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 to be saved to disk.
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&...
Only directoriesCamel supports only 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 ${} placeholders. Again use the fileName option to specify the dynamic part of the filename.
Avoid reading files currently being written by another applicationBeware the JDK File IO API is a bit limited in detecting whether another application is currently writing/copying a file. And the implementation can be different depending on OS platform as well. This could lead to that Camel thinks the file is not locked by another process and start consuming it. Therefore you have to do you own investigation what suites your environment. To help with this Camel provides different readLock options and doneFileName option that you can use. See also the section Consuming files from folders where others drop files directly.
URI Options
Common
confluenceTableSmallName | Default Value | Description |
|---|
autoCreate
| true
| Automatically create missing directories in the file's path name. For the file consumer, that means creating the starting directory. For the file producer, it means the directory the files should be written to. |
bufferSize
| 128kb
| Write buffer sized in bytes. |
fileName
| null
| Use Expression such as File Language to dynamically set the filename. For consumers, it's used as a filename filter. For producers, it's used to evaluate the filename to write. If an expression is set, it take precedence over the CamelFileName header. (Note: The header itself can also be an Expression). The expression options support both String and Expression types. If the expression is a String type, it is always evaluated using the File Language. If the expression is an Expression type, the specified Expression type is used - this allows you, for instance, to use OGNL expressions. For the consumer, you can use it to filter filenames, so you can for instance consume today's file using the File Language syntax: mydata-${date:now:yyyyMMdd}.txt. From Camel 2.11 onward 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 received in CamelFileName header will be stripped for any leading paths. |
charset
| null
| Camel 2.9.3: this option is used to specify the encoding of the file. You can use this on the consumer, to specify the encodings of the files, which allow Camel to know the charset it should load the file content in case the file content is being accessed. Likewise when writing a file, you can use this option to specify which charset to write the file as well. See further below for a examples and more important details. |
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
confluenceTableSmallName | Default Value | Description |
|---|
initialDelay
| 1000
| Milliseconds before polling the file/directory starts. |
delay
| 500
| Milliseconds before the next poll of the file/directory. |
useFixedDelay
| | Controls if fixed delay or fixed rate is used. See ScheduledExecutorService in JDK for details. In Camel 2.7.x or older the default value is false. From Camel 2.8 onward the default value is true. |
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, Camel will set idempotent=true as well, to avoid consuming the same files over and over again. |
preMove
| null
| Expression (such as File Language) used 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
| Expression (such as File Language) used to dynamically set the filename when moving it after processing. To move files into a .done subdirectory just enter .done. |
moveFailed
| null
| Expression (such as File Language) used to dynamically set a different target directory when moving files in case of processing (configured via move defined above) failed. For example, to move files into a .error subdirectory use: .error. Note: When moving the files to the “fail” location Camel will handle the error and will not 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 onward). |
exclude
| null
| Is used to exclude files, if filename matches the regex pattern (matching is case in-sensitive from Camel 2.17 onward). |
antInclude
| null
| Camel 2.10: Ant style filter inclusion, for example antInclude=*/.txt. Multiple inclusions may be specified in comma-delimited format. See below 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 below 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 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=${file:name}-${file:size} |
idempotentRepository
| null
| A pluggable repository org.apache.camel.spi.IdempotentRepository which by default use MemoryMessageIdRepository if none is specified and idempotent is true. |
inProgressRepository
| memory
| A pluggable in-progress repository org.apache.camel.spi.IdempotentRepository . 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. More details in section below. |
filterDirectory
| null
| Camel 2.18: Filters the directory based on Simple language. For example to filter on current date, you can use a simple date pattern such as ${date:now:yyyMMdd}. |
filterFile
| null
| Camel 2.18: Filters the file based on Simple language. For example to filter on file size, you can use ${file}:size > 5000. |
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 e.g., the file is not in-progress or being written. Camel will wait until the file lock is granted. This option provides the built-in strategies: none is for no read locks at all. markerFile Camel creates a marker file fileName.camelLock and then holds a lock on it. This option is not available for the FTP component. changed is using file length/modification timestamp to detect whether the file is currently being copied or not. Will at least use 1 sec. 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 option readLockCheckInterval can be used to set the check frequency. This option is only avail for the FTP component from Camel 2.8 onward. Note: from Camel 2.10.1 onward the FTP option fastExistsCheck can be enabled to speedup this readLock strategy, if the FTP server support the LIST operation with a full file name (some servers may not).fileLock is for using java.nio.channels.FileLock. This option is not avail for the FTP component. 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 (only file component) is for using a idempotentRepository as the read-lock. This allows to use read locks that supports clustering if the idempotent repository implementation supports that. idempotent-changed Camel 2.19 (only file component) is for using a idempotentRepository and changed as combined read-lock. This allows to use read locks that supports clustering if the idempotent repository implementation supports that. idempotent-rename Camel 2.19 (only file component) is for using a idempotentRepository and rename as combined read-lock. This allows to use read locks that supports clustering if the idempotent repository implementation supports that.
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 Hazelcast Component or Infinispan. |
readLockTimeout
| 10000
| Optional timeout in milliseconds for the readLock, if supported. 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. Use a value of 0 or lower to indicate forever. In Camel 2.0 the default value is 0. Starting with Camel 2.1 the default value is 10000. Currently fileLock, changed and rename support the timeout. Note: for FTP the default readLockTimeout value is 20000 instead of 10000. The readLockTimeout value must be higher than readLockCheckInterval, but a rule of thumb is to have a timeout that is at least 2 or more times higher than the readLockCheckInterval. This is needed to ensure that ample time is allowed for the read lock process to try to grab the lock before the timeout was hit. |
readLockCheckInterval
| 1000
| Camel 2.6: Interval in milliseconds 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. For FTP the default readLockCheckInterval is 5000. The readLockTimeout value must be higher than readLockCheckInterval, but a rule of thumb is to have a timeout that is at least 2 or more times higher than the readLockCheckInterval. This is needed to ensure that ample time is allowed for the read lock process to try to grab the lock before the timeout was hit. |
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. |
readLockMinAge
| 0
| Camel 2.15: This option applies only to readLock=change. This option allows you to specify a minimum age a file must be before attempting to acquire the read lock. For example, use readLockMinAge=300s to require that the file is at least 5 minutes old. This can speedup the poll when the file is old enough as it will acquire the read lock immediately. Notice for FTP: file timestamps reported by FTP servers are often reported with resolution of minutes, so readLockMinAge parameter should be defined in minutes, e.g. 60000 for 1 minute. Notice that Camel supports specifying this as 60s, or 1m, etc. |
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 the readLock types: |
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 applied only for readLock=idempotent. This option allows to specify whether to remove the file name entry from the idempotent repository when processing the file failed and a rollback happens. If this option is false, then the file name entry is confirmed (as if the file did a commit). |
readLockRemoveOnCommit | false
| Camel 2.16: This option applied only for readLock=idempotent. This option allows to specify whether to remove the file name entry from the idempotent repository when processing the file succeeded and a commit happens. By default the file is not removed which ensures that any race-condition do not occur so another active node may attempt to grab the file. Instead the idempotent repository may support eviction strategies that you can configure to evict the file name entry after X minutes - this ensures no problems with race conditions. |
readLockDeleteOrphanLockFiles
| true
| Camel 2.16: Whether or not read lock with marker files should upon startup delete any orphan read lock files, which may have been left on the file system, if Camel was not properly shutdown (such as a JVM crash). If turning this option to false then any orphaned lock file will cause Camel to not attempt to pickup that file, this could also be due another node is concurrently reading files from the same shared directory. |
directoryMustExist
| false
| 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. |
exclusiveReadLockStrategy
| null
| Pluggable read-lock as a org.apache.camel.component.file.GenericFileExclusiveReadLockStrategy implementation. |
maxMessagesPerPoll
| 0
| An integer to define a maximum messages to gather per poll. By default no maximum is set. Can be used to set a limit of e.g. 1000 to avoid when starting up the server that there are thousands of files. Set a value of 0 or negative to disable it. See more details at Batch Consumer. Notice: If this option is in use then the File and FTP components will limit before any sorting. For example if you have 100000 files and use maxMessagesPerPoll=500, then only the first 500 files will be picked up, and then sorted. You can use the eagerMaxMessagesPerPoll option and set this to false to allow to scan all files first and then sort afterwards. |
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 supported by FTP consumer from Camel 2.8.2, 2.9 onward. |
maxDepth
| Integer.MAX_VALUE
| Camel 2.8: The maximum depth to traverse when recursively processing a directory. This option is supported by FTP consumer from Camel 2.8.2, 2.9 onward. |
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
| Camel 2.5: 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 thrown 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 that may occur during the poll operation but before an Exchange has been created and routed by Camel. In other words the error occurred while the polling was gathering information e.g., 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 pickup files, or the likes, 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 the following section for more details: 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: To use a custom scheduler to trigger the consumer to run. See more details at Polling Consumer, for example there is a Quartz2, and Spring based scheduler that supports CRON expressions. |
backoffMultiplier
| 0
| Camel 2.12: To let the scheduled polling consumer backoff if there has been a number of subsequent idles/errors in a row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use then backoffIdleThreshold and/or backoffErrorThreshold must also be configured. For more details see: 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 enable then the consumer uses Files#probeContentType(java.nio.file.Path) to determine the content-type of the file, and store that as a header with key Exchange#FILE_CONTENT_TYPE on the Message. Camel 2.15-2.16.x the default is true. |
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 e.g., basic:creationTime, posix:group or simple wildcard e.g., posix:*. If the attribute name is not prefixed, the basic attributes are queried. The result is stored as a header with key CamelFileExtendedAttributes and it is of type Map<String, Object> where the key is the name of the attribute e.g., posix:group and the value is the attributed 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: include or exclude are used.
Producer
confluenceTableSmallName | Default Value | Description |
|---|
fileExist
| Override
| What to do if a file already exists with the same name. The following values can be specified: Override 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.
Move (Camel 2.10.1 onward) requires that the option moveExisting be configured as well. The eagerDeleteTargetFile can be used to control what to do if moving the file, and there already exists a file, otherwise causing the move operation to fail. The Move option will move any existing files, before writing the target file.
TryRename (Camel 2.11.1 onward) 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 to 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. |
moveExisting
| null
| Camel 2.10.1: Expression (such as File Language) used to compute file name to use when fileExist=Move is configured. To move files into a backup subdirectory just enter backup. This option only supports the following File Language tokens: file:name
file:name.ext
file:name.noext
file:onlyname
file:onlyname.noext
file:ext
file:parent
Note: the file:parent token is not supported by the FTP component which can only move files to a directory relative to the current directory. |
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. It cannot be used 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 exist while the temp file is being written. This ensures that the target file is only deleted at the very last moment, just before the temp file is being renamed to the target filename. From Camel 2.10.1 onward this option is also used to control whether to delete any existing files when fileExist=Move is enabled, and an existing file exists. If this option copyAndDeleteOnRenameFail is false, then an exception will be thrown if an existing file existed. When true the existing file is deleted before the move operation. |
doneFileName
| null
| Camel 2.6: If provided, then Camel will write a second file (called done file) when the original file has been written. The done file will be empty. This option configures what file name to use. You can either 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. |
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 the a message 'Cannot write null body to file' will be thrown. If fileExist=Override the file will be truncated. If fileExist=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: Specify the file permissions which is sent by the producer, the chmod value must be between 000 and 777; If there is a leading digit like in 0755 we will ignore it. |
chmodDirectory
| null
| Camel 2.17.0: Specify the directory permissions used when the producer creates missing directories, the chmod value must be between 000 and 777; If there is a leading digit like in 0755 we will ignore it. |
Default behavior for file producer
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:
javafrom("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 the preMove options are 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 e.g., 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, 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:
javafrom("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.
javafrom("file://inbox?preMove=inprogress")
.to("bean:handleOrder");
You can combine the pre move and the regular move:
javafrom("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 Using The move and preMove Options
The move and preMove options are Expression-based, so we have the full power of the File Language to do advanced configuration of the directory and name pattern.
Camel will, in fact, internally convert the directory name you enter into a File Language expression. So when we enter move=.done Camel will convert this into: ${file:parent}/.done/${file:onlyname}. This is only done if Camel detects that you have not provided a ${} in the option value yourself. So when you enter a ${} Camel will not convert it and thus you have the full power.
So if we want to move the file into a backup folder with today's date as the pattern, we can do:
move=backup/${date:now:yyyyMMdd}/${file:name}
About moveFailed
The moveFailed option allows you to move files that could not be processed successfully to another location such as a error folder of your choice. For example to move the files in an error folder with a timestamp you can use moveFailed=/error/${file:name.noext}-${date:now:yyyyMMddHHmmssSSS}.${file:ext}.
See more examples at File Language
The following headers are supported by this component:
File producer only
confluenceTableSmallHeader | Description |
|---|
CamelFileName
| Specifies the name of the file to write (relative to the endpoint directory). This name can be a String; a String with a File Language or Simple expression; or an Expression object. If it's null then Camel will auto-generate a filename based on the message unique ID. |
CamelFileNameProduced
| The absolute file path (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
confluenceTableSmallHeader | 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. In Camel 2.10.3 and older the type is Date. |
Batch Consumer
This component implements the Batch Consumer.
Exchange Properties, file consumer only
As the file consumer implements the BatchConsumer it supports batching the files it polls. By batching we mean that Camel will add the following additional properties to the Exchange, so you know the number of files polled, the current index, and whether the batch is already completed.
confluenceTableSmallProperty | 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 instance to know how many files exist in this batch and for instance let the Aggregator2 aggregate this number of files.
Using charset
Available as of Camel 2.9.3
The charset option allows for configuring an encoding of the files on both the consumer and producer endpoints. For example if you read utf-8 files, and want to convert the files to iso-8859-1, you can do:
from("file:inbox?charset=utf-8")
.to("file:outbox?charset=iso-8859-1")
You can also use the convertBodyTo in the route. In the example below we have still input files in utf-8 format, but we want to convert the file content to a byte array in iso-8859-1 format. And then let a bean process the data. Before writing the content to the outbox folder using the current charset.
from("file:inbox?charset=utf-8")
.convertBodyTo(byte[].class, "iso-8859-1")
.to("bean:myBean")
.to("file:outbox");
If you omit the charset on the consumer endpoint, then Camel does not know the charset of the file, and would by default use "UTF-8". However you can configure a JVM system property to override and use a different default encoding with the key org.apache.camel.default.charset.
In the example below this could be a problem if the files is not in UTF-8 encoding, which would be the default encoding for read the files.
In this example when writing the files, the content has already been converted to a byte array, and thus would write the content directly as is (without any further encodings).
from("file:inbox")
.convertBodyTo(byte[].class, "iso-8859-1")
.to("bean:myBean")
.to("file:outbox");
You can also override and control the encoding dynamic when writing files, by setting a property on the exchange with the key Exchange.CHARSET_NAME. For example in the route below we set the property with a value from a message header.
from("file:inbox")
.convertBodyTo(byte[].class, "iso-8859-1")
.to("bean:myBean")
.setProperty(Exchange.CHARSET_NAME, header("someCharsetHeader"))
.to("file:outbox");
We suggest to keep things simpler, so if you pickup files with the same encoding, and want to write the files in a specific encoding, then favor to use the charset option on the endpoints.
Notice that if you have explicit configured a charset option on the endpoint, then that configuration is used, regardless of the Exchange.CHARSET_NAME property.
If you have some issues then you can enable DEBUG logging on org.apache.camel.component.file, and Camel logs when it reads/write a file using a specific charset.
For example the route below will log the following:
from("file:inbox?charset=utf-8")
.to("file:outbox?charset=iso-8859-1")
And the logs:
DEBUG GenericFileConverter - Read file /Users/davsclaus/workspace/camel/camel-core/target/charset/input/input.txt with charset utf-8
DEBUG FileOperations - Using Reader to write file: target/charset/output.txt with charset: iso-8859-1
Common gotchas with folder and filenames
When Camel is producing files (writing files) there are a few gotchas affecting 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 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");
... 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 to 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 readLock 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 file) to signal when a file is done and ready to be consumed.
Using 'done' Files
Available as of Camel 2.6
See also 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.
javafrom("file:bar?doneFileName=done");
Will only consume files from the bar folder, if a done file exists in the same directory as the target files. Camel will automatically delete the done file when it's done consuming the files. From Camel 2.9.3 onward Camel will not automatically delete the done file if noop=true is configured.
However it is 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 ${}. The consumer only supports the static part of the done file name as either prefix or suffix (not both).
javafrom("file:bar?doneFileName=${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
You can also use a prefix for the done file, such as:
javafrom("file:bar?doneFileName=ready-${file:name}");
Writing 'done' Files
Available as of Camel 2.6
After you have written a file you may want to write an additional done file as a kind 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.
java.to("file:bar?doneFileName=done");
Will simply create a file named done in the same directory as the target file.
However it is 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 ${}.
java.to("file:bar?doneFileName=done-${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.
java.to("file:bar?doneFileName=${file:name}.done");
Will for example create a file named foo.txt.done if the target file was foo.txt in the same directory as the target file.
java.to("file:bar?doneFileName=${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.
Examples
Read from a directory and write to another directory
javafrom("file://inputdir/?delete=true")
.to("file://outputdir")
Read from a directory and write to another directory using a overrule dynamic name
javafrom("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
javafrom("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:
javafrom("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
Camel will by default move any processed file into a .camel subdirectory in the directory the file was consumed from.
javafrom("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.
Writing to files
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 being written to a directory.{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/component/file/ToFileRouteTest.java}
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:
xml <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.
javafrom("direct:start")
.to("file:///var/myapp/finalDirectory?tempPrefix=/../filesInProgress/");
Using Expressions for Filenames
In this sample we want to move consumed files to a backup folder using today's date as a sub-folder name:
javafrom("file://inbox?move=backup/${date:now:yyyyMMdd}/${file:name}")
.to("...");
See File Language for more samples.
Avoiding reading the same file more than once (idempotent consumer)
Camel supports Idempotent Consumer directly within the component so it will skip already processed files. This feature can be enabled by setting the idempotent=true option.
javafrom("file://inbox?idempotent=true")
.to("...");
Camel uses the absolute file name as the idempotent key, to detect duplicate files. From Camel 2.11 onward you can customize this key by using an expression in the idempotentKey option. For example to use both the name and the file size as the key
xml <route>
<from uri="file://inbox?idempotent=true&idempotentKey=${file:name}-${file:size}"/>
<to uri="bean:processInbox"/>
</route>
By default Camel uses a 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.
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>
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. When the file grows larger Camel will truncate the file store, rebuilding 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:{snippet:id=example|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/processor/idempotent/fileConsumerIdempotentTest.xml}
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}Next, 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:
xml <route>
<from uri="file://inbox?idempotent=true&idempotentRepository=#jpaStore"/>
<to uri="bean:processInbox"/>
</route>
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 built 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 defined in the spring XML file:
xml <!-- 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
New options from Camel 2.10 onwardsThere are now antInclude and antExclude options to make it easy to specify ANT style include/exclude without having to define the filter. See the URI options above for more information.
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:
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}
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 built 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:
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>
URI options can reference beans using the # syntaxIn the Spring DSL route above 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.
Sorting using sortBy
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 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 has 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 abort() method (Camel 2.10) special logic can be executed in case the begin operation returned false, for example to cleanup resources etc.
In the commit() method we can move the actual file and also delete the ready file.
Using filter
The filter option allows you to implement a custom filter in Java code by implementing the org.apache.camel.component.file.GenericFileFilter interface. This interface has an accept method that returns a boolean. Return true to include the file, and false to skip the file. From Camel 2.10 onward, there is a isDirectory method on GenericFile whether the file is a directory. This allows you to filter unwanted directories, to avoid traversing down unwanted directories.
For example to skip any directories which starts with "skip" in the name, can be implemented as follows:{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/component/file/FileConsumerDirectoryFilterTest.java}
How to use the Camel error handler to deal with exceptions triggered outside the routing engine
The file and ftp consumers, will by default try to pickup files. Only if that is successful then a Camel Exchange can be created and passed in the Camel routing engine. When the Exchange is processed by the routing engine, then the Camel Error Handling takes over e.g., the onException / errorHandler in the routes. However outside the scope of the routing engine, any exceptions handling is component specific. Camel offers a org.apache.camel.spi.ExceptionHandler that allows components to use that as a pluggable hook for end users to use their own implementation. Camel offers a default LoggingExceptionHandler that will log the exception at ERROR/WARN level.
For the file and ftp components this would be the case. However if you want to bridge the ExceptionHandler so it uses the Camel Error Handling, then you need to implement a custom ExceptionHandler that will handle the exception by creating a Camel Exchange and send it to the routing engine; then the error handling of the routing engine can get triggered.
Easier with Camel 2.10The new option consumer.bridgeErrorHandler can be set to true, to make this even easier. See further below for more details.
Here is such an example based upon an unit test.
First we have a custom ExceptionHandler where you can see we deal with the exception by sending it to a Camel Endpoint named direct:file-error:{snippet:id=e1|title=MyExceptionHandler|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/component/file/FileConsumerCustomExceptionHandlerTest.java}
Then we have a Camel route that uses the Camel routing error handler, which is the onException where we handle any IOException being thrown. We then send the message to the same direct:file-error endpoint, where we handle it by transforming it to a message, and then being sent to a Mock endpoint. This is just for testing purpose. You can handle the exception in any custom way you want, such as using a Bean or sending an email, etc.
Notice how we configure our custom MyExceptionHandler by using the consumer.exceptionHandler option to refer to #myExceptionHandler which is a id of the bean registered in the Registry. If using Spring XML or OSGi Blueprint, then that would be a <bean id="myExceptionHandler" class="com.foo.MyExceptionHandler"/>:{snippet:id=e2|title=Camel route with routing engine error handling|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/component/file/FileConsumerCustomExceptionHandlerTest.java}
The source code for this example can be seen here
Using consumer.bridgeErrorHandler
Available as of Camel 2.10
If you want to use the Camel Error Handler to deal with any exception occurring in the file consumer, then you can enable the consumer.bridgeErrorHandler option as shown below:{snippet:id=e2|title=Using consumer.bridgeErrorHandler|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/component/file/FileConsumerBridgeRouteExceptionHandlerTest.java}So all you have to do is to enable this option, and the error handler in the route will take it from there.
Important when using consumer.bridgeErrorHandlerWhen using consumer.bridgeErrorHandler, then interceptors, OnCompletions 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.
Endpoint See Also
