ASP.NET Web APIでマルチパートフォームデータを読み取る方法
次のようにマルチパートフォームデータをWeb APIに送信します。
string example = "my string";
HttpContent stringContent = new StringContent(example);
HttpContent fileStreamContent = new StreamContent(stream);
using (var client = new HttpClient())
{
using (var content = new MultipartFormDataContent())
{
content.Add(stringContent, "example", "example");
content.Add(fileStreamContent, "stream", "stream");
var uri = "http://localhost:58690/api/method";
HttpResponseMessage response = await client.PostAsync(uri, content);
これはWeb APIです。
[HttpPost]
[Route("api/method")]
public async Task<HttpResponseMessage> Method()
{
// take contents and do something
}
Web APIでリクエスト本文から文字列とストリームを読み取る方法
これはあなたが始めるのに役立つはずです：
var uploadPath = HostingEnvironment.MapPath("/") + @"/Uploads";
Directory.CreateDirectory(uploadPath);
var provider = new MultipartFormDataStreamProvider(uploadPath);
await Request.Content.ReadAsMultipartAsync(provider);
// Files
//
foreach (MultipartFileData file in provider.FileData)
{
Debug.WriteLine(file.Headers.ContentDisposition.FileName);
Debug.WriteLine("File path: " + file.LocalFileName);
}
// Form data
//
foreach (var key in provider.FormData.AllKeys)
{
foreach (var val in provider.FormData.GetValues(key))
{
Debug.WriteLine(string.Format("{0}: {1}", key, val));
}
}
これは、jsonデータ+オプションファイルを受信するために以前に使用したコードです。
var result = await Request.Content.ReadAsMultipartAsync();
var requestJson = await result.Contents[0].ReadAsStringAsync();
var request = JsonConvert.DeserializeObject<MyRequestType>(requestJson);
if (result.Contents.Count > 1)
{
var fileByteArray = await result.Contents[1].ReadAsByteArrayAsync();
...
}
このようなリクエストでさまざまなタイプのデータを組み合わせることができるのは本当にすてきです。
編集：このリクエストの送信方法の例：
let serialisedJson = JSON.stringify(anyObject);
let formData = new FormData();
formData.append('initializationData', serialisedJson);
// fileObject is an instance of File
if (fileObject) {
// the 'jsonFile' name might cause some confusion:
// in this case, the uploaded file is actually a textfile containing json data
formData.append('jsonFile', fileObject);
}
return new Promise((resolve, reject) => {
let xhr = new XMLHttpRequest();
xhr.open('POST', 'http://somewhere.com', true);
xhr.onload = function(e: any) {
if (e.target.status === 200) {
resolve(JSON.parse(e.target.response));
}
else {
reject(JSON.parse(e.target.response));
}
};
xhr.send(formData);
});
この方法でローカルディスクにコピーせずに、コンテンツを読み取り、すべてのファイル情報を取得できます（私の例ではイメージ）。
public async Task<IHttpActionResult> UploadFile()
{
if (!Request.Content.IsMimeMultipartContent())
{
return StatusCode(HttpStatusCode.UnsupportedMediaType);
}
var filesReadToProvider = await Request.Content.ReadAsMultipartAsync();
foreach (var stream in filesReadToProvider.Contents)
{
// Getting of content as byte[], picture name and picture type
var fileBytes = await stream.ReadAsByteArrayAsync();
var pictureName = stream.Headers.ContentDisposition.FileName;
var contentType = stream.Headers.ContentType.MediaType;
}
}
複数のファイルを送信する場合
System.Web.HttpFileCollection hfc = System.Web.HttpContext.Current.Request.Files;
//// CHECK THE FILE COUNT.
for (int iCnt = 0; iCnt <= hfc.Count - 1; iCnt++)
{
System.Web.HttpPostedFile hpf = hfc[iCnt];
string Image = UploadDocuments.GetDocumentorfileUri(hpf);
UploadDocuments.UploadDocumentsIntoData(Image, hpf.FileName, id);
}
// read the file content without copying to local disk and write the content byte to file
try
{
var filesReadToProvider = await Request.Content.ReadAsMultipartAsync();
JavaScriptSerializer json_serializer = new JavaScriptSerializer();
foreach (var stream in filesReadToProvider.Contents)
{
//getting of content as byte[], picture name and picture type
var fileBytes = await stream.ReadAsByteArrayAsync();
var fileName = stream.Headers.ContentDisposition.Name;
var pictureName = stream.Headers.ContentDisposition.FileName;
var contentType = stream.Headers.ContentType.MediaType;
var path = Path.Combine(HttpContext.Current.Server.MapPath("~/Images/Upload/"), json_serializer.Deserialize<string>(pictureName));
File.WriteAllBytes(path, fileBytes);
}
return Request.CreateResponse(HttpStatusCode.OK);
}catch(Exception ex)
{
return Request.CreateErrorResponse(HttpStatusCode.InternalServerError, ex);
}
// Webユーザーインターフェイスメソッドprotected void btnPrescAdd_Click（object sender、EventArgs e）{
NameValueCollection collection = new NameValueCollection();
collection.Set("c1", Session["CredID"].ToString());
collection.Set("p1", "");
collection.Set("p2", Request.Form["ctl00$MainContent$hdnHlthId"]);
collection.Set("p3", Request.Form["ctl00$MainContent$PresStartDate"]);
collection.Set("p4", Request.Form["ctl00$MainContent$PrescEndDate"]);
FileUpload fileUpload = PrescUpload;
ApiServices<Status> obj = new ApiServices<Status>();
Status objReturn = obj.FetchObjectUploadAPI("POSTUHRPL", collection,
fileUpload, ApiServices<Status>.ControllerType.DU);
}
//リクエストメソッド
public T1 FetchObjectUploadAPI(string strAPIMethod, NameValueCollection collection, FileUpload file, ControllerType enObj)
{
T1 objReturn;
try
{
string url = strWebAPIUrl + getControllerName(enObj) + strAPIMethod;
MultipartFormDataContent content = new MultipartFormDataContent();
int count = collection.Count;
List<string> Keys = new List<string>();
List<string> Values = new List<string>();
//MemoryStream filedata = new MemoryStream(file);
//Stream stream = filedata;
for (int i = 0; i < count; i++)
{
Keys.Add(collection.AllKeys[i]);
Values.Add(collection.Get(i));
}
for (int i = 0; i < count; i++)
{
content.Add(new StringContent(Values[i], Encoding.UTF8, "multipart/form-data"), Keys[i]);
}
int fileCount = file.PostedFiles.Count();
HttpContent filecontent = new StreamContent(file.PostedFile.InputStream);
content.Add(filecontent, "files");
HttpClient client = new HttpClient();
HttpResponseMessage response = client.PostAsync(url, content).Result;
if (response.IsSuccessStatusCode)
{
objReturn = (new JavaScriptSerializer()).Deserialize<T1>(response.Content.ReadAsStringAsync().Result);
}
else
objReturn = default(T1);
}
catch (Exception ex)
{
Logger.WriteLog("FetchObjectAPI", ex, log4net_vayam.Constants.levels.ERROR);
throw (ex);
}
return objReturn;
}