将文件写入 .NET Core 中的临时文件夹后无法读取文件

Question

在我的场景中，我有一个用例，我必须接收一个压缩文件，进行一些验证，然后在存档中找到我必须通过第三方库处理的特定文件。不过，我在让这样的库读取文件时遇到了一些麻烦。这是我到目前为止想出的：

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);
            }
        }
    }
}

请注意，我正在使用 "old way" 复制流，因为 Stream.CopyTo 和 Stream.CopyToAsync 正在创建空文件，显式调用 fileStream.Close() 看起来是唯一的方法以某种方式将字节放入文件中，但这超出了我的观点。无论如何，在 关闭流 之后，调用 featureSource.Open() 我的应用程序抛出

"The process cannot access the file 'C:\Users\me\AppData\Local\Temp\tmpE926.tmp' because it is
being used by another process."

tmpE926.tmp 显然每次都不一样。另请注意，我正在创建一个文件，因为 ShapeFileFeatureSource 的构造函数不需要流、字节数组，而是路径。

更短的实现

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);
        }
    }
}

实际上会产生相同的错误。老实说，我不认为问题出在这个库中，而是我以某种方式把它搞砸了。有没有人有任何想法或者我应该联系供应商的（无响应的）技术支持？

编辑：以防万一，这就是这样的库 Install-Package ThinkGeo.UI.WebApi 但您必须订阅才能评估才能使用它。

Answer 1

我找不到这样的 .NET Core 包类，所以我通过 .NET Framework Nuget 包复制了它。我的回答主要是演示如何处理流。如果无法访问您拥有的库，很难判断您的代码有什么问题

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\Downloads70055001_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：安装了 ThinkGeo 库的试用版，而不是未经授权的异常，它给了我 FileNotFoundException 和给定的堆栈跟踪

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 ？所以我想我应该以这种方式深入研究

var featureSource = new ShapeFileFeatureSource(tempFile);
featureSource.RequireIndex = false; // no luck
featureSource.Open();

我试图找到它想要的任何对 idx 文件的引用，它有属性 IndexFilePathName，但不幸的是，我运气不好。（也尝试了不同的文件夹，所以这不是 'Temp' 文件夹问题）

Answer 2

这段代码变形了几天，直到我联系到技术支持，他们稍微修改了一下，想出了这个：

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);
                }
            }
        }
    }
}

有效。我很开心。

将文件写入 .NET Core 中的临时文件夹后无法读取文件

Can't read file after writing it to temp folder in .NET Core

c#

.net-core

shapefile

memorystream