根据 .NET Core 文件名中的 ContentType 添加文件扩展名

Question

我需要使用上传的文件扩展名保存文件。例如，如果文件名是“Test_upload”，我必须将文件扩展名附加到该名称。因此，我只有可用的内容类型。下面是示例代码

       if (suggestedFileName != null && !System.IO.Path.HasExtension(suggestedFileName))
      {
    // Get the file extension from the ContentType
    string[] contentTypeParts = HttpContext.Request.ContentType.Split('/');
    if (contentTypeParts.Length == 2)
    {
        string fileExtension = contentTypeParts[1];

        // Handle spreadsheets differently
        if (fileExtension == "vnd.openxmlformats-officedocument.spreadsheetml.sheet")
        {
            // For spreadsheet, use '.xlsx' extension
            suggestedFileName = $"{suggestedFileName}.xlsx";
        }
        else
        {
            // For other file types, append the retrieved extension
            suggestedFileName = $"{suggestedFileName}.{fileExtension}";
        }
    }
    else
    {
        // Default to '.txt' extension if content type doesn't have two parts
        suggestedFileName = $"{suggestedFileName}.txt";
    }
}

如何处理任何类型的 ContentType 有人可以帮忙吗

Answer 1

{
    {"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "xlsx"},
    {"application/pdf", "pdf"},
    {"image/jpeg", "jpg"},
    {"image/png", "png"},
    {"text/plain", "txt"},
};

if (suggestedFileName != null && !System.IO.Path.HasExtension(suggestedFileName))
{
    string contentType = HttpContext.Request.ContentType;
    string fileExtension = "txt"; 
    if (mimeTypeToExtension.TryGetValue(contentType, out var extension))
    {
        fileExtension = extension;
    }
    else
    {
        string[] contentTypeParts = contentType.Split('/');
        if (contentTypeParts.Length == 2)
        {
            string subtype = contentTypeParts[1];
            fileExtension = subtype;
        }
    }
    suggestedFileName += $".{fileExtension}";
}