Storing into a string the content of a folder using zip compression

[francescofabbro]

HI to all,

I'm currently looking for a solution on how to store in a database field the content of a folder.

my idea is to compress the folder I want to store into the db into a zip file... then read the zip file like a text file and store the resulting string.

by now the main problem is to convert the zip file I create to a string and back.

if I simply read the zip file and re-write it into another zip file i obtain that the second file is corrupted.

my guess is that I'm not able to properly read the zip file... does anyone have advice?

[Hooovahh]

I'd be interested in seeing some code.  Because what you described should be possible.  As long as the database can store nulls without treating it like a string I think you should be fine.  It will just end up being an array of bytes that you can read, save to a temp location, and then open as a normal zip.  I'm interested in seeing how you are reading and writing the zip file.  Are you using the read from text file?  Do you have Convert EOL on these nodes?  They are on by default and can modify your read or write.  The Read/Write binary file might be a better option.  Also maybe compare the string value in the database, to the hex representation of the zip file before storing it.  How are they different?

[francescofabbro]

here is my unit test code

basically i select a folder and the vi creates a zip file "original" (which is not corrupted) then the vi tries to read the zip as a text and then re build a new zip file... which is corrupted😓

[wiebe@CARYA]

Can't see your code, 21 is too new for me.

Is Convert EOL off (right click the file function used to read and write)?

[francescofabbro]

 

[francescofabbro]

convert EOL is on

[rolfk]

---

@francescofabbro wrote:

convert EOL is on

---

That’s wrong! Disable it or use the Read Binary and Write Binary File functions instead!
A ZIP is a binary stream formaf and should never be read and written in text mode.

[Kyle97330]

If you use "Write to binary file" remember to always turn off "prepend array or string size", otherwise you get 4 bytes at the front you weren't expecting.

[francescofabbro]

hi,

I tried to put on false that input but nothing changes.

can it be a matter of encoding?

[rolfk]

ZIP files are binary. There is no character encoding involved at any stage as far as the overall structure of a ZIP file is involved. There are text elements inside ZIP archives that COULD involve encoding but they have no influence on the level you are working here.

Try to not just see if the strings (really byte arrays but in LabVIEW these are unfortunately still the same things) are the same, but where they actually differ. Length, what bytes are different and so on. That will give you (or at least us) a clue to what might be the problem.