I am trying to send the form data including excel file through fetch. But unable to hit the server using asp.net core.
const formdata = new FormData();
formdata.append('excel', file);
formdata.append('name', "importFile");
Client Side:
fetch(url, {
method: 'POST',
body: formdata
})
.then(data => {
return data;
});
Server Side:
[HttpPost]
[Route("api/Home/ValidateFile")]
public ActionResult ValidateFile([FromBody] IFormFile file)
{
using (var reader = new StreamReader(file.OpenReadStream()))
{
var fileContent = reader.ReadToEnd();
var parsedContentDisposition = ContentDispositionHeaderValue.Parse(file.ContentDisposition);
}
}
Can you please let me know how to read the excel file.
send the form data including excel file through fetch. But unable to hit the server using asp.net core.
Please note that applying the [FromBody] attribute to a parameter will populate its properties from the body of an HTTP request, not from posted form fields.
To send file with other data through formdata and read it on server side, you can try to modify the code like below.
[HttpPost]
[Route("api/Home/ValidateFile")]
public IActionResult ValidateFile([FromForm]FileUploadViewModel file)
{
//...
//code logic here
//...
FileUploadViewModel class
public class FileUploadViewModel
{
public string name { get; set; }
public IFormFile excel { get; set; }
}
Test Result
Related
Using .NET Core 3.1, I have the following Http client which builds a HTTP POST containing multipart/form-data body:
public async Task SendRequest(string randomString, IFormFileCollection files)
{
var form = new MultipartFormDataContent();
form.Add(new StringContent(randomString), "randomString");
foreach (var file in files)
{
var stream = new MemoryStream();
await file.CopyToAsync(stream, cancellationToken);
form.Add(new StreamContent(stream), "files");
}
using var request = new HttpRequestMessage(HttpMethod.Post, $"api/endpoint")
{
Content = form
};
await _httpClient.SendAsync(request);
}
The receiving controller looks like this:
[Consumes("multipart/form-data")]
[HttpPost]
public async Task ReceiveForm([FromForm] RequestModel request)
{
//Do stuff
}
RequestModel looks like this:
public class RequestModel
{
[JsonPropertyName("randomString")]
public string RandomString { get; set; }
[JsonPropertyName("files")]
public IFormFileCollection Files { get; set; }
}
The problem I am seeing is that requestModel.RandomString gets populated, but the requestModel.Files does not - it is null.
What am I doing wrong?
thanks for the perfect code in example!
You should set both parameters (name and fileName) to files - form.Add(new StreamContent(stream), "files", "files");
Method description:
Parameters:
content: The HTTP content to add to the collection.
name: The name for the HTTP content to add.
fileName: The file name for the HTTP content to add to the collection.
This is my example:
var fileName = "files";
var byteArrayContent = new ByteArrayContent(fileBytes1);
form.Add(byteArrayContent, fileName, fileName);
var stream = new MemoryStream(fileBytes2);
form.Add(new StreamContent(stream), fileName, fileName);
Results:
i have a web application that does an action to upload image to api
the code like this
[HttpPost]
public async Task<IActionResult> Upload([FromForm] UploadModel model)
{
var upload = AccountApi.UploadFile(model);
return Ok("OK");
}
public static object UploadFile(UploadModel model)
{
RestClient client = InitClient();
request.Resource = "Account/UploadFile";
request.Method = Method.POST;
request.AddJsonBody(model);
IRestResponse<object> response = client.Execute<object>(request);
return response.Data;
}
public class UploadModel
{
public long UserId { get; set; }
public string Token { get; set; }
public IFromFile File { get; set; }
}
and there's a web API to handle Rest request above
the code like this
[HttpPost("UploadFile")]
public async Task<object> UploadFileAction(UploadModel model)
{
// the code handle upload file request here
return "Success";
}
my issue is the UploadModel model in web application contains the right value that requested from front-end (UserId = 10, Token = "eyJ..........", File = [object])
but when it posted to API, the 3 properties in UploadModel didn't get the value posted from web application (UserId = 0, Token = null, File = null)
could you help me to find the solution for this. Thanks all
I found the solution myself.
instead of using IFormFile to post, I serialized the image file to a base64 string and post it over API. and in API, I convert it to File object
Thanks for following my question
I am trying to upload a file and also JSON body at the same time to a POST method as below
public async Task<ResponseModel<PersonWriteResponse>> AddPerson([FromForm]IFormFile file, [FromForm]PersonPostRequest request)
{
var person = await _service.AddPerson(file,request);
return ResponseModelHelper.BuildResponse(person, $"/production/person", "person");
}
Both parameters are always null. In postman, I am specifying the content-type as "Multipart/form-data"
Is this the correct way of passing file and json data?
Alan-
I try to use model witch include IFormFile, and it's works
[HttpPost]
[AllowAnonymous]
public async Task<IActionResult> update([FromForm]MyFile model)
{
return Ok("Success!");
}
public class MyFile
{
public string Id { get; set; }
public IFormFile File { get; set; }
// Other properties
}
PostMan request here
You may set breakPoint at the return Ok("Success!"); line and saw what you get
I am working on an ASP.NET Core 2.0 API in VS2017.
I want to create a controller action for an HTTP Post method that accept string and byte[] values that I will then use to create records in my SQL database.
From what I understand, if I want to post both string data and a byte[] that represents a file, I have to use MultipartFormDataContent as the type of content in the request from my client.
So, on the API controller action, how is that mapped? Can I have a DTO class in the API that has properties for both the string values and the byte[] value and have it passed into the API controller action via the [FromBody]UploadsDto dto
For example, have a DTO class like this...
public class UploadFileRecordForCreationDto
{
public int LocationId { get; set; }
public string FileName { get; set; }
public byte[] UploadedFile { get; set; }
}
Then have a controller action with this signature...
[HttpPost(Name = "CreateUploadFileRecord")]
public IActionResult CreateUploadFileRecord([FromBody]UploadFileRecordForCreationDto dto)
{
...
...
...
return CreatedAtRoute("GetUploadedFileFile", new { id = linkedResourceToReturn["Id"] }, linkedResourceToReturn);
}
And then have that API action accept a request created using something similar to what I am doing with this test console application on the client side;
static async Task CreateUploadFileRecordAsync()
{
httpClient.BaseAddress = new Uri("https://localhost:44369");
httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
string relativeUrl = "/api/UploadFilesManager";
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, relativeUrl);
HttpResponseMessage response = new HttpResponseMessage();
using (var content = new MultipartFormDataContent("--UploadTest"))
{
var values = new[]
{
new KeyValuePair<string,string>("LocationId","1"),
new KeyValuePair<string,string>("FileName","TestFile-01.txt"),
};
foreach (var keyvaluepair in values)
{
content.Add(new StringContent(keyvaluepair.Value, Encoding.UTF8, "application/json"), keyvaluepair.Key);
}
var fileContent = new ByteArrayContent(File.ReadAllBytes(#"C:\testfile-01.txt"));
fileContent.Headers.ContentDisposition = new ContentDispositionHeaderValue(DispositionTypeNames.Attachment)
{
Name = "UploadedFile",
FileName = "testfile-01.txt"
};
content.Add(fileContent);
request.Content = content;
response = await httpClient.SendAsync(request);
}
if (response.IsSuccessStatusCode)
{
string result = response.Headers.Location.ToString();
Console.WriteLine("Success:\n");
Console.WriteLine($"New Record Link: [{result}]\n");
}
else
{
Console.WriteLine($"Failed to create new UploadFile record. Error: {0}\n", response.ReasonPhrase);
}
}
If it doesn't just map to a DTO in the FromBody, can anyone provide an example of how to deal with this use case?
I'm attempting to build an ASP.NET Core 1.1 Controller method to handle an HTTP Request that looks like the following:
POST https://localhost/api/data/upload HTTP/1.1
Content-Type: multipart/form-data; boundary=--------------------------625450203542273177701444
Host: localhost
Content-Length: 474
----------------------------625450203542273177701444
Content-Disposition: form-data; name="file"; filename="myfile.txt"
Content-Type: text/plain
<< Contents of my file >>
----------------------------625450203542273177701444
Content-Disposition: form-data; name="text"
Content-Type: application/json
{"md5":"595f44fec1e92a71d3e9e77456ba80d0","sessionIds":["123","abc"]}
----------------------------625450203542273177701444--
It's a multipart/form-data request with one part being a (small) file and the other part a json blob that is based on a provided specification.
Ideally, I'd love my controller method to look like:
[HttpPost]
public async Task Post(UploadPayload payload)
{
// TODO
}
public class UploadPayload
{
public IFormFile File { get; set; }
[Required]
[StringLength(32)]
public string Md5 { get; set; }
public List<string> SessionIds { get; set; }
}
But alas, that doesn't Just Work {TM}. When I have it like this, the IFormFile does get populated, but the json string doesn't get deserialized to the other properties.
I've also tried adding a Text property to UploadPayload that has all the properties other than the IFormFile and that also doesn't receive the data. E.g.
public class UploadPayload
{
public IFormFile File { get; set; }
public UploadPayloadMetadata Text { get; set; }
}
public class UploadPayloadMetadata
{
[Required]
[StringLength(32)]
public string Md5 { get; set; }
public List<string> SessionIds { get; set; }
}
A workaround that I have is to avoid model binding and use MultipartReader along the lines of:
[HttpPost]
public async Task Post()
{
...
var reader = new MultipartReader(Request.GetMultipartBoundary(), HttpContext.Request.Body);
var section = await reader.ReadNextSectionAsync();
var filePart = section.AsFileSection();
// Do stuff & things with the file
section = await reader.ReadNextSectionAsync();
var jsonPart = section.AsFormDataSection();
var jsonString = await jsonPart.GetValueAsync();
// Use $JsonLibrary to manually deserailize into the model
// Do stuff & things with the metadata
...
}
Doing the above bypasses model validation features, etc. Also, I thought maybe I could take that jsonString and then somehow get it into a state that I could then call await TryUpdateModelAsync(payloadModel, ...) but couldn't figure out how to get there either - and that didn't seem all that clean either.
Is it possible to get to my desired state of "transparent" model binding like my first attempt? If so, how would one get to that?
The first problem here is that the data needs to be sent from the client in a slightly different format. Each property in your UploadPayload class needs to be sent in its own form part:
const formData = new FormData();
formData.append(`file`, file);
formData.append('md5', JSON.stringify(md5));
formData.append('sessionIds', JSON.stringify(sessionIds));
Once you do this, you can add the [FromForm] attribute to the MD5 property to bind it, since it is a simple string value. This will not work for the SessionIds property though since it is a complex object.
Binding complex JSON from the form data can be accomplished using a custom model binder:
public class FormDataJsonBinder : IModelBinder
{
public Task BindModelAsync(ModelBindingContext bindingContext)
{
if(bindingContext == null) throw new ArgumentNullException(nameof(bindingContext));
// Fetch the value of the argument by name and set it to the model state
string fieldName = bindingContext.FieldName;
var valueProviderResult = bindingContext.ValueProvider.GetValue(fieldName);
if(valueProviderResult == ValueProviderResult.None) return Task.CompletedTask;
else bindingContext.ModelState.SetModelValue(fieldName, valueProviderResult);
// Do nothing if the value is null or empty
string value = valueProviderResult.FirstValue;
if(string.IsNullOrEmpty(value)) return Task.CompletedTask;
try
{
// Deserialize the provided value and set the binding result
object result = JsonConvert.DeserializeObject(value, bindingContext.ModelType);
bindingContext.Result = ModelBindingResult.Success(result);
}
catch(JsonException)
{
bindingContext.Result = ModelBindingResult.Failed();
}
return Task.CompletedTask;
}
}
You can then use the ModelBinder attribute in your DTO class to indicate that this binder should be used to bind the MyJson property:
public class UploadPayload
{
public IFormFile File { get; set; }
[Required]
[StringLength(32)]
[FromForm]
public string Md5 { get; set; }
[ModelBinder(BinderType = typeof(FormDataJsonBinder))]
public List<string> SessionIds { get; set; }
}
You can read more about custom model binding in the ASP.NET Core documentation: https://learn.microsoft.com/en-us/aspnet/core/mvc/advanced/custom-model-binding
I'm not 100% clear on how this would work for ASP.NET Core but for Web API (so I assume a similar path exists here) you'd want to go down the road of a Media Formatter. Here's an example (fairly similar to your question) Github Sample with blog post
Custom formatters might be the ticket? https://learn.microsoft.com/en-us/aspnet/core/mvc/advanced/custom-formatters