In this transfer pattern, you use the RETR transfer command from an FTP client to send files from an FTP server to the FTP client.

The following figure shows the procedure for transferring a file.

Figure 8-6 Procedure for transferring files from an FTP server to an FTP client

The following describes the control flow, data transfer flow, and business process flow in the figure. The following numbers correspond to the numbers in the figure.

1. The FTP client executes a transfer command (RETR command).
2. The FTP inbound adapter that receives the transfer command invokes the FTP reception.
3. The FTP reception creates a work folder.
4. The FTP reception invokes a business process. At this time, the information received from the FTP client, such as the transfer command, is stored in a request message and passed to the business process.
5. The FTP adapter is invoked from the business process. Then, the FTP adapter obtains a file from the FTP server, and then outputs it to the work folder as an intermediate file.
6. The file operations adapter is invoked from the business process. Then, the file operations adapter reads the intermediate file from the work folder, and then performs processing such as converting the layout and code.
7. A reply activity is executed with the business process, and then a response message containing intermediate file information is passed to the FTP reception.
8. The intermediate file data indicated in the response message is transferred from the work folder to the FTP client.
9. The FTP reception deletes the work folder and the intermediate file in the work folder.
10. The FTP reception returns a response to the FTP inbound adapter.
11. The FTP inbound adapter that receives the response returns the execution result of the transfer command to the FTP client.