ant style filter inclusion, for example antInclude=\*{}*/*{}.txt. Multiple inclusions may be specified in comma-delimited format. See the section called “Filtering using ANT path matcher” for more details about ant path filters.
antExclude null Camel 2.10: Ant style filter exclusion. If both antInclude and antExclude are used, antExclude takes precedence over antInclude. Multiple exclusions may be specified in comma-delimited format. See the section called “Filtering using ANT path matcher” for more details about ant path filters.
antFilterCaseSensitive true Camel 2.11: Ant style filter which is case sensitive or not.
idempotent false Option to use the Idempotent Consumer EIP pattern to let Apache Camel skip already processed files. Will by 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.
idempotentKey Expression Camel 2.11: To use a custom idempotent key. By default the absolute path of the file is used. You can use the File Language, for example to use the file name and file size, you can do: idempotentKey=$-$ .
idempotentRepository null Pluggable repository as a org.apache.camel.processor.idempotent.MessageIdRepository class. Will by default use MemoryMessageIdRepository if none is specified and idempotent is true.
inProgressRepository memory Pluggable in-progress repository as a org.apache.camel.processor.idempotent.MessageIdRepository class. The in-progress repository is used to account the current in progress files being consumed. By default a memory based repository is used.
filter null Pluggable filter as a org.apache.camel.component.file.GenericFileFilter class. Will skip files if filter returns false in its accept() method. Apache Camel also ships with an ANT path matcher filter in the camel-spring component. More details in section below.
shuffle false Camel 2.16: To shuffle the list of files (sort in random order)
sorter null Pluggable sorter as a java.util.Comparator<org.apache.camel.component.file.GenericFile> class.
sortBy null Built-in sort 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 none
Used by consumer, to only poll the files if it has exclusive read-lock on the file (i.e. the file is not in-progress or being written). Apache Camel will wait until the file lock is granted.
The readLock option supports the following built-in strategies:
  • none is for no read locks at all.
  • changed uses a length/modification timestamp to detect whether the file is currently being copied or not. Will wait at least 1 second to determine this, so this option cannot consume files as fast as the others, but can be more reliable as the JDK IO API cannot always determine whether a file is currently being used by another process. The readLockCheckInterval option can be used to set the check frequency.
  • markerFile Camel creates a marker file, fileName.camelLock. and then holds a lock on it. This option is not available for the FTP component
  • fileLock is for using java.nio.channels.FileLock. This approach should be avoided when accessing a remote file system via a mount/share unless that file system supports distributed file locks.
  • rename is for using a try to rename the file as a test if we can get exclusive read-lock.
  • idempotent (Camel 2.16) is for using a idempotentRepository as the read-lock. This allows you to use read locks that support clustering, if the idempotent repository implementation supports that.
Note: In cases where a foreign program is writing the files, Red Hat recommends using the doneFileName option instead of the readLock option.
Warning: Most of the read lock strategies are not suitable for use in clustered mode. That is, you cannot have multiple consumers attempting to read the same file in the same directory. In this case, the read locks will not function reliably. The idempotent read lock supports clustered reliably if you use a cluster aware idempotent repository implementation such as from the Hazelcast Component.
readLockTimeout 0 (for FTP, 2000) Optional timeout in milliseconds for the read-lock, if supported by the read-lock. If the read-lock could not be granted and the timeout triggered, then Apache Camel will skip the file. At next poll Apache Camel, will try the file again, and this time maybe the read-lock could be granted. Currently fileLock, changed and rename support the timeout.
readLockCheckInterval 1000 (for FTP, 5000) Camel 2.6: Interval in millis for the read-lock, if supported by the read lock. This interval is used for sleeping between attempts to acquire the read lock. For example when using the changed read lock, you can set a higher interval period to cater for slow writes. The default of 1 sec. may be too fast if the producer is very slow writing the file.
readLockMinLength 1 Camel 2.10.1: This option applied only for readLock=changed. This option allows you to configure a minimum file length. By default Camel expects the file to contain data, and thus the default value is 1. You can set this option to zero, to allow consuming zero-length files.
readLockLoggingLevel WARN Camel 2.12: Logging level used when a read lock could not be acquired. By default a WARN is logged. You can change this level, for example to OFF to not have any logging. This option is only applicable for readLock of types: changed, fileLock, rename.
readLockMarkerFile true
Camel 2.14: Whether to use marker file with the changed, rename, or exclusive read lock types. By default a marker file is used as well to guard against other processes picking up the same files. This behavior can be turned off by setting this option to false. For example if you do not want to write marker files to the file systems by the Camel application.
readLockRemoveOnRollback true
Camel 2.16: This option applies only for readLock=idempotent. Specifies whether to remove the file name entry from the idempotent repository when file processing fails and a rollback occurs. If false, the file name entry is confirmed (as if the file did a commit).
readLockRemoveOnCommit false
Camel 2.16: This option applies only for readLock=idempotent. Specifies whether to remove the file name entry from the idempotent repository when file processing succeeds and a commit occurs. By default, the entry is not removed which ensures that a race-condition will not occur if another active node attempts to grab the file. In this case, it is recommended that you configure an eviction strategy on the idempotent repository, so that the file name entry is evicted after X minutes (after the risk of a race condition is over).
readLockDeleteOrphanLockFiles true
Camel 2.16: This option applies only for readLock=markerFile. On startup, specifies whether or not to delete orphan read lock files, which might have been left on the file system if Camel was not properly shut down (JVM crash). If false, an orphaned lock file could potentially block Camel from attempting to pick up the corresponding file.
directoryMustExist
Camel 2.5: Similar to startingDirectoryMustExist but this applies during polling recursive sub directories.
doneFileName null Camel 2.6: If provided, Camel will only consume files if a done file exists. This option configures what file name to use. Either you can specify a fixed name. Or you can use dynamic placeholders. The done file is always expected in the same folder as the original file. See using done file and writing done file sections for examples. Note: In case of the foreign program writing the files, Red Hat recommend you to use the doneFileName option.
exclusiveReadLockStrategy null Pluggable read-lock as a org.apache.camel.component.file.GenericFileExclusiveReadLockStrategy implementation.
maxMessagesPerPoll 0 An integer that defines the maximum number of messages to gather per poll. By default, no maximum is set. Can be used to set a limit of e.g. 1000 to avoid having the server read thousands of files as it starts up. Set a value of 0 or negative to disabled it.
eagerMaxMessagesPerPoll true
Camel 2.9.3: Allows for controlling whether the limit from maxMessagesPerPoll is eager or not. If eager then the limit is during the scanning of files. Where as false would scan all files, and then perform sorting. Setting this option to false allows for sorting all files first, and then limit the poll. Mind that this requires a higher memory usage as all file details are in memory to perform the sorting.
minDepth 0 Camel 2.8: The minimum depth to start processing when recursively processing a directory. Using minDepth=1 means the base directory. Using minDepth=2 means the first sub directory. This option is not supported by FTP consumer.
maxDepth Integer.MAX_VALUE Camel 2.8: The maximum depth to traverse when recursively processing a directory. This option is not supported by FTP consumer.
processStrategy null A pluggable org.apache.camel.component.file.GenericFileProcessStrategy allowing you to implement your own readLock option or similar. Can also be used when special conditions must be met before a file can be consumed, such as a special ready file exists. If this option is set then the readLock option does not apply.
startingDirectoryMustExist false Whether the starting directory must exist. Mind that the autoCreate option is default enabled, which means the starting directory is normally auto-created if it doesn't exist. You can disable autoCreate and enable this to ensure the starting directory must exist. Will throw an exception, if the directory doesn't exist.
pollStrategy null
A pluggable org.apache.camel.spi.PollingConsumerPollStrategy allowing you to provide your custom implementation to control error handling usually occurred during the poll operation before an Exchange have been created and being routed in Camel. In other words, the error occurred while the polling was gathering information, for instance access to a file network failed so Camel cannot access it to scan for files. The default implementation will log the caused exception at WARN level and ignore it.
sendEmptyMessageWhenIdle false
Camel 2.9: If the polling consumer did not poll any files, you can enable this option to send an empty message (no body) instead.
consumer.bridgeErrorHandler false
Camel 2.10: Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while trying to pick up files, or the like, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that by default will be logged at WARN/ERROR level and ignored. See further below on this page fore more details, at section How to use the Camel error handler to deal with exceptions triggered outside the routing engine.
scheduledExecutorService null
Camel 2.10: Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool. This option allows you to share a thread pool among multiple file consumers.
scheduler null Camel 2.12: Use a custom scheduler to trigger the consumer to run. For more details, see Polling Consumer. For example, there is a Quartz2, and Spring-based scheduler that supports CRON expressions.
backoffMultiplier 0 Camel 2.12: Let the scheduled polling consumer backoff if a number of subsequent idles/errors occurred in a row. The multiplier is then the number of polls that will be skipped before the next attempt is made. When this option is set, backoffIdleThreshold and/or backoffErrorThreshold must also be configured. See more details at Polling Consumer.
backoffIdleThreshold 0 Camel 2.12: The number of subsequent idle polls that should happen before the backoffMultipler should kick-in.
backoffErrorThreshold 0 Camel 2.12: The number of subsequent error polls (failed due some error) that should happen before the backoffMultipler should kick-in.
onCompletionExceptionHandler Camel 2.16: To use a custom org.apache.camel.spi.ExceptionHandler to handle any thrown exceptions that happens during the file on completion process where the consumer does either a commit or rollback. The default implementation will log any exception at WARN level and ignore.
probeContentType false
Camel 2.17: Whether to enable probing of the content type. If enabled, the consumer uses Files#probeContentType(java.nio.file.Path) to determine the Content-Type of the file, and store that as a header with the key Exchange#FILE_CONTENT_TYPE on the Message.
Note: From Camel 2.15 onwards this function was introduced and was always enabled. But from Camel 2.17 it is off by default, as it can cause problems on some file systems.
extendedAttributes null Camel 2.17: To enable gathering extended file attributes through java.nio.file.attribute classes using Files.getAttribute(ava.nio.file.Path, java.lang.String attribute) or Files.readAttributes(ava.nio.file.Path, java.lang.String attributes) depending on the option value. This option supports a comma-delimited list of attributes to collect—for example: basic:creationTime, posix:group—or a simple wildcard—for example, posix:*. If the attribute name is not prefixed, the basic attributes are queried. The result is stored as a header with key, CamelFileExtendedAttributes, of Map<String, Object> type, where the key is the name of the attribute (for example, posix:group) and the value is the attribute returned by the call to Files.getAttribute() or Files.readAttributes.

Default behavior for file consumer

  • By default the file is not locked for the duration of the processing.
  • After the route has completed, files are moved into the .camel subdirectory, so that they appear to be deleted.
  • The File Consumer will always skip any file whose name starts with a dot, such as ., .camel, .m2 or .groovy.
  • Only files (not directories) are matched for valid filename, if options such as: includeNamePrefix, includeNamePostfix, excludeNamePrefix, excludeNamePostfix, regexPattern are used.

Producer only

Name Default Value Description
fileExist Override What to do if a file already exists with the same name. The following values can be specified: Override, Append, Fail, Ignore, Move, and TryRename (Camel 2.11.1). Override, which is the default, replaces the existing file. Append adds content to the existing file. Fail throws a GenericFileOperationException, indicating that there is already an existing file. Ignore silently ignores the problem and does not override the existing file, but assumes everything is okay. The Move option requires Camel 2.10.1 onwards, and the corresponding moveExisting option to be configured as well. The option eagerDeleteTargetFile can be used to control what to do if an moving the file, and there exists already an existing file, otherwise causing the move operation to fail. The Move option will move any existing files, before writing the target file. TryRenameCamel 2.11.1 is only applicable if tempFileName option is in use. This allows to try renaming the file from the temporary name to the actual name, without doing any exists check. This check may be faster on some file systems and especially FTP servers.
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 when uploading big files.
tempFileName null Camel 2.1: The same as tempPrefix option but offering a more fine grained control on the naming of the temporary filename as it uses the File Language.
keepLastModified false Camel 2.2: Will keep the last modified timestamp from the source file (if any). Will use the Exchange.FILE_LAST_MODIFIED header to located the timestamp. This header can contain either a java.util.Date or long with the timestamp. If the timestamp exists and the option is enabled it will set this timestamp on the written file. Note: This option only applies to the file producer. You cannot use this option with any of the ftp producers.
eagerDeleteTargetFile true Camel 2.3: Whether or not to eagerly delete any existing target file. This option only applies when you use fileExists=Override and the tempFileName option as well. You can use this to disable (set it to false) deleting the target file before the temp file is written. For example you may write big files and want the target file to exists during the temp file is being written. This ensure the target file is only deleted until the very last moment, just before the temp file is being renamed to the target filename. From Camel 2.10.1 on this option is also used to control whether to delete any existing files when fileExist=Move is enabled, and an existing file exists. If the option copyAndDeleteOnRenameFail is false, an exception will be thrown if an existing file existed; if it's true, the existing file is deleted before the move operation.
doneFileName null Camel 2.6: If provided, then Camel will write a 2nd done file when the original file has been written. The done file will be empty. This option configures what file name to use. Either you can specify a fixed name. Or you can use dynamic placeholders. The done file will always be written in the same folder as the original file. See writing done file section for examples. Note: In case of the foreign program writing the files, Red Hat recommend you to use the doneFileName option.
allowNullBody false Camel 2.10.1: Used to specify if a null body is allowed during file writing. If set to true then an empty file will be created, when set to false, and attempting to send a null body to the file component, a GenericFileWriteException of 'Cannot write null body to file.' will be thrown. If the `fileExist` option is set to 'Override', then the file will be truncated, and if set to `append` the file will remain unchanged.
forceWrites true Camel 2.10.5/2.11: Whether to force syncing writes to the file system. You can turn this off if you do not want this level of guarantee, for example if writing to logs / audit logs etc; this would yield better performance.
chmod null Camel 2.15.0: Specifies the file permissions sent by the producer, where the chmod value must be between 000 and 777. Leading digits—for example, 0755—are ignored.
chmodDirectory null Camel 2.17.0: Specifies the directory permissions used when the producer creates missing directories, where the chmod value must be between 000 and 777. Leading digits—for example, 0755—are ignored.

Default behavior for file producer

  • By default it will override any existing file, if one exist with the same name. In Apache Camel 1.x the Append is the default for the file producer. We have changed this to Override in Apache Camel 2.0 as this is also the default file operation using java.io.File. And also the default for the FTP library we use in the camel-ftp component.

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:
    from("file://inbox?move=.done").to("bean:handleOrder");
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 object. 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.
The move and preMove options is considered as a directory name (though if you use an expression such as File Language, or Simple then the result of the expression evaluation is the file name to be used - eg if you set
move=../backup/copy-of-${file:name}
then that's using the File Language which we use return the file name to be used), which can be either relative or absolute. If relative, the directory is created as a sub-folder from within the folder where the file was consumed.
By default, Apache Camel will move consumed files to the .camel sub-folder relative to the directory where the file was consumed.
If you want to delete the file after processing, the route should be:
    from("file://inobox?delete=true").to("bean:handleOrder");
We have introduced a pre move operation to move files before they are processed. This allows you to mark which files have been scanned as they are moved to this sub folder before being processed.
    from("file://inbox?preMove=inprogress").to("bean:handleOrder");
You can combine the pre move and the regular move:
    from("file://inbox?preMove=inprogress&move=.done").to("bean:handleOrder");
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.

Fine grained control over Move and PreMove option

The move and preMove option is Expression-based, so we have the full power of the File Language to do advanced configuration of the directory and name pattern. Apache Camel will, in fact, internally convert the directory name you enter into a File Language expression. So when we enter move=.done Apache Camel will convert this into: ${file:parent}/.done/${file:onlyname}. This is only done if Apache Camel detects that you have not provided a ${ } in the option value yourself. So when you enter an expression containing ${ }, the expression is interpreted as a File Language expression.
So if we want to move the file into a backup folder with today's date as the pattern, we can do:
move=backup/${date:now:yyyyMMdd}/${file:name}

About moveFailed

The moveFailed option allows you to move files that could not be processed succesfully to another location such as a error folder of your choice. For example to move the files in an error folder with a timestamp you can use moveFailed=/error/${file:name.noext}-${date:now:yyyyMMddHHmmssSSS}.${file:name.ext}.
See more examples at File Language.

Message Headers

The following headers are supported by this component:

File producer only

Header Description
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 it's null then Apache Camel will auto-generate a filename based on the message unique ID.
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 with the name of the file that was written.
CamelOverruleFileName Camel 2.11: Is used for overruling CamelFileName header and use the value instead (but only once, as the producer will remove this header after writing the file). The value can be only be a String. Notice that if the option fileName has been configured, then this is still being evaluated.

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 (the name with no leading paths).
CamelFileAbsolute A boolean option specifying whether the consumed file denotes an absolute path or not. Should normally be false for relative paths. Absolute paths 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 value containing the file size.
CamelFileLastModified A long value containing the last modified timestamp of the file.

Batch Consumer

This component implements the Batch Consumer.

Exchange Properties, file consumer only

As the file consumer is BatchConsumer it supports batching the files it polls. By batching it means that Apache Camel will add some properties to the Exchange so you know the number of files polled the current index in that order.
Property Description
CamelBatchSize The total number of files that was polled in this batch.
CamelBatchIndex The current index of the batch. Starts from 0.
CamelBatchComplete A boolean value indicating the last Exchange in the batch. Is only true for the last entry.
This allows you, for example, to know how many files exists in this batch and let the Aggregator aggregate this number of files.

Common gotchas with folder and filenames

When Apache Camel is producing files (writing files) there are a few gotchas affecting how to set a filename of your choice. By default, Apache 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 you must provide a filename in the CamelFileName message header. The constant, Exchange.FILE_NAME, can also be used.
The sample code below produces files using the message ID as the filename:
from("direct:report").to("file:target/reports");
To use report.txt as the filename you have to do:
from("direct:report").setHeader(Exchange.FILE_NAME, constant("report.txt")).to( "file:target/reports");
Or the same as above, but with CamelFileName:
from("direct:report").setHeader("CamelFileName", constant("report.txt")).to( "file:target/reports");
And a syntax where we set the filename on the endpoint with the fileName URI option.
from("direct:report").to("file:target/reports/?fileName=report.txt");

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.

Consuming files from folders where others drop files directly

Beware if you consume files from a folder where other applications write files directly. Take a look at the different readLock options to see what suits your use cases. The best approach is however to write to another folder and after the write move the file in the drop folder. However if you write files directly to the drop folder then the option changed could better detect whether a file is currently being written/copied as it uses a file changed algorithm to see whether the file size / modification changes over a period of time. The other read lock options rely on Java File API that sadly is not always very good at detecting this. You may also want to look at the doneFileName option, which uses a marker file (done) to signal when a file is done and ready to be consumed.

Using done files

Available as of Camel 2.6
Also, see the section writing done files below.
If you want only to consume files when a done file exists, then you can use the doneFileName option on the endpoint.
from("file:bar?doneFileName=done");
Will only consume files from the bar folder, if a file name done exists in the same directory as the target files. Camel will automatically delete the done file when it's done consuming the files.
However its more common to have one done file per target file. This means there is a 1:1 correlation. To do this you must use dynamic placeholders in the doneFileName option. Currently Camel supports the following two dynamic tokens: file:name and file:name.noext which must be enclosed in ${ }. The consumer only supports the static part of the done file name as either prefix or suffix (not both).
from("file:bar?doneFileName=${file:name}.done");
In this example only files will be polled if there exists a done file with the name file name.done. For example
  • hello.txt - is the file to be consumed
  • hello.txt.done - is the associated done file
You can also use a prefix for the done file, such as:
from("file:bar?doneFileName=ready-${file:name}");
  • hello.txt - is the file to be consumed
  • ready-hello.txt - is the associated done file

Writing done files

Available as of Camel 2.6
After you have written af file you may want to write an additional done file as a kinda of marker, to indicate to others that the file is finished and has been written. To do that you can use the doneFileName option on the file producer endpoint.
.to("file:bar?doneFileName=done");
Will simply create a file named done in the same directory as the target file.
However its more common to have one done file per target file. This means there is a 1:1 correlation. To do this you must use dynamic placeholders in the doneFileName option. Currently Camel supports the following two dynamic tokens: file:name and file:name.noext which must be enclosed in ${ }.
.to("file:bar?doneFileName=done-${file:name}");
Will for example create a file named done-foo.txt if the target file was foo.txt in the same directory as the target file.
.to("file:bar?doneFileName=${file:name}.done");
Will for example create a file named foo.txt.done if the target file was foo.txt in the same directory as the target file.
.to("file:bar?doneFileName=${file:name.noext}.done");
Will for example create a file named foo.done if the target file was foo.txt in the same directory as the target file.

Read from a directory and write to another directory

from("file://inputdir/?delete=true").to("file://outputdir")

Read from a directory and write to another directory using a overrule dynamic name

from("file://inputdir/?delete=true").to("file://outputdir?overruleFile=copy-of-${file:name}")
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.

Reading recursively from a directory and writing to another

from("file://inputdir/?recursive=true&delete=true").to("file://outputdir")
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. Will scan recursively into sub-directories. Will lay out the files in the same directory structure in the outputdir as the inputdir, including any sub-directories.
inputdir/foo.txt
inputdir/sub/bar.txt
Will result in the following output layout:
outputdir/foo.txt
outputdir/sub/bar.txt

Using flatten

If you want to store the files in the outputdir directory in the same directory, disregarding the source directory layout (e.g. to flatten out the path), you just add the flatten=true option on the file producer side:
from("file://inputdir/?recursive=true&delete=true").to("file://outputdir?flatten=true")
Will result in the following output layout:
outputdir/foo.txt
outputdir/bar.txt

Reading from a directory and the default move operation

Apache Camel will by default move any processed file into a .camel subdirectory in the directory the file was consumed from.
from("file://inputdir/?recursive=true&delete=true").to("file://outputdir")
Affects the layout as follows: before
inputdir/foo.txt
inputdir/sub/bar.txt
after
inputdir/.camel/foo.txt
inputdir/sub/.camel/bar.txt
outputdir/foo.txt
outputdir/sub/bar.txt

Read from a directory and process the message in java

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
  }
});
The body will be a File object that points to the file that was just dropped into the inputdir directory.

Read files from a directory and send the content to a jms queue

from("file://inputdir/").convertBodyTo(String.class).to("jms:test.queue")
By default the file endpoint sends a FileMessage which contains a File object as the 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, which is probably what you want.
The route above using Spring DSL:
   <route>
      <from uri="file://inputdir/"/>
      <convertBodyTo type="java.lang.String"/>
      <to uri="jms:test.queue"/>
   </route>

Writing to files

Apache Camel is of course also able to write files, i.e. produce files. In the sample below we receive some reports on the SEDA queue that we process before they are written to a directory.
public void testToFile() throws Exception {
    MockEndpoint mock = getMockEndpoint("mock:result");
    mock.expectedMessageCount(1);
    mock.expectedFileExists("target/test-reports/report.txt");

    template.sendBody("direct:reports", "This is a great report");

    assertMockEndpointsSatisfied();
}

protected JndiRegistry createRegistry() throws Exception {
    // bind our processor in the registry with the given id
    JndiRegistry reg = super.createRegistry();
    reg.bind("processReport", new ProcessReport());
    return reg;
}

protected RouteBuilder createRouteBuilder() throws Exception {
    return new RouteBuilder() {
        public void configure() throws Exception {
            // the reports from the seda queue is processed by our processor
            // before they are written to files in the target/reports directory
            from("direct:reports").processRef("processReport").to("file://target/test-reports", "mock:result");
        }
    };
}

private static class ProcessReport implements Processor {

    public void process(Exchange exchange) throws Exception {
        String body = exchange.getIn().getBody(String.class);
        // do some business logic here

        // set the output to the file
        exchange.getOut().setBody(body);

        // set the output filename using java code logic, notice that this is done by setting
        // a special header property of the out exchange
        exchange.getOut().setHeader(Exchange.FILE_NAME, "report.txt");
    }

}

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:
  <route>
    <from uri="bean:myBean"/>
    <to uri="file:/rootDirectory"/>
  </route>
You can have myBean set the header Exchange.FILE_NAME to values such as:
Exchange.FILE_NAME = hello.txt => /rootDirectory/hello.txt
Exchange.FILE_NAME = foo/bye.txt => /rootDirectory/foo/bye.txt
This allows you to have a single route to write files to multiple destinations.

Writing file through the temporary directory relative to the final destination

Sometime you need to temporarily write the files to some directory relative to the destination directory. Such situation usually happens when some external process with limited filtering capabilities is reading from the directory you are writing to. In the example below files will be written to the /var/myapp/filesInProgress directory and after data transfer is done, they will be atomically moved to the /var/myapp/finalDirectory directory.
from("direct:start").
  to("file:///var/myapp/finalDirectory?tempPrefix=/../filesInProgress/");

Using expression for filenames

In this sample we want to move consumed files to a backup folder using today's date as a sub-folder name:
from("file://inbox?move=backup/${date:now:yyyyMMdd}/${file:name}").to("...");
See File Language for more samples.

Avoiding reading the same file more than once (idempotent consumer)

Apache 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.
from("file://inbox?idempotent=true").to("...");
Camel uses the absolute file name as the idempotent key, to detect duplicate files. From Camel 2.11 onwards you can customize this key by using an expression in the idempotentKey option. For example to use both the name and the file size as the key
  <route>
    <from uri="file://inbox?idempotent=true&dempotentKey=${file:name}-${file:size}"/>
    <to uri="bean:processInbox"/>
  </route>
By default Apache Camel uses an in-memory based store for keeping track of consumed files, it uses a least recently used cache 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 the specified id.
   <!-- define our store as a plain spring bean -->
   <bean id="myStore" class="com.mycompany.MyIdempotentStore"/>

  <route>
    <from uri="file://inbox?idempotent=true&dempotentRepository=#myStore"/>
    <to uri="bean:processInbox"/>
  </route>
Apache Camel will log at DEBUG level if it skips a file because it has been consumed before:
DEBUG FileConsumer is idempotent and the file has been consumed before. Will skip this file: target\idempotent\report.txt

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 stores the key in separate lines in the file. By default, the file store has a size limit of 1mb and when the file grows larger, Apache Camel will truncate the file store and rebuild the content by flushing the 1st level cache into 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:
<!-- this is our file based idempotent store configured to use the .filestore.dat as file -->
<bean id="fileStore" class="org.apache.camel.processor.idempotent.FileIdempotentRepository">
    <!-- the filename for the store -->
    <property name="fileStore" value="target/fileidempotent/.filestore.dat"/>
    <!-- the max filesize in bytes for the file. Apache Camel will trunk and flush the cache
         if the file gets bigger -->
    <property name="maxFileStoreSize" value="512000"/>
    <!-- the number of elements in our store -->
    <property name="cacheSize" value="250"/>
</bean>

<camelContext xmlns="http://camel.apache.org/schema/spring">
    <route>
        <from uri="file://target/fileidempotent/?idempotent=true&dempotentRepository=#fileStore&ove=done/${file:name}"/>
        <to uri="mock:result"/>
    </route>
</camelContext>

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.
<persistence-unit name="idempotentDb" transaction-type="RESOURCE_LOCAL">
  <class>org.apache.camel.processor.idempotent.jpa.MessageProcessed</class>

  <properties>
    <property name="openjpa.ConnectionURL" value="jdbc:derby:target/idempotentTest;create=true"/>
    <property name="openjpa.ConnectionDriverName" value="org.apache.derby.jdbc.EmbeddedDriver"/>
    <property name="openjpa.jdbc.SynchronizeMappings" value="buildSchema"/>
    <property name="openjpa.Log" value="DefaultLevel=WARN, Tool=INFO"/>
  </properties>
</persistence-unit>
Then we need to setup a Spring jpaTemplate in the spring XML file:
<!-- this is standard spring JPA configuration -->
<bean id="jpaTemplate" class="org.springframework.orm.jpa.JpaTemplate">
    <property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
    <!-- we use idempotentDB as the persitence unit name defined in the persistence.xml file -->
    <property name="persistenceUnitName" value="idempotentDb"/>
</bean>
And finally we can create our JPA idempotent repository in the spring XML file as well:
<!-- we define our jpa based idempotent repository we want to use in the file consumer -->
<bean id="jpaStore" class="org.apache.camel.processor.idempotent.jpa.JpaMessageIdRepository">
    <!-- Here we refer to the spring jpaTemplate -->
    <constructor-arg index="0" ref="jpaTemplate"/>
    <!-- This 2nd parameter is the name  (= a cateogry name).
         You can have different repositories with different names -->
    <constructor-arg index="1" value="FileConsumer"/>
</bean>
And then we just need to reference the jpaStore bean in the file consumer endpoint, using the idempotentRepository option and the # syntax:
  <route>
    <from uri="file://inbox?idempotent=true&dempotentRepository=#jpaStore"/>
    <to uri="bean:processInbox"/>
  </route>

Filter using org.apache.camel.component.file.GenericFileFilter

Apache 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 built our own filter that skips files starting with skip in the filename:
public class MyFileFilter implements GenericFileFilter {
    public boolean accept(GenericFile pathname) {
        // we dont accept any files starting with skip in the name
        return !pathname.getFileName().startsWith("skip");
    }
}
And then we can configure our route using the filter attribute to reference our filter (using # notation) that we have defined in the spring XML file:
   <!-- define our filter as a plain spring bean -->
   <bean id="myFilter" class="com.mycompany.MyFileFilter"/>

  <route>
    <from uri="file://inbox?filter=#myFilter"/>
    <to uri="bean:processInbox"/>
  </route>

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 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:
<camelContext xmlns="http://camel.apache.org/schema/spring">
    <template id="camelTemplate"/>

    <!-- use myFilter as filter to allow setting ANT paths for which files to scan for -->
    <endpoint id="myFileEndpoint" uri="file://target/antpathmatcher?recursive=true&ilter=#myAntFilter"/>

    <route>
        <from ref="myFileEndpoint"/>
        <to uri="mock:result"/>
    </route>
</camelContext>

<!-- we use the antpath file filter to use ant paths for includes and exlucde -->
<bean id="myAntFilter" class="org.apache.camel.component.file.AntPathMatcherGenericFileFilter">
    <!-- include and file in the subfolder that has day in the name -->
    <property name="includes" value="**/subfolder/**/*day*"/>
    <!-- exclude all files with bad in name or .xml files. Use comma to seperate multiple excludes -->
    <property name="excludes" value="**/*bad*,**/*.xml"/>
</bean>

Sorting using Comparator

Apache 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 Apache Camel sort the files before being processed.
In the sample we have built our own comparator that just sorts by file name:
public class MyFileSorter implements Comparator<GenericFile> {
    public int compare(GenericFile o1, GenericFile o2) {
        return o1.getFileName().compareToIgnoreCase(o2.getFileName());
    }
}
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:
   <!-- 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>
URI options can reference beans using the # syntax
In the Spring DSL route about notice that we can reference beans in the Registry by prefixing the id with #. So writing sorter=#mySorter, will instruct Apache Camel to go look in the Registry for a bean with the ID, mySorter.

Sorting using sortBy

Apache Camel supports pluggable sorting strategies. This strategy it to use the File Language to configure the sorting. The sortBy option is configured as follows:
sortBy=group 1;group 2;group 3;...
Where each group is separated with semi colon. In the simple situations you just use one group, so a simple example could be:
sortBy=file:name
This will sort by file name, you can reverse the order by prefixing reverse: to the group, so the sorting is now Z..A:
sortBy=reverse:file:name
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:
sortBy=file:length
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:
sortBy=ignoreCase:file:name
You can combine ignore case and reverse, however reverse must be specified first:
sortBy=reverse:ignoreCase:file:name
In the sample below we want to sort by last modified file, so we do:
sortBy=file:modified
And then we want to group by name as a 2nd option so files with same modifcation is sorted by name:
sortBy=file:modified;file:name
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 milliseconds, but what if we want to sort by date only and then subgroup 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:
sortBy=date:file:yyyyMMdd;file:name
Yeah, that is pretty powerful, oh by the way you can also use reverse per group, so we could reverse the file names:
sortBy=date:file:yyyyMMdd;reverse:file:name

Using GenericFileProcessStrategy

The option processStrategy can be used to use a custom GenericFileProcessStrategy that allows you to implement your own begin, commit and rollback logic. For instance lets assume a system writes a file in a folder you should consume. But you should not start consuming the file before another ready file have been written as well.
So by implementing our own GenericFileProcessStrategy we can implement this as:
  • In the begin() method we can test whether the special ready file exists. The begin method returns a boolean to indicate if we can consume the file or not.
  • in the commit() method we can move the actual file and also delete the ready file.
Important when using consumer.bridgeErrorHandler
When using consumer.bridgeErrorHandler, then interceptors, OnCompletion does not apply. The Exchange is processed directly by the Camel Error Handler, and does not allow prior actions such as interceptors, onCompletion to take action.

Debug logging

This component has log level TRACE that can be helpful if you have problems.
See also: