How can I send file to list - .net core web api - postman

Question

I'm trying to send a file from a postman to a web api, method on web api is expecting a list of type which contains doc type, file and folder name.. posted below:

Web api method:

[HttpPost("post-images")]
public async Task<IList<RepositoryItem>> PostAnImages (IList<PostRepoRequest> request)
{
    // rest of the code 
}

PostRepoRequest class:

public class PostRepoRequest
{
    public FileType FileType { get; set; }
    public IFormFile File { get; set; }
    public string Folder { get; set; }
}

As it's possible to notice I've never received a file, its allways null, I've tried also setting a header content-type as multipart/form-data but that didn't worked aswell..

What might be the trick here?

Thanks

Cheers

You should use multipart/form-data but accept and process it differently on the server side. You can check this link: learn.microsoft.com/en-us/aspnet/web-api/overview/advanced/… — Oguz Ozgul
– Oguz Ozgul, Commented Mar 31, 2020 at 18:33
@OguzOzgul I've tried adding content-type as I said in post but that didn't helped I've received File as null... maybe because it's part of the list ?.. hmmm not sure — Roxy'Pro
– Roxy'Pro, Commented Mar 31, 2020 at 18:36
I think you need to use [FromForm]IFormFile (attribute) as parameter in your backend method — AlleXyS
– AlleXyS, Commented Mar 31, 2020 at 18:39
Did you check the link I've provided? Changing the content-type only is not enough. multipart/form-data has a format which uses boundaries to separate the parts. Please read the documentation. It must be handled differently. — Oguz Ozgul
– Oguz Ozgul, Commented Mar 31, 2020 at 18:40
You just need to take in a List<IFormFile> because all the other info is there already. — Jonathan Alfaro
– Jonathan Alfaro, Commented Mar 31, 2020 at 20:19

SuleymanSah · Accepted Answer · 2020-09-05 11:52:40Z

6

You need to change the request body with dot pattern like this:

Then you need to add [FromForm] attribute to the controller input parameter. Also note that the variable names in the postman and controller must match.

[HttpPost("post-images")]
public async Task<IList<RepositoryItem>> PostAnImages ([FromForm]IList<PostRepoRequest> repositoryItems)

With these changes, you will be able to get the request correctly:

edited Sep 5, 2020 at 11:52

answered Mar 31, 2020 at 19:53

SuleymanSah

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8 Comments

Roxy'Pro Over a year ago

thanks for example I will check it now ! What was wrong with me implementation where I used to receive List of PostRepoRequestDTO ? instead of only one PostRepoRequestDTO ?

Roxy'Pro Over a year ago

this example really works but how come? Why did you convert List<PostRepoRequest> request to PostRepoRequestDTO request.. what was wrong with List<PostRepoRequest> request ? Wouldnt be nicer if we received few objects with those properties? instead of this arrays? Thanks a lot for your help

SuleymanSah Over a year ago

@Roxy'Pro you are right, no need to change request object, I updated the answer with a shorter a nicer way. Can you try please? All you need to change in code is adding [FromForm] as I indicated in the updated answer.

Roxy'Pro Over a year ago

now when I've changed it to [FromForm] List<PostRepoRequest> request , now I can't receive data from postman :( Could you try also please?

SuleymanSah Over a year ago

@Roxy'Pro the input name on the controller and postman must match. Both of them must be same. Please try like this ([FromForm]IList<PostRepoRequest> repositoryItems), I updated it in the answer now.

|

AlleXyS · Accepted Answer · 2020-03-31 18:53:57Z

1

Try to send file as separated parameter

[HttpPost("post-images")]
public async Task<IList<RepositoryItem>> PostAnImages (IList<PostRepoRequest> request, [FromForm]List<IFormFile> files)
{
    // rest of the code 
}

and in client (assuming that can be Angular):

let input = new FormData();
for (var i = 0; i < this.filesToUpload.length; i++) {
   input.append("files", this.filesToUpload[i]);
}

edited Mar 31, 2020 at 18:53

answered Mar 31, 2020 at 18:40

AlleXyS

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1 Comment

Roxy'Pro Over a year ago

Good point but I need it as part of a list because I would like to send list of the files to web api...

Cotur · Accepted Answer · 2020-03-31 18:43:21Z

0

There is an invisible selectbox, just move your cursor to left and you'll see the selectable area. Then select it as a file.

And add [FromBody] at he beginnig of ypur method parameter like ([FromBody]IList<PostRepoRequest> request)

And last, update the Key to ...[0][file] (you've forgot [])

edited Mar 31, 2020 at 18:43

answered Mar 31, 2020 at 18:37

Cotur

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2 Comments

Roxy'Pro Over a year ago

it's allready a file, how otherwise I could select a file from computer :)

Roxy'Pro Over a year ago

thanks for noticing that, I've tried that earlier also

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