Javascript JSON to PHP Array

Question

In my Javascript I am assembling and array like so:

    cachePHP = "'lat':'" + (Number(upDataItems[2])).toFixed(5)+"'";
cachePHP = cachePHP + ",'lon':'" + (Number(upDataItems[3])).toFixed(5)+"'";
cachePHP = cachePHP + ",'msec':'" + (parseInt(upDataItems[7])-parseInt(tz))+"'";
cachePHP = cachePHP + ",'spd':'" + (Number(upDataItems[0])).toFixed(1)+"'";
cachePHP = cachePHP + ",'hdg':'" + (Number(upDataItems[1])).toFixed(1)+"'";

dataCacheNew.push("{"+cachePHP+"}");

I add a varying amount of data to the array, could be 10 items, could be 100...I then shove this over to a PHP file. The PHP file is called from the Javascript like so:

"my.php?che="+JSON.stringify(dataCacheNew);

In the PHP, How can I grab the data so I can 'parse' it and post it to my database?

UPDATE 03/13: I still can't get this to work. Updated per suggestions below, and still...no workie!

My Javascript (jQuery):

     var jsonData = new Array();
    jsonData.push({
    lat: Number(56.34).toFixed(2),
    lon: Number(12.56).toFixed(2),
    msec: Number(123456799000).toFixed(2),
    spd: Number(4.2).toFixed(2),
    hdg: Number(1.4).toFixed(2)
}); 

jsonData.push({
    lat: Number(12.34).toFixed(2),
    lon: Number(34.56).toFixed(2),
    msec: Number(123456789000).toFixed(2),
    spd: Number(1.2).toFixed(2),
    hdg: Number(3.4).toFixed(2)
});


    $.ajax({
        url: 'insertCache.php',
        type: 'POST',
        data: "che="+JSON.stringify(jsonData),
        dataType: 'json',
        contentType: "application/json",
        success: function(result) {
            alert(result);
        }
    });

My PHP:

$cache = $_POST['che'];
    writeData($cache,"insertCache.txt");

$cacheDecode = json_decode($cache);
writeData($cacheDecode,"insertCacheDecode.txt");

insertCache.txt:

[{\"lat\":\"56.34\",\"lon\":\"12.56\",\"msec\":\"123456799000.00\",\"spd\":\"4.20\",\"hdg\":\"1.40\"},{\"lat\":\"12.34\",\"lon\":\"34.56\",\"msec\":\"123456789000.00\",\"spd\":\"1.20\",\"hdg\":\"3.40\"}]

insertCacheDecode.txt COMPLETELY BLANK

what gives?

Why are you using JSON in the first place? Why not just send the data as a query string to PHP? eg. my.php?lat=123&lon=456 — gen_Eric
– gen_Eric, Commented Mar 12, 2013 at 20:08
I want to post all the data to a file on the server, as well as the database. I have been posting each individual array element, one at a time, but with 500+ items, that gets slow... — Sam Grant
– Sam Grant, Commented Mar 12, 2013 at 20:12
You can post multiple things in a GET array. my.php?che[0][lat]=124&che[0][lon]=456&che[1][lat]=789&che[1][lon]=101, but this may actually be harder to create (without a library like jQuery), so JSON is ok here :) — gen_Eric
– gen_Eric, Commented Mar 12, 2013 at 20:14

jcubic · Accepted Answer · 2013-03-12 20:11:51Z

4

you can use code like this:

$array = json_decode($_GET['che']);

Note that you don't need to create strings, you can stringify nested object:

dataCacheNew.push({
    lat: (Number(upDataItems[2])).toFixed(5),
    lon: (Number(upDataItems[3])).toFixed(5),
    msec: (parseInt(upDataItems[7])-parseInt(tz)),
    spd: (Number(upDataItems[0])).toFixed(1),
    hdg: (Number(upDataItems[1])).toFixed(1)
});

edited Mar 12, 2013 at 20:11

answered Mar 12, 2013 at 20:01

jcubic

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4 Comments

Sam Grant Over a year ago

Currently I am doing this: $cache = $_GET['che']; $cacheArray=json_decode($cache); But when I do a $cacheCnt = count($cacheArray); $cacheCnt is equal to 0;

Sam Grant Over a year ago

Ok, tried to get this working this morning...No dice. I do get the data transferred OK. But still, my array in PHP is showing a size of 0.

jcubic Over a year ago

@SamGrant if you contatenate string to send get data (and not $.get jquery that allow to send object) then you may need to encode the array first using "my.php?che="+encodeURIComponent(JSON.stringify(dataCacheNew))

Sam Grant Over a year ago

In my PHP, I do a $cache = $_GET['che']; , then I write the $cache to a text file. The data in the text file looks to be OK:

[{\"rid\":3158,\"uid\":\"1\",\"bid\":\"1\"},{\"lat\":\"30.0\",\"lon\":\"-86.0\",\"msec\":1363165240000,\"spd\":\"4.3\",\"hdg\":\"53.6\"}]

. But doing a json_decode on the $cache, then checking the resulting array for a size, yeilds 0.

Ruan Mendes · Accepted Answer · 2013-03-12 20:05:05Z

1

Your JSON is invalid because you're using single quotes for your attribute names. And on top of that, you're stringifying your already badly encoded JSON.

Use the following instead

dataCacheNew.push({
    lat: Number(upDataItems[2]).toFixed(5),
    lon: Number(upDataItems[3]).toFixed(5),
    ...
});
"my.php?che=" + JSON.stringify(dataCahceNew);

answered Mar 12, 2013 at 20:05

Ruan Mendes

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Comments

gen_Eric · Accepted Answer · 2013-03-12 20:06:45Z

1

Do not try to build a JSON string by yourself. Languages have built-in methods for this. Instead build the object the way you want it, then encode it as JSON.

var cachePHP = {
    lat: (Number(upDataItems[2])).toFixed(5),
    lon:(Number(upDataItems[3])).toFixed(5),
    msec: (parseInt(upDataItems[7])-parseInt(tz)),
    spd: (Number(upDataItems[0])).toFixed(1),
    hdg: (Number(upDataItems[1])).toFixed(1),
};

dataCacheNew.push(cachePHP);

console.log(JSON.stringify(dataCacheNew));

answered Mar 12, 2013 at 20:06

gen_Eric

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