Download one file at a time through the same session in Apache Camel FTP - ftp

Question

I want to implement following use case with Apache Camel FTP:
On a remote location I have 0 to n amount of files stored.
When I receive a command, using FTP, I want to download one file as a byte array (which one does not matter), if any files are available.
When the file is downloaded, I want to save it in a database as a blob.
Then I want to delete the stored/processed file on the remote location
Wait for the next download command and once received go back to step 1.
The files have to be downloaded through the same FTP session.
My problem is that if I use a normal FTP route, it downloads all available files.
When I tell the route to only download one, I have to create a new route for the other files and I cannot reuse the FTP session.
Is there a way to implement this use case with Apache Camel FTP?

Answer 1

Camel-ftp doesn't consume all available files at once it consumes them individually one after another meaning that each file gets processed separately. If you need to process them in some specific order you can try using file-name or modified date with sortBy option.
If you want to control when file gets downloaded i.e when command gets called you can call FTP Consumer endpoint using pollEnrich
Example:
// 1. Loads one file from ftp-server with timeout of 3 seconds.
// 2. logs the body and headers
from("direct:example")
.pollEnrich("ftp:host:port/directoryName", 3000)
.to("log:loggerName?showBody=true&showHeaders=true");
You can call the direct consumer endpoint with ProducerTemplate you can obtain from CamelContext or change it to whatever consumer endpoint fits your use case.
If you need to use dynamic URI you can use simple to provide the URI for poll-enrich and also also provide timeout afterwards.
from("direct:example")
.pollEnrich()
.simple("ftp:host:port/directoryName?fileName=${headers.targetFile}")
.timeout(3000)
.to("log:loggerName?showBody=true&showHeaders=true");