I'm using ZipFile.Open() to create an archive, then adding entries using CreateEntryFromFile(). The resulting file is invalid according to Windows. 7-zip can open the file, but only part of the files are listed.
The code looks like this:
using (ZipArchive archive = ZipFile.Open(archivePath, ZipArchiveMode.Create))
{
while (reader.Read())
{
object myValue = reader.GetValue(0);
string objectId = myValue.ToString();
string objectPath = Path.Combine(myPath, objectId);
string[] files = Directory.GetFiles(objectPath);
if (files.Length > 0)
{
archive.CreateEntryFromFile(files[0], Path.GetFileName(files[0]));
}
}
}
As you can see, I do dispose of the ZipArchive when I'm done, and unlike every other question about this problem, I don't use any streams, so there's nothing to flush.
Anyone know what's wrong?
It could be possible that the file being added to the archive is being used by another process and cannot be accessed. To avoid this, you can try wrapping the CreateEntryFromFile method in a try-catch block and handle the IOException that could be thrown if the file is in use. You can also try closing any streams or file handles that may have been opened on the file before adding it to the archive.
Related
I have the following method that validates if certain file exist in the a zipped file.
The method might get a zipped file or not from IFormFile.
private static bool FileExistsInZip(IFormFile uploadedFile, string fileName)
{
using ZipArchive archive = new ZipArchive(uploadedFile.OpenReadStream(), ZipArchiveMode.Read);
return archive.Entries.Any(entry => entry.Name.Equals(fileName, StringComparison.OrdinalIgnoreCase));
}
So in the above method, uploaded file could be zip file or just text file or an image. I was wondering if ZipArchive will return false in this case but it throws ArgumentOutOfRange exception when trying to open file type that is not in Zip format. For example a 4 byte txt file.
What would be the right approach to handle this kind of scenario ?
The typical solution when there is an exception is to catch it and handle it somehow.
However, if you want to test if a file is a zip file you can instead check the header. For zip files this should be 0x04034b50. So something like:
using var br = new BinaryReader(uploadedFile.OpenReadStream());
if(br.ReadUint32 == 0x04034b50){
//is zip file
}
This will only check if the header has the correct magic numbers, it will not tell if the actual file is corrupted, for that you might need to read the entire file, including any entries, and catch any exception that occur. If you want to know the specific file type there are lists of magic numbers for different file formats.
This is the code:
string file = Path.Combine(Environment.CurrentDirectory, "test.txt");
if (!File.Exists(file)) {
File.CreateText(file); // will throw always
}
using (var writer = new StreamWriter(file)) { // will throw always
//...
}
This will throw a DirectoryNotFoundException if the file doesn't exist and if it attempts to create it, and if the file does exist, then it will throw DirectoryNotFoundException when trying to use StreamWriter. I don't believe this code is wrong, so I am at a loss at what is the problem.
Update
The value of file is /tmp/test.txt. Yes, it always is throwing, the exception is
System.IO.DirectoryNotFoundException: Could not find a
part of the path '/tmp/test.txt'
Update
A reboot has fixed this. I have no idea why this was being caused, but it might've simply been an IDE issue.
You are opening a file with
File.CreateText(file);
File.CreateText(String) Method
Returns StreamWriter A StreamWriter that writes to the specified file
using UTF-8 encoding.
Then you are not closing it. Then you are trying to access the open file by opening it again
using (var writer = new StreamWriter(file))
However, the exception you are getting is another problem again. When using StreamWriter
DirectoryNotFoundException The specified path is invalid (for example,
it is on an unmapped drive).
All the above aside, what i suggest you do is
string file = Path.Combine(Environment.CurrentDirectory, "test.txt");
Console.WriteLine(file);
//FileMode.Create will create or overwwrite the file
using (var fs = new FileStream(file,FileMode.Create))
using (var writer = new StreamWriter(fs))
{
}
Then if you still have problems, go to that directory and check if the file is there, check the permissions on the directory and file and make sure you have the appropriate access.
In short your code is suspect and you need to fix it, secondly you need to be sure what file it is your opening, thirdly, you need to check the permissions for that file and or directory
I am using C# in Microsoft Visual Studio 2012, I am working on the following code:
string source = "d:\\source.txt";
string newFile = "d:\\newFile.txt";
if(!File.Exists(newFile))
{
File.Create(newFile);
string content = File.ReadAllText(source);
File.AppendAllText(newFile,content);
}
This code successfully creates the File but when it compiles the File.AppendAllText(newFile,content) it generates the error:
the process cannot access the file "d:\newFile.txt" because it is being used by another process.
Why would this be?
The File.Create method returns a FileStream object. This is holding the file open for write. Until that object is closed the file cannot be written to. The best way to fix this is to simply close the returned file
File.Create(newFile).Close();
This code is essentially copying the contents of an existing file to a new one. There is already an API available that does exactly that: File.Copy. Your code could be simplified to the following
try {
File.Copy(source, newFile);
} catch (Exception) {
// File already exists or write can't occur
}
you don't need to create file , AppendAllText create if not exist, you get exception because File.Create return open file stream and then you try to access same file again. you need to properly close that stream before access the same file.
string source = "d:\\source.txt";
string newFile = "d:\\newFile.txt";
if(!File.Exists(newFile))
{
File.AppendAllText(newFile,File.ReadAllText(source););
}
File.AppendAllText:
Opens a file, appends the specified string to the file, and then
closes the file. If the file does not exist, this method creates a
file, writes the specified string to the file, then closes the file.
but you can simply do your task by one line
File.Copy(source , newFile , false);
I have a problem aith multithreading when copying and accessing files.
I have a service, that downloads and unpacks a Zip archive, then it copies a file from unzipped folder to the right location:
//Download, and uzip archive...
//Copy a needed file to its right location
File.Copy(fileName, fileDestination);
Then I start a separate thread, that needs to access the copied files:
TheadPool.QueueUserWorkItem(s => processCopiedFile(fileDestination));
Here's the code fragment from ProcessCopiedFile:
private void ProcessCopiedFile(string filePath)
{
...
//Load the file, previously copied here
var xml = XDocument.Load(filePath);
...
//Do other work...
}
The XDoument.Load call fails with exception:
The process cannot access the file <FileName> because it is used by another process.
Seems like File.Copy keeps the result file locked. When do all work synchronuously, it works without errors.
Have you any thoughts?
Thx.
File.Copy does not keep anything open or locked, it is an atomic operation which requires some time, depending of course on Disk/Network I/O and file size.
Of course while moving from sync to async you should make sure you do not access the destination file while the copy is still in progress.
Copy the file with a stream to avoid windows lock from File.Copy
using(var s = new MemoryStream(File.ReadAllBytes(filePath))
{
using(var fs = new FileStream(newLocation, FileMode.Create))
{
s.WriteTo(fs);
}
}
while deleting a file dynamically using c# it couldn't be deleted because its being used
by another process but i have no other process which has been using this file.
foreach (string file in filess)
{
// FileInfo fi2 = new FileInfo(file);
// fi2.Delete();
File.Delete(file);
// ii = 0;
}
Generally if it say that it is used by another process then you should consider this as true. To have sure you can verify this with this tool: Process Explorer
It will tell you what process is locking file.
You should always make sure you close the streams you opened it:
using (FileStream stream = File.Create("C:\\1.txt"))
{
// your code goes here
}// the object will be closed here
because if you don't put this using block it will cause a lot of bugs even if you closed it manually with stream.Close();
If the File is in use you can't delete it, do the deletion in a try catch clauses. I would determine if the process using that file is your own app or some other process. You can use the Unlocker for that.
This is How you can delete simply
// File.Copy(#"C:\Users\Asus\Desktop\New.txt", #"D:\New.txt");
string rootFolder = #"D:\";
string authorsFile = "Gym.mdf";
File.Delete(Path.Combine(rootFolder, authorsFile));
string authorsFile2 = "Gym_log.ldf";
File.Delete(Path.Combine(rootFolder, authorsFile2));