Can't download log files with long lines or weird chars

[hsvtoolfool]

Recent versions of FileZilla will not download certain text log files which contain very long lines or weird escape characters. I know one or the other causes the issue, but I can't tell which is the problem. I can upload these weird text files using FZ, but they cannot be downloaded using FZ. I have tried "auto", "text", and "binary" modes when downloading.

The attached "access_log_search.2018-08-01" file is an Apache server log file in text format from my hosted site. This file is a compilation of a certain type of SQL hack. This type of attack has no affect on my site, but the very long lines or an escape character prevents me from downloading the server log for that day. This is VERY annoying and so I must fall back to other methods to download the log file. While every line in my example log file is weird, just ONE of these weird lines in a log file causes FZ download to fail on that line.

I can understand that if "text" or "auto" modes were used to download, an extremely long line-length or perhaps some weird escape characters inside the file might cause FZ to fail. But I don't understand why the file download hangs if "binary" mode is used. FZ should not process the file contents in that mode. It should just flow the data to my computer.

This download error type seems to be due to a relatively recent change in FZ. I've downloaded these rather strange log files many times in the past. From my experience, the issue seems to have been introduced within the past 6 months.

However, I cannot decide if this is a FileZilla issue or an FTP host issue. My hosting company (Web.com) says this is a FZ issue. I do not have any problems using the online file manager to download these weird log files. But using the Web.com online file manager is a nuisance.

Here is my system information from the FZ "About" dialog...

FileZilla Client

---

Version: 3.35.1

Build information:

Compiled for: x86_64-w64-mingw32
Compiled on: x86_64-pc-linux-gnu
Build date: 2018-07-23
Compiled with: x86_64-w64-mingw32-gcc (GCC) 6.3.0 20170516
Compiler flags: -g -O2 -Wall

Linked against:

wxWidgets: 3.0.5
SQLite: 3.22.0
GnuTLS: 3.5.18

Operating system:

Name: Windows 8.1 (build 9600), 64-bit edition
Version: 6.3
Platform: 64-bit system
CPU features: sse sse2 sse3 ssse3 sse4.1 sse4.2 avx avx2 aes pclmulqdq rdrnd bmi2 bmi2

From the verbose mode FZ debug log below, the error line which appears to describe the problem is....

"Error: File transfer failed after transferring 1,400 bytes in 20 seconds"

The retry gives this similar error line...

"Error: File transfer failed"

The full verbose level 3 debug log from is attached as "filezilla.log". I also appended the status screen log from an earlier attempt in "filezilla status window.txt".

By the way, all personal information was masked in both FZ logs. This is a security issue which should be corrected in the FZ log files. The debug logs do NOT need to include FTP hosts, URLs, usernames, or IP address specific to an FTP host.

[hsvtoolfool]

filezilla verbose log file

[hsvtoolfool]

Apache log file causing error

[hsvtoolfool]

filezilla status window capture

[Tim Kosse]

FileZilla does not care about file contents in any way when using binary data type.

Which server software (product and version) are you using?

Either the server itself has a bug or there's a malicious firewall or NAT router dropping the connection without telling you.