What is the best way to go about monitoring a folder to see when an image file has been added to it? Files are added approximately once a minute and the naming goes like this... image0001.jpg, image0002.jpg, image0003.jpg etc. I need to know when a file has been written to the folder so that my app can access and use it.
Look into directory change notifications.
As per previously mentioned, the directory change notifications is what you want.
I have looked into them as well, and the caveat I have seen is that windows will fire off the notification when the file starts to be written to the folder. If the file is large enough then you will receive the notification before the file has finished being written.
Check out this google search for various solutions for waiting until the file is completely written
Edit: I just saw that the question was tagged with c++, and I linked to a .Net search. Although what I provided may not be the correct language, I would think that you will still have the same issues on Windows no matter what system you are coding with.
FileSystemWatcher should be able to do that for you.
Change notifactions may cause some overhead, if you've NTFS, consider NTFS change journals.
You can use a polling method to monitor the folder. The loop will execute every 5 seconds, for example.
This method returns a list of new files:
List<string> files = new List<string>();
string path = #"C:\test\"; // whatever the path is
public List<string> GetNewFiles(string path)
{
// store all the filenames (only .jpg files) in a list
List<string> currentFiles = System.IO.Directory.GetFiles(path, "*.jpg");
if ( currentFiles.Count() > files.Count() )
{
count = newFiles.Length - files.Length;
List<string> newFiles = new List<string>();
foreach ( string file in currentFiles )
{
if ( !files.Contains(file) )
{
newFiles.Add(file);
}
}
}
files = currentFiles;
return newFiles;
}
This is the method that will poll every 5 seconds and call the previous method.
public void MonitorFolder()
{
while (true)
{
List<string> newFiles = GetNewFiles(path);
System.Threading.Thread.Sleep(5000); // 5000 milliseconds
}
}
Synch.variant FindFirstChangeNotification
Asynch.variant ReadDirectoryChangesW
This was the top google result for my search so I'll add this as an answer.
If you're using Qt, there's QFileSystemWatcher. I didn't know this existed and we happened to be using Qt, so I wasted more than a few hours using FindFirstChangeNotification to rewrite what was readily available to me until a colleague showed me the light.
Good learning experience though.
inotify might be your thing
Related
There is queue with links of files to download. I'm trying find the way to continue downloading when application goes to suspend mode.
According to official microsoft documentation suitable class for this is BackgroundDownloader, but it's handles only one current downloading process. It looks wrong to call in loop CreateDownload() method for every link without waiting for the completion of previous links, isn't right?
More logical in my opinion is using in-process background task. I see it this way:
Implement Run(IBackgroundTaskInstance) method of interface IBackgroundTask (it should stay alive even when app is suspended, right?)
Using custom event transmit the queue to the implemented method
Inside Run(IBackgroundTaskInstance) method use BackgroundDownloader (by implementing the execution of one instance at a time)
But I'm stuck even with simple implementation for one file downloading. Bellow my Run(IBackgroundTaskInstance) method implementation:
void Task::DownloaderTask::Run(IBackgroundTaskInstance ^ taskInstance)
{
TaskDeferral = taskInstance->GetDeferral();
std::wstring filename = L"Pleiades_large.jpg";
Uri^ uri = ref new Uri(ref new Platform::String(L"https://upload.wikimedia.org/wikipedia/commons/4/4e/Pleiades_large.jpg"));
Concurrency::create_task(KnownFolders::GetFolderForUserAsync(nullptr, KnownFolderId::PicturesLibrary))
.then([this, filename, uri](StorageFolder^ picturesLibrary)
{
return picturesLibrary->CreateFileAsync(ref new Platform::String(filename.c_str()), CreationCollisionOption::GenerateUniqueName);
}).then([this, filename, uri](StorageFile^ destinationFile) {
BackgroundDownloader^ downloader = ref new BackgroundDownloader();
DownloadOperation^ download = downloader->CreateDownload(uri, destinationFile);
download->StartAsync();
}).then([this](Concurrency::task<void> previousTask)
{
try
{
previousTask.get();
TaskDeferral->Complete();
}
catch (Platform::Exception^ ex)
{
wchar_t buffer[1024];
swprintf_s(buffer, L"Exception: %s", ex->Message);
OutputDebugString(buffer);
}
});
}
The code above only creates empty file, but using the same code without BackgroundTask it works correctly. I didn't find any restrictions for BackgroundDownloader inside BackgroundTask.
So, my questions are:
Is it right way of usage BackgroundTask?
Is there another approach to solving the problem?
Is this problem solvable at all?
I've found the cause of the unexpected behavior:
The line of code TaskDeferral->Complete(); was at the end of the method at first while it should be at the end of async call.
Therefore, initial implementation (published in question) is correct.
All that had to be done was to Rebuild project.
I'm having difficulty with my in-repo addon writing to appDir/public. What I'd like to do is write out a JSON file on each build to be included in the app /dist. The problem I'm running into is when running "ember serve", the file watcher detects the new file and rebuilds again, causing an endless loop.
I've tried writing the JSON file using preBuild() and postBuild() hooks, saving to /public, but after build, the watcher detects it and rebuild over and over, writing a new file again each time. I also tried using my-addon/public folder and writing to that, same thing.
The only thing that partially works is writing on init(), which is fine, except I don't see the changes using ember serve.
I did try using the treeForPublic() method, but did not get any further. I can write the file and use treeForPublic(). This only runs once though, on initial build. It partially solves my problem, because I get the files into app dist folder. But I don't think ember serve will re-run treeForPublic on subsequent file change in the app.
Is there a way to ignore specific files from file watch? Yet still allow files to include into the build? Maybe there's an exclude watch property in ember-cli-build?
Here's my treeForPublic() , but I'm guessing my problems aren't here:
treeForPublic: function() {
const publicTree = this._super.treeForPublic.apply(this, arguments);
const trees = [];
if (publicTree) {
trees.push(publicTree);
}
// this writes out the json
this.saveSettingsFile(this.pubSettingsFile, this.settings);
trees.push(new Funnel(this.addonPubDataPath, {
include: [this.pubSettingsFileName],
destDir: '/data'
}));
return mergeTrees(trees);
},
UPDATE 05/20/2019
I should probably make a new question at this point...
My goal here is to create an auto-increment build number that updates both on ember build and ember serve. My comments under #real_ates's answer below help explain why. In the end, if I can only use this on build, that's totally ok.
The answer from #real_ate was very helpful and solved the endless loop problem, but it doesn't run on ember serve. Maybe this just can't be done, but I'd really like to know either way. I'm currently trying to change environment variables instead of using treeforPublic(). I've asked that as a separate question about addon config() updates to Ember environment:
Updating Ember.js environment variables do not take effect using in-repo addon config() method on ember serve
I don't know if can mark #real_ate's answer as the accepted solution because it doesn't work on ember serve. It was extremely helpful and educational!
This is a great question, and it's often something that people can be a bit confused about when working with broccoli (I know for sure that I've been stung by this in the past)
The issue that you have is that your treeForPublic() is actually writing a file to the source directory and then you're using broccoli-funnel to select that new custom file and include it in the build. The correct method to do this is instead to use broccoli-file-creator to create an output tree that includes your new file. I'll go into more detail with an example below:
treeForPublic: function() {
const publicTree = this._super.treeForPublic.apply(this, arguments);
const trees = [];
if (publicTree) {
trees.push(publicTree);
}
let data = getSettingsData(this.settings);
trees.push(writeFile('/data/the-settings-file.json', JSON.stringify(data)));
return mergeTrees(trees);
}
As you will see the most of the code is exactly the same as your example. The two main differences are that instead of having a function this.saveSettingsFile() that writes out a settings file on disk we now have a function this.getSettingsData() that returns the content that we would like to see in the newly created file. Here is the simple example that we came up with when we were testing this out:
function getSettingsData() {
return {
setting1: 'face',
setting2: 'my',
}
}
you can edit this function to take whatever parameters you need it to and have whatever functionality you would like.
The next major difference is that we are using the writeFile() function which is actually just the broccoli-file-creator plugin. Here is the import that you would put at the top of the file:
let writeFile = require('broccoli-file-creator');
Now when you run your application it won't be writing to the source directory any more which means it will stop constantly reloading 🎉
This question was answered as part of "May I Ask a Question" Season 2 Episode 2. If you would like to see us discuss this answer in full you can check out the video here: https://youtu.be/9kMGMK9Ur4E
I have been trying to to create an extension that highlights specific line numbers for me in Visual Studio in the margins.
I manged to get my marking in the margins using predefined line number but for it to work properly I need to know what the current document FullName is (Path and filename)
After much googling I figured out how to do it with the sample code (which is not ideal)
DTE2 dte = (DTE2)System.Runtime.InteropServices.Marshal.GetActiveObject("VisualStudio.DTE.15.0");
var activeDocument = dte.ActiveDocument;
var docName = activeDocument.Name;
var docFullName = activeDocument.FullName;
Now I know the problems here
is that is for specific version bases on the text
there is no way to select which instance (when running more than one VS)
It seems to be very slow
I have a feeling I should be doing this with MEF Attributes but the MS docs examples are so simple that they do not work for me. I scanned a few SO questions too and I just cannot get them to work. They mostly talk about Services.. which I do not have and have no idea how to get.
The rest of my code uses SnapshotSpans as in the example Extension of Todo_Classification examples which is great if you do NOT need to know the file name.
I have never done any extensions development. Please can somebody help me do this correctly.
You can use following code to get a file from a snapshot without any dependencies.
public string GetDocumentPath(Microsoft.VisualStudio.Text.ITextSnapshot ts)
{
Microsoft.VisualStudio.Text.ITextDocument textDoc;
bool rc = ts.TextBuffer.Properties.TryGetProperty(
typeof(Microsoft.VisualStudio.Text.ITextDocument), out textDoc);
if (rc && textDoc != null)
return textDoc.FilePath;
return null;
}
If you don't mind adding Microsoft.CodeAnalysis.EditorFeatures.Text to your project it will provide you with an extension method Document GetOpenDocumentInCurrentContextWithChanges() on the Microsoft.VisualStudio.Text.Snapshot class. (Plus many other Rosyln based helpers)
using Microsoft.CodeAnalysis.Text;
Document doc = span.Snapshot.GetOpenDocumentInCurrentContextWithChanges();
Just tried out the blueimp "out of the box" files.
With a few hurdles, I got the plugin to work on my site.
In my application, I want to store the uploaded files in specific directories based on the file name.
The PHP code to do this is pretty straight forward:
function StoreAudioFiles()
{
$TempFileName = $_FILES['file']['tmp_name'];
$OriginalFileName= $_FILES['file']['name'];
$TheFolderName=MyCustomFunction($OriginalFileName);
move_uploaded_file($TempFileName,$TheFolderName.$OriginalFileName);
}
I have no idea where to modify the 'out-of-the-box' file "UploadHandler.php" to insert my code.
Given the fact that the file is 55 pages long when opened in Word, any help would be appreciated.
David
I worked out a solution and am posting it here for others to use.
In the index.php file that comes with blueimp, add functions after the object is created. Here's what I did:
require('UploadHandler.php');
$upload_handler = new UploadHandler();
//Now Add whatever custom functionality you want from here on.
MoveFiles();
function MoveFiles()
{
$UploadDir="files/";
$TheHandle=opendir($UploadDir);
while (False !== ($FileName = readdir($TheHandle))) MoveThisFile($FileName);
}
function MoveThisFile($TheFileName)
{
if(strlen($TheFileName)<4) return;
$UploadFilePath='mysite/server/php/files/';
$TheFolderName=MyCustomFolderName($TheFileName);
$OriginalFileName=$UploadFilePath.$TheFileName;
$TargetFileName=$TheFolderName.$TheFileName;
rename($OriginalFileName,$TargetFileName);
}
I'm working on a project in C# that involves parsing .pst files and my group has chosen to use the Redemption library to do so. We have successfully parsed the email files in to RDOMail objects, however now we want to write a subset of those emails to a new .pst file. I have successfully written the subset to .eml files using the email.SaveAs() function, but I'm at a loss to figure out how to save that list as a .pst. I've been sifting through the documentation, however it leaves much to be desired. Can anyone who has used Redemption point me in the right direction or provide an example?? Thanks in advance for your help!
You will need to create/open a PST file using RDOSession.Stores.AddPstStore (returns RDOPSTStore object). Once you have the store, you can open/create folders (starting with the RDOStore.IPMRootFolder), create messages (RDOFolder.Items.Add) and copy old messages into new messages (RDOMail.CopyTo(RDOMail/RDOFolder)).
I have been struggling to do this for the last few hours and would like to save that time to others
You have to install redemption and add it as a reference to your project for it to work
RDOSession session = new RDOSession(); // throws exception 1
session.LogonPstStore(#"c:\temp\output.pst");
RDOFolder folder = session.GetDefaultFolder(rdoDefaultFolders.olFolderInbox);
string[] fileEntries = Directory.GetFiles(#"C:\emlFiles\", "*.eml");
foreach (string filePath in fileEntries)
{
RDOMail mail = folder.Items.Add("IPM.Mail");
mail.Sent = true;
mail.Import(filePath, 1024);
// folder.Items.Add(mail);
mail.Save();
}
session.Logoff();
I also created a small sample windows forms app for it, I know the code is ugly but it does the trick