Javascript json parsing of php response

Question

I'm working on a project and use ajax to update some informations in forms.

Here is my ajax function :

function update_ad() {
    var project_name = document.getElementById("mol_project").value;
    if (project_name !== '') {
        $.ajax({
            type: 'POST',
            url: "controllers/get_project.php",
            data: {project_name: project_name},
            dataType: 'text',
            success: function (data) {
                var result = JSON.parse(data);

            }
        });
    }
}

On my development environement everything works fine. The function get the json text from php server and parse it so I can use data after that.

But on my production environement, I receive a parsing error :

SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

Here is the received Json :

{"project_name":"Jaguar","project_ORB_code":null,"project_manager":null,"project_abbr":"JR","project_mol_index":"2","project_comment":null}

Jquery, apache and php version are the same on both environements. I guess it's a server configuration issue but I can't figure out where it is.

Do you get any PHP errors on production? Notices, something? — Andrei, Jul 01 '15 at 09:18
Try setting `dataType: 'json'` and then you don't need to use `JSON.parse()` as jQuery will provide you the deserialised object in the `data` parameter. Also, are you sure that is the exact response you're receiving? Check the network tab of the console to confirm it. — Rory McCrossan, Jul 01 '15 at 09:18
Unrelated, but, try setting header in your PHP just before you echo your JSON -> `header("Content-type: application/json; charset=utf-8");` — lshettyl, Jul 01 '15 at 09:29

anilviradiya · Answer 1 · 2015-07-01T09:41:09.540

1

replace dataType: 'text' to dataType: json,

Look at the spec for JSON (easily understood version here: http://json.org/). There is nowhere that says that parenthesis are valid. ({"foo": true}), for example will never parse. It may be evaled as it is valid javascript, but javascript is not JSON.

edited Jul 01 '15 at 09:41

answered Jul 01 '15 at 09:35

anilviradiya

139
7

Do you even understand why is it throwing an error? Your answer has no effect. – Praveen Kumar Purushothaman Jul 01 '15 at 09:36
when use the php that type you will use data is a php array encoded to json using json_encode($myarray) – anilviradiya Jul 01 '15 at 09:43
its tell you that hows the json structure is that.your simply mistakes in your code gives you that type of error. – anilviradiya Jul 01 '15 at 10:16
It simply tells you that you don't know English and you didn't understand the situation. Read my answer and let's see if you understand! Please delete your answer, which is nowhere near correct! – Praveen Kumar Purushothaman Jul 01 '15 at 10:25

score 0 · Accepted Answer · edited May 23 '17 at 10:26

0

Okay, in your JSON, there's a UTF-8 BOM in the front. Can you find the difference between:

{"project_name":"Jaguar","project_ORB_code":null,"project_manager":null,"project_abbr":"JR","project_mol_index":"2","project_comment":null}

And:

{"project_name":"Jaguar","project_ORB_code":null,"project_manager":null,"project_abbr":"JR","project_mol_index":"2","project_comment":null}

Where the latter is a valid JSON. Check it out with JSONLint. You need to make sure that the output you are receiving is free of UTF-8 BOM.

When I tried using the encodeURI() function on the JSON, it gave me this output:

encodeURI(' {"pr'); // "%20%EF%BB%BF%7B%22pr" - Wrong one!
encodeURI(' {"pr'); // "%20%7B%22pr"          - Correct one!

We can make use of encodeURI to detect the anamolies and fix it in the client side. I am working on a solution.

The unicode signature, if you see, is EF BB BF, which is explained in this article. We can make use of this signature and try to correct it.

If you have the access to the PHP source, try setting the right headers:

header("Content-type: application/json; charset=utf-8");

edited May 23 '17 at 10:26

Community

1
1

answered Jul 01 '15 at 09:20

Praveen Kumar Purushothaman

164,888
24
203
252

Ok my production server send invalid Json with exactly the same piece of code... I don't know how to free my output from BOM... – Xavier Doustaly Jul 01 '15 at 09:26
@XavierDoustaly I am figuring out a way to catch in the client. Behold. – Praveen Kumar Purushothaman Jul 01 '15 at 09:27
Interesting. How did you guess it's a BOM issue? – TaoPR Jul 01 '15 at 09:40
@TaoP.R. I actually explained that in my answer. See the `EF BB BF` part. – Praveen Kumar Purushothaman Jul 01 '15 at 10:01
@PraveenKumar I'm now trying to correct the unicode signature. I'll look later for a way to convert all my project files to utf8- without BOM – Xavier Doustaly Jul 01 '15 at 10:09
1

Thanks it worked : `var encoded_data = encodeURI(data); var encoded_data_wo_bom = encoded_data.replace("%EF%BB%BF", ""); var decoded_data = decodeURI(encoded_data_wo_bom); alert(encoded_data_wo_bom);` – Xavier Doustaly Jul 01 '15 at 10:12

Javascript json parsing of php response

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