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How to upload multiple images from front-end using JavaScript, jQuery, Ajax in JSP file and send it into Spring Boot Controller?

I am working on a spring boot web application, where I want to upload multiple images of a product at a time along with other fields (for example product name, SKU code, category, tags, subcategory, etc). I have written code for RESTful API to upload multiple images and it is working perfectly for me. I tested API using postman and it is working fine. But, I don't know how to do it from the front end. I am showing you my front-end code below, where I am sending a single image to my controller using Ajax.
$("#file").change(function(){
var formData = new FormData();
var fileSelect = document.getElementById("file");
if(fileSelect.files && fileSelect.files.length == 1) {
var file = fileSelect.files[0];
formData.set("file",file,file.name);
}else{
$("#file").focus();
return false;
}
var request = new XMLHttpRequest();
try {
request.onreadystatechange=function() {
if(request.readyState==4) {
var v = JSON.parse(request.responseText);
if(v.status==="OK") {
alert("Product Image Uploaded Successfully")
document.getElementById('imagepath').value = v.response;
}
}
}
request.open('POST',"<%=AkApiUrl.testuploadfile%>");
request.send(formData);
} catch(e) {
swal("Unable to connect to server","","error");
}
});
As I told you, the above code is to send a single file at a time. I am showing you my API controller code also:
#RequestMapping(value = AkApiUrl.testuploadfile, method = { RequestMethod.POST, RequestMethod.GET }, produces = {MediaType.APPLICATION_JSON_VALUE }) public ResponseEntity<?> testuploadfile(HttpServletRequest request, #RequestParam("files") MultipartFile[] files) {
CustomResponse = ResponseFactory.getResponse(request);
String imgurl = "NA";
try {
String path = Constants.webmedia;
String relativepath = "public/media/";
System.out.println("Here is the image: ");
List<MultipartFile> multifile = Arrays.asList(files);
if( null != multifile && multifile.size()>0) {
for (int i=0; i < multifile.size(); i++) {
String filename = files[i].getOriginalFilename();
String extension = filename.substring(filename.lastIndexOf("."), filename.length());
int r = (int )(Math.random() * 500 + 1);
SimpleDateFormat format = new SimpleDateFormat("yyyyMMddhhmmss");
Date date = new Date();
String formatdate = format.format(date);
formatdate = "ECOM" + formatdate + r;
byte[] bytes = files[i].getBytes();
BufferedOutputStream stream = new BufferedOutputStream( new FileOutputStream(new File(path + File.separator + formatdate + extension)));
stream.write(bytes);
stream.flush();
stream.close();
String newimgurl = relativepath + formatdate + extension;
imgurl = imgurl+"##"+newimgurl;
if(imgurl != null) {
CustomResponse.setResponse(imgurl);
CustomResponse.setStatus(CustomStatus.OK);
CustomResponse.setStatusCode(CustomStatus.OK_CODE);
}
}
}
} catch (Exception e) {
e.printStackTrace();
CustomResponse.setResponse(null);
CustomResponse.setStatus(CustomStatus.Error);
CustomResponse.setStatusCode(CustomStatus.Error_CODE);
CustomResponse.setResponseMessage(CustomStatus.ErrorMsg);
}
return new ResponseEntity<ResponseDao>(CustomResponse, HttpStatus.OK);
}
This API is working fine, I am getting desired response. But I do not know how should I implement this thing on the JSP page. Please, any suggestions would be appreciated.

Queries can not be applied to a response content of type 'System.Net.Http.StreamContent'. The response content must be an ObjectContent

I am trying to download a file using knockout v3.2.0, webapi, odata and get this error when I try to return the file as HttpResponseMessage.
Here is my controller code:
[EnableQuery]
public HttpResponseMessage GetAttachment([FromODataUri] int key)
{
try
{
DataAccess.Attachment a = db.Attachments.Where(x => x.AttachmentId == key).FirstOrDefault();
HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
MemoryStream memStream = new MemoryStream();
memStream.Write(a.AttachmentData, 0, a.AttachmentData.Length);
result.Content = new StreamContent(memStream);
result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment");
result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
result.Content.Headers.ContentDisposition.FileName = a.AttachmentName;
return result;
//return Request.CreateResponse(HttpStatusCode.OK, result);
}
catch (Exception exception)
{
Request.CreateErrorResponse(HttpStatusCode.InternalServerError, exception.Message);
return null;
}
}
That's how I am trying to download from JavaScript:
self.downloadDocument = function (attachmentId) {
var serviceRequestUrl = dbhdd.buildUrl.buildSPContextUrl("/api/Attachments(" + 1 + ")");
window.location.href = serviceRequestUrl;
};
Which gives me this error- Queries can not be applied to a response content of type 'System.Net.Http.StreamContent'. The response content must be an ObjectContent.
I am relatively new to this. Any guidance in fixing this/alternate approach will be highly appreciated.

So I removed [EnableQuery] and it worked both in IE and Chrome!

Retrieve image from database using Web API, then displaying it in angularJS

Seems like a straightforward issue, but how can you retrieve an image stored in a database, using Web API, then display it using Angular?
Here is an example Web API service which is correctly returning a JPG file (using HttpResponseMessage):
public HttpResponseMessage GetIncidentImages(Guid IncidentIDX) {
var response = new HttpResponseMessage();
List<T_EM_INCIDENT_ATTACH> att = db_Layer.GetT_EM_INCIDENT_ATTACH_byIncidentIDX(IncidentIDX);
if (att != null)
{
if (att.Count > 0)
{
var pictureBytes = att[0].ATTACH_CONTENT; //ATTACH_CONTENT is a byte array
if (pictureBytes == null)
response.StatusCode = HttpStatusCode.NotFound;
else
{
response.Content = new ByteArrayContent(pictureBytes);
response.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg");
}
}
else
response.StatusCode = HttpStatusCode.NotFound;
}
return response;
}
Then on the http client-side, I am using angular to retrieve the data. Data is definitely getting retrieved, but just not displayed.
dbManagerService.syncIncidentAttach(ehConstants.incidenT_IDX).then(function (res) {
console.log("return", res);
$scope.cameraPic = res;
});
function _syncIncidentAttach(incIDX) {
var deferred = $q.defer();
$http.get($rootScope.serverBaseUrl + 'api/incident/GetIncidentImages?IncidentIDX=' + incIDX, { responseType: "blob" })
.success(function (res, status, headers, config) {
// encode data to base 64 url
fr = new FileReader();
fr.onload = function () {
// this variable holds your base64 image data URI (string)
// use readAsBinary() or readAsBinaryString() below to obtain other data types
console.log(fr.result);
};
fr.readAsDataURL(res);
deferred.resolve(fr);
})
.error(function(data, status, headers, config) {
conole.log('error getting image');
});
return deferred.promise;
}
And the html:
<img ng-src="{{cameraPic}}" /> </div>

Looking at your server side code, I think you can directly write like this:
<img ng-src="{{serverBaseUrl}}api/incident/GetIncidentImages?IncidentIDX={{ehConstants.incidenT_IDX}}" />
Just make sure you are replacing ehConstants.incidenT_IDX with actual content.

As documented in this answer, you can also do something like
<img ng-src="{{'data:image/png;base64,' + main.user.imageData}}">

AngularJS: $http.get method to download the pdf file

I'm using the $http.get(...) method in SPA to get pdf download.
In the SPA ,print method give the blank pdf .
But when i did the debug, data come from the API.
Can you help on this?
This is the API implementation to response the stream out as application/pdf
public Stream GetConsumerInformationReport(Guid id)
{
..........
var stream = cryRpt.ExportToStream(ExportFormatType.PortableDocFormat);
return stream;
}
SPA implementation of get the data from API
var print = function () {
var downloadPath = apiEndPoint + 'Reports/' + $state.current.data.printPrefix + '.pdf';
$http.get(downloadPath,httpConfig).
success(function (data) {
var blob = new Blob([data], { type: "application/pdf" });
var objectUrl = URL.createObjectURL(blob);
$window.open(objectUrl);
}).
error(function (data, status, headers, config) {
// if there's an error you should see it here
});
};

Use FileSaver.js from here http://purl.eligrey.com/github/FileSaver.js/blob/master/FileSaver.js
Then define your download method like this. Take it only as an inspiration, do not copy-paste-run :)
The original version can be found here - http://davidjs.com/2015/07/download-files-via-post-request-in-angularjs/
//Define method download() in your ng controller
$scope.download = () => {
//Indicates that download is in progress
$scope.isDownloading = true;
return $http.get(downloadPath,httpConfig).$promise.then((data: any) => {
//using saveAs.js (part of upcoming HTML5 API, but so far a polyfill)
var blob = data.response.blob;
var fileName: string = data.response.fileName || 'document.pdf';
//SaveAs is available at saveAs.js from http://purl.eligrey.com/github/FileSaver.js/blob/master/FileSaver.js
(<any>$window).saveAs(blob, fileName);
})
.finally(() => {
$scope.isDownloading = false;
});
}

generate csv from mvc web api httpresponse and receive it by angularjs for download

I am trying to generate a CSV file from my web api and receive that file through angularjs. I have an API controller like below:
[HttpPost]
public HttpResponseMessage GenerateCSV(FieldParameters fieldParams)
{
var output = new byte[] { };
if (fieldParams!= null)
{
using (var stream = new MemoryStream())
{
this.Serialize(fieldParams, stream);
stream.Flush();
output = stream.ToArray();
}
}
var result = new HttpResponseMessage(HttpStatusCode.OK) { Content = new ByteArrayContent(output) };
result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
{
FileName = "Fields.csv"
};
return result;
}
In my angularjs, i have this:
$scope.save = function () {
var csvInput= extractDetails();
// File is an angular resource. We call its save method here which
// accesses the api above which should return the content of csv
File.save(csvInput, function (content) {
console.log(content);
// only creates a csv file with "[object Object]" written in it
var hiddenElement = document.createElement('a');
hiddenElement.href = 'data:text/csv;charset=utf-8,\uFEFF' + encodeURI(content.Parameters);
hiddenElement.target = '_blank';
hiddenElement.download = 'myFile.csv';
hiddenElement.click();
});
};
Lets say for example, in my API controller, the content of response is
output
{byte[152]}
[0]: 83
[1]: 101
[2]: 44
[3]: 67
[4]: 10
When I receive this in angularjs and I put the value of content in the console log (chrome), this is what I get:
{Parameters: Array[1], $promise: Object, $resolved: true, $get: function, $save: function…}
0:"S"
1: "e"
2: ","
3: "C"
4: "↵"
$promise: object
$resolved: true`
Why did the content received in the angularjs contain characters
already instead of a byte of array?
How can I control the content in such a way that I will only use
the csv related data and remove $promise and $resolved? Why are they included in the first place? How to remove them?
What is the proper way of generating a csv if what I am doing is
wrong? :|

Forgot to update this, but i now found a way to solve this:
There will be two API's, one (POST) will remember the data to be used in the processing and another one (GET) which will dispense the file.
POST:
[HttpPost]
public async Task<HttpResponseMessage> BuildFile(FileParameters fileParams)
{
var guid = Guid.NewGuid().ToString();
if (fileParams!= null)
{
await Task.Run(() => FileContents.Add(guid, fileParams));
return this.Request.CreateResponse(HttpStatusCode.OK, new { Value = guid });
}
return this.Request.CreateErrorResponse(HttpStatusCode.BadRequest, "Invalid data");
}
In AngularJs, remember the guid returned and pass this to another api:
location.href = '/api/file/generatefile' + '?guid=' + generatedGuidFromAPI + '&reportName=' + $scope.reportName;
And here is the generatefile API controller in MVC:
GET:
[HttpGet]
public async Task<HttpResponseMessage> GenerateFile(string guid, string reportName)
{
byte[] output = null;
if (FileContents.ContainsKey(guid))
{
await Task.Run(() =>
{
using (var stream = new MemoryStream())
{
this.CreateFile(FileContents[guid], stream);
stream.Flush();
output = stream.ToArray();
}
});
}
FileContents.Remove(guid);
if (output != null)
{
var result = new HttpResponseMessage(HttpStatusCode.OK) { Content = new ByteArrayContent(output) };
result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
{
FileName = reportName + ".csv"
};
return result;
}
return this.Request.CreateErrorResponse(HttpStatusCode.NoContent, "No record found");
}
using location.href will cause the browser to automatically download the file, asking you whether to save it or not.

Here's how I do it: (tested in chrome)
// WebAPI controller action
public IHttpActionResult Get(string rpt, DateTime date)
{
List<DailyMIReportViewModel> list = new List<DailyMIReportViewModel>();
// Do some stuff to generate list of items
// Download Requested
if (rpt == "dailymidl")
{
// Create byte array of csv
byte[] csvData = WriteCsvWithHeaderToMemory(list);
// create FileContentResult of cdv byte array
FileContentResult result = new FileContentResult(csvData, "application/octet-stream");
// set filename in FileContentResult
result.FileDownloadName = "Report.csv";
return Ok(result);
}
// Data Requested
return Ok(list);
// Client-side angularjs
// Called on button click
$scope.generateMIDownload = function (forDate) {
// Using $resource to return promise with FileContentResult payload
reportsRepository.dailymidl(forDate).$promise.then(
function (data) {
//ok
// NOTE: the base64 part is what got it working
var dataUrl = 'data:application/octet-stream;base64,' + data.FileContents
var link = document.createElement('a');
angular.element(link)
.attr('href', dataUrl)
.attr('download', data.FileDownloadName)
.attr('target','_blank')
link.click();
},
function (response) {
//not ok
});
}
// Reports Repository (for ref)
angular.module('msgnr').factory('reportsRepository', function ($resource) {
return {
dailymidl: function (date) {
return $resource('/api/Report/', { rpt: 'dailymidl', date: date, toDate: date }).get();
}
}
});
Incase it helps anyone else.