Should have seen this coming - Where to write temp files?

Chris Fullmer

So here's what I've come up with. I did like Dan just suggested in the above post - I just copied their method and put it into my module I'm making. This is what I am using:


tmp = ""
for dir in [ENV['TMPDIR'], ENV['TMP'], ENV['TEMP'], ENV['USERPROFILE'], '/tmp']
  if dir and File.directory?(dir) and File.writable?(dir)
    tmp = File.join( dir, 'temp_model')
    break
  end
end
@@temp_dir = File.expand_path(tmp)
Dir.mkdir( @@temp_dir, 777 )

It is working great on y PC, but the guy testing it on a Mac is getting permission denied errors. Any good reason he should be getting an error?

Also, is there any way that the above script will ever not find a writable directory?

Chris

Dan Rathbun

@chris fullmer said:

Also, is there any way that the above script will ever not find a writable directory?

On Mac, if somebody wipes out the ENV['TEMPDIR'] value, AND the directory '/tmp' does not exist, then after the for loop, tmp would be empty.
Make sure to add:
` if tmp.empty?

make a tempTemp dir below HOME dir

ie: delete the dir when done.

end`

ENV['USERPROFILE'] is Windows only.
On Mac, it's ENV['HOME'].

Myself.. I "hate" when programs write crap into my home dir.
I'd prefer a "/temp" subdir if that was the only way to solve the issue.

Dan Rathbun

There's also a File.writable_real?(dir) method.
Returns true if the named file is writable by the real user id of this process.

Chris Fullmer

What does the "real user" mean. I saw that in the docs but didn't understand the difference between the "effective user" and the "real user".

Also, another thing I am doing in my script. I find their ENV[temp] directory as I showed in my example script. And then I write my own subdir called temp_model and then I try to write files to that subdir. When I make my subdir, I am giving it 777 permissions mkdir( mydir_string, 777 ). That should in theory be alloweable right? My subdir should have all the right permissions for me to write to it?

Dan Rathbun

@unknownuser said:

(http://en.wikipedia.org/wiki/Chmod)":1q6nz2xj]The chmod command accepts up to four digits to represent an octal number. The octets refer to bits applied to the file owner, group and other users, respectively. Use of three digits is discouraged because it leaves the fourth as the default and this value is not fixed.

You can try: "777".oct
see: String.oct

also see: cacls for NT

Jim

777 is a decimal number. 0o777 is an octal number. 0xDEADBEEF is a hexidecimal number. and 0b111111111 is a binary.

The file permission is a bit field - 3 sets of 3 bits.

If you want to set all 9 bits to 1, use 0o777 because:
0b111_111_111.to_s(8) 777

(You could just use 0b111111111 instead of 0o777, too)

Want to set just the owner to full rights, and deny eveyone else? Use 0700:
0b111000000.to_s(8) 700

Dan Rathbun

@chris fullmer said:

What does the "real user" mean. I saw that in the docs but didn't understand the difference between the "effective user" and the "real user".

see the setuid link (below)

@unknownuser said:

(http://en.wikipedia.org/wiki/Chmod#Special_modes)":2b9d9a8z]Special modes
The chmod command is also capable of changing the additional permissions or special modes of a file or directory. The symbolic modes use s to represent the setuid and setgid modes,

See also:

Ruby methods:
File.setuid? File.setgid?

At the console:
"%b" % "777".oct

111111111
-> rwxrwxrwx

Dan Rathbun

@jim said:

777 is a decimal number. 0777 is an octal number. 0xDEADBEEF is a hexidecimal number. and 0b111111111 is a binary. Enter these in the Ruby Console to see.

I could not remember how to specify octals (which is why I went with the String method,) until you posted, reminding me of the " 0x" and " 0b" prefixes.

0o777

511

so:
"%b" % 0o777

Pout

i tend to do write temp content next to the Sketchup file and in the end just delete it again.
that location should be writable for sure.

Chris Fullmer

Yeah, I'm writing a LOT of files and they are persistant while the model is open. So I could have a few thousand files xluttering up someone's desktop hehhe. Might not go over well.

I still can't figure out why my Mac tester's computer won't let me write to his temp folder. It lets me create my folder, but then won't let me write to it.....grr. Oh yes, though come to think of it, he has not tested my new version using the different permission settings the Jim and Dan suggested. I better get him to try that soon.

Dan Rathbun

And you may have set the "special" bits, by accident, when you sent int(777) instead of int(511)...

.. I suggest having the tester, totally delete the folder manually, before trying the new version.

Chris Fullmer

Ahh, good point.

Thanks so much everyone for all the help always. Its nice to be able to help people from time to and time, and even nicer when there are amazing people out there who are willing and able to help when needed. Very grateful, thanks Dan (et al)

Chris

Dan Rathbun

Just noticed ANOTHER standard Ruby extension that bears on this subject.

With a path to the local standard Ruby lib dir pushed into the $LOAD_PATH array, you add the following to your module:
require('tmpdir.rb')

This standard extension adds the class methods:
Dir::tmpdir and Dir::mktmpdir

If you read the file, you'll recognize the Dir::tmpdir method as the 'progenitor' of the edition in the Google 'webtextures_loader.rb' file. (Google "lifted" it, and stripped out the Win32 specific part.)

So (above) when we talked about whether to rely on the WebTextures plugin, my advice is, to instead rely on the Standard Ruby library.