I have an AliasRecord creating using the Alias Manager function FSNewAlias(fromFSRef, targetFSRef, &aliasRecordHandle). My understanding is that the resulting alias record will contain information for a relative path search (relative to fromFSRef). Because my users are on networked home directories and mobile accounts, these aliases do not appear to persist the location of a file in the user's home directory between the networked and mobile home directories because they are on different volumes. If the original fromFSRef corresponded to /Network/.../Users/user/Desktop in the network account, I would like to be able to resolve the alias using FSResolveAlias(newFromFSRef, aliasRecordHandle, &targetFSRef, &changed) with newFSRef corresponding to /Users/user/Desktop (i.e. the mobile account). Is this possible?
The solution I've resorted to is to persist the alias record and the relative path. I use the relative path to create a new alias if alias resolution fails.
It appears that the solution proposed in the question—persisting both the alias record and a relative path is the only option. If alias resolution fails, we try using the relative path (along with an application or user-defined root) to find the file. If this succeeds, we update the alias record with the new path. Otherwise, we fall back to asking the user to find the "lost" file.
Related
I downloaded nltk data into the data directory in my Flask app. The views reside in a blueprint in another directory on the same level as the data directory. In the view I'm trying to set the path to the data, but it doesn't work.
nltk.data.path.append('../nltk_data/')
This doesn't work. If I use the whole path, it does work.
nltk.data.path.append('/home/username/myapp/app/nltk_data/')
Why does the first form not work? How can I refer to the location of the data correctly?
In Python (and most languages), where the code resides in a package is different than what the working directory is when running a program. All relative paths are relative to the current working directory, not the code file it's written in. So you would use the relative path nltk_data/ even from a blueprint, or you would use the absolute path and leave no ambiguity.
The root_path attribute on an app (or blueprint) refers to the package directory for the app (or blueprint). Join your relative path to that to get the absolute path.
resource_path = os.path.join(app.root_path, 'enltk_data')
There's probably no reason to be appending this folder every time you call a view. I'm not familiar with nltk specifically, but there's probably a way to structure this so you set up the data path once when you create your app.
project / app / blueprint
/ data
^ join with root_path to get here
^ app.root_path always points here, no matter where cwd is
^ current working directory
I am trying to make a windows application. In this application, some files get modified as a user add or delete an entry. I saved these files on the application folder itself.
But After making binary file I installed it, As I try to add a entry it get crashed.
So, I figured out the issue. The windows doesn't allow to modified files inside C:\Program Files.
So, I installed it in other drive and it works. It solved my issue temporarily but I want to know how other application works in windows.
Where do those applications save their data?
I am not talking about some data which get saved in "Documents" but something which is essential need to modified every time user makes change like theme, formates.
No user access is allowed to the "program folder", and that's for good: it is a system folder, and it should only be accessed for system related operations (like installing or uninstalling a program).
There are many places where "program data" can be stored depending on the situation, and QStandardPaths provides access to their paths, according to the category location. What you might be interested in are:
ConfigLocation: Returns a directory location where user-specific configuration files should be written. This may be either a generic value or application-specific, and the returned path is never empty.
AppDataLocation: Returns a directory location where persistent application data can be stored. This is an application-specific directory.
AppLocalDataLocation: As the previous one, but Windows specific.
AppConfigLocation: Returns a directory location where user-specific configuration files should be written. This is an application-specific directory, and the returned path is never empty.
Those paths (along with the others listed in the documentation) can be accessed using the following static methods:
standardLocations(locationType): returns a list of paths for the requested location type, in order of priority (the first is usually the preferred one);
writableLocation(locationType): returns the preferred path for which write access is allowed (usually the first of the standardLocations());
If you need to store the user configuration, you can use QStandardPaths.writableLocation(AppConfigLocation), while if you have some user-specific internal data that is used by the application (email database, document templates, etc) QStandardPaths.writableLocation(AppLocalDataLocation) should be a good choice.
In both cases, those paths may not exist, so you need to ensure that and eventually create them, possibly by using QDir(path):
dataPath = QtCore.QStandardPaths.writableLocation(AppLocalDataLocation)
dataPathDir = QtCore.QDir(dataPath)
if not dataPathDir.exists():
# create the directory (including parent directories if they don't exist);
# that the argument of mkpath is relative to the QDir's object path, so
# using '.' means that it will create the actual dataPath
dataPathDir.mkpath('.')
Note that for all of the above (especially the last 3) it's required that you correctly set both the organizationName and the applicationName.
I downloaded nltk data into the data directory in my Flask app. The views reside in a blueprint in another directory on the same level as the data directory. In the view I'm trying to set the path to the data, but it doesn't work.
nltk.data.path.append('../nltk_data/')
This doesn't work. If I use the whole path, it does work.
nltk.data.path.append('/home/username/myapp/app/nltk_data/')
Why does the first form not work? How can I refer to the location of the data correctly?
In Python (and most languages), where the code resides in a package is different than what the working directory is when running a program. All relative paths are relative to the current working directory, not the code file it's written in. So you would use the relative path nltk_data/ even from a blueprint, or you would use the absolute path and leave no ambiguity.
The root_path attribute on an app (or blueprint) refers to the package directory for the app (or blueprint). Join your relative path to that to get the absolute path.
resource_path = os.path.join(app.root_path, 'enltk_data')
There's probably no reason to be appending this folder every time you call a view. I'm not familiar with nltk specifically, but there's probably a way to structure this so you set up the data path once when you create your app.
project / app / blueprint
/ data
^ join with root_path to get here
^ app.root_path always points here, no matter where cwd is
^ current working directory
I'm trying to save a CFPropertyList to a location in the user's home folder. Using the code below I'm getting errorCode = -10 (unknown error).
CFURLRef fileURL = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, CFSTR("~/testfile.txt"), kCFURLPOSIXPathStyle, false );
SInt32 errorCode;
Boolean status = CFURLWriteDataAndPropertiesToResource(fileURL, xmlData, NULL, &errorCode);
If I change the path to something like "/testfile.txt" without the '~' then everything works. How can one save a property list to the current user's home folder? Must one obtain the user's name first and include it in the path such as /users/toffler/testfile.txt?
With Foundation, you can call the NSHomeDirectory function to get the absolute path to the user's home directory. You can then use the path-manipulation methods of NSString or of NSURL, or the equivalent function for CFURL, to tack a sub-path onto that.
However, please don't put files into the top level of my Home folder unless I, as the user, tell you to.
If you want to save a file at the user's request, run a save panel, and then save it where the user told you to.
If you want to save a preferences file, you probably should be using NSUserDefaults or CFPreferences, instead of handling plists yourself.
If you have some other reason to save a user-specific file, it should generally go into either the chewable items folder, the Caches folder, or the Preferences folder. The two functions that I linked to are the easiest ways to access those two of those three folders; the harder way, and the only one that works on all three, is the FSFindFolder function. Unlike most of the Folder Manager, FSFindFolder is not deprecated and is available in 64-bit.
Updates from the year 2012
Nowadays, you should use URLs, not paths. NSFileManager has a method for getting a URL to a desired directory.
Stapling paths (or file URLs) together does not work in a sandboxed application, because you don't have authorization to access the path you just made up. You need to get the path (or URL) from a system API, whether it's NSFileManager, NSSavePanel, or something else.
For saving and restoring file references, use NSURL's security-scoped bookmarks feature.
NSUserDefaults and CFPreferences work as expected in a sandbox.
The Folder Manager is now fully deprecated as of 10.8.
Polluting the user's Home folder is still bad manners.
Automatic ~ expansion is a feature of the shell.
If you are using Cocoa/Foundation, you can use the NSString methods
- (NSString *)stringByAbbreviatingWithTildeInPath;
- (NSString *)stringByExpandingTildeInPath;
otherwise, you'll have to write some code yourself to do this. Getting the user's login name and constructing the path /Users/login-name/ is not the correct way to do this. (While most users will have their home directory here, some will not.)
I used to be able to launch a locally installed helper application by registering a given mime-type in the Windows registry. This enabled me to allow users to be able to click once on a link to the current install of our internal browser application. This worked fine in Internet Explorer 5 (most of the time) and Firefox but now does not work in Internet Explorer 7.
The filename passed to my shell/open/command is not the full physical path to the downloaded install package. The path parameter I am handed by IE is
"C:\Document and Settings\chq-tomc\Local Settings\Temporary Internet Files\
EIPortal_DEV_2_0_5_4[1].expd"
This unfortunately does not resolve to the physical file when calling FileExists() or when attempting to create a TFileStream object.
The physical path is missing the Internet Explorer hidden caching sub-directory for Temporary Internet Files of "Content.IE5\ALBKHO3Q" whose absolute path would be expressed as
"C:\Document and Settings\chq-tomc\Local Settings\Temporary Internet Files\
Content.IE5\ALBKHO3Q\EIPortal_DEV_2_0_5_4[1].expd"
Yes, the sub-directories are randomly generated by IE and that should not be a concern so long as IE passes the full path to my helper application, which it unfortunately is not doing.
Installation of the mime helper application is not a concern. It is installed/updated by a global login script for all 10,000+ users worldwide. The mime helper is only invoked when the user clicks on an internal web page with a link to an installation of our Desktop browser application. That install is served back with a mime-type of "application/x-expeditors". The registration of the ".expd" / "application/x-expeditors" mime-type looks like this.
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.expd]
#="ExpeditorsInstaller"
"Content Type"="application/x-expeditors"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ExpeditorsInstaller]
"EditFlags"=hex:00,00,01,00
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ExpeditorsInstaller\shell]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ExpeditorsInstaller\shell\open]
#=""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\ExpeditorsInstaller\shell\open\command]
#="\"C:\\projects\\desktop2\\WebInstaller\\WebInstaller.exe\" \"%1\""
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\MIME\Database\Content Type\application/x-expeditors]
"Extension"=".expd"
I had considered enumerating all of a user's IE cache entries but I would be concerned with how long it may take to examine them all or that I may end up finding an older cache entry before the current entry I am looking for. However, the bracketed filename suffix "[n]" may be the unique key.
I have tried wininet method GetUrlCacheEntryInfo but that requires the URL, not the virtual path handed over by IE.
My hope is that there is a Shell function that given a virtual path will hand back the physical path.
I believe the sub-directories created by IE are randomly generated, so you won't be able guarantee that it will be named the same every time, and the problem I see with the registry method is that it only works when the file is still in the cache...emptying the cache would purge the file requiring yet another installation.
Would it not be better to install this helper into application data?
I'm not sure about this but perhaps this may lead you in the right direction: try using URL cache functions from the wininet DLL: FindFirstUrlCacheEntry, FindNextUrlCacheEntry, FindCloseUrlCache for enumeration and when you locate an entry whose local file name matches the given path maybe you can use RetrieveUrlCacheEntryFile to retrieve the file.
I am using a similar system with the X-Appl browser to display WAML web applications and it works perfectly. Maybe you should have a look at how they managed to do it.
It looks like iexplore is passing the shell namespace "name" of the file rather than the filesystem name.
I dont think there is a documented way to be passed a shell item id on the command line - explorer does it to itself, but there are marshaling considerations as shell item ids are (pointers to) binary data structures that are only valid in a single process.
What I might try doing is:
1. Call SHGetDesktopFolder which will return the root IShellFolder object of the shell namespace.
2. Call the IShellFolder::ParseDisplayName to turn the name you are given back into a shell item id list.
3. Try the IShellFolder::GetDisplayNameOF with the SHGDN_FORPARSING flag - which, frankly, feels like w'eve just gone in a complete circle and are back where we started. Because I think its this API thats ultimately responsible for returning the "wrong" filesystem relative path.
Some follow-up to close out this question.
Turned out the real issue was how I was creating the file handle using TFileStream. I changed to open with fmOpenRead or fmShareDenyWrite which solved what turned out to be a file locking issue.
srcFile := TFileStream.Create(physicalFilename, fmOpenRead or fmShareDenyWrite);