Let's say I have an UIImage cached in my Cache folder:
/.../Cache/Image Cache/<firstImage.id>
Now I want this folder to only ever have 10 image cached at a time, so if a new one comes in I want to take a file and replace the entire file and not just the contents of it. I.e.
/.../Cache/Image Cache/<firstImage.id> becomes
/.../Cache/Image Cache/<secondImage.id>.
As far as I can tell, replaceItem(at:withItemAt:backupItemName:options: only replaces the contents of the file but the file name remains the same. And I'm not too sure what replaceItem(at:withItemAt:backupItemName:options:resultingItemURL:) does even though it might be what I'm looking for (I don't know what an AutoreleasingUnsafeMutablePointer<NSURL?>? was but it sounded dangerous so I decided to leave it alone, specially since it has the word "unsafe" in it).
Is there a straightforward way of doing using an in-built function or is manually deleting the old file and adding the new file the best way? Please let me know.
Thanks in advance!
Related
I have massive tiff file that contains 8 directories (resolutions). It's also a tiled.
I can cycle thru the directories and get the resolution of each. I want to save the 4th directory to a new tif file. I think it's possible but can't get my hands on it.
Basically want to do this:
using (LibTiff.Classic.Tiff image = LibTiff.Classic.Tiff.Open(file, "r"))
{
if (image.NumberOfDirectories() > 4) {
image.SetDirectory(4);
image.WriteDirectory("C:\\Temp\Test.tif");
}
}
It would be so nice if that was possible but I know I have to create an output image and copy the rows of data into it. Not sure how yet. Any help would be much appreciated.
There are no built-in methods in LibTiff.Net library that can be used to copy one directory into a new file.
The task is quite complex and the best place to start is to look at TiffCP utility's source code.
The utility no only can copy images but it can also extract directories.
Is original_filename method in ActionDispatch::Http::UploadedFile safe to use to save as file in host system, without further sanitize it?
Looking at the source, it doesn't look like they do any checking of the filename, so unless they do it somewhere else (which would be bad design and thus unlike the Rails team), the real question is: what harm can a filename do? The only cases I can think of that it might be possible to use it maliciously is:
if the file is named ".". Those can be hard to delete if you actually succeed in creating them. I doubt that Ruby would let you save a file by that name, you can try it and see. If it doesn't, this this point can be ignored.
or maybe a really long name might cause a buffer overflow somewhere deeper in the API code of the OS.
Note that neither of those should be a problem. OSes try to make it impossible to create . files, but I've seen it done. And since (most?) filesystems already have a max filename limit, they should just error or truncate the file for you; truncating yourself is a borderline paranoid measure to protect against buffer overflow exploits that may be found in the OS's API code in the future. Such an exploit is very unlikely to exist.
So, if you really want to, just check for these two cases and you should be okay. You might want to do this by subclassing the UploadedFile class and adding the functionality that, if the name is "." or "..", then you just give it a random name; and if it is over, say 100 chars, then truncate it.
But I would say that neither of these are likely enough to warrant the introduction of a nonstandard class into your code base. I would just try saving the file by the given name and depend on the underlying file saving API to catch errors, check for said errors, and report them back to the user.
I'd like to get a file last modified time in Delphi.
Normally something like FileAge() would do the trick, only the problem is: if I overwrite *File A* with File B using CopyFile, File A's modified date is not updated with current overwrite time as it should(?)
I get that: CopyFile also copy file attributes, but I really need to get the modified date that also works when a file is overwritten.
Is there such function? My whole application relies on modification time to decide whether or not I should proceed with files!
EDIT Just to clarify: I'm only monitoring the files. It's not my application who's modifying them.
The documentation for CopyFile says:
File attributes for the existing file are copied to the new file.
Which means that you cannot use base your program on the last modified attribute of the file, or indeed any attribute of the file. Indeed there are all sorts of ways for the last modified attribute of the file to change. It can in fact go backwards in time.
Instead I suggest that you use ReadDirectoryChangesW to keep track of modifications. That will allow you to receive notifications whenever a file is modified. You can write your program in an event based manner based on the ReadDirectoryChangesW API.
If you can't use ReadDirectoryChangesW and the file attributes, then you'll have to base your decisions on the contents of the file.
Some kind of problem I can't resolve…
In some app, a method called on :before_create was prefixing the file's extension with a double-dot (ex. /images/13402/medium/hey-1..jpg)
The problem is fixed for the new ones, but nothing occurs when I apply a reprocess! on the old ones; and I'd like to know if anyone could help about it
Reprocess / refresh only takes your original image and recreates the defined styles in your model class. So if your original image contains a file path with double dots in it, these are also applied to the generated styles. You have to clean up your original files and the stored file paths in your model records.
The only way I know would be to write a little script to modify this. Basically
foreach image
strip out double dots from original file name
rename file
store new file path in model record
end
And then rake paperclip:refresh
I have this code,
showmessage('C:\TEMP\'+openfiles[openfilelist.ItemIndex].ID);
if removedir('C:\TEMP\'+openfiles[openfilelist.ItemIndex].ID) then
showmessage('Removed')
else
showmessage('Failed');
The message shows C:\TEMP\0 and this directory does exist as the program created it earlier and used files inside it and then later deletes them. I can see the files and directories so I know they're there. The program successfully deletes the files but does not remove the directory.
If I hardcode the directory it works - this means that it accepts the string
C:\TEMP\0 but does not accept C:\TEMP\'+openfiles[openfilelist.ItemIndex].ID both equate to C:\TEMP\0. I cannot hardcode these directories, so what can I do? How do I convert from a string + string to whatever removedir() is expecting. I looked this up at Delphi basics and it's expecting a string.
I'm confused, since string + string = string. What is going on?
Make sure that neither your program nor any other program have the directory as their current working directory. When you recompile the program this may no longer be the case, so it may be a red herring that the hardcoded value works for you.
In addition to the other good answers, you should not be storing your temp folder in C:\TEMP. Use the value returned from GetTempFilename, instead. Unlike C:\TEMP, this location (which varies by operating system) will work on all operating systems, and all levels of user access control. This also eliminates the risk that the location you have hardcoded might also be hardcoded into another system.
If I understood correctly, openfiles[openfilelist.ItemIndex].ID is a string that contains number?
If so, did you check that it does not contain blanks? Something like this:
filename := 'C:\TEMP\' + trim(openfiles[openfilelist.ItemIndex].ID);
showmessage(filename);
if removedir(filename) then
showmessage('Removed')
else
showmessage('Failed');
What type of objects are openfiles and openfilelist?
Do they open folders at all, if so they may still be open when your trying to delete the folder.