Getting safe temp folder in Windows - windows

I need to get a safe temp folder where I could store temporary files for my application, but so far my research has lead me to conclusion that all approaches I've found are flawed.
The first idea was to use GetTempPath function, but that causes two problems:
The folder might not exist, so I would have to truncate folders one by one up to root, and recreate them if they do not exist back to full path (error prone, tedious)
From "Larry Osterman's WebLog" click it seems that GetTempPath might fallback to USERPROFILE or Windows directory and extract whole lot of files right in there, which is SUPER BAD(TM)!
In the same post, there is a suggestion to use GetEnvironmentVariable, but this seems a dangerous function to me (missing TMP & TEMP envvars for instance).
Is there a cleaner function I could use? Seems that SHGetKnownFolderPath has no clue what temp folder is.

Your program is probably not the only one to rely on GetTempPath, so it's reasonable to expect it to return a proper writable path. Especially since Windows automatically initializes the TMP and TEMP environment variables for you; someone would have to go to some trouble to override them, and it would be their responsibility to make sure the change did not mess up their system.
I would go ahead and assume GetTempPath works properly, and worry about failures when you try to create the temporary file - there are other errors that might occur at that time that you need to check for anyway.

An idea would be to get the path where your application is (GetModuleFileNameEx combined with GetModuleHandle(NULL) and GetCurrentProcess) since this directory cannot be deleted under windows as long as your application is running from it (maybe I'm wrong ...some years ago I couldn't do this :) ) and in this directory create a temporary directory.

Your first bullet point is the solution. Wrap it up in a method so that you don't duplicate code.

According to this answer, Boost's Filesystem library can be used for this.

Related

Copying files from one directory to another is not working in Ruby

I am using fastlane and snapshot to create screenshots automatically. To facilitate this I need to copy data into the app. In this case a series of folders and documents from one folder into another within a .app container.
So far the Documents folder is being created but no files are ever copied into it. At this point I’m not sure if I’m suppling the path incorrectly or what else I might be doing wrong to lead to this. It may be simply that I’ve got the wrong code to do that since I’m not that familiar with Ruby.
Any suggestions would be greatly appreciated, so tell me, what am I missing?
example_files = "./sample_data/Documents"
folder_name = "Documents"
setup_for_device_change do |lang, device|
app_path = "/tmp/snapshot/build/SyncSpace.app/"
FileUtils.mkdir_p(File.join(app_path, folder_name))
Dir.glob(File.join(example_files, '*')).each do |example_path|
FileUtils.cp_r(example_path, File.join(app_path, folder_name)) rescue nil # in case the file already exists
end
end
Update -
In the end my problem is that the path I’m using doesn’t work correctly for the files I want to transfer. When I give it a full path from the root level to the folder I need it works. Trying to use a shorter path with just the additional folders over the working directory fails.
So as a follow up, when my working directory is .../fastlane and my data is in .../fastlane/sample_data/Documents then why doesn’t just using ./sample_data/Documents work?
Don't use rescue nil. Ever, or at least until you're very aware of what your code could be doing and why you would want to use that. Instead use the normal form of:
begin
do_something
rescue TheExactExceptionYouWantToHandle => e
# handle the exception
end
That way you handle what you expect and blow up if it's something you didn't expect.
One of my programming mentors years ago told me
Never test for an error condition you don't know how to handle.
On the surface that sounds silly but experience teaches us we can get into situations where the program does the wrong thing trying to do the right thing. It's better to crash fast and safely and spew out an error, than to drag it out and damage things trying to recover or silently cover the error. Debugging a program that's rescuing improperly can be a major pain and a trailing rescue is a common culprit.

Command Prompt: Move a file to an Unknownly named folder

So, is there a possible way to move Test.txt to C:\ProgramData\CsD2\Tools\("Unknown Folder Name")\data\per Using command prompt?
using foxidrives solution for your previous question for detecting the correct directory, then just
move test.txt "%folder%\"
Short answer: yes. Not quite sure what the situation is that has left only the middle part of your path unknown, and the need to use the comnand line, but I have encountered similar cases on Linux and expect the algoirthm can be adapted to Windows commands. It's possible to do this by hand rather than writing a shell script, but it's up to you and your skills.
Permissions matter. Make sure you elevate yours enough to read and write in Tools before continuing.
First, change directory to C:\ProgramData\CsD2\Tools\
Presumably there are many items here. Some may be "hidden," so list the contents of this directory and be sure to include an option to show hidden files and folders. If you can, restrict the search to directories only.
It's tempting to display contents recursively in the above step. It's up to you, but I find it makes the output cluttered without a script to do the rest of the work.
Now it's time to search for the subfolder set that theoretically only exists in your target folder. Suppose Tools contains the directories fldr1, fldr2, and fldr3. Use your command to list a directory's contents with the path "fldr1\data\per", then use "fldr2\data\per", and so on until it doesn't return an error. Per may be empty, but that should look different from the path not found error.
Now you've found the name of your mystery folder. Write it down for future reference.
At thus point, you know the path to Test.txt, and the full path to the destination directory. Do a move command to relocate Test.txt, and you're done. I like to relist the contents of the target directory after to be comfortable that it arrived.

Testing File/Folder Navigation and Manipulation

I am working on a module that supplies methods for navigating directories and manipulating files. Basically it will be a combination of the Dir and File classes, with options specific to the needs of a project I'm working on.
Right now I have started writing tests for some of these methods and things are getting messy.
Example
One of the methods I have is a tree function that returns a hash of files and folders where you can pass options like tree(only: 'folders', limit: 3). In order to test that it only goes down 3 levels, I would have to have 4+ subfolders with dummy files in them.
The Problem
Right now I'm testing on folders outside the project since the subfolders are already there, but I want to move away from this, especially considering the implausibility of testing on system files once I start testing methods equivalent to rm -rf (as well as the lack of portability).
I'm starting to think that I need to create a "lab rat" type folder that I do all my "experiments" on, but I have no clue how to approach creating it.
Do I create a function that creates the files?
Do I pull files and folders from another location?
Do I use some sort of "lorem ipsum" generator for file structures?
Do I make all these files and folders manually(ugh)?
Do I just mock and stub the hell out of everything and not actually create/delete the files and folders?(I don't see this happening)
So...
How would someone normally approach testing excessive amounts of file and folder manipulation?
I don't think you want to use mocks/stubs. The file system of your OS should be well tested and fast, so the benefit of mocks/stubs is minimal. Creating a mock/stub system increases the complexity without much benefit.
Here's my answers:
Do I create a function that creates the files?
Yes. You can create tests for these functions to make sure that they are correct. Instead of calling Dir and File, write helper functions that make the code simple and readable. Maybe you can share the helper functions between the source/test code...
Do I pull files and folders from another location?
Not sure what this is for...
Do I use some sort of "lorem ipsum" generator for file structures?
Yes, if you mean create functions that generate file structures.
Do I make all these files and folders manually(ugh)?
No.
Do I just mock and stub the hell out of everything and not actually create/delete the files and folders?(I don't see this happening)
No. One benefit of creating files/directories is that you can manually check what is going on and not be 100% dependent on the tests. This is actually a good approach because without it there could be a bug where both the source code and test code is not doing what you expect, but you wouldn't know because everything seems to be working.

Rename file in Win32 to name with only differences in capitalization

Does anyone know a pure Win32 solution for renaming a file and only changing its capitalization, that does not involve intermediate renaming to a different name or special privileges (e.g. backup, restore).
Since the Win32 subsystem generally regards two file names differing only in capitalization as the same, I haven't been able to find any solution to the problem.
A test program I made with the MoveFile API seems to work. So does the rename command in cmd.exe. What have you tried, and what error are you getting?
This isn't relevant, but further testing shows that renaming a long filename in this way works but will change the short filename (alternating between ~1 and ~2 for example), incidentally.
Just use the normal MoveFile API. That call probably just turns into ZwSetInformationFile(..., FileRenameInformation,...) The docs for FILE_RENAME_INFORMATION states that you need DELETE access and the file can't be locked etc, but those restrictions will probably apply to other solutions also.
I do not believe there is a way to expose two files with identical names that differ only in spelling to the Win32 subsystem. Even if some how you were able to create these files, the most likely result would be that only one file would be accessible - defeating the purpose of staying soley in Win32.
If you want to go into the Native layer, you can create a file with NtCreateFile and InitializeObjectAttributes w/o OBJ_CASE_INSENSITIVE or you can pad the end with extra spaces (if you pad with extra spaces, the file will not be accessible from Win32 dos paths). See here: http://www.osronline.com/ddkx/kmarch/k109_66uq.htm . I'm pretty sure you were already aware but I included it incase you did not know.
So long as your file is not immediately needed by another program, you can use my solution.
When you rename the file, capitalize, and delete the last letter. Then rename again and return the letter.
:)

Ruby - How to prevent wiping your hard drive when using delete file and directory commands in your code

I'm writing some code that at run time may create or delete directories within the project path. I haven't really used ruby for file processing so i'm really uneasy about having code that, with a few mistypes weeks down the line, could result in wiping other directories outside of my project path.
Is there anyway to make it impossible for the program to delete files outside of its own path regardless of whats typed in destructive calls?
Pathname is a wrapper class for almost any file operations.
require "pathname"
path= Pathname.new("/home/johannes")
path.directory? # => true
path.children # => [#<Pathname:.bash_history>, #<Pathname:Documents>, #<Pathname:Desktop>]
path.children.each do |p|
p.delete if p.file?
end
Pathname#children does not contain . or .. so you don't accidently walk up the tree instead of down. If you still don't trust in the code, you can even check if on path is contained in another
Pathname.new("test") <=> Pathname.new("test/123") # => -1
You might want to create a wrapper method around your favourite delete method (or, perhaps, around whole class, because not only deleting files is potentially destructive file operation), which would expand all the submitted paths and check whether they begin with your "sandbox" path). You can also try to redefine delete method, if you are willing to cripple it through whole application.
And maybe the cleanest solution of them all would be to create a new user on your system and run your program as him.
On a POSIX system, you can use Dir.chroot to change the root that your application sees. Then ALL actions, not just delete ones, will be limited to the project directory. This does mean that external commands will be unavailable unless you make them part of your project directory as well.
This is the standard 'sandboxing' method used in Unix based systems. It can be difficult to setup (eliminating all external dependancies is sometimes hard), but affords significant protection when configured properly.
You could generate an Array of filenames in your project directory using
my_files = Dir["/bla/bla/your/directory/**/*"]
and then simply check if the filename passed to your "delete" function exist in your my_files array.
I'm sure there is a more elegant solution, but this could work ^_^
You could use File.expand_path and File.dirname on the input, and check that against __FILE__. So something like this might work:
File.delete(path) if File.dirname(File.expand_path(path)).include? File.dirname(File.expand_path(__FILE__))
I've got automated tests that routinely create and wipe out directories. I've taken two approaches:
Use /tmp as much as possible. The 'tmpdir' standard library module will create temporary directories which will be destroyed when your program exits. Or,
When the code creates a directory that it will later be deleting, it drops a marker file into the directory. When it comes time to delete the directory, if the marker file is not found, the code refuses to delete the directory. A marker file might be called ".ok_to_delete", for example.

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