force-download xlsx from ajax response not working - php

Question

I have this little problem with downloading my xlsx-file.
I am sending my request for the file over jquery Ajax and on the backend the data is correctly collected and assembled to a xlsx-file. So now on its way back to the frontend i am setting all the headers in preparation to force download the file, but the download never starts.
These are the response headers of my request:
Connection Keep-Alive
Content-Disposition attachment; filename="export.xlsx"
Content-Length 346420
Content-Type application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Date Mon, 23 Nov 2015 13:23:30 GMT
Keep-Alive timeout=5, max=91
Server Apache/2.4.16 (Win32) OpenSSL/1.0.1p PHP/5.6.12
Set-Cookie <cookiesettings>
content-transfer-encoding binary
x-powered-by PHP/5.6.12
imho the download should start immediately, but nothing happens.
EDIT:
Until now I used a form submit, but the data amount is really big so the time which is needed to assemble the file is also really long and sometimes a couple of minutes or even an hour, so this was no longer possible.
So I built a java-job to build the file and startet an ajax snippet which asks for completion every second or so.
So here is my Code.
Frontend:
This is called on button-click
download: function (type, maximum) {
var
self = this,
oParams = this.oTable.oApi._fnAjaxParameters(this.oTable.fnSettings()),
aoPost = [
{ 'name': 'exportType', 'value': type },
{ 'name': 'exportMax', 'value': maximum },
{ 'name': 'handleId', 'value': self.options.handleId }
],
nIFrame, nContentWindow, nForm, nInput, i
;
// Call a self made function to get extra search parameters
// without call an data update AJAX call.
self.oTable.fnSettings().addAdditionalSearchData(oParams);
// Create an IFrame to do the request
nIFrame = document.createElement('iframe');
nIFrame.setAttribute('id', 'RemotingIFrame');
nIFrame.style.border = '0px';
nIFrame.style.width = '0px';
nIFrame.style.height = '0px';
document.body.appendChild(nIFrame);
nContentWindow = nIFrame.contentWindow;
nContentWindow.document.open();
nContentWindow.document.close();
nForm = nContentWindow.document.createElement('form');
nForm.className = 'export-table';
nForm.setAttribute('method', 'post');
// Add POST data.
var formData = {};
for (i = 0; i < aoPost.length; i++) {
nInput = nContentWindow.document.createElement('input');
nInput.setAttribute('name', aoPost[ i ].name);
nInput.setAttribute('type', 'text');
nInput.value = aoPost[ i ].value;
nForm.appendChild(nInput);
formData[aoPost[ i ].name] = aoPost[ i ].value;
}
// Add dataTables POST.
for (i = 0; i < oParams.length; i++) {
nInput = nContentWindow.document.createElement('input');
nInput.setAttribute('name', oParams[ i ].name);
nInput.setAttribute('type', 'text');
nInput.value = oParams[ i ].value;
nForm.appendChild(nInput);
formData[oParams[ i ].name] = oParams[ i ].value;
}
nForm.setAttribute('action', '/service/exportTableData');
// Add the form and the iFrame.
nContentWindow.document.body.appendChild(nForm);
// Send the request.
//nForm.submit();
// Send the request.
var form = $(nContentWindow.document.body).find('form.export-table');
var jobId = 0;
form.ajaxForm(
{
'showMessagesOnSuccess': false
},
{
'getData': function () {
return formData;
}
}
).data('ajaxForm').submit();
}
The Ajax request on submit:
$.ajax({
type: 'POST',
url: self.handler.getServiceUrl(),
timeout: GLOBALS.AJAX_REQUEST_TIMEOUT,
cache: false,
data: (<get the Data>)
,
success: function (response) {
if (response.success === true) {
// Check if we have to wait for a result.
if (response.jobId !== undefined && response.jobId !== 0) {
self.checkJobStatus(response.jobId);
} else {
<success - show some messages>
}
} else {
self.handler.error(response);
}
},
error: function () {
<Show error Message>
}
});
The CheckJobStatus:
checkJobStatus: function (jobId) {
var self = this;
$.ajax({
type: 'POST',
timeout: GLOBALS.AJAX_REQUEST_TIMEOUT,
cache: false,
data: { 'jobId': jobId },
url: self.handler.getServiceUrl(),
success: function (response) {
if(response !== null && response.data !== undefined) {
if (response.data.isFinished === true) {
if (response.success === true) {
// Check if we have to wait for a result.
self.handler.success(response);
} else {
self.handler.error(response);
}
} else if (response.success === true && response.data !== null) {
setTimeout(
function () {
self.checkJobStatus(jobId);
},
500
);
} else {
Helper.logFrontendError();
}
} else if (response !== null && response.success === true) {
setTimeout(
function () {
self.checkJobStatus(jobId);
},
1000
);
} else {
Helper.logFrontendError();
}
},
error: function (response) {
Helper.logFrontendError();
}
});
}
Backend - php:
(...)
if ($action == 'exportTableData' || $action == 'exportChartData') {
$responseData = $service->execute();
if(isset($responseData->data['contentType']) && $responseData->data['contentType'] != null && isset($responseData->data['data'])) {
$this->sendTextData($responseData->data['contentType'], $responseData->data['data']);
} else {
$this->sendJsonData($responseData);
}
} else {
$this->sendJsonData($service->execute());
}
(...)
private function sendTextData($contentType, $data) {
$this->set('filename', 'export.xlsx');
$this->set('data', $data);
$this->response->type($contentType);
$this->render('/Layouts/excel', 'excel');
}
(...)
$handlerResult = new HandlerResult();
if($dataServiceResult == null) {
$service = new DataService();
$dataServiceResult = $service->exportTableData(
$controller->Auth->User('id'),
json_encode($request->data),
null
);
} else {
if ($dataServiceResult->header->resultKey == 0) {
$handlerResult->wsData['data'] = $dataServiceResult->data;
$handlerResult->wsData['contentType'] = $dataServiceResult->contentType;
}
}
$handlerResult->wsResultHeader = $dataServiceResult->header;
return $handlerResult; // ++++ this result returns to the first codeblock in this section ++++
Backend - java - This is where the File is assembled:
(...)
if (jobId > 0) {
FrontendJobStatus status = FrontendJobQueue.getJobStatus(context.userId, jobId);
this.result = (WSExportTableDataResult) status.getResult();
logger.info((this.result.data == null) ? "ByteArray is EMPTY" : "ByteArray is NOT EMPTY");
} else {
this.jobId = FrontendJobQueue.addJob(this.context.userId, new ExportTableDataJob(this.context, this.postData));
this.result.header.jobId = this.jobId;
}
(...)
The Jop:
<Workbook assembly>
ByteArrayOutputStream out = new ByteArrayOutputStream();
wb.write(out);
this.result.data = out.toByteArray();
this.result.contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
// this.result.contentType = "application/vnd.ms-excel";
this.result.setResultHeader(APIConstants.RESULT_SUCCESS);
Layout/excel:
<?php
header('Content-Disposition: attachment; filename="'.$filename.'"');
header('Content-Transfer-Encoding: binary');
ob_clean();
echo $data;
EDIT 2:
So I tried to open a new window on success with the Data, and i could start the download, but the file ist no valid xlsx File anymore.
var reader = new FileReader();
var blob = new Blob([response.responseText], { type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" });
reader.readAsDataURL(blob);
reader.onloadend = function (e) {
window.open(reader.result, 'Excel', 'width=20,height=10,toolbar=0,menubar=0,scrollbars=no', '_blank');
}
Any Ideas?

Answer 1

After a lot of research i found this site and the essence of its statment is that jquery ajax does not support receiving binary data, but provides a solution for implementing plain xhr request which support blob transfer.
The Site:
http://www.henryalgus.com/reading-binary-files-using-jquery-ajax/

Answer 2

To expand on my comment, instead of trying to send back binary data via ajax, simply save to a temp file , send the file reference back to js. On receiving the file reference, simply set window.location.href to point to a filereading endpoint, passing the file reference. I have done this a few times and it works fine even on ancient browsers:
$('#start').click(function(){
$.post('/createfile.php', {some:data}, function(response){
if(response.started){
pollFile(response.fileId);
}
});
);
function pollFile(fileId){
$.get('/filestatus.php?fileid=' + fileId, function(response){
if(response.fileCompleted){
window.location.href = '/downloadfile.php?fileid=' + fileId;
}else{
setTimeout('pollFile', 5000, fileId);
}
});
}
//createfile.php
$fileId = uniqid();
SomePersistentStorage::addJob($fileID);
//start file job here, code should run in a seperate process/thread, so
//either use a job queue system, use shell_exec or make an http request,
//then once job is queued/started:
header('Content-Type: application/json');
echo json_encode(['started'=>true, 'fileId'=>$fileId]);
//processjob.php - the file that does the work, could be your java
//program for example, just using php here for consistency
//after file is done
file_put_contents($filepath, $data);
SomePersistentStorage::updateJob($fileID, true);
//filestatus.php
$fileId = $_GET['fileid'];
header('Content-Type: application/json');
echo json_encode(['fileCompleted'=>SomePersistentStorage::isJobCompleted($fileID)]);
//downloadfile.php
$fileId = $_GET['fileid'];
$filepath = 'tmp/' . $fileId . '.tmp';
//correct headers here, then
readfile($filepath);
unlink($filepath);
If you dont want to imediatly delete the file, then you could just run a cron to delete files in the specific folder, that are older than x.