[英]Can't read file after writing it to temp folder in .NET Core
在我的場景中,我有一個用例,我必須接收一個壓縮文件,進行一些驗證,然后在存檔中找到一個我必須通過第三方庫處理的特定文件。 不過,我在讓這樣的庫讀取文件時遇到了一些麻煩。 這是我到目前為止想出的:
public async Task ShapeIt(ZipArchive archive)
{
foreach (var entry in archive.Entries)
{
if (Path.GetExtension(entry.FullName).Equals(".shp"))
{
var stream = entry.Open();
using var ms = new MemoryStream();
await stream.CopyToAsync(ms);
ms.Position = 0;
var fileName = Path.GetTempFileName();
try
{
using var fileStream = File.Open(fileName, FileMode.OpenOrCreate, FileAccess.Write,
FileShare.ReadWrite);
var bytes = new byte[ms.Length];
ms.Read(bytes, 0, (int)ms.Length);
fileStream.Write(bytes, 0, bytes.Length);
fileStream.Flush();
fileStream.Close();
var featureSource = new ShapeFileFeatureSource(fileName); // Class from 3rd-party
featureSource.Open();
// Do my stuff with the shapefile
}
finally
{
File.Delete(fileName);
}
}
}
}
請注意,我正在使用復制流的“舊方法”,因為Stream.CopyTo
和Stream.CopyToAsync
正在創建空文件,顯式調用fileStream.Close()
看起來像是以某種方式將字節放入文件的唯一方法,但是這超出了我的意思。 無論如何,在關閉流后,調用featureSource.Open()
我的應用程序拋出
"The process cannot access the file 'C:\\Users\\me\\AppData\\Local\\Temp\\tmpE926.tmp' because it is
being used by another process."
tmpE926.tmp
都不同,很明顯。 還要注意,我正在創建一個文件,因為ShapeFileFeatureSource
的構造函數需要的不是流,也不是字節數組,而是路徑。
一個更短的實現
public async Task ShapeIt(ZipArchive archive)
{
foreach (var entry in archive.Entries)
{
var tempFile = Path.GetTempFileName();
try
{
entry.ExtractToFile(tempFile, true);
if (Path.GetExtension(entry.FullName).Equals(".shp"))
{
var featureSource = new ShapeFileFeatureSource(tempFile);
featureSource.Open();
var type = featureSource.GetShapeFileType();
}
}
finally
{
File.Delete(tempFile);
}
}
}
實際上會導致相同的錯誤。 老實說,我不認為問題出在這個庫中,而是我以某種方式把它搞砸了。 有沒有人有任何想法,或者我應該聯系供應商的(沒有響應的)技術支持嗎?
編輯:以防萬一,這是這樣的庫Install-Package ThinkGeo.UI.WebApi
但你必須訂閱評估才能使用它。
我找不到帶有此類類的 .NET Core 包,因此我通過 .NET Framework Nuget 包復制了它。 我的回答主要展示了如何處理流。 如果無法訪問您擁有的庫,就很難判斷您的代碼有什么問題
using DotSpatial.Data;
using System.IO;
using System.IO.Compression;
namespace ConsoleApp12
{
class Program
{
static void Main(string[] args)
{
using (var fs = File.OpenRead(@"C:\Users\jjjjjjjjjjjj\Downloads\1270055001_mb_2011_vic_shape.zip"))
using (var zipFile = new ZipArchive(fs))
{
foreach (var entry in zipFile.Entries)
{
if (entry.FullName.EndsWith(".shp"))
{
var tempFile = Path.GetTempFileName();
try
{
using (var entryStream = entry.Open())
using (var newFileStream = File.OpenWrite(tempFile))
{
entryStream.CopyTo(newFileStream);
}
var featureSource = ShapefileFeatureSource.Open(tempFile);
var type = featureSource.ShapeType;
}
finally
{
File.Delete(tempFile);
}
}
}
}
}
}
}
UPD:安裝了 ThinkGeo 庫的試用版,而不是未經授權的異常,它給我FileNotFoundException
和給定的堆棧跟蹤
at ThinkGeo.Core.ValidatorHelper.CheckFileIsExist(String pathFilename)
at ThinkGeo.Core.ShapeFileIndex.xh8=(FileAccess readWriteMode)
^^^^^^^^^^^^^^^^^^^^^^^^^ Are we supposed to have index?
at ThinkGeo.Core.ShapeFile.xh8=(FileAccess readWriteMode)
at ThinkGeo.Core.ShapeFileFeatureSource.WjE=()
at ThinkGeo.Core.ShapeFileFeatureSource.OpenCore()
at ThinkGeo.Core.FeatureSource.Open()
at ConsoleApp20.Program.Main(String[] args) in
C:\Users\jjjjjjjjjjjj\source\repos\ConsoleApp20\ConsoleApp20\Program.cs:line 45
ShapeFileIndex
? 所以我想我應該以這種方式深入研究
var featureSource = new ShapeFileFeatureSource(tempFile);
featureSource.RequireIndex = false; // no luck
featureSource.Open();
我試圖找到它想要的 idx 文件的任何引用,它具有屬性IndexFilePathName
,但不幸的是,我運氣不好。 (也試過不同的文件夾,所以它不是“臨時”文件夾問題)
這段代碼修改了幾天,直到我聯系了技術支持,他們對它進行了一些修改並想出了這個:
public async Task ProcessFile(IFormFile file)
{
if (!Path.GetExtension(file.FileName).Equals(".zip"))
throw new System.Exception("File should be compressed in '.zip' format");
var filePaths = new List<string>();
using (var stream = new MemoryStream())
{
await file.CopyToAsync(stream);
using (var archive = new ZipArchive(stream, ZipArchiveMode.Read, false))
{
var replaceList = new Dictionary<string, string>();
foreach (ZipArchiveEntry entry in archive.Entries)
{
var tempPath = Path.GetTempFileName();
string key = Path.GetFileNameWithoutExtension(entry.FullName);
string value = Path.GetFileNameWithoutExtension(tempPath);
if (replaceList.ContainsKey(key))
{
value = replaceList[key];
}
else
{
replaceList.Add(key, value);
}
string unzippedPath = Path.Combine(Path.GetDirectoryName(tempPath), value + Path.GetExtension(entry.FullName));
entry.ExtractToFile(unzippedPath, true);
filePaths.Add(unzippedPath);
}
foreach (var unzippedPath in filePaths)
{
if (Path.GetExtension(unzippedPath).Equals(".shp"))
{
// Successfully doing third-party library stuff
}
}
foreach (var unzippedPath in filePaths)
{
if (File.Exists(unzippedPath))
{
File.Delete(unzippedPath);
}
}
}
}
}
有用。 我很高興。
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