关于MVC4.0 WebAPI上传图片重命名以及图文结合
MVC4.0 WebAPI上传后的图片默认以字符串bodypart结合Guid来命名，且没有文件后缀，为解决上传图片重命名以及图文结合发布的问题，在实体对象的处理上，可将图片属性定义为byte[]对象，至于图片的重命名，通过重写继承MultipartFormDataStreamProvider类来解决！
参照API的官方文档，上传文件代码大致如下：
public class FileUploadController : ApiController
{
public Task<HttpResponseMessage> PostFile() { HttpRequestMessage request = this.Request; string root = System.Web.HttpContext.Current.Server.MapPath("~/App_Data/uploads"); //var provider = new MultipartFormDataStreamProvider(root);//原写法 var provider = new RenamingMultipartFormDataStreamProvider(root);//重命名写法 //provider.BodyPartFileNames.sel(kv => kv.Value) var task = request.Content.ReadAsMultipartAsync(provider). ContinueWith<HttpResponseMessage>(o => { string file1 = provider.BodyPartFileNames.First().Value;//多张图片循环provider.BodyPartFileNames或provider.FileData
//string file1 = provider.GetLocalFileName(provider.FileData[0].Headers);//返回重写的文件名（注意，由于packages包版本的不同，用BodyPartFileNames还是FileData需要留意） // this is the file name on the server where the file was saved return new HttpResponseMessage() { Content = new StringContent("File uploaded." + file1) }; } ); return task; }
}
再来看看继承MultipartFormDataStreamProvider的类:
public class RenamingMultipartFormDataStreamProvider : MultipartFormDataStreamProvider { public string Root { get; set; } //public Func<FileUpload.PostedFile, string> OnGetLocalFileName { get; set; } public RenamingMultipartFormDataStreamProvider(string root) : base(root) { Root = root; } public override string GetLocalFileName(HttpContentHeaders headers) { string filePath = headers.ContentDisposition.FileName; // Multipart requests with the file name seem to always include quotes. if (filePath.StartsWith(@"""") && filePath.EndsWith(@"""")) filePath = filePath.Substring(1, filePath.Length - 2); var filename = Path.GetFileName(filePath); var extension = Path.GetExtension(filePath); var contentType = headers.ContentType.MediaType; return filename; } }
该方法通过直接指定form的action为请求的WebAPI上传地址来处理；如：
<form name="form1" method="post" enctype="multipart/form-data" action="http://localhost:8000/api/FileUpload/PostFile">。
另外我们还可以通过向WebAPI提交byte[]形式的文件来解决(以HttpClient方式向WebAPI地址提交上传对象)，首先定义文件上传类，以最简单的为例：
相关上传实体类：
/// <summary> /// 文件上传 /// </summary> public class UploadFileEntity { /// <summary> /// 文件名 /// </summary> public string FileName { get; set; } /// <summary> /// 文件二进制数据 /// </summary> public byte[] FileData { get; set; } } /// <summary> /// 文件上传结果信息 /// </summary> public class ResultModel { /// <summary> /// 返回结果 0: 失败，1: 成功。 /// </summary> public int Result { get; set; } /// <summary> /// 操作信息，成功将返回空。 /// </summary> public string Message { get; set; } }
上传的Action方法：
public ActionResult UploadImage() { byte[] bytes = null; using (var binaryReader = new BinaryReader(Request.Files[0].InputStream)) { bytes = binaryReader.ReadBytes(Request.Files[0].ContentLength); } string fileExt = Path.GetExtension(Request.Files[0].FileName).ToLower(); UploadFileEntity entity = new UploadFileEntity(); entity.FileName = DateTime.Now.ToString("yyyyMMddHHmmss") + fileExt;//自定义文件名称，这里以当前时间为例 entity.FileData = bytes; ResultModel rm = HttpClientOperate.Post<ResultModel>("/UploadFile/SaveFile", APIUrl, entity);//封装的POST提交方法，APIUrl为提交地址，大家可还原为HttpClient的PostAsync方式提交 return Content("{\"msg\":\"" + rm.Message + "\"}"); }
WebAPI接收端，主要方法如下（Controller代码略）：
public string SaveFile(UploadFileEntity entity) { string retVal = string.Empty; if (entity.FileData != null && entity.FileData.Length > 0) {//由于此例生成的文件含子目录文件等多层，下面处理方法不一定适合大家，保存地址处理大家根据自己需求来 entity.FileName = entity.FileName.ToLower().Replace("\\", "/"); string savaImageName = HttpContext.Current.Server.MapPath(ConfigOperate.GetConfigValue("SaveBasePath")) + entity.FileName;//定义保存地址 string path = savaImageName.Substring(0, savaImageName.LastIndexOf("/")); DirectoryInfo Drr = new DirectoryInfo(path); if (!Drr.Exists) { Drr.Create(); } FileStream fs = new FileStream(savaImageName, FileMode.Create, FileAccess.Write); fs.Write(entity.FileData, 0, entity.FileData.Length); fs.Flush(); fs.Close(); #region 更新数据等其他逻辑 #endregion retVal = ConfigOperate.GetConfigValue("ImageUrl") + entity.FileName; } return retVal;//返回文件地址 }
Httpclient相关扩展方法如下：
public static T Post<T>(string requestUri, string webapiBaseUrl, HttpContent httpContent)
{
var httpClient = new HttpClient()
{
MaxResponseContentBufferSize = 1024 * 1024 * 2,
BaseAddress = new Uri(webapiBaseUrl)
};
T t = Activator.CreateInstance<T>();
HttpResponseMessage response = new HttpResponseMessage();
try
{
httpClient.PostAsync(requestUri, httpContent).ContinueWith((task) =>
{
if (task.Status != TaskStatus.Canceled)
{
response = task.Result;
}
}).Wait(waitTime);
if (response.Content != null && response.StatusCode == HttpStatusCode.OK)
{
t = response.Content.ReadAsAsync<T>().Result;
}
return t;
}
catch { return t; }
finally
{
httpClient.Dispose();
response.Dispose();
}
}
public static T Post<T>(string requestUri, string webapiBaseUrl, string jsonString)
{
HttpContent httpContent = new StringContent(jsonString);
httpContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
return Post<T>(requestUri, webapiBaseUrl, httpContent);
}
public static T Post<T>(string requestUri, string webapiBaseUrl, object obj = null)
{
string jsonString = JsonOperate.Convert2Json<object>(obj);//可换成Newtonsoft.Json的JsonConvert.SerializeObject方法将对象转化为json字符串
return Post<T>(requestUri, webapiBaseUrl, jsonString);
}
简单调用示例如下：
UploadFileEntity entity = new UploadFileEntity();
entity.FileName = DateTime.Now.ToString("yyyyMMddHHmmssffff") + fileExt;//自定义文件名称，这里以当前时间为例
entity.FileData = GetByte(Request.Files[0].InputStream);
var request = JsonConvert.SerializeObject(entity);
HttpContent httpContent = new StringContent(request);
httpContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
var httpClient = new HttpClient();
httpClient.PostAsync("http://localhost:7901/api/FileUpload/SaveFile", httpContent);
public static byte[] GetByte(Stream stream)
{
byte[] fileData = new byte[stream.Length];
stream.Read(fileData, 0, fileData.Length);
stream.Close();
return fileData;
}