使用示例代码

Question

我试图使用国家气象服务（美国）数据，但最近发生了一些变化，GZip文件不再打开。

.NET 4.5抱怨......

extension UIPasteboard {
    func arrayForPasteboardType(pasteboardType: String) -> NSArray? {
        switch valueForPasteboardType(pasteboardType) {
        case let array as NSArray:
            return array
        case let data as NSData:
            if let array = NSPropertyListSerialization.propertyListWithData(data, options: 0, format: nil, error: nil) as? NSArray {
                return array
            }
        default:
            break
        }

        return nil
    }
}

我不明白发生了什么变化，但这已经成为一个真正的表演者。任何有GZip格式经验的人都可以告诉我发生了什么变化让这个停止工作吗？

有效的文件：

http://www.srh.noaa.gov/ridge2/Precip/qpehourlyshape/2015/201504/20150404/nws_precip_2015040420.tar.gz

无法正常工作的文件：

http://www.srh.noaa.gov/ridge2/Precip/qpehourlyshape/2015/201505/20150505/nws_precip_2015050505.tar.gz

使用示例代码

进行更新

Message=The magic number in GZip header is not correct. Make sure you are passing in a GZip stream.
Source=System
StackTrace:
   at System.IO.Compression.GZipDecoder.ReadHeader(InputBuffer input)
   at System.IO.Compression.Inflater.Decode()
   at System.IO.Compression.Inflater.Inflate(Byte[] bytes, Int32 offset, Int32 length)
   at System.IO.Compression.DeflateStream.Read(Byte[] array, Int32 offset, Int32 count)

Answer 1

看来此服务SOMETIMES返回伪装成tar的{{1}}格式文件。这非常令人困惑，但如果您检查前两个字节是.tar.gz和0x1F，您可以通过手动检查其幻数来检测文件是否为GZip。

0x8B

Answer 2

[已解决] GZipStream抱怨标题中的幻数不正确

//异常幻数tar.gz文件

Migcal错误原因

文件未正确压缩到tar.gz
文件太大，超过1 + GB

解决方案

使用.net framework 4.5.1来解决此异常// OR //
在不改变.net框架的情况下完成现有解决方案。请按照实施步骤进行操作。
1. Remane abc.tar.gz as abc（删除扩展名）。
2. 传递此文件并直接命名为压缩功能

* public static void Compress（DirectoryInfo directorySelected，string directoryPath）

    {
        foreach (FileInfo fileToCompress in directorySelected.GetFiles())
        {
            using (FileStream originalFileStream = fileToCompress.OpenRead())
            {
                if ((File.GetAttributes(fileToCompress.FullName) &
                   FileAttributes.Hidden) != FileAttributes.Hidden & fileToCompress.Extension != ".tar.gz")
                {
                    using (FileStream compressedFileStream = File.Create(fileToCompress.FullName + ".tar.gz"))
                    {
                        using (System.IO.Compression.GZipStream compressionStream = new System.IO.Compression.GZipStream(compressedFileStream,
                           System.IO.Compression.CompressionMode.Compress))
                        {
                            originalFileStream.CopyTo(compressionStream);
                        }
                    }
                    FileInfo info = new FileInfo(directoryPath + "\\" + fileToCompress.Name + ".tar.gz");
                }
            }
        }
    }


3. implement this code in following exception handler try catch block
    try
    {
        TarGzFilePath=@"c:\temp\abc.tar.gz";
        FileStream streams = File.OpenRead(TarGzFilePath);
        string FileName=string.Empty;
        GZipInputStream tarGz = new GZipInputStream(streams);
        TarInputStream tar = new TarInputStream(tarGz);
        // exception will occured in below lines should apply try catch

        TarEntry ze;
            try
            {
                ze = tar.GetNextEntry();// exception occured here "magical number"
            }
            catch (Exception extra)
            {
                tar.Close();
                tarGz.Close();
                streams.Close();
                //please close all above , other wise it will come with exception "tihs process use by another process"
                //rename your file *for better accuracy you can copy file to other location 

                File.Move(@"c:\temp\abc.tar.gz", @"c:\temp\abc"); // rename file 
                DirectoryInfo directorySelected = new DirectoryInfo(Path.GetDirectoryName(@"c:\temp\abc"));
                Compress(directorySelected, directoryPath); // directorySelected=c:\temp\abc , directoryPath=c:\temp\abc.tar.gz // process in step 2 function 
                streams = File.OpenRead(TarGzFilePath);
                tarGz = new GZipInputStream(streams);
                tar = new TarInputStream(tarGz);
                ze = tar.GetNextEntry();                    
            }
            // do anything with extraction with your code
    }
    catch (exception ex)
    {
        tar.Close();
        tarGz.Close();
        streams.Close();
    }

GZipStream抱怨标题中的幻数不正确

使用示例代码

2 个答案: