I am learning/looking QT. When I want to reach a folder or file, it is exist or not, program always return folder is not exist (NO).
QDir myDir("D:\try"); //I created try folder under D disk.
if (myDir.exists())
{
qDebug("YES");
}
else
{
qDebug("NO");
}
The '\t' in "D:\try" is interpreted as a tab character by the compiler. And the path "D: try" presumably does not exist.
It's often useful in these kind of tests to print out the string you are using in the debug statement, rather than just the success/fail message, so you can validate that the input is actually what you expect.
Related
I want my modPath variables to be from one directory, is the following correct? Using C#. Thank you ^^
private readonly string modPath = #"C:\Users\SusanPeter\Mods";
if (string.IsNullOrEmpty(modPath))
{
MessageBox.Show("Sorry wrong directory");
return;
}
I am a beginning, learning to Write a program to check whether this particular Path (C:\Users\SusanPeter\Mods) is valid, and as long as not empty.
If this program is not placed in (C:\Users\SusanPeter\Mods), it will prompt for a message. I am sort of ensuring the path is correct before starting the program.
I'm making an application part of which is reading from an XML which stores some preferences. However, whenever I build the project, all the sources get copied but the preferences file does not! I have added the following to the .pro file -
RESOURCES += rsc.qrc
And my rsc.qrc contains
<!DOCTYPE RCC><RCC version="1.0">
<qresource>
<file>data/preferences.xml</file>
<file>data/gamedata.xml</file>
</qresource>
</RCC>
Now whenever I try to open preferences.xml
QFile preferences(":/data/preferences.xml");
if(!preferences.exists()){
preferences.open(QFile::WriteOnly);
preferences.write("abc");
qDebug() << "Written";
}
else {
qDebug() << "File exists";
}
Absolutely nothing gets printed and even the rest of the application stops working.
You don't use the resource part correctly in your example.
It will most likely not work because you try to write to a resource that is embedded into your executable after you have build your application. Reading is fine, but writing can't work by definition.
If you want a editable setting files, you have to distribute them along with your executable, or use a different method for reading/writing your settings like QSettings.
However using QSettings also means, that you will need to configure all your default settings in your loading function in case the values do not exist if you use the default configuration. Meaning you use registry on windows.
You have the option to force the use of a INI file format in the constructor of QSettings, this can make sense if you want to provide a default settings INI file instead of your xml files.
In case you want to store more complex data a xml file might be needed anyway, so if you want to stick with that you will need a way to copy your setting files to your build path. This can be done within your pro file with QMAKE_POST_LINK.
Example:
COPY_CMD = "$$PWD\\data\\preferences.xml $$OUT_PWD\\release\\data\\preferences.xml"
COPY_CMD = $${QMAKE_COPY} $$replace( COPY_CMD, "/", "\\" ) $$escape_expand( \\n\\t )
QMAKE_POST_LINK += $$COPY_CMD
I am working on Nginx server, with PHP-FPM. I installed Laravel 4.1 and bootstrap v3.1.1., and here is the problem. For the last 30 minutes, I have been trying to change a css rule that I first declared to check boostrap.
.jumbotron{
background: red;
}
The first time it worked. The jumbotron container was red. So, I removed that css value and started working, but still no matter which browse I use, the container is red. I even checked the css file through the Google Chromes inspection tool, and it is showing me that first value when jumbotron had a background:red. I deleted the css file and renamed it and add new styles, I configured chrome not to cache pages. But Still the same value. I'm convinced now, that Laravel has kept a cache of the first style declaration.
Is there any way to disable this at all?
General explanation
When you access a Laravel Blade view, it will generate it to a temporary file so it doesn't have to process the Blade syntax every time you access to a view. These files are stored in app/storage/view with a filename that is the MD5 hash of the file path.
Usually when you change a view, Laravel regenerate these files automatically at the next view access and everything goes on. This is done by comparing the modification times of the generated file and the view's source file through the filemtime() function. Probably in your case there was a problem and the temporary file wasn't regenerated. In this case, you have to delete these files, so they can be regenerated. It doesn't harm anything, because they are autogenerated from your views and can be regenerated anytime. They are only for cache purposes.
Normally, they should be refreshed automatically, but you can delete these files anytime if they get stuck and you have problems like these, but as I said these should be just rare exceptions.
Code break down
All the following codes are from laravel/framerok/src/Illuminate/View/. I added some extra comments to the originals.
Get view
Starting from Engines/CompilerEngine.php we have the main code we need to understand the mechanics.
public function get($path, array $data = array())
{
// Push the path to the stack of the last compiled templates.
$this->lastCompiled[] = $path;
// If this given view has expired, which means it has simply been edited since
// it was last compiled, we will re-compile the views so we can evaluate a
// fresh copy of the view. We'll pass the compiler the path of the view.
if ($this->compiler->isExpired($path))
{
$this->compiler->compile($path);
}
// Return the MD5 hash of the path concatenated
// to the app's view storage folder path.
$compiled = $this->compiler->getCompiledPath($path);
// Once we have the path to the compiled file, we will evaluate the paths with
// typical PHP just like any other templates. We also keep a stack of views
// which have been rendered for right exception messages to be generated.
$results = $this->evaluatePath($compiled, $data);
// Remove last compiled path.
array_pop($this->lastCompiled);
return $results;
}
Check if regeneration required
This will be done in Compilers/Compiler.php. This is an important function. Depending on the result it will be decided whether the view should be recompiled. If this returns false instead of true that can be a reason for views not being regenerated.
public function isExpired($path)
{
$compiled = $this->getCompiledPath($path);
// If the compiled file doesn't exist we will indicate that the view is expired
// so that it can be re-compiled. Else, we will verify the last modification
// of the views is less than the modification times of the compiled views.
if ( ! $this->cachePath || ! $this->files->exists($compiled))
{
return true;
}
$lastModified = $this->files->lastModified($path);
return $lastModified >= $this->files->lastModified($compiled);
}
Regenerate view
If the view is expired it will be regenerated. In Compilers\BladeCompiler.php we see that the compiler will loop through all Blade keywords and finally give back a string that contains the compiled PHP code. Then it will check if the view storage path is set and save the file there with a filename that is the MD5 hash of the view's filename.
public function compile($path)
{
$contents = $this->compileString($this->files->get($path));
if ( ! is_null($this->cachePath))
{
$this->files->put($this->getCompiledPath($path), $contents);
}
}
Evaluate
Finally in Engines/PhpEngine.php the view is evaluated. It imports the data passed to the view with extract() and include the file with the passed path in a try and catch all exceptions with handleViewException() that throws the exception again. There are some output buffering too.
Same issue here. I am using VirtualBox with Shared Folders pointing to my document root.
This pointed me in the right direction:
https://stackoverflow.com/a/26583609/1036602
Which led me to this:
http://www.danhart.co.uk/blog/vagrant-virtualbox-modified-files-not-updating-via-nginx-apache
and this:
https://forums.virtualbox.org/viewtopic.php?f=1&t=24905
If you're mounting your local dev root via vboxsf Shared Folders, set EnableSendFile Off in your apache2.conf (or sendfile off if using Nginx).
For what it's worth and because this answer came up first in my google search...
I had the same problem. The CSS and JS files wouldn't update. Deleting the cache files didn't work. The timestamps were not the problem. The only way I could update them was to change the filename, load it directly to get the 404 error, and then change the name back to the original name.
In the end the problem was not related to Laravel or the browser cache at all. The problem was due to NginX using sendfile which doesn't work with remote file systems. In my case, I was using VirtualBox for the OS and the remote file system was vboxsf through Guest Additions.
I hope this saves someone else some time.
In Laravel 5.8+ you can use so:
The version method will automatically append a unique hash to the filenames of all compiled files, allowing for more convenient cache busting:
mix.js('resources/js/app.js', 'public/js').version();
After generating the versioned file, you won't know the exact file name. So, you should use Laravel's global mix function within your views to load the appropriately hashed asset. The mix function will automatically determine the current name of the hashed file:
<script src="{{ mix('/js/app.js') }}"></script>
full document: https://laravel.com/docs/5.8/mix
When I instantiate a Directory in Dart, and that file exists, how can I check whether the Directory is a real folder, or just a symlink?
The way you can recognize a symlink is if the path differs from the full path. Directory doesn't have fullPath() or fullPathSync(), but File.fullPathSync() works on directories. So you can do this:
bool maybeIsSymlink(String path) {
var fullPath = new File(path).fullPathSync();
return path != fullPath;
}
However this only works correctly when path is absolute, and none of its ancestors are symlinks. To work around that you can get the full path of the directory's parent, append the directory name and compare that:
bool isSymlink(String pathString) {
var path = new Path(path);
var parentPath = path.directoryPath;
var fullParentPath = new File.fromPath(parentPath).fullPathSync();
var expectedPath = new Path(fullParentPath).append(path.filename).toString();
var fullPath = new File.fromPath(path).fullPathSync();
return fullPath != expectedPath;
}
Note that I have not tested this, but I've dealt with symlinks a lot in Dart, and this should work. If pathString ends in '/' you'll have to remove it. I usually end up getting paths from a directory listing, so I track the expected path as I recurse down the directory structure.
You can see a special listDirectory() implementation that detects symlinks and sends Symlink instances to the stream along with Files and Directorys in a branch in buildtool: https://github.com/dart-lang/buildtool/blob/m4/lib/src/util/io.dart
In bleeding edge, there now is a static FileSystemEntity.isLinkSync(path) methods that will tell you if something is a symlink; also when it is a broken symlink.
http://api.dartlang.org/docs/bleeding_edge/dart_io/FileSystemEntity.html
For operations on links we are adding a Link class. The code is out for review now:
https://codereview.chromium.org/12691002
If you want to check from the command line to verify what is happening,
ls -al DIRNAME and check for 'l' in the permissions section, and examine what it's pointing "to" on the right side of the output.
see also man 1 stat
If you're wanting to check that from within Dart itself, I don't know how.
FileSystemEntity.typeSync(path)
return an FileSystemEntityType with one of the values
FileSystemEntityType.DIRECTORY
FileSystemEntityType.FILE
FileSystemEntityType.LINK
FileSystemEntityType.NOT_FOUND
I have the following issue: I create a QFileSystemWatcher and it runs and works nicely on Linux, but no way on Windows 7. Can you spot anything in the code that might make it not to work?
Thx.
Here is the code to initialize it:
mConfigChangeWatcher = new QFileSystemWatcher();
mConfigChangeWatcher->addPath(config_file_name);
QObject::connect(mConfigChangeWatcher,
SIGNAL(fileChanged(QString)),
this,
SLOT(configFileChanged(QString)));
and this is supposed to be the slot getting the work done:
void MyClass::configFileChanged(const QString &file)
{
qDebug() << "Changed: " << file ;
}
When you check if the file is added to the watcher using QFileSystemWatcher::files() method after the first modification in the file do you get the correct list?
I was with the issue that some applications, when modifing a file, delete the old file from the system and write it again.
Note that QFileSystemWatcher stops monitoring files once they have been renamed or removed from disk, and directories once they have been removed from disk.
I was using QFileSystemWatcher to watch an image file edited by Photoshop. Somehow the file gets removed from the list of files being watched.
I had the same problem and solved it very fast.
Within the slot that manages the fileChanged signal I noted the path disappears from files(). I simply make a check and re-add it if necessary
if (! watcher_.files().contains(path))
{
watcher_.addPath(path);
}
I hope this helps
Fabio