<flow name="onNewFile">
<file:listener config-ref="file" directory="test-data/in" autoDelete="true">
<scheduling-strategy>
<fixed-frequency frequency="1000"/>
</scheduling-strategy>
</file:listener>
<flow-ref name="processFile" />
</flow>
To Trigger a Flow When a New File is Created or Modified
The File, FTP, and SFTP connectors provide a listener (called On New or Updated file
in Studio and Design Center) that polls a directory for files that have been created or updated. A message is generated for each file that is found.
The key part of this functionality is how to determine that a file is new. There are three strategies for making this determination:
-
Set the
autoDelete
parameter totrue
. This setting deletes each file after it has been processed so that all files found in the next poll are new. -
Set
moveToDirectory
parameter to move each processed file to a different directory after it has been processed. This produces the same effect asautoDelete
but without deleting the file. -
Use the
watermark
parameter to only pick files that have been created or updated after the last poll was executed. -
Use a matcher to filter the files.
Listener
Listeners function similarly for the FTP, SFTP, and File connectors. However, the XML element used for them is different.
Watermarking
For the File connector, the watermarking strategy can be used in two different modes: CREATION_TIMESTAMP
or MODIFIED_TIMESTAMP
. The strategy depends on whether you want to filter files based on their creation or modification time.
<file:listener doc:name="On New File"
config-ref="File_Config1"
watermarkMode="CREATED_TIMESTAMP">
<scheduling-strategy >
<fixed-frequency />
</scheduling-strategy>
</file:listener>
Repeatable Streams
The List operation makes use of the repeatable streams functionality introduced in Mule 4. The operation returns a list of messages, where each message represents a file in the list and holds a stream to the file. A stream is repeatable by default.
For more information on this topic, see Streaming in Mule 4.