Passing JSON object to PHP with jQuery AJAX

Question

I have 3 different JSON objects I want to concatenate and send over to a PHP file with jQuery AJAX. I can retrieve the JSON object in the PHP file, but cannot figure out how to loop through the results.

Here's what I have so far:

 //my 3 JSON objects:
 var json_obj_1{
 "test1_key":"test1_val",
 "test2_key":"test2_val",
 "test3_key":"test3_val"
 }
 var json_obj_2{
 "test4_key":"test4_val"
 }
 var json_obj_3{
 "json_arr":[
 {
 "test1":"test2",
 "test3":"test4"
 }
 ]
 }
 //concat these to send over to the PHP file:
 var my_json_obj = json_obj_1.concat(json_obj_2);
 //I found if I didn't stringify obj_3 they didn't concatenate for some reason
 my_json_obj = my_json_obj.concat(JSON.stringify(json_obj_3));
 //my_json_obj now looks like this:
 {
 "test1_key":"test1_val",
 "test2_key":"test2_val",
 "test3_key":"test3_val"
 }
 {
 test4_key: test4_val
 }
 {
 "json_obj_3":[
 {"test1":"test2","test3":"test4"}
 ]
 }

Based on this question: Sending JSON to PHP using ajax, I don't stringify the final JSON object.

Here's the AJAX call to the PHP file:

$.ajax({
 url: 'my_php_file.php',
 data: {my_json_data: my_json_obj},
 type: 'POST',
 async: false,
 dataType: 'json',
 cache:false,
 success:function(data, textStatus, jqXHR){
 console.log('AJAX SUCCESS');
 }, 
 complete : function(data, textStatus, jqXHR){
 console.log('AJAX COMPLETE');
 }
});

This is what it looks like when retrieved in my PHP file:

echo $_POST['my_json_data'];
//outputs:
{
 "test1_key":"test1_val",
 "test2_key":"test2_val",
 "test3_key":"test3_val"
}
{
 test4_key: test4_val
}
{
 "json_obj_3":[
 {"test1":"test2","test3":"test4"}
 ]
}

Here's where I run in to problems. I want to be able to loop through this in a foreach. From what I have read (php: loop through json array) I have to decode the JSON object. However when I do this and loop through the results I get: " PHP Warning: Invalid argument supplied for foreach() ".

Even if I stringify the JSON object before sending it over to the PHP file I get the same problem. I have been banging my head against a brick wall for hours with this. Any help will be massively appreciated.

Thanks in advance.

Solved:

I was going wrong when concatenating my JSON objects following this question: Merge two json/javascript arrays in to one array. Instead I just put them together like so:

my_json_obj = '['+json_obj_1+','+json_obj_2+', '+JSON.stringify(json_obj_3)+']';

I then use json_decode in my PHP file which works a treat. http://json.parser.online.fr/ was invaluable in debugging my dodgy JSON. A great tool for JSON beginners.

Answer 1

You should be stringifying the whole object, try the following:

var my_json_obj = json_obj_1;
$.each(json_obj_2, function(key,value){
 my_json_obj[key]=value;
});
$.each(json_obj_3, function(key,value){
 my_json_obj[key]=value;
});

Ajax request:

data: {my_json_data: JSON.stringify(my_json_obj)}, 

PHP:

print_r(json_decode($_POST['my_json_data']));

Answer 2

As you say you need to decode the JSON, but your JSON is not well formed so I think the decode function is failing which causes the foreach error. There needs to be a , between objects, there's missing quotes around test4_val and it needs to be inside a singular object/array

You can check your JSON is wellformed at:-

http://json.parser.online.fr/

I think you want it to look more like:-

[{
"test1_key":"test1_val",
"test2_key":"test2_val",
"test3_key":"test3_val"
},
{
 "test4_key": "test4_val"
},
{
"json_obj_3":[
 {"test1":"test2","test3":"test4"}
]
}]

• MP_Webby: Thanks joep1978, for someone new to working with JSON pointing me to json.parser.online.fr was a great idea, solved a lot of problems.