Unzip Password Protected File in R using WinZip - r

Question

I am trying to use R to unzip password protected files from a drive without using 7-zip. My organisation doesn't have access to it, we use WinZip for everything.
I have searched far and wide here but cannot find a post that satisfies the question.
I have a file that is zipped and contains a single XML file. I need to automate the collation of this data, my thinking is unzip then read. I have found these that I can't see what I need to do:
Using unzip does not support passwords - unzip a .zip file
e.g. unzip(file.xml.zip) produces
Warning message: In unzip(zipfile = "file.xml.zip") : zip file is corrupt
And the file is not corrupt as I can manually unzip it fine afterwards.
Using 7-Zip (I can't access this) - Unzip a password protected file with Powershell
Reading without unzipping (get "error reading from the connection) - Extract files from password protected zip folder in R
read_xml(unz("file.xml", "file.xml.zip"))
produces
Error in open.connection(x, "rb") : cannot open the connection In addition: Warning message: In open.connection(x, "rb") : cannot open zip file 'file.xml'
I have tried looking at Expand-Archive in PowerShell and trying to call that through R but am not having much luck, please someone help me!
With PowerShell I use
Expand-Archive -Path 'file'
which produces:
Exception calling "ExtractToFile" with "3" argument(s): "The archive entry was compressed using an unsupported compression method."

Answer 1

I don't have WinZip, but since both it and unzip.exe (within Rtools-4.2) support password-encoding, then we should be able to use similar methods. (Or perhaps you can use unzip included with Rtools.)
Setup:
$ echo 'hello world' > file1.txt
$ echo -e 'a,b\n11,22' > file2.csv
$ c:/rtools42/usr/bin/zip.exe -P secretpassword files.zip file1.txt file2.txt
adding: file1.txt (stored 0%)
adding: file2.txt (stored 0%)
$ unzip -v files.zip
Archive: files.zip
Length Method Size Cmpr Date Time CRC-32 Name
-------- ------ ------- ---- ---------- ----- -------- ----
12 Stored 12 0% 2023-02-09 10:03 af083b2d file1.txt
10 Stored 10 0% 2023-02-09 10:03 1c1d572e file2.csv
-------- ------- --- -------
22 22 0% 2 files
$ unzip -c files.zip file1.txt
Archive: files.zip
[files.zip] file1.txt password:
Okay, now we have a password-protected zip file.
In R,
readLines(pipe("unzip -q -P secretpassword -c files.zip file1.txt"))
# [1] "hello world"
read.csv(pipe("unzip -q -P secretpassword -c files.zip file2.csv"))
# a b
# 1 11 22
WinZip does support a command-line interface, so we should be able to use it within pipe (or system or similar). It does support passwords, I believe it uses the -s argument instead of -P. I don't know if it supports extracting a file to stdout, so you might need to explore its command-line options for that, and if not then work out storing the document to a temporary directory.
Or, assuming you have Rtools installed, you can use its unzip as above without relying on WinZip.
Note:
Including the password as a command-line argument is relatively unsafe: users on the same host (if a multi-user system) can see the password in clear text by looking at the process list. I'm not certain if there's an easy way around this.