I'm working on a project where i can select an image (simple file select) and send it via JSON to a PHP MySQL insert page.
Upload page looks like this:
if (input.files && input.files[0]) {
var FR = new FileReader();
FR.onload = function(e) {
$('#img').attr("src", e.target.result);
var Naam = $('input[type=file]').val();
$('#base').text(e.target.result);
var Foto = e.target.result;
var Barcode = $('#barcode').val();
obj['Barcode'] = Barcode;
obj['Naam'] = Naam;
obj['Foto'] = Foto;
//execute ajax send
$.ajax({
url : 'insert.php',
type : 'POST',
data : obj,
dataType : 'json',
success : function(msg) {
alert("msg");
}
});
//$.post("insert.php", obj, function (data) {}, "json");
//alert("msg");
};
FR.readAsDataURL(input.files[0]);
and my PHP page:
$Barcode = $_POST["Barcode"];
$Naam = $_POST["Naam"];
$Name = preg_replace('/^.+[\\\\\\/]/', '', $Naam);
$Foto = base64_decode($_POST["Foto"]);
$query = "INSERT INTO voorraad_foto (barbody, location, foto) VALUES ('$Barcode','$Name','{$Foto}')";
$results = mysqli_query($db,$query);
And my table field is a BLOB.
But when it execute this, everything works fine except that it doesn't insert it as a blob, but pure string
I've tried with removing the
preg_replace('#data:image/[^;]+;base64,#', '', $Foto)
but doesn't make any difference, same when trying to add headers, but nothing..
What am i doing wrong, or is there something obvious that i'm not getting?
Thx.
I solved it in some kind of way:
I wrote a function that gets the Base64 string, decodes it and writes it to a Temp file.
Then i read that file again and upload that to my databse.
When success, delete the file.
It may not be the most effecient way, but it works!
function WriteToImageAndGetData($base64_string, $File) {
//Write to file
$ifp = fopen($File, "wb");
$data = explode(',', $base64_string); //Split Base64 string
fwrite($ifp, base64_decode($data[1])); //Decode Base64 string
fclose($ifp);
//Read from file
$fp = fopen($File, 'r');
$data = fread($fp, filesize($File)); //Read file contents
$data = addslashes($data);
fclose($fp);
return $data;
}
I have written a jQuery script that takes a JSON encoded list produced with this function is run in my theme's functions.php and creates a playlist for my jPlayer. However, the script only works when the $file variable is hard coded (for example, OH0400). But I need it to pick up the $file variable based on the page being loaded. But when I switch to this method (using URL), the script says the JSON is null.
I've run the script in multiple ways and the output between the hard coded $file and the variable based $file appear to be the same. Why do I get null when I make the switch?
Here's the PHP in my theme functions.php.
function MyjPlayerList(){
$url = explode( '/', $_SERVER['REQUEST_URI'] );
$file = strtoupper($url[2]);
//$file = 'OH0400';
$filename = '/dir/oralhistory/mp3files/'.$file.'*.mp3';
$FILES = glob( $filename );
foreach( $FILES as $key => $mp3 ) {
$mp3 = str_replace( '/dir/oralhistory/mp3files/', '',$mp3);
$FILE_LIST[ $key ][ 'title' ] = $mp3;
$FILE_LIST[ $key ][ 'mp3' ] = 'http://websiteurl.org/mp3files/'.$mp3;
}
$myjplayerdata = json_encode( $FILE_LIST );
header ( 'Content-type: application/json' );
echo $myjplayerdata;
exit;
die();
};
Here is my javascript:
ajax_player = function() {
jQuery('div#player').load('/js/player.html' , function() {
var cssSelector= {
jPlayer: "#jquery_jplayer_1",
cssSelectorAncestor: "#jp_container_1"
};
var playlist = [];
var options = {
swfPath: "/js/Jplayer.swf",
supplied: "mp3",
smoothPlayBar: true,
keyEnabled: true
};
var myPlaylist = new jPlayerPlaylist(cssSelector, playlist, options);
jQuery.ajax({
url: "/wp-admin/admin-ajax.php" ,
type: "POST",
dataType: "text json",
data: { action: "MyjPlayerList"},
success:(function(data) {
jQuery.each(data, function(index, value){
myPlaylist.add(value); // add each element in data in myPlaylist
console.log(data);
})
})//function (data) close
})//ajax close
})//jquery.load
}//ajax_player
Yes, check the character encoding you're using. That could be the problem.
thanks to the debugging of Marc,turns out that what I get when i run the script in page & what i get when I call the script w/ javascript are different. it's trying to glob admin-ajax.php instead of the URL.
I'm working on a generative art project where I would like to allow users to save the resulting images from an algorithm. The general idea is:
Create an image on an HTML5 Canvas using a generative algorithm
When the image is completed, allow users to save the canvas as an image file to the server
Allow the user to either download the image or add it to a gallery of pieces of produced using the algorithm.
However, I’m stuck on the second step. After some help from Google, I found this blog post, which seemed to be exactly what I wanted:
Which led to the JavaScript code:
function saveImage() {
var canvasData = canvas.toDataURL("image/png");
var ajax = new XMLHttpRequest();
ajax.open("POST", "testSave.php", false);
ajax.onreadystatechange = function() {
console.log(ajax.responseText);
}
ajax.setRequestHeader("Content-Type", "application/upload");
ajax.send("imgData=" + canvasData);
}
and corresponding PHP (testSave.php):
<?php
if (isset($GLOBALS["HTTP_RAW_POST_DATA"])) {
$imageData = $GLOBALS['HTTP_RAW_POST_DATA'];
$filteredData = substr($imageData, strpos($imageData, ",") + 1);
$unencodedData = base64_decode($filteredData);
$fp = fopen('/path/to/file.png', 'wb');
fwrite($fp, $unencodedData);
fclose($fp);
}
?>
But this doesn’t seem to do anything at all.
More Googling turns up this blog post which is based off of the previous tutorial. Not very different, but perhaps worth a try:
$data = $_POST['imgData'];
$file = "/path/to/file.png";
$uri = substr($data,strpos($data, ",") + 1);
file_put_contents($file, base64_decode($uri));
echo $file;
This one creates a file (yay) but it’s corrupted and doesn’t seem to contain anything. It also appears to be empty (file size of 0).
Is there anything really obvious that I’m doing wrong? The path where I’m storing my file is writable, so that isn’t an issue, but nothing seems to be happening and I’m not really sure how to debug this.
Edit
Following Salvidor Dali’s link I changed the AJAX request to be:
function saveImage() {
var canvasData = canvas.toDataURL("image/png");
var xmlHttpReq = false;
if (window.XMLHttpRequest) {
ajax = new XMLHttpRequest();
}
else if (window.ActiveXObject) {
ajax = new ActiveXObject("Microsoft.XMLHTTP");
}
ajax.open("POST", "testSave.php", false);
ajax.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
ajax.onreadystatechange = function() {
console.log(ajax.responseText);
}
ajax.send("imgData=" + canvasData);
}
And now the image file is created and isn’t empty! It seems as if the content type matters and that changing it to x-www-form-urlencoded allowed the image data to be sent.
The console returns the (rather large) string of base64 code and the datafile is ~140 kB. However, I still can’t open it and it seems to not be formatted as an image.
Here is an example of how to achieve what you need:
Draw something (taken from canvas tutorial)
<canvas id="myCanvas" width="578" height="200"></canvas>
<script>
var canvas = document.getElementById('myCanvas');
var context = canvas.getContext('2d');
// begin custom shape
context.beginPath();
context.moveTo(170, 80);
context.bezierCurveTo(130, 100, 130, 150, 230, 150);
context.bezierCurveTo(250, 180, 320, 180, 340, 150);
context.bezierCurveTo(420, 150, 420, 120, 390, 100);
context.bezierCurveTo(430, 40, 370, 30, 340, 50);
context.bezierCurveTo(320, 5, 250, 20, 250, 50);
context.bezierCurveTo(200, 5, 150, 20, 170, 80);
// complete custom shape
context.closePath();
context.lineWidth = 5;
context.fillStyle = '#8ED6FF';
context.fill();
context.strokeStyle = 'blue';
context.stroke();
</script>
Convert canvas image to URL format (base64)
// script
var dataURL = canvas.toDataURL();
Send it to your server via Ajax
$.ajax({
type: "POST",
url: "script.php",
data: {
imgBase64: dataURL
}
}).done(function(o) {
console.log('saved');
// If you want the file to be visible in the browser
// - please modify the callback in javascript. All you
// need is to return the url to the file, you just saved
// and than put the image in your browser.
});
Save base64 on your server as an image (here is how to do this in PHP, the same ideas is in every language. Server side in PHP can be found here):
I played with this two weeks ago, it's very simple. The only problem is that all the tutorials just talk about saving the image locally. This is how I did it:
1) I set up a form so I can use a POST method.
2) When the user is done drawing, he can click the "Save" button.
3) When the button is clicked I take the image data and put it into a hidden field. After that I submit the form.
document.getElementById('my_hidden').value = canvas.toDataURL('image/png');
document.forms["form1"].submit();
4) When the form is submited I have this small php script:
<?php
$upload_dir = somehow_get_upload_dir(); //implement this function yourself
$img = $_POST['my_hidden'];
$img = str_replace('data:image/png;base64,', '', $img);
$img = str_replace(' ', '+', $img);
$data = base64_decode($img);
$file = $upload_dir."image_name.png";
$success = file_put_contents($file, $data);
header('Location: '.$_POST['return_url']);
?>
I think you should convert the image to base64 and then to Blob and send it to the server. When you use base64 images, a lot of lines will be sent to server. With blob, it's only the file.
You can use this code bellow:
function dataURLtoBlob(dataURL) {
let array, binary, i, len;
binary = atob(dataURL.split(',')[1]);
array = [];
i = 0;
len = binary.length;
while (i < len) {
array.push(binary.charCodeAt(i));
i++;
}
return new Blob([new Uint8Array(array)], {
type: 'image/png'
});
};
And canvas code here:
const canvas = document.getElementById('canvas');
const file = dataURLtoBlob( canvas.toDataURL() );
After that you can use ajax with Form:
const fd = new FormData;
fd.append('image', file);
$.ajax({
type: 'POST',
url: '/url-to-save',
data: fd,
processData: false,
contentType: false
});
The code in CoffeeScript syntax:
dataURLtoBlob = (dataURL) ->
# Decode the dataURL
binary = atob(dataURL.split(',')[1])
# Create 8-bit unsigned array
array = []
i = 0
while i < binary.length
array.push binary.charCodeAt(i)
i++
# Return our Blob object
new Blob([ new Uint8Array(array) ], type: 'image/png')
And canvas code here:
canvas = document.getElementById('canvas')
file = dataURLtoBlob(canvas.toDataURL())
After that you can use ajax with Form:
fd = new FormData
# Append our Canvas image file to the form data
fd.append 'image', file
$.ajax
type: 'POST'
url: '/url-to-save'
data: fd
processData: false
contentType: false
Send canvas image to PHP:
var photo = canvas.toDataURL('image/jpeg');
$.ajax({
method: 'POST',
url: 'photo_upload.php',
data: {
photo: photo
}
});
Here's PHP script:
photo_upload.php
<?php
$data = $_POST['photo'];
list($type, $data) = explode(';', $data);
list(, $data) = explode(',', $data);
$data = base64_decode($data);
mkdir($_SERVER['DOCUMENT_ROOT'] . "/photos");
file_put_contents($_SERVER['DOCUMENT_ROOT'] . "/photos/".time().'.png', $data);
die;
?>
I've worked on something similar.
Had to convert canvas Base64-encoded image to Uint8Array Blob.
function b64ToUint8Array(b64Image) {
var img = atob(b64Image.split(',')[1]);
var img_buffer = [];
var i = 0;
while (i < img.length) {
img_buffer.push(img.charCodeAt(i));
i++;
}
return new Uint8Array(img_buffer);
}
var b64Image = canvas.toDataURL('image/jpeg');
var u8Image = b64ToUint8Array(b64Image);
var formData = new FormData();
formData.append("image", new Blob([ u8Image ], {type: "image/jpg"}));
var xhr = new XMLHttpRequest();
xhr.open("POST", "/api/upload", true);
xhr.send(formData);
If you want to save data that is derived from a Javascript canvas.toDataURL() function, you have to convert blanks into plusses. If you do not do that, the decoded data is corrupted:
<?php
$encodedData = str_replace(' ','+',$encodedData);
$decocedData = base64_decode($encodedData);
?>
http://php.net/manual/ro/function.base64-decode.php
In addition to Salvador Dali's answer:
on the server side don't forget that the data comes in base64 string format. It's important because in some programming languages you need to explisitely say that this string should be regarded as bytes not simple Unicode string.
Otherwise decoding won't work: the image will be saved but it will be an unreadable file.
I just made an imageCrop and Upload feature with
https://www.npmjs.com/package/react-image-crop
to get the ImagePreview ( the cropped image rendering in a canvas)
https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toBlob
canvas.toBlob(function(blob){...}, 'image/jpeg', 0.95);
I prefer sending data in blob with content type image/jpeg rather than toDataURL ( a huge base64 string`
My implementation for uploading to Azure Blob using SAS URL
axios.post(azure_sas_url, image_in_blob, {
headers: {
'x-ms-blob-type': 'BlockBlob',
'Content-Type': 'image/jpeg'
}
})
I'm using an ajax query to upload canvas image data, along with a few other variables. Here's what the relevant code looks like on the client side:
front_content = document.getElementById("front_paint_canvas").toDataURL("image/png");
ajaxHandler.open("POST", "upload_card", true);
ajaxHandler.setRequestHeader("Content-type","application/x-www-form-urlencoded");
ajaxHandler.send("name="+name+"&front_content="+front_content);
And here's what I have on the server side:
$front_content = substr($_POST['front_content'], strpos($_POST['front_content'], ",")+1);
$decodedData=base64_decode($front_content);
$fp = fopen( getcwd().'/assets/img/canvas.png', 'wb' );
fwrite( $fp, $decodedData);
fclose( $fp );
This creates a file that appears to be the right size, and is also of the right dimensions. However, the file is blank. None of the image data that was in the canvas shows up. What's being done wrong here?
When using jQuery.post() see: http://api.jquery.com/jQuery.post/ the ""application/x-www-form-urlencoded" content-type is not needed:
javascript:
// save canvas image as data url (png format by default)
var dataURL = canvas.toDataURL();
$.post("canvasdata.php", { data: dataURL } );
php:
//see: How to save a html5 Canvas.toDataURl string as a png on a php backend string-as-a-png-on-a-php-backend
file_put_contents('test.png', base64_decode(substr($_POST['data'], strpos($_POST['data'], ",")+1)));
update
If you don't use jquery use this:
// save canvas image as data url (png format by default)
var dataURL = canvas.toDataURL();
//$.post("canvasdata.php", { data: dataURL } );
var ajaxHandler = new XMLHttpRequest();
ajaxHandler.open("POST", "canvasdata.php", true);
//ajaxHandler.setRequestHeader("Content-type","application/x-www-form-urlencoded");
//ajaxHandler.send("name=test&data="+dataURL);
var formData = new FormData();
formData.append("name", "test");
formData.append("data", dataURL);
ajaxHandler.send(formData);
I have a highcharts svg which I have converted to a png via canvg and displayed on the webpage. I would like to then send this png to the server to create a link to the image. I was following the answer code on another topic:
Renaming an image created from an HTML5 canvas
My javascript code is the following:
var timeout = window.setTimeout(function() {
canvg(document.getElementById('canvas'), chart.getSVG());
}, 10000);
var canvas = document.getElementById("canvas");
var img = canvas.toDataURL("images/png");
document.write('<img src="'+img+'"/>');
saveDataURL(img)
function saveDataURL(canvas) {
var request = new XMLHttpRequest();
request.onreadystatechange = function () {
if (request.readyState === 4 && request.status === 200) {
window.location.href = request.responseText;
}
};
request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
request.open("POST", "saveDataURL.php", true);
request.send("dataURL=" + canvas.toDataURL());
}
My php called saveDataURL.php is then:
$dataURL = $_POST["dataURL"];
$encodedData = explode(',', $dataURL)[1];
$decodedData = base64_decode($encodedData);
file_put_contents("temp/faizan.png", $decodedData);
echo "http://whichchart.com/temp/faizan.png";
In firefox 12 the following error is thrown up at the "request.setRequestHeader" line:
Component returned failure code: 0x804b000f (NS_ERROR_IN_PROGRESS) [nsIXMLHttpRequest.setRequestHeader]
http://whichchart.com/oil.js
Line 102
In chrome the error on the same line is:
Uncaught Error: INVALID_STATE_ERR: DOM Exception 11
saveDataURLoil.js:106
(anonymous function)
The example can be viewed here: whichchart.com. Can you help? Thanks.
Ok, so I found a different solution after much searching. The link is here:
http://permadi.com/blog/2010/10/html5-saving-canvas-image-data-using-php-and-ajax/
Assuming you have a canvas called testCanvas, this javascript and php will work:
var canvasData = testCanvas.toDataURL("image/png");
var ajax = new XMLHttpRequest();
ajax.open("POST",'testSave.php',false);
ajax.setRequestHeader('Content-Type', 'application/upload');
ajax.send(canvasData );
<?php
if (isset($GLOBALS["HTTP_RAW_POST_DATA"]))
{
// Get the data
$imageData=$GLOBALS['HTTP_RAW_POST_DATA'];
// Remove the headers (data:,) part.
// A real application should use them according to needs such as to check image type
$filteredData=substr($imageData, strpos($imageData, ",")+1);
// Need to decode before saving since the data we received is already base64 encoded
$unencodedData=base64_decode($filteredData);
//echo "unencodedData".$unencodedData;
// Save file. This example uses a hard coded filename for testing,
// but a real application can specify filename in POST variable
$fp = fopen( 'test.png', 'wb' );
fwrite( $fp, $unencodedData);
fclose( $fp );
}
?>