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POST JSON from HTML form to PHP API and download the received file in the browser

I have an existing API that only accepts JSON values via a POST, it responds with a downloadable zip file that is only session based, not on a server. I wanted to create an HTML form that could be filled out and POST the JSON values to the API then receive the download. Once the API receives the JSON it will respond with a Zip file that should be downloaded through the browser. I spent a lot of time searching for how to do this and eventually pulled together the components to make it happen. I wanted to share it here because I saw many other people searching for the same thing but with no clear answers or script that worked, lost of GET examples but no POST with in memory server data. In fact may folks said it just couldn't be done with POST.
<script src="https://code.jquery.com/jquery-1.9.1.js"></script>
<script>
$(function () {
$('form').on('submit', function (event) {
//Function montiors for the form submit event
event.preventDefault(); // Prevents the default action of the form submit button
var jsonData = '{"PONumber":"' + form1.PONumber.value //JSON data being submitted to the API from the HTML form
+ '","CompanyName":"' + form1.CompanyName.value
+ '","CompanyID":"' + form1.CompanyID.value
+ '","ProductName":"' + form1.ProductName.value
+ '","Quantity":"' + form1.quantity.value
+ '","Manufacturer":"' + form1.Manufacturer.value + '"}';
var xhr = new XMLHttpRequest();
xhr.open('POST', 'api_page.php', true); //The POST to the API page where the JSON will be submitted
xhr.responseType = 'blob';
xhr.setRequestHeader('Content-type', 'application/json'); //Additional header fields as necessary
xhr.setRequestHeader('Authorization', 'Bearer ' + 'eyJ0eXAiOiJKV1QiLCJhbGciO----< SNIP >---547OWZr9ZMEvZBiQpVvU0K0U');
xhr.onload = function(e) {
if (this.status == 200) {
var blob = new Blob([this.response], {type: 'application/zip'}); //We're downloading a Zip file
var downloadUrl = URL.createObjectURL(blob);
var a = document.createElement("a");
a.href = downloadUrl;
a.download = "download_file.zip"; //The name for the downloaded file that will be saved
document.body.appendChild(a);
a.click(); //Automatically starts the download
} else {
alert('Unable to download file.')
}
};
xhr.send(jsonData); //Sends the JSON data to the destination POST page
});
});
</script>
<form method="post" name="form1" id="form1" action="" >
<td><center><input name="submit" type="submit" value="submit"></center></td>
<td ><strong>ENTER QUANTITY OF UNITS: </strong></td><td> </td>
<td><input name="quantity" type="text" size="17" value="<?php echo $row['value'];?>"></td>
</form>
Here is the code for the PHP server side of the application. The first part is to receive the request.
//Receive the incoming JSON data from the form POST
$jsonRequest = trim(file_get_contents("php://input"));
//Attempt to decode the incoming RAW post data.
$requestDecoded = json_decode($jsonRequest, true);
//Do something with the data and then respond with a zip file.
Here is the PHP code that sends the Zip file back to the original requesting page for download.
$fp = fopen('php://output', 'w'); //Creates output buffer
$mfiles = $yourZipFile
if($fp && $mfiles) {
header("Cache-Control: no-cache");
header("Content-Type: application/zip");
header("Content-Disposition: attachment;
filename=\"".basename($zipName)."\";");
header("Content-Transfer-Encoding: binary");
header("Content-Length: " .strlen($mfiles));
header("Response-Data: ".$responseData);
ob_end_clean();
if (fputs($fp, $mfiles, strlen($mfiles))===FALSE){
throw new Exception($e);
}
}
else {
throw new Exception($e);
}

Place the javascript code in the body of your HTML page and it should work just fine. I hope this helps someone else out there in the same position. I've tried to describe each component as best I can and include all of the pieces to make it work.
Request: Browser --> HTML form --> JSON --> POST --> PHP
Response: PHP --> zip file --> Browser Download --> Local PC

Change name of uploaded file on client

I have the following.
<form method="post" action="/send" enctype="multipart/form-data">
<input type="file" name="filename" id="AttachFile">
</form>
I want to change the name of the file the user uploads.
If the user selects "Document.docx" I want to change it to "Bank - Document.docx".
I still want to read the file the user selected, not some other file, just use a different name for it when sending to the server.
I'm working within bounds of an application which doesn't allow control of the server side, so ideally I need to do this on the client. Furthermore I need this to work within the confines of a form.
I have tried variations of the following without success:
document.getElementById("AttachFile").name = "test.txt"
document.getElementById("AttachFile").files = "test.txt"
document.getElementById("AttachFile").value ="test.txt"

You can do it through the File API. We can also use the Blob API to be compatible with Microsoft edge.
var file = document.getElementById("AttachFile").files[0];
var newFile = new File([file], "Bank - Document.docx", {
type: file.type,
});
Here's a complete example — see comments:
HTML:
<input type="file" id="AttachFile">
<input type="button" id="BtnSend" value="Send">
JavaScript:
document.getElementById("BtnSend").addEventListener("click", function() {
// Get the file the user picked
var files = document.getElementById("AttachFile").files;
if (!files.length) {
return;
}
var file = files[0];
// Create a new one with the data but a new name
var newFile = new File([file], "Bank - Document.docx", {
type: file.type,
});
// Build the FormData to send
var data = new FormData();
data.set("AttachFile", newFile);
// Send it
fetch("/some/url", {
method: "POST",
body: data
})
.then(response => {
if (!response.ok) {
throw new Error("HTTP error " + response.status);
}
return response.text(); // or response.json() or whatever
})
.then(response => {
// Do something with the response
})
.catch(error => {
// Do something with the error
});
});

You can't rename the file using a standard form submission. The name of the file being uploaded is read-only. To do this, you'd have to do it server-side. (The designers of file uploads seem to have either not considered this rename-on-upload use case or not felt it needed to be addressed by the API.)
However, you can prevent the default form submission and instead submit it programmatically via ajax, which does allow you to rename the file; see man tou's answer.

If you cannot work on the server side then you have to either rename the file BEFORE upload or AFTER download. How you present the name for the user is you to decide.

How to upload a .mp3 file in HTML / Javascript and send to Java backend

We're trying to upload a song (.mp3) file from a JSP frontend written in HTML / Javascript. We need to upload to our Java backend using websockets. Does anyone have any suggestions on how we would could go about doing this?
Currently we are doing something like this on our JSP file:
<h1>Please Choose a Song file</h1>
<form name = "JSONUploadForm">
<input type = "file" name="file" accept = ".mp3"/> <br/>
<input type = "button" value = "Click to upload!" name = "button" onClick = "submitSong();"/>
</form>
Then we have our javascript function submitSong()
function submitSong(){
var songStuffs = document.getElementById("file");
console.log(songStuffs); --> we get "null" here
sendMessage(songStuffs);
alert("song sent");
}
function sendMessage(val, string) {
socket.send(string);
return false;
}
Also, here is our connect to server function. However, this functions correctly.
function connectToServer() {
socket = new
WebSocket("ws://localhost:8080/Project/socket");
socket.onopen = function(event) {
console.log("connected!");
}
You can also see our server side (.java file):
#OnMessage
public void onMessage(String message, Session session) throws IOException, EncodeException {
FileWriter fw = new FileWriter(new File(songName + ".mp3"));
fw.write(song);
BufferedReader fr = new BufferedReader(new FileReader(songName + ".mp3"));
String data = fr.readLine();
System.out.println("Song: " + data); --> Here we get "song: null"
}
Any suggestions would be greatly appreciated!

In your code you have an error
"var songStuffs = document.getElementById("file");"
Your file input without id.
this will work "var songStuffs = document.querySelector("[name=file]");"
I prefer using querySelector, because it mo flexeble and works exactly like jquery query selectors)))
You do not need any form, for upload files.
Please read this article https://www.html5rocks.com/en/tutorials/websockets/basics/,
it will be useful for you (search words "blob" at the page)
Html
<input id="file" type = "file" name="file" accept = ".mp3"/>
Code
var fileInput = document.querySelector("#file");
fileInput.addEventListener("change",function(){
connection.send(fileInput.files[0]);
});
If you need to send file and fields, you have 3 variants
create JSON {"field1":"value1","field2":"value1",
"file":"base64"}
manualy create formdata and parse form data at the
server with some webform stuff (example
https://stackoverflow.com/a/47279216/5138198)
Firstly send JSON
data, secondly send a file

Try with this, If you have to upload file you should add enctype in form.
<form enctype="multipart/form-data">
<input type = "file" name="file" id="song" accept = ".mp3"/>
</form>
Update:
You can use simply WebSocketFileTransfer plugin to send your file. This plugin helps in with many features like Auth, progress status, file/blob compatibility.
var songStuffs = document.getElementById("song").files[0];
var transfer = new WebSocketFileTransfer({
url: 'ws://ip:port/path/to/upload_web_socket_server',
file: songStuffs,
progress: function(event) {
// Update the progress bar
},
success: function(event) {
// Do something
}
});
transfer.start();

unable to dynamically get the filename from spring controller to the html page to load the newly created file

I want to load the PDF file dynamically and show on browser. PDF file is created on the fly when user clicks on button and the filename has timestamp in it. So i cannot give the PDF filename in the html code as shown below as it changes based on the timestamp(PDF file name is given along with the timestamp when it was created as shown in below spring controller).
Below is the code.
html code:
<div ng-controller="generatePDFController">
<button ng-click="generatePDF()">Re-Generate PDF</button>
<object data="C:/allFiles/PDFFiles/spreadDetails.pdf" type="application/pdf" width="100%" height="100%">
<iframe src="C:/allFiles/PDFFiles/spreadDetails.pdf" width="100%" height="100%" style="border: none;">
This browser does not support PDFs.
Download PDF
</iframe>
</object>
</div>
js code:
app.controller('generatePDFController', function($scope, MyService) {
$scope.generatePDF = function() {
MyService.createPDF().then(
function(response) {
$scope.pdf = response;
},
function(errResponse) {
});
}
});
//service call
_myService.createPDF = function() {
var deferred = $q.defer();
var repUrl = sURL + '/allDataGeneration/generatePDF.form';
$http.get(repUrl)
.then(
function(response) {
deferred.resolve(response.data);
},
function(errResponse) {});
return deferred.promise;
}
spring controller:
#RequestMapping(value = "/generatePDF", method = RequestMethod.GET)
public# ResponseBody List < MyDTO > generatePDF() {
List < MyDTO > response = service.getAllData();
//create PDF and write the response in it
createPDFFile(response);
return response;
}
void createPDFFile(List < MyDTO > res) {
String FILE_PATH = "C:\\allFiles\\PDFFiles\\spreadDetails";
String FILE_EXTENSION = "pdf";
DateFormat df = new SimpleDateFormat("MM-dd-yyyy hh-mm-ssa");
String filename = null;
try {
filename = FILE_PATH + df.format(new Date()) + "." + FILE_EXTENSION;
} catch (Exception e) {
e.printStackTrace();
}
File file = new File(filename);
System.out.println("-----filename------------ " + filename); //PDF file is created successfully
//spreadDetails07-13-2017 02-59-51PM ,when user clicks on GeneratePDF in UI, it hits this controller and generates the PDF
//logic to write the data inside PDF file
}
The above shown code is the complete flow of my sample application. Now when user clicks on Re-Generate PDF button, it comes to above mentioned spring controller creates a file with timestamp and writes the data in it.How to pass the newly created pdf filename to the html code <object data="C:/allFiles/PDFFiles/spreadDetails.pdf" .. so that when pdf file is created it dynamically loads and show on UI.
---EDITED---
Please see the above edited code. createPDF(List<MyDTO>) is a new method in which i'm creating a pdf file and writing the content. I will be reusing this method.

Try to follow these steps :
Change the signature of the Java method generatePDF() in order to return a String representing the name of your file. This gives you the possibility to pass the name of the file to your JavaScript ;
In your controller, do $scope.pdfName = response. This way the name of the file is store the variable $scope.pdfName ;
Last step, replace <object data="C:/allFiles/PDFFiles/spreadDetails.pdf" ...> by <object data="{$scope.pdfName}" ...>
This should work.
Marine
EDIT given your own edit :
Your method generatePdf() is incorrect : you wrote that it must return a List<MyDto> but the keyword return is nowhere.
Do you really need to return he object List<MyDto> ? In any case, you need to return the name of the file to be able to use it in your JavaScript. So, you have two solutions : either this method only returns a String representing the name of the PDF, or it returns an object with two fields, one String and one List<MyDto>. In this second cas, you will need to do
$scope.pdfName = response.fieldContainingTheNameOfTheFile.

Javascript uploading multiple auto generated file forms

In my page I had only one html file input :
input type="file" name="file" files-model="service.file" id="filo" accept=".zip" />
And I used to get my file to be uploaded in a multi-part file request like this :
var fd = new FormData();
fd.append('file', filo.files[0]);//filo is the id of the input
//and send my http request having fd as a parameter
The problem is that now I have auto generated forms in my page with angular ng-repeat so I can no more get my file using the input ID, how can I do this now ?
Cheers,

It will be a bit tricky with javascript. this library worked for me. see example below.
<a class="btn btn-sm btn-primary"
type="file"
ngf-select="receiveSlectedFiles($file)">
Select Logo
</a>
whenever you select file, you will get it in receiveSlectedFiles($file) function. when user select valid file it will be in $file if not the $file will be null.
example in controller:
var arrayOfFiles = [];
$scope.receiveSlectedFiles = function (file) {
if (file) {
arrayOfFiles.push(file);
}
};
In service, inject Upload and then use below code to upload image:
this.uploadMultiple = function (files) {
var uri = yourApiUrl;
return Upload.upload({
url: uri,
arrayKey: '',
data: {
files: files
}
})
};
in controller, you just need to pass array of files to this service.