display binary image with php, jquery - javascript

I have this code which makes a binary image from a normal image and displays it into an .img
$host=$_POST['hostname'];
$type=$_POST['type_char'];
include('rrdtools.inc.php');
include('graphs/'.$type.'.inc.php');
function graph_error($string,$rrd_options)
{
$graphfile ='/tmp/'. strgen().'.png';
$rrd_options .= ' HRULE:0#555555';
$rrd_options .= " --title='".$string."'";
rrdtool_graph($graphfile, $rrd_options);
header('Content-type: image/png');
$fd = fopen($graphfile, 'r');
fpassthru($fd);
fclose($fd);
unlink($graphfile);
}
graph_error($type,$rrd_options);
I send the hostname,type_char to the file using ajax and this is the code
$('.print_graph').click(function(e) {
e.preventDefault();
var type_char='fortigate_sessions';//$('#graph').val();
var hostname='10.10.0.144';//$(this).attr('id');
//$('#device_host').val(id);
$.ajax({
type: 'POST',
url: 'SNMP/graph.php',
data: {'hostname':hostname,'type_char':type_char },
success: function(data) {
alert(data);
// show the response
$("#grph").attr("src", 'SNMP/graph.php');
console.log(data);
}
});
as you can see in the javascript code I used this code to display image
$("#grph").attr("src", 'SNMP/graph.php');
and this code will call graph.php again without parameters and the result is wrong
how can I pass parameters to graphs.php .
I wish I explained my problem clearly

You can solve this by making graph.php look for GET parameters instead of POST and then setting the image source directly without using AJAX:
Change
$host=$_POST['hostname'];
$type=$_POST['type_char'];
to
$host=$_GET['hostname'];
$type=$_Get['type_char'];
and also change
$.ajax({
type: 'POST',
url: 'SNMP/graph.php',
data: {'hostname':hostname,'type_char':type_char },
success: function(data) {
alert(data);
// show the response
$("#grph").attr("src", 'SNMP/graph.php');
console.log(data);
}
});
to simply
$("#grph").attr("src", 'SNMP/graph.php?hostname='+hostname+'&type_char='+type_char);
This will mean that the image data returned by graph.php is used directly in the img tag instead of ending up in a JavaScript variable.
P.S. I note you are using the $type variable to directly create an include() statement in PHP. This is potentially very insecure, as you're letting the client have very direct control over what code is executed and this could be abused to execute code which shouldn't be executed at this time. You should make sure the value submitted contains a value you are expecting and is allowed before using it in your include() statement.

Related

Trying to pass variable from JavaScript to PHP using Ajax but got error " Undefined array key"

I have had this error for multiple days now, I have tried searching this error up but whenever I search this error up it gives a different reason for the error and when I try to add what other sites say it doesn't work which is why I am asking here as I don't see what else I can do.
I am trying to pass a variable from JavaScript to PHP but it is not working and I have no idea why.
Here is my JavaScript code:
<head>
<script type="text/javascript" src="jquery.js"> </script>
</head>
<script>
var variable = "hello";
console.log(variable);
$.ajax
({
url: "ajax.php",
type: "POST",
data:{pass : variable},
success: function() {
alert("Success");
}
});
</script>
Here is my PHP code:
$variable = $_POST['pass'];
echo($variable);
Everything seems to work perfectly. It writes the variable to the console, it comes up with the alert saying success. However I get an error message saying: 'Undefined array key "pass"'
What is causing this? Thank you?
Edit: People have told me to use isset, I have added that it removed the error however it still does not echo the PHP variable, meaning it is still not been passed to PHP, I am still trying to find how to fix this.
Your front end code looks OK, but I don't know your target PHP environement, but maybe your environnement doesn't accept formData.
By default, jQuery send ajax POST data as formData.
Try to send data as JSON
$.ajax({
url: "ajax.php",
type: "POST",
data: JSON.stringify({pass : variable}),
dataType: "json",
contentType: "application/json; charset=utf-8",
success: function(data){alert(data);},
});
And then you will probably have to adapt your php code:
$json = file_get_contents('php://input');
// Converts it into a PHP array
$data = json_decode($json, true);
$variable = $data['pass'];
echo($variable);
Can you please use the developer tools in chrome browser that will help you to find if data is properly sent to php file.
Also you can try $_REQUEST instead of post just to check what data is coming in REQUEST as it works for GET & POST both. If it still does not help you.
Also can you please use
data: {'pass':variable}
instead of
data: {pass:variable}
let me know if it works for you.
If you get this error in your ajax.php file which you Post the data to it, I say it's normal because when you open that file (ajax.php) it's like that there is no $_POST['pass'] because you just opened that file without running JS to send data.
If you want to receive data that you send you can do this:
Your JS code I call this file index:
var variable = "hello";
$.ajax
({
url: "ajax.php",
type: "POST",
data:{pass : variable},
success: function(res) {
alert(res);
}
});
The PHP file:
$variable = $_POST['pass'];
echo($variable);
Then if You open up that index file, after running the JS code it'll send that post data to your PHP file and your PHP file will echo that, then the value will store in that res variable which when every thing went fine, you can see the alert of that res in the page (index file).
Notice that as I said you can't open up the PHP file lonely because it doesn't receive a post data on its own, it is normal for undefined to return.
Re: #puckloe your code is working, php echo wouldn't be printed with ajax(correction echo is working but wouldn't show on page if you don't print it with JS too), you have to catch the response in ajax success function ( like success: function(response) ) and print or alert the response --> success: function(response) { alert("hi look this is echo from php"+response) }
you ajax code should look like
$.ajax
({
url: "ajax.php",
type: "POST",
data:{pass : variable},
success: function(response) {
alert("hi look this is echo from php" + response);
}
});

Send array with Ajax to PHP script in wordpress

I'm trying to send an array from a JS file to a PHP file in the server but when I try to use the array in php, I got nothing.
This is my function in JS:
var sortOrder = [];
var request = function() {
var jsonString = JSON.stringify(sortOrder);
$.ajax({
type: "POST",
url: '<?php echo get_template_directory_uri(); ?>/MYPAGE.php',
data: { sort_order : jsonString },
cache: false,
success: function() {
alert('data sent');
}
})
};
and this is my php file MYPAGE.php:
<?php
$arrayJobs = json_decode(stripslashes($_POST['sort_order']));
echo($arrayJobs);?>
This is the first time that I use ajax and honestly I'm also confused about the url because I'm working on a template in wordpress.
Even if I don't use json it doesn't work!
These are the examples that I'm looking at:
Send array with Ajax to PHP script
Passing JavaScript array to PHP through jQuery $.ajax
First, where is that javascript code? It needs to be in a .php file for the php code (wordpress function) to execute.
Second, how do you know that there is no data received on the back-end. You are sending an AJAX request, and not receiving the result here. If you read the documentation on $.ajax you'll see that the response from the server is passed to the success callback.
$.ajax({
type: "POST",
url: '<?php echo get_template_directory_uri(); ?>/MYPAGE.php',
data: { sort_order : jsonString },
cache: false,
success: function(responseData) {
// consider using console.log for these kind of things.
alert("Data recived: " + responseData);
}
})
You'll see whatever you echo from the PHP code in this alert. Only then you can say if you received nothing.
Also, json_decode will return a JSON object (or an array if you tell it to). You can not echo it out like you have done here. You should instead use print_r for this.
$request = json_decode($_POST['sort_order']);
print_r($request);
And I believe sort_order in the javascript code is empty just for this example and you are actually sending something in your actual code, right?
the problem is in your url, javascript cannot interprate the php tags, what I suggest to you is to pass the "get_template_directory_uri()" as a variable from the main page like that :
<script>
var get_template_directory_uri = "<?php get_template_directory_uri() ?>";
</script>
and after, use this variable in the url property.
Good luck.
I hope it helps

Extract Json response

I am trying to to extract a Json response in jquery sent from a php file.
This is the .js code:
$.ajax({
url: 'index.php?page=register', //This is the current doc
type: 'POST',
datatype: 'json',
data: {'userCheck': username},
success: function(data){
// Check if username is available or not
},
error: function(){
alert('Much wrong, such sad');
}
});
This is the response from the php file:
if($sth->fetchColumn()!=0){
//$response = array("taken");
$response = array("username"=>"taken");
echo json_encode($response);
//echo '{"username':'taken"}';
}else{
//$response = array("available");
$response = array("username"=>"available");
echo json_encode($response);
//echo '{"username":"available"}';
}
I have tried all combinations I can think of in both files, but nothing seems to work. It is a simple check for a username in the database. If I console log the data I get from the response, I get this:
{"username":"available"}<!DOCTYPE html>
// The rest of the page html
So the info is there, but how do I access it? I have tried several syntaxes found around the internet, but no luck so far. I seem to recall that a json response only can contain valid json, so is the problem the html? I don't think I can avoid this due to the structure of my application, so hopefully it is possible to access the json with my present structure.
in you Ajax
EDIT:
change
datatype:"json",
the case of parameter name was not respected, the t must be T
dataType:"json",
now retry please
$.ajax
({
url: 'index.php?page=register', //This is the current doc
type: 'POST',
dataType: 'json',
data: {'userCheck': username},
success: function(data)
{
// Check if username is available or not
switch(data.username)
{
case "available":
// do you want
break;
case "taken":
// do you want
break;
}
},
error: function()
{
alert('Much wrong, such sad');
}
});
in PHP
simply that, and don't forget to exit; to avoid include html page in your json response !
This is the code coming after the }".... who break your json output
and make it unreadable by javascript (worste, it simply break your javascript !)
echo json_encode(["username"=> ($sth->fetchColumn()!=0) ? "taken":"available"]);
exit;
When you're responding to an AJAX call, you should just return the JSON response, not the HTML of the page. Add:
exit();
after this code so you don't display the HTML after the JSON.
In the JS code, use if (data.username == 'available') to tell whether the username is available.
The other problem in your code is that you have a typo here:
datatype: 'json',
It should be dataType, with an uppercase T.
You can also put:
header("Content-type: application/json");
before echoing the JSON in the script, and jQuery will automatically parse the response.
Also you can set request headers in your jQuery ajax call beforeSend function like follows
beforeSend: function (xhr) {
xhr.setRequestHeader('Content-Type', 'application/json;charset=utf-8');
xhr.setRequestHeader('Accept', 'application/json');
}
So you're strictly declaring the data type to be json

Posting JSON string to PHP page

Okay, I'm having some suicidal issues posting a JSON string to a PHP page. I have literally been through the top ten results on Google and plenty of SO questions related to my problem, but still can't work out what I'm doing wrong.
I have multiple forms on a page and want to collect all form fields, turn them into a JSON string and post them to a PHP page, where a script iterates each item and updates the relevant database tables.
This is my jQuery/JS script to collect the data from all the forms:
var photo_annotations = {};
$('form').each(function(i) {
var id = $(this).attr('id');
photo_annotations[id] = {
caption: $('#'+id+'_caption').val(),
keywords: $('#'+id+'_keywords').val(),
credit: $('#'+id+'_credit').val(),
credit_url: $('#'+id+'_credit_url').val()
};
});
If I console.log my photo_annotations object, this is what is produced, based on a two form example:
({11:{caption:"Caption for first photo.", keywords:"Keyword1,
Keyword2, Keyword3", credit:"Joe Bloggs",
credit_url:"www.a-domain.com"}, 12:{caption:"Caption for Lady Gaga.",
keywords:"Keyword3, Keyword4", credit:"John Doe",
credit_url:"www.another-domain.com"}})
I then need to POST this as a string/JSON to a PHP page, so I've done this:
$.ajax({
type: 'POST',
dataType: 'html',
url: 'ajax/save-annotations.php',
data: { data: JSON.stringify(photo_annotations) },
contentType: "application/json; charset=utf-8",
success: function(data) {
if (data) {
$('#form_results').html(data);
} else {
alert("No data");
}
}
});
And on my PHP page, I've got this:
<?php
//print_r($_POST['data']);
$decoded = json_decode($_POST['data'],true);
print_r($decoded);
?>
Now, this isn't the only thing I've tried. I've tried to remove all the JSON settings from the AJAX script, in a bid to just send a pure string. I've tried removing contentType and JSON.stringify but still won't go. My PHP page just can't get the data that I'm sending.
Please help push me in the right direction. I've got to the point where I can't remember all the variations I've tried and this little script is now on day 2!
MANAGED TO FIX IT
I rewrote my AJAX function and it worked. I have no idea what was going wrong but decided to test my AJAX function with a very basic data string test=hello world and found that no POST data could be read from the PHP page, even though Firebug says that the page did in fact receive post data matching what I sent. Very strange. Anyway, this is the revised AJAX script:
var the_obj = JSON.stringify(photo_annotations);
var post_data = "annotations="+the_obj;
$.ajax({
url: 'ajax/save-annotations',
type: 'POST',
data: post_data,
dataType: 'html',
success: function(data) {
$('#form_results').html(data);
}
});
Try:
$.ajax({
// ...
data: { data: JSON.stringify(photo_annotations) },
// ...
});
If you just set the "data" property to a string, then jQuery thinks you want to use it as the actual query string, and that clearly won't work when it's a blob of JSON. When you pass jQuery an object, as above, then it'll do the appropriate URL-encoding of the property names and values (your JSON blob) and create the query string for you. You should get a single "data" parameter at the server, and it's value will be the JSON string.
Try urldecode or rawurldecode as follows:
<?php
$decoded = json_decode(urldecode($_POST['data']), true);
print_r($decoded);
?>
I rewrote my AJAX function and it now works. I have no idea what was going wrong but decided to test my AJAX function with a very basic data string test=hello world and found that no POST data could be read from the PHP page, even though Firebug says that the page did in fact receive post data matching what I sent. Very strange. Anyway, this is the revised AJAX script:
var the_obj = JSON.stringify(photo_annotations);
var post_data = "annotations="+the_obj;
$.ajax({
url: 'ajax/save-annotations',
type: 'POST',
data: post_data,
dataType: 'html',
success: function(data) {
$('#form_results').html(data);
}
});
The only thing I can think of is that the order of AJAX settings needed to be in a particular order. This is my old AJAX script which does not send POST data successfully - well it does send, but cannot be read!!
var the_obj = JSON.stringify(photo_annotations);
var data_str = "annotations="+the_obj;
$.ajax({
type: 'POST',
dataType: 'html',
data: data_str,
url: 'ajax/save-annotations.php',
success: function(data) {
$('#form_results').html(data);
}
});
in your ajax call try resetting the dataType to json
dataType: "json",
You wouldn't have to use the JSON.stringify() either. On your php script you won't have to decode [json_decode()] the data from the $_POST variable. The data will be easy readable by your php script.

how do i use the success function with an $.ajax call

I don't understand how the success function works in a $.ajax call with jquery.
for instance
$.ajax({
type: "POST",
url: "ajax.php",
data: "function=1",
success: function(data,response,jqxhr){
useReturnData(data /* ??? not sure how to use the data var */ );
}
};
ajax.php:
<?php
if ($_REQUEST['function'] == '1'){
$string = "this is the data i want to return and use";
}
?>
how do i use that data within the success function? No where seems to explain what the data parameter is, they just seem to use it ambiguously.
another side question, is the data: "function=1" related to the data as a parameter for the success function?
The data variable contains the output of your php file, so if in your php file you do:
echo "<p>success</p>";
data will contain <p>success</p>.
In your example you would change your php file to:
<?php
if ($_REQUEST['function'] == '1'){
$string = "this is the data i want to return and use";
}
// other stuff...
echo $string;
?>
The content of the data parameter depends on the type of the response. If the Content-Type is application/json, then it's parsed as JSON. If it's text/html or similar, the content is HTML. In your case, it looks like you're returning text. If you make your Content-Type header text/plain or similar, then data should just be a string.
To answer your second question, the data property for the Ajax request is something different; it specifies the request data that is sent. In other words, it's the query string if you have a GET request, and the post "form" variables if it's a POST request.
data is whatever is returned by the server side script, so in this case it would be
this is the data i want to return and use
Providing the if() condition is met.
Nobody really says what data contains because it can contain various different things, although it's always a string. Sometimes it's HTML, sometimes it's JSON and sometimes just a return message.
In your case, data will just be a string providing you echo the string out in your server side script.
The easiest way is to load the data into some placeholder element (div?)
E.G.
$.ajax({
type: "POST",
url: "ajax.php",
data: "function=1",
success: function(data,response,jqxhr){
$('div.selector').load(data);
}
};

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