C# 应用

1. 代码

/// <summary>
/// 文件上传下载控制器
/// </summary>
public class FileController : ApiController
{
    /// <summary>
    /// 上传文件
    /// </summary>
    /// http://192.168.11.67:8077/file
    /// <returns></returns>
    [HttpPost]
    public Task<IList<UploadFile>> Upload()
    {
        // 获取请求客户端的IP地址
        var ipAddr = GetRemoteClientIPAddress();
        
        try
        {
            //如果文件路径不存在，创建路径
            if (!Directory.Exists(UploadFolder)) Directory.CreateDirectory(UploadFolder);
            
            if (Request.Content.IsMimeMultipartContent())
            {
            	// 读取文件数据
            	var task = Request.Content.ReadAsMultipartAsync().ContinueWith(t =>
            	{
                    // 如果上传过程失败或被取消，则返回错误信息
                    if (t.IsFaulted || t.IsCanceled)
                    {
                    	throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.InternalServerError, "上传过程出错或被取消"));
                    }
        
                    try
                    {
                        // 读取请求数据
                        var provider = t.Result;
                        
                        IList<UploadFile> files = new List<UploadFile>();
                        // 有可能一次上传多个文件，循环保存文件
                        foreach (var filecontent in provider.Contents)
                        {
                            // 读取文件对应的byte数组
                            var byteArray = filecontent.ReadAsByteArrayAsync().Result;
                            // 获取文件信息
                            var fileinfo = GetFileInfo(filecontent, byteArray.Length);
                            // 保存文件
                            if (fileinfo.StatusCode == 1)
                            {
                            	fileinfo.StatusCode = FileHelper.WriteFile(fileinfo.UploadPath, byteArray, fileinfo.UploadName) ? 1 : 0;
                            }
                            // 记录文件信息
                            files.Add(fileinfo);
                            
                            if (fileinfo.StatusCode == 1)
                            {
                                Trace.WriteLine("客户端【" + ipAddr + "】请求上传文件" + fileinfo.UploadPath + "/" + fileinfo.UploadName + "成功");
                            	WriteLog.WriteLogger.Info("客户端【" + ipAddr + "】请求上传文件" + fileinfo.UploadPath + "/" + fileinfo.UploadName + "成功");
                            }
                            else
                            {
                                Trace.WriteLine("客户端【" + ipAddr + "】请求上传文件" + fileinfo.UploadPath + "/" + fileinfo.UploadName + "失败");
                            	WriteLog.WriteLogger.Info("客户端【" + ipAddr + "】请求上传文件" + fileinfo.UploadPath + "/" + fileinfo.UploadName + "成功");
                            }
                        }
                        return files;
                    }
                    catch (Exception ex)
                    {
                        Trace.WriteLine("客户端【" + ipAddr + "】上传文件失败！");
                    	WriteLog.WriteLogger.Error("客户端【" + ipAddr + "】上传文件失败！", ex);
                    	throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.InternalServerError, ex));
                    }
                });
                return task;
            }
            else
            {
                // 请求格式错误
                throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.UnsupportedMediaType, "请求内容格式不正确！"));
            }
        }
        catch (Exception ex)
        {
            Trace.WriteLine("客户端【" + ipAddr + "】上传文件失败！");
        	WriteLog.WriteLogger.Error("客户端【" + ipAddr + "】上传文件失败！", ex);
        	// 返回异常到请求端
        	if (ex is HttpResponseException) throw ex; else throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.BadRequest, ex.Message));
        }
    }

    /// <summary>
    /// 下载文件     注意：加上 attachment 这个header，在浏览器访问 url 链接时会弹出下载框
    /// http://192.168.11.67:8077/file?name=filename
    /// </summary>
    /// <param name="name">文件相对路径</param>
    /// <returns></returns>
    [HttpGet]
    public HttpResponseMessage Download(string name)
    {
    	// 客户端请求IP
    	var ipAddr = GetRemoteClientIPAddress();
    
    	var result = new HttpResponseMessage();
    	// 读取文件
    	FileInfo file = new FileInfo(Path.Combine(UploadFolder, name.TrimStart('/', '\')));
    	if (file.Exists)
    	{
            var isImg = IsImage(name);
            // 如果是图片，返回流，否则弹出下载框下载文件
            if (isImg)
            {
                try
                {
                    // 返回图片流
                    result.StatusCode = HttpStatusCode.OK;
                    result.Content = new StreamContent(new MemoryStream(File.ReadAllBytes(file.FullName)));
                    result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/" + name.Substring(name.LastIndexOf('.') + 1));
                    Trace.WriteLine("客户端【" + ipAddr + "】请求访问图片【" + name + "】成功");
                    WriteLog.WriteLogger.Info("客户端【" + ipAddr + "】请求访问图片【" + name + "】成功");
                }
                catch (Exception ex)
                {
                    result.StatusCode = HttpStatusCode.InternalServerError;
                    Trace.WriteLine("客户端【" + ipAddr + "】请求访问图片【" + name + "】失败");
                    WriteLog.WriteLogger.Error("客户端【" + ipAddr + "】请求访问图片【" + name + "】失败!", ex);
                }
            }
            else
            {
                try
                {
                    // 返回文件流
                    FileStream fs = new FileStream(file.FullName, FileMode.Open);
                    result = new HttpResponseMessage(HttpStatusCode.OK);
                    result.Content = new StreamContent(fs);
                    result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
                    // 加上attachment，浏览器会自动弹出下载框
                    result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
                    result.Content.Headers.ContentDisposition.FileName = file.Name;
                    //fs.Close();
                    Trace.WriteLine("客户端【" + ipAddr + "】请求下载文件【" + name + "】成功");
                    WriteLog.WriteLogger.Info("客户端【" + ipAddr + "】请求下载文件【" + name + "】成功");
                }
                catch (Exception ex)
                {
                    result = new HttpResponseMessage(HttpStatusCode.InternalServerError);
                    Trace.WriteLine("客户端【" + ipAddr + "】请求下载文件【" + name + "】失败");
                    WriteLog.WriteLogger.Error("客户端【" + ipAddr + "】请求下载文件【" + name + "】失败!", ex);
                }
            }
        }
        else
        {
            result.StatusCode = HttpStatusCode.NotFound;
            result.Content = new StringContent("找不到文件：" + name);
            Trace.WriteLine("服务器上查找不到名为【" + name + "】的文件");
            WriteLog.WriteLogger.Info("服务器上查找不到名为【" + name + "】的文件");
        }
        return result;
    }


    /// <summary>
    /// 上传存储文件夹
    /// </summary>
    private string UploadFolder = System.Configuration.ConfigurationManager.AppSettings.Get("FileSaveFolder");

    /// <summary>
    /// 图片后缀
    /// </summary>
    private string[] PicSuffixArray = { "png", "jpg", "jpeg" };
 
    /// <summary>
    /// 返回文件上传时的文件信息
    /// </summary>
    /// <param name="content">请求标头</param>
    /// <param name="sizelength">文件字节流长度</param>
    /// <returns></returns>
    [NonAction()]
    public UploadFile GetFileInfo(HttpContent content, int sizelength)
    {
        try
        {
            // 文件保存路径(源路径+前缀路径)
            string savepath = UploadFolder;
            string filenamestar = "";
            if (!string.IsNullOrEmpty(content.Headers.ContentDisposition.FileNameStar))
            {
                filenamestar = content.Headers.ContentDisposition.FileNameStar.TrimStart('/', '\').Trim(Path.GetInvalidPathChars());
                savepath = Path.Combine(savepath, filenamestar);
            }
            // 文件名
            string filename;
            if (!string.IsNullOrEmpty(content.Headers.ContentDisposition.FileName))
            {
                filename = content.Headers.ContentDisposition.FileName.TrimStart('/', '\').Trim(Path.GetInvalidFileNameChars());
            }
            else
            {
                filename = Guid.NewGuid().ToString();
            }
            while (File.Exists(Path.Combine(savepath, filename)))
            {
                // 文件名重复在后面增加日期
                filename = filename.Insert(filename.LastIndexOf('.'), "_" + DateTime.Now.ToString("yyyyMMdd"));
            }
            // 计算文件大小
            var size = string.Empty;
            if (sizelength > 1024 * 1024)
            {
                size = (sizelength * 100 / 1024 / 1024 / 100.00).ToString() + "MB";
            }
            else
            {
            	if (sizelength > 1024)
            	{
                    size = (sizelength * 100 / 1024 / 100.00).ToString() + "KB";
            	}
            	else
            	{
                    size = sizelength.ToString() + "B";
            	}
            }
            return new UploadFile(savepath, filename, string.Format("?name={0}", Path.Combine(filenamestar, filename)), size);
        }
        catch (Exception ex)
        {
            WriteLog.WriteLogger.Error("上传文件时获取文件信息失败！", ex);
            return new UploadFile("", "", "上传失败", "", 1);
        }
    }

    /// <summary>
    /// 判断是否为图片
    /// </summary>
    /// <param name="fileName"></param>
    /// <returns></returns>
    [NonAction()]
    private bool IsImage(string fileName)
    {
        bool result = false;
        try
        {
            fileName = fileName.ToLower();
            var suffix = fileName.Substring(fileName.LastIndexOf(".") + 1);
            if (PicSuffixArray.Where(x => x == suffix.ToLower()).Count() > 0)
            {
                result = true;
            }
        }
        catch (Exception ex)
        {
            WriteLog.WriteLogger.Error("判断文件" + fileName + "是否图片", ex);
        }
        return result;
    }
    
    /// <summary>
    /// 获取请求客户的 ip 地址
    /// </summary>
    /// <returns></returns>
    [NonAction()]
    private string GetRemoteClientIPAddress()
    {
        var result = string.Empty;
    
        try
        {
            if (Request.Properties.ContainsKey("MS_OwinContext"))
                result = ((OwinContext)Request.Properties["MS_OwinContext"]).Request.RemoteIpAddress;
        }
        catch(Exception ex)
        {
            WriteLog.WriteLogger.Error("获取请求客户的 ip 地址出错！", ex);
        }
    
        return result;
    }
}

/// <summary>
/// 上传文件信息
/// </summary>
public class UploadFile
{
    /// <summary>
    /// 
    /// </summary>
    /// <param name="name">上传时的文件原名</param>
    /// <param name="paramurl">上传后访问路径</param>
    /// <param name="size">文件大小</param>
    /// <param name="namestar">存储的文件路径</param>
    public UploadFile(string path, string name, string paramurl, string size, int statuscode = 1)
    {
    	UploadPath = path;
    	UploadName = name;
    	ParamUrl = paramurl;
    	Size = size;
    	StatusCode = statuscode;
    }
    
    /// <summary>
    /// 上传文件结果，1是成功
    /// </summary>
    public int StatusCode { get; set; }
    
    /// <summary>
    /// 上传时的文件前缀路径
    /// </summary>
    public string UploadPath { get; set; }
    
    /// <summary>
    /// 上传时的文件名
    /// </summary>
    public string UploadName { get; set; }
    
    /// <summary>
    /// 文件访问的路径参数
    /// </summary>
    public string ParamUrl { get; set; }
    
    /// <summary>
    /// 文件大小
    /// </summary>
    public string Size { get; set; }
}

2. Http 系列

2.1 发起请求

使用 HttpWebRequest 发起 Http 请求：https://www.cnblogs.com/MichaelLoveSna/p/14501036.html
使用 WebClient 发起 Http 请求 ：https://www.cnblogs.com/MichaelLoveSna/p/14501582.html
使用 HttpClient 发起 Http 请求：https://www.cnblogs.com/MichaelLoveSna/p/14501592.html
使用 HttpClient 发起上传文件、下载文件请求：https://www.cnblogs.com/MichaelLoveSna/p/14501603.html

2.2 接受请求

使用 HttpListener 接受 Http 请求：https://www.cnblogs.com/MichaelLoveSna/p/14501628.html
使用 WepApp 接受 Http 请求：https://www.cnblogs.com/MichaelLoveSna/p/14501612.html
使用 WepApp 处理文件上传、下载请求：https://www.cnblogs.com/MichaelLoveSna/p/14501616.html