分享WebApi2 檔案圖片上傳與下載功能實例

這篇文章主要介紹了WebApi2 檔案圖片上傳與下載功能,需要的朋友可以參考下

#Asp.Net Framework webapi2 檔案上傳與下載#前端介面採用Ajax的方式執行

一、專案結構

1.App_Start配置了跨域訪問，以免請求時候因跨域問題不能提交。具體的跨域配置方式如下，了解的朋友請自行略過。

跨網域設定：NewGet安裝dll Microsofg.AspNet.Cors

然後在App_Start 資料夾下的WebApiConfig.cs中寫入跨網域設定碼。

public static class WebApiConfig
  {
    public static void Register(HttpConfiguration config)
    {
      // Web API configuration and services
      // Web API routes
      config.MapHttpAttributeRoutes();
      // Web API configuration and services
      //跨域配置 //need reference from nuget
      config.EnableCors(new EnableCorsAttribute("*", "*", "*"));
      config.Routes.MapHttpRoute(
        name: "DefaultApi",
        routeTemplate: "api/{controller}/{id}",
        defaults: new { id = RouteParameter.Optional }
      );
      //if config the global filter input there need not write the attributes
      //config.Filters.Add(new App.WebApi.Filters.ExceptionAttribute_DG());
    }
  }

跨域就算完成了，請自行測試。

2.新建兩個控制器，一個PicturesController.cs，一個FilesController.cs當然圖片也是文件，這裡圖片和文件以不同的方式處理的，因為圖片的方式文件上傳沒有成功，所以另尋他路，如果在座的有更好的方式，請不吝賜教！

二、專案程式碼

1.我們先說圖片上傳、下載控制器接口，這裡其實沒什麼好說的，就一個Get取得文件，參數是文件全名；Post上傳文件；直接上碼。

using QX_Frame.App.WebApi;
using QX_Frame.FilesCenter.Helper;
using QX_Frame.Helper_DG;
using QX_Frame.Helper_DG.Extends;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
using System.Web.Http;
/**
 * author:qixiao
 * create:2017-5-26 16:54:46
 * */
namespace QX_Frame.FilesCenter.Controllers
{
  public class PicturesController : WebApiControllerBase
  {
    //Get : api/Pictures
    public HttpResponseMessage Get(string fileName)
    {
      HttpResponseMessage result = null;
      DirectoryInfo directoryInfo = new DirectoryInfo(IO_Helper_DG.RootPath_MVC + @"Files/Pictures");
      FileInfo foundFileInfo = directoryInfo.GetFiles().Where(x => x.Name == fileName).FirstOrDefault();
      if (foundFileInfo != null)
      {
        FileStream fs = new FileStream(foundFileInfo.FullName, FileMode.Open);
        result = new HttpResponseMessage(HttpStatusCode.OK);
        result.Content = new StreamContent(fs);
        result.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/octet-stream");
        result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
        result.Content.Headers.ContentDisposition.FileName = foundFileInfo.Name;
      }
      else
      {
        result = new HttpResponseMessage(HttpStatusCode.NotFound);
      }
      return result;
    }
    //POST : api/Pictures
    public async Task<IHttpActionResult> Post()
    {
      if (!Request.Content.IsMimeMultipartContent())
      {
        throw new Exception_DG("unsupported media type", 2005);
      }
      string root = IO_Helper_DG.RootPath_MVC;
      IO_Helper_DG.CreateDirectoryIfNotExist(root + "/temp");
      var provider = new MultipartFormDataStreamProvider(root + "/temp");
      // Read the form data. 
      await Request.Content.ReadAsMultipartAsync(provider);
      List<string> fileNameList = new List<string>();
      StringBuilder sb = new StringBuilder();
      long fileTotalSize = 0;
      int fileIndex = 1;
      // This illustrates how to get the file names.
      foreach (MultipartFileData file in provider.FileData)
      {
        //new folder
        string newRoot = root + @"Files/Pictures";
        IO_Helper_DG.CreateDirectoryIfNotExist(newRoot);
        if (File.Exists(file.LocalFileName))
        {
          //new fileName
          string fileName = file.Headers.ContentDisposition.FileName.Substring(1, file.Headers.ContentDisposition.FileName.Length - 2);
          string newFileName = Guid.NewGuid() + "." + fileName.Split(&#39;.&#39;)[1];
          string newFullFileName = newRoot + "/" + newFileName;
          fileNameList.Add($"Files/Pictures/{newFileName}");
          FileInfo fileInfo = new FileInfo(file.LocalFileName);
          fileTotalSize += fileInfo.Length;
          sb.Append($" #{fileIndex} Uploaded file: {newFileName} ({ fileInfo.Length} bytes)");
          fileIndex++;
          File.Move(file.LocalFileName, newFullFileName);
          Trace.WriteLine("1 file copied , filePath=" + newFullFileName);
        }
      }
      return Json(Return_Helper.Success_Msg_Data_DCount_HttpCode($"{fileNameList.Count} file(s) /{fileTotalSize} bytes uploaded successfully!   Details -> {sb.ToString()}", fileNameList, fileNameList.Count));
    }
  }
}

裡面可能有部分程式碼在Helper幫助類別裡面寫的，其實也只是取得伺服器根路徑和如果判斷資料夾不存在則建立目錄，這兩個程式碼的實作如下：

 public static string RootPath_MVC
     {
       get { return System.Web.HttpContext.Current.Server.MapPath("~"); }
     }
//create Directory
    public static bool CreateDirectoryIfNotExist(string filePath)
    {
      if (!Directory.Exists(filePath))
      {
        Directory.CreateDirectory(filePath);
      }
      return true;
    }

2.檔案上傳下載介面和圖片大同小異。

using QX_Frame.App.WebApi;
using QX_Frame.FilesCenter.Helper;
using QX_Frame.Helper_DG;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
using System.Web;
using System.Web.Http;
/**
 * author:qixiao
 * create:2017-5-26 16:54:46
 * */
namespace QX_Frame.FilesCenter.Controllers
{
  public class FilesController : WebApiControllerBase
  {
    //Get : api/Files
    public HttpResponseMessage Get(string fileName)
    {
      HttpResponseMessage result = null;
      DirectoryInfo directoryInfo = new DirectoryInfo(IO_Helper_DG.RootPath_MVC + @"Files/Files");
      FileInfo foundFileInfo = directoryInfo.GetFiles().Where(x => x.Name == fileName).FirstOrDefault();
      if (foundFileInfo != null)
      {
        FileStream fs = new FileStream(foundFileInfo.FullName, FileMode.Open);
        result = new HttpResponseMessage(HttpStatusCode.OK);
        result.Content = new StreamContent(fs);
        result.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/octet-stream");
        result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
        result.Content.Headers.ContentDisposition.FileName = foundFileInfo.Name;
      }
      else
      {
        result = new HttpResponseMessage(HttpStatusCode.NotFound);
      }
      return result;
    }
    //POST : api/Files
    public async Task<IHttpActionResult> Post()
    {
      //get server root physical path
      string root = IO_Helper_DG.RootPath_MVC;
      //new folder
      string newRoot = root + @"Files/Files/";
      //check path is exist if not create it
      IO_Helper_DG.CreateDirectoryIfNotExist(newRoot);
      List<string> fileNameList = new List<string>();
      StringBuilder sb = new StringBuilder();
      long fileTotalSize = 0;
      int fileIndex = 1;
      //get files from request
      HttpFileCollection files = HttpContext.Current.Request.Files;
      await Task.Run(() =>
      {
        foreach (var f in files.AllKeys)
        {
          HttpPostedFile file = files[f];
          if (!string.IsNullOrEmpty(file.FileName))
          {
            string fileLocalFullName = newRoot + file.FileName;
            file.SaveAs(fileLocalFullName);
            fileNameList.Add($"Files/Files/{file.FileName}");
            FileInfo fileInfo = new FileInfo(fileLocalFullName);
            fileTotalSize += fileInfo.Length;
            sb.Append($" #{fileIndex} Uploaded file: {file.FileName} ({ fileInfo.Length} bytes)");
            fileIndex++;
            Trace.WriteLine("1 file copied , filePath=" + fileLocalFullName);
          }
        }
      });
      return Json(Return_Helper.Success_Msg_Data_DCount_HttpCode($"{fileNameList.Count} file(s) /{fileTotalSize} bytes uploaded successfully!   Details -> {sb.ToString()}", fileNameList, fileNameList.Count));
    }
  }
}

實現了上述兩個控制器程式碼以後，我們需要前端程式碼來偵錯對接，程式碼如下所示。

<!doctype>
<head>
  <script src="jquery-3.2.0.min.js"></script>
  <!--<script src="jquery-1.11.1.js"></script>-->
  <!--<script src="ajaxfileupload.js"></script>-->
  <script>
    $(document).ready(function () {
      var appDomain = "http://localhost:3997/";
      $("#btn_fileUpload").click(function () {
        /**
         * 用ajax方式上传文件  -----------
         * */
        //-------asp.net webapi fileUpload
        //
        var formData = new FormData($("#uploadForm")[0]);
        $.ajax({
          url: appDomain + &#39;api/Files&#39;,
          type: &#39;POST&#39;,
          data: formData,
          async: false,
          cache: false,
          contentType: false,
          processData: false,
          success: function (data) {
            console.log(JSON.stringify(data));
          },
          error: function (data) {
            console.log(JSON.stringify(data));
          }
        });
        //----end asp.net webapi fileUpload
        //----.net core webapi fileUpload
        // var fileUpload = $("#files").get(0);
        // var files = fileUpload.files;
        // var data = new FormData();
        // for (var i = 0; i < files.length; i++) {
        //    data.append(files[i].name, files[i]);
        // }
        // $.ajax({
        //   type: "POST",
        //   url: appDomain+&#39;api/Files&#39;,
        //   contentType: false,
        //   processData: false,
        //   data: data,
        //   success: function (data) {
        //     console.log(JSON.stringify(data));
        //   },
        //   error: function () {
        //     console.log(JSON.stringify(data));
        //   }
        // });
        //--------end net core webapi fileUpload
        /**
         * ajaxfileupload.js 方式上传文件
         * */
        // $.ajaxFileUpload({
        //   type: &#39;post&#39;,
        //   url: appDomain + &#39;api/Files&#39;,
        //   secureuri: false,
        //   fileElementId: &#39;files&#39;,
        //   success: function (data) {
        //     console.log(JSON.stringify(data));
        //   },
        //   error: function () {
        //     console.log(JSON.stringify(data));
        //   }
        // });
      });
      //end click
    })
  </script>
</head>
<title></title>
<body>
  <article>
    <header>
      <h2>article-form</h2>
    </header>
    <p>
      <form action="/" method="post" id="uploadForm" enctype="multipart/form-data">
        <input type="file" id="files" name="files" placeholder="file" multiple>file-multiple属性可以选择多项<br><br>
        <input type="button" id="btn_fileUpload" value="fileUpload">
      </form>
    </p>
  </article>
</body>

至此，我們的功能已全部實現，下面我們來測試一下：

可見，檔案上傳成功，按預期格式返回！

下面我們測試單圖上傳->

然後我們按回傳的位址進行存取圖片地址。

發現並無任何壓力！

下面測試多圖片上傳->

完美~

 至此，我們已經實現了WebApi2檔案和圖片上傳，下載的全部功能。

 這裡要注意Web.config的設定上傳檔案支援的總大小，我這裡設定的是最大支援的檔案大小為1MB

<requestFiltering>
  <requestLimits maxAllowedContentLength="1048576" />
</requestFiltering>
  <system.webServer>
   <handlers>
    <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
    <remove name="OPTIONSVerbHandler" />
    <remove name="TRACEVerbHandler" />
    <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
   </handlers>
   <security>
   <requestFiltering>
    <requestLimits maxAllowedContentLength="1048576" /><!--1MB-->
    </requestFiltering>
  </security>
  </system.webServer>

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