exceptionfactory opened a new pull request #5655: URL: https://github.com/apache/nifi/pull/5655
#### Description of PR NIFI-6266 Corrects proxy connection handling for FTP components and adds support for SOCKS proxy servers with authentication. The current `FTPTransfer` class attempted FTP server host resolution using `InetAddress.getByName()` in order to pass an instance of `InetAddress` to Commons Net `FTPClient.connect()`. Although `FTPClient.connect()` accepts a `String` for the host parameter, the `connect()` implementation performs the same `InetAddress.getByName()` resolution. In environments where the NiFi system cannot resolve the destination FTP server address, the `InetAddress.getByName()` throws an exception. To resolve this problem, a new `ProxyFTPClient` extends the standard `FTPClient` and overrides the `connect(String host, int port)` method to create an `InetSocketAddress` that allows the host to be unresolved. This approach allows a proxy socket to pass the unresolved host to the proxy server, relying on the proxy server to perform name resolution. Proxy server connections require FTP passive mode, which is the default setting for the `Connection Mode` property. In addition to overriding the `FTPClient.connect()` method, disabling the Passive NAT Workaround Hostname Resolver is also necessary. Calling `FTPClient.setPassiveNatWorkaroundStrategy()` with a `null` value disables potential hostname resolution that could also cause transfers to fail when connecting through a proxy server. Additional changes include refactoring `FTPClient` creation using a new `FTPClientProvider` that follows the same approach as the `SSHClientProvider`. The `StandardFTPClientProvider` handles configuring processor properties and also disconnects the `FTPClient` on initial failures, such as authentication problems. These changes also provided the opportunity to remove several unused utility classes. In order to streamline the review of the contribution we ask you to ensure the following steps have been taken: ### For all changes: - [X] Is there a JIRA ticket associated with this PR? Is it referenced in the commit message? - [X] Does your PR title start with **NIFI-XXXX** where XXXX is the JIRA number you are trying to resolve? Pay particular attention to the hyphen "-" character. - [X] Has your PR been rebased against the latest commit within the target branch (typically `main`)? - [X] Is your initial contribution a single, squashed commit? _Additional commits in response to PR reviewer feedback should be made on this branch and pushed to allow change tracking. Do not `squash` or use `--force` when pushing to allow for clean monitoring of changes._ ### For code changes: - [X] Have you ensured that the full suite of tests is executed via `mvn -Pcontrib-check clean install` at the root `nifi` folder? - [X] Have you written or updated unit tests to verify your changes? - [X] Have you verified that the full build is successful on JDK 8? - [X] Have you verified that the full build is successful on JDK 11? - [ ] If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under [ASF 2.0](http://www.apache.org/legal/resolved.html#category-a)? - [ ] If applicable, have you updated the `LICENSE` file, including the main `LICENSE` file under `nifi-assembly`? - [ ] If applicable, have you updated the `NOTICE` file, including the main `NOTICE` file found under `nifi-assembly`? - [ ] If adding new Properties, have you added `.displayName` in addition to .name (programmatic access) for each of the new properties? ### For documentation related changes: - [ ] Have you ensured that format looks appropriate for the output in which it is rendered? ### Note: Please ensure that once the PR is submitted, you check GitHub Actions CI for build issues and submit an update to your PR as soon as possible. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@nifi.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org