File Upload In Angular?

Question

I know this is very a general question but I am failing to upload a file in Angular 2. I have tried

1) http://valor-software.com/ng2-file-upload/ and

2) h

Answer 1

Thanks to @Eswar. This code worked perfectly for me. I want to add certain things to the solution :

I was getting error : java.io.IOException: RESTEASY007550: Unable to get boundary for multipart

In order to solve this error, you should remove the "Content-Type" "multipart/form-data". It solved my problem.

Answer 2

This simple solution worked for me: file-upload.component.html

<div>
  <input type="file" #fileInput placeholder="Upload file..." />
  <button type="button" (click)="upload()">Upload</button>
</div>

And then do the upload in the component directly with XMLHttpRequest.

import { Component, OnInit, ViewChild } from '@angular/core';

@Component({
  selector: 'app-file-upload',
  templateUrl: './file-upload.component.html',
  styleUrls: ['./file-upload.component.css']
})
export class FileUploadComponent implements OnInit {

  @ViewChild('fileInput') fileInput;

  constructor() { }

  ngOnInit() {
  }

  private upload() {
    const fileBrowser = this.fileInput.nativeElement;
    if (fileBrowser.files && fileBrowser.files[0]) {
      const formData = new FormData();
      formData.append('files', fileBrowser.files[0]);
      const xhr = new XMLHttpRequest();
      xhr.open('POST', '/api/Data/UploadFiles', true);
      xhr.onload = function () {
        if (this['status'] === 200) {
            const responseText = this['responseText'];
            const files = JSON.parse(responseText);
            //todo: emit event
        } else {
          //todo: error handling
        }
      };
      xhr.send(formData);
    }
  }

}

If you are using dotnet core, the parameter name must match the from field name. files in this case:

[HttpPost("[action]")]
public async Task<IList<FileDto>> UploadFiles(List<IFormFile> files)
{
  return await _binaryService.UploadFilesAsync(files);
}

This answer is a plagiate of http://blog.teamtreehouse.com/uploading-files-ajax

Edit: After uploading, you have to clear the file-upload so that the user can select a new file. And instead of using XMLHttpRequest, maybe it is better to use fetch:

private addFileInput() {
    const fileInputParentNative = this.fileInputParent.nativeElement;
    const oldFileInput = fileInputParentNative.querySelector('input');
    const newFileInput = document.createElement('input');
    newFileInput.type = 'file';
    newFileInput.multiple = true;
    newFileInput.name = 'fileInput';
    const uploadfiles = this.uploadFiles.bind(this);
    newFileInput.onchange = uploadfiles;
    oldFileInput.parentNode.replaceChild(newFileInput, oldFileInput);
  }

  private uploadFiles() {
    this.onUploadStarted.emit();
    const fileInputParentNative = this.fileInputParent.nativeElement;
    const fileInput = fileInputParentNative.querySelector('input');
    if (fileInput.files && fileInput.files.length > 0) {
      const formData = new FormData();
      for (let i = 0; i < fileInput.files.length; i++) {
        formData.append('files', fileInput.files[i]);
      }

      const onUploaded = this.onUploaded;
      const onError = this.onError;
      const addFileInput = this.addFileInput.bind(this);
      fetch('/api/Data/UploadFiles', {
        credentials: 'include',
        method: 'POST',
        body: formData,
      }).then((response: any) => {
        if (response.status !== 200) {
          const error = `An error occured. Status: ${response.status}`;
          throw new Error(error);
        }
        return response.json();
      }).then(files => {
        onUploaded.emit(files);
        addFileInput();
      }).catch((error) => {
        onError.emit(error);
      });
    }

https://github.com/yonexbat/cran/blob/master/cranangularclient/src/app/file-upload/file-upload.component.ts

Answer 3

Since the code sample is a bit outdated I thought I'd share a more recent approach, using Angular 4.3 and the new(er) HttpClient API, @angular/common/http

export class FileUpload {

@ViewChild('selectedFile') selectedFileEl;

uploadFile() {
let params = new HttpParams();

let formData = new FormData();
formData.append('upload', this.selectedFileEl.nativeElement.files[0])

const options = {
    headers: new HttpHeaders().set('Authorization', this.loopBackAuth.accessTokenId),
    params: params,
    reportProgress: true,
    withCredentials: true,
}

this.http.post('http://localhost:3000/api/FileUploads/fileupload', formData, options)
.subscribe(
    data => {
        console.log("Subscribe data", data);
    },
    (err: HttpErrorResponse) => {
        console.log(err.message, JSON.parse(err.error).error.message);
    }
)
.add(() => this.uploadBtn.nativeElement.disabled = false);//teardown
}

Answer 4

Try not setting the options parameter

this.http.post(${this.apiEndPoint}, formData)

and make sure you are not setting the globalHeaders in your Http factory.

Answer 5

This is useful tutorial, how to upload file using the ng2-file-upload and WITHOUT ng2-file-upload.

For me it helps a lot.

At the moment, tutorial contains a couple of mistakes:

1- Client should have same upload url as a server, so in app.component.ts change line

const URL = 'http://localhost:8000/api/upload';

to

const URL = 'http://localhost:3000';

2- Server send response as 'text/html', so in app.component.ts change

.post(URL, formData).map((res:Response) => res.json()).subscribe(
  //map the success function and alert the response
  (success) => {
    alert(success._body);
  },
  (error) => alert(error))

to

.post(URL, formData)  
.subscribe((success) => alert('success'), (error) => alert(error));

Answer 6

Today I was integrated ng2-file-upload package to my angular 6 application, It was pretty simple, Please find the below high-level code.

import the ng2-file-upload module

app.module.ts

    import { FileUploadModule } from 'ng2-file-upload';

    ------
    ------
    imports:      [ FileUploadModule ],
    ------
    ------

Component ts file import FileUploader

app.component.ts

    import { FileUploader, FileLikeObject } from 'ng2-file-upload';
    ------
    ------
    const URL = 'http://localhost:3000/fileupload/';
    ------
    ------

     public uploader: FileUploader = new FileUploader({
        url: URL,
        disableMultipart : false,
        autoUpload: true,
        method: 'post',
        itemAlias: 'attachment'

        });

      public onFileSelected(event: EventEmitter<File[]>) {
        const file: File = event[0];
        console.log(file);

      }
    ------
    ------

Component HTML add file tag

app.component.html

 <input type="file" #fileInput ng2FileSelect [uploader]="uploader" (onFileSelected)="onFileSelected($event)" />

Working Online stackblitz Link: https://ng2-file-upload-example.stackblitz.io

Stackblitz Code example: https://stackblitz.com/edit/ng2-file-upload-example

Official documentation link https://valor-software.com/ng2-file-upload/