Develop Reference

Properly returning a JSON object with an embedded JS function

Updated Post
I have a solution for that problem which works with me so far (only tested on Firefox).
My main goal was to dynamically update a Flot graph with Ajax. I also need to dynamically update the axis styles and you can do this by the tickFormatter option. To avoid the problems I previously had, I simply insert the desired return string in the PHP array and JSON encode that array. After returned to the Ajax function I create a new function using the javascript Function() constructor (Link). I hope this helps someone.
Ajax
$.ajax({
url: 'someControllerWhichCreatesJSONdata',
data: 'some Value',
type: 'post',
cache: false,
datatype: 'json'
})
.success(function(data) {
var datas = data[0]; // fetch data array
var options = data[1]; // fetch options array
var xReturn = options.xaxes[0].tickFormatter; // fetch return string
var yReturn = options.yaxes[0].tickFormatter;
var xFunc = new Function("val", "axis", xReturn); // create function
var yFunc = new Function("val", "axis", yReturn);
options.xaxes[0].tickFormatter = xFunc; // update tickFormatter with function
options.yaxes[0].tickFormatter = yFunc;
$.plot($("#yw0"), datas, options);
})
.error(function(data) {
$("#error").html(data.responseText); // show error in separate div
});
PHP array
$options = array(
'legend' => array(
'position' => 'nw',
'show' => true,
'margin' => 10,
'backgroundOpacity' => 0.5
),
'grid' => array(
'clickable' => true,
'hoverable' => true
),
'pan' => array('interactive' => true),
'zoom' => array('interactive' => true),
'axisLabels' => array('show' => true),
'xaxes' => array(
array(
'axisLabel' => 'someUnit',
'tickFormatter' => 'return "foo bar"' // enter whatever return value you need
)
),
'yaxes' => array(
array(
'axisLabel' => 'someUnit',
'tickFormatter' => 'return "foo bar"'
)
)
);
I skip the data array as it looks similar. Both arrays get combined and JSON encoded.
public function actionSomeControllerWhichCreatesJSONdata() {
$returnArray = array($data, $options);
echo json_encode($returnArray);
return true;
}
The resulting array looks like the one I've posted in the bottom of this post.
Original Post
I'm trying for hours now, but I can't get this to work.
I have an Ajax request which gets a JSON object as return value on success. This works fine as long as I don't use a JS function in my JSON array. So my JSON array looks as follows (after json_encode):
[{
"data": [{
{1,2},
{3,4},
}],
"function": "function(){return \"foo bar\";}"
}]
In order to get rid of the "'s in the function string. I use str_replace and replace the quoted string with an unquoted one. This then looks like so:
[{
"data": [{
{1,2},
{3,4},
}],
"function": function(){return "foo bar";}
}]
The plain json_encode works fine and my Ajax function reads it as a JSON object. After I replace the string it turns out that the return value is no longer a JSON object but a plain text string. I've tried to parse the string again with jquery.parseJSON() but this results in the syntax error:
SyntaxError: JSON.parse: unexpected keyword at line 1 column 396 of the JSON data
Ajax function:
$.ajax({
url: 'someControllerWhichCreatesJSONdata',
data: 'some Value',
type: 'post',
cache: false,
datatype: 'json' // or text when trying to parse
})
.success(function(data) {
console.log(data);
var dat = jQuery.parseJSON(data); // trying to parse (only when dataType: "text")
var datas = dat[0]; // or data[0] when datType = json
var options = dat[1]; // ---
$.plot($("#yw0"), datas, options); // trying to update a FLOT window
})
.error(function(data) {
console.log("error");
$("#error").html(data.responseText); // show error in separate div
});
So when using this function and setting the return type to "json", it produces an error. If the return type is "text" and I try to parse the string I get the error above. Is there any solution for this problem or am I doing something completely wrong?
Thank's for your help!
UPDATE
Sorry of course my JSON data is not valid! As I said, my JSON object gets created by json_encode which I guess should get the syntax right. The plain array after son_encode looks like:
[[{
"data":[[0.0042612,0.0042612]],
"label":"WISE.W3: Cutri et. al 2012",
"lines":{"show":false},
"points":{"show":true,"radius":3}}],
{
"legend": {
"position":"nw",
"show":true,
"margin":10,
"backgroundOpacity":0.5},
"grid": {
"clickable":true,
"hoverable":true},
"pan":{"interactive":true},
"zoom":{"interactive":true},
"axisLabels":{"show":true},
"axisLabel": {
"unit":"Jy",
"id":null,
"name":null},
"tickFormatter":"$tickFormatter$",
"position":"right"
}]
and after str_replace I get
[[{
"data":[[0.0042612,0.0042612]],
"label":"WISE.W3: Cutri et. al 2012",
"lines":{"show":false},
"points":{"show":true,"radius":3}}],
{
"legend": {
"position":"nw",
"show":true,
"margin":10,
"backgroundOpacity":0.5},
"grid":{"clickable":true,"hoverable":true},
"pan":{"interactive":true},
"zoom":{"interactive":true},
"axisLabels":{"show":true},
"axisLabel":{"unit":"Jy","id":null,"name":null},
"tickFormatter":function(val, axis){return val.toExponential(2)},
"position":"right"
}]

Adeno pointed it out already, your JSON syntax is not valid.
Please try to validate your JSON with a linter, like http://jsonformatter.curiousconcept.com/
This is a bit better:
[{"data":[["1","2"],["3","4"]],"function":"function(){return \"foo bar\";}"}]
And the other thing is: you should not manually deserialize the JSON. All newer versions of jQuery will automatically deserialize JSON based on the response's content-type header.
You already set dataType to json for the ajax request.
The response is JSON and will be de-serialized.
So you can directly use
.success: function(response) {
console.log(response.data);
console.log(response.function);
}
Answer for the questions/issue from the comments:
Now you created invalid JSON again, because "tickFormatter" : function(val, axis){return val.toExponential(2)}, misses the quotes around the function string.
Before you insert the string with str_replace(), you need to take care of escaping and quoting.
You may need a little helper function, which properly escapes a string - to be valid JSON.
you need to use str_replace() correctly: not replacing the outer quotes, just the inner $tickFormatter$.
Wait.. i will provide an example:
// we already have an array, which is JSON encoded
// now you want to insert additional JSON content.
// therefore we use a token replace approach.
// valid JSON - with $token$
$json = '[{"data":[["1","2"],["3","4"]],"tickFormatter":"$tickFormatter$"}]';
// the (future) javascript function is a string.
// it's not properly escaped or quoted to be JSON
// this allows for copy and pasting JS into PHP
$unescaped_functionString = 'function(){return "foo bar";}';
// in order escapre properly, we need a json escaping helper
/**
* #param $value
* #return mixed
*/
function escapeJsonString($value) { # list from www.json.org: (\b backspace, \f formfeed)
$escapers = array("\\", "/", "\"", "\n", "\r", "\t", "\x08", "\x0c");
$replacements = array("\\\\", "\\/", "\\\"", "\\n", "\\r", "\\t", "\\f", "\\b");
$result = str_replace($escapers, $replacements, $value);
return $result;
}
// then we escape the function string
$functionString = escapeJsonString($unescaped_functionString);
// now its ready to be inserted into the existing JSON,
// where token $tickFormatter$ is defined
// the token must be in single quotes. you replace just the $token$ and not "$token$".
$json = str_replace('$tickFormatter$', $functionString, $json);
echo $json;
// The result is valid JSON again:
// [{"data":[["1","2"],["3","4"]],"tickFormatter":"function(){return \"foo bar\";}"}]
Next step:
The ajax request is made, the json data is transferred to the client and you want to execute the function you passed in.
So the new question is "How to call/exec a JavaScript function from a string - without using eval?"
In general tunneling is a bad practice, see: Is it valid to define functions in JSON results?
Anyway, there a different ways to do this:
Referencing: http://everythingfrontend.com/posts/studying-javascript-eval.html
eval() - evil, but works.
setTimeout()
setTimeout(" function ", 0);
new Function()
var codeToExecute = "My.Namespace.functionName()";
var tmpFunc = new Function(codeToExecute);
tmpFunc();
document.write
document.write('<script> JS </script>')
data URI
var s = document.createElement('script');
s.src = 'data:text/javascript,' + encodeURIComponent('alert("lorem ipsum")')
document.body.appendChild(s);

JSON cannot contain functions like this.
You can however use Javascript to inject the function into the DOM, so what you want to do is skip the str_replace part and simply create a <script type="text/javascript"></script> element in the DOM and insert the data.function property into there.

JSON format issue in JavaScript

Following is my JavaScript code to get JSON data:
$(document).ready(function()
{
$.support.cors = true;
$.getJSON('http://example.com/root_dir/test_json.php', function(data1)
{
alert("data1= "+data1);
});
});
but the above alert shows me JSON in following format-
If I hit my php script URL in browser, it shows JSON data in expected formate as shown below-
[{"name":"AB","std":"7","number":"82"},{"name":"CD","std":"9","number":"90"},{"name":"PQ","std":"12","number":"79"}]
Following is my test_json.php code-
<?php
//Create an array
$json_response = array();
$row_array['name'] = 'AB';
$row_array['std'] = '7';
$row_array['number'] = '82';
array_push($json_response,$row_array);
$row_array['name'] = 'CD';
$row_array['std'] ='9';
$row_array['number'] = '90';
array_push($json_response,$row_array);
$row_array['name'] = 'PQ';
$row_array['std'] = '12';
$row_array['number'] = '79';
//push the values in the array
array_push($json_response,$row_array);
echo json_encode($json_response);
?>

getJSON decodes the JSON into a JavaScript data structure.
Concatenating it with a string will implicitly call toString() on it. That will turn arrays in to a comma-seperated format and plain objects into "[Object object]".
Nothing is going wrong. That is the expected behaviour.
If you want to see the data in JSON format, then use JSON.stringify(data) or use .ajax instead of .getJSON and access the raw text data in the jqXHR object.

Unable to post Javascript array via jQuery ajax

I am extremely reluctant to ask this question as I know it is something really stupid I am missing, but I simply cannot get this to work. Code below:
<script>
var formArray = new Array();
formArray['start'] = "one";
formArray['stopat'] = "two";
formArray['stop_at'] = "three";
$('#my_button').click(function() {
$.ajax({
type: "POST",
url: "scheduler.php",
data: formArray,
success: function(response){
console.log(response);
}
});
});
</script>
Server side PHP Script scheduler.php
<?php
print_r($_POST);
?>
All I get back logged to the console is an empty array:
Array
(
)
If I console.log formArray within the click function it shows the complete array just fine. So why is it not posting it to my PHP file?
Thanks in advance

Changing Array() to Object() would work as well.
You would get:
Array
(
[start] => one
[stopat] => two
[stop_at] => three
)

You are adding string properties to an array, which is for storing numeric indices.
Use an object instead:
var formArray = {};
formArray['start'] = "one";
formArray['stopat'] = "two";
formArray['stop_at'] = "three";
jQuery will iterate over the indices in an array, using a for (var i = 0; i < formArray.length; ++i) loop, which will completely miss any properties you've added to the array.
Also, new Array should have been [] (as {} should be preferred over new Object). Don't use the new X method of initialization for built-in types. (Crockford, The Good Parts)

JavaScript Arrays are designed to hold an ordered sequence of items with integer keys. When jQuery converts a data structure into Form URL Encoded data and encounters an array, it will iterate over those integer keys and not over named keys.
Use an Object if you want to have named keys.
Change new Array() to newObject()

Edit your Ajax like this and see if it works: data: {data: formArray}, dataType: 'JSON'
$.ajax({
type: "POST",
url: "scheduler.php",
data: {data : formArray},
dataType: 'JSON'
success: function(response){
console.log(response);
}
});
PHP:
print_r($_POST['data']);

How could I JSON.parse nested object inside array

I'm trying to pass this structure on a PHP/Ajax response:
{"asn":"167", "jte":"[[1381547700000,0.0], [1381548600000,0.0]]", "visitas":"[{x:1380596400000,text:'HELLO WORLD.',title:'X'}]"}
But JSON.parse returns an error.
SyntaxError: JSON.parse: expected property name or '}'
Without the "visitas" object everything runs fine. Is it possible to "nest" as this?
UPDATE:
Ajax Part:
$.ajax({
type: 'post',
url: 'cxxx.php',
data: { asn: asn },
success: function(p){
p = JSON.parse(p);
jusante=JSON.parse(p.jusante);
montante=JSON.parse(p.montante);
vazao=JSON.parse(p.vazao);
minima=JSON.parse(p.minima);
fator=JSON.parse(p.fator);
visitas=JSON.parse(p.visitas)
and PHP part:
$v="[";
while(odbc_fetch_row($res)){
$datavisita = odbc_result($res, "DATA_VISITA");
$descricaovisita = odbc_result($res, "DESCRICAO_VISITA");
$login = odbc_result($res, "LOGIN");
$descricaomotivo = odbc_result($res, "DESCRICAO_MOTIVO");
$id_motivo=odbc_result($res, "ID_MOTIVO");
$datavisita=date("U", strtotime($datavisita))*1000;
$descricaovisita=preg_replace("/\r|\n/", "", $descricaovisita);
$v.="{x:$datavisita,text:'$descricaovisita',title:'$id_motivo'}, ";
}
$v=rtrim($v,", ")."]";
echo "{\"asn\": \"$asn\", \"description\": \"$description\", \"jusante\": \"$o\", \"montante\": \"$m\", \"vazao\": \"$f\", \"minima\": \"$mn\", \"fator\": \"$fp\", \"visitas\": \"$v\" }";

the Json you are using is valid, I checked it on JSONLint, so your problem might be with serialization, just make sure your "visitas" object is serialized correctly because the problem might be happening because it's the only member with an object value inside

Remove the quotes around the visitas array:
var json = JSON.parse('{"asn": "167","jte": "[[1381547700000,0.0], [1381548600000,0.0]]", "visitas": [{"x": "1380596400000", "text":"HELLOWORLD.","title":"X"}]}');

While the outermost JSON object looks fine, there might be a problem with the nested one!
If you are trying to parse the nested JSON element "visitas" you might have a problem in the fact that your property names (e.g. x, text and title) are not enclosed in quotation marks ("). This is of course a bit tricky since you are trying to include the visitas element as a string.
A solution might be to include the visitas element as a proper JSON element instead.

You need to escape the single quotes. I imagine you are surrounding the above in single quotes when you pass it to JSON.parse.
The below works.
JSON.parse('{"asn":"167", "jte":"[[1381547700000,0.0], [1381548600000,0.0]]", "visitas":"[{x:1380596400000,text:\'HELLO WORLD.\',title:\'X\'}]"}');
Note the slashes before the single quotes inside the string.

I would do the following:
var jsondata = {
"asn": "167",
"jte": "[[1381547700000,0.0], [1381548600000,0.0]]",
"visitas": "[{x:1380596400000,text:'HELLO WORLD.',title:'X'}]"
};
jsondata = JSON.stringify(jsondata);
then send it to php
var postdata = { data : jsondata};
var url = "<?php echo base_url(); ?>"+"test";
$.post(url, postdata, function(result){
console.log(result);
});

sice your php result is echoed the wrong way you should fix that first. Create arrays so that you can easily use the JSON_ENCODE function like so:
$array = array(
"asn" => "test_asn",
"description" => "description_test",
"jusante" => "jusante_test",
"montante" => "montante_test",
"vazao" => "vazao_test",
"minima" => "minima_test",
"fator" => "fator_test",
"visitas" => "visitas_test"
);
$json = json_encode($array);
echo $json;

JSON parsing with javascript

I am trying to parse a JSON response from a server using javascript/jquery. This is the string:
{
"status": {
"http_code": 200
},
"contents": "HTTP/1.1 200 OK\r\nTransfer-Encoding: chunked\r\nDate: Tue, 07 Feb 2012 08:14:38 GMT\r\nServer: localhost\r\n\r\n {\"response\": \"true\"} "
}
I need to get the response value.
Here is what I am trying in the success function of my POST query:
success: function(data) {
var objstring = JSON.stringify(data);
var result = jQuery.parseJSON(JSON.stringify(data));
alert(objstring);
var result1 = jQuery.parseJSON(JSON.stringify(result.contents[0]));
alert(result1.response);
alert(data.contents[0].response);
But so far nothing I have tried returns the correct result' I keep getting undefined, however the contents of objstring are correct and contain the JSON string.

First, set dataType to json. Then data will be an object containing the data specified:
dataType: 'json',
success: function(data) {
alert(data.status.http_code);
alert(data.contents);
}
Read the API for more explanation of what these properties achieve. It would also probably help you to use a Javascript console, so you can use console.log, a much more powerful tool than alert.

Seems like the JSON response itself contains JSON content. Depending on how you call the jQuery.post() method, you'll either get a string or a JSON object. For the first case, use jQuery.parseJSON() to convert the string to a JSON object:
data = jQuery.parseJSON(theAboveMentionedJsonAsString);
Next, get everything inside the contents property after the first \r\n\r\n:
var contentBody = data.contents.split("\r\n\r\n", 2)[1];
Lastly, convert that string to JSON and get the desired value:
var response = jQuery.parseJSON(contentBody).response;
// "true"

try it this way:
var objstring=JSON.stringify(data);
var result=JSON.parse(objstring);
alert("http code:" + result.status.http_code);
alert("contents:" + result.contents);