Issue with json_decode and json_encode - it adds keys to original JSON
Posting this here since it'd be too ugly in a comment, but this is what I get on PHP 5.3.6 after doing a echo json_encode(json_decode('...your json...', true));
:
{"product": [
{"id":"1","title":"producta","size":"50","weight":"1000","price":"30","quantity":"100","cartID":"1"},
{"id":"1","title":"producta","size":"50","weight":"1000","price":"30","quantity":"100","cartID":"2"}
]}
Note the lack of extra keys. Are you doing any manipulations on the decoed array before re-encoding?
add new field and data with php to json encoded object with quotes removed
You cant add data to the json string, because its a string.
Add the data before you json encode it:
$data['message']=1;
$data_string = json_encode($data);
Or if the original php object $data
is out of scope by this point, you must decode to php object, add data and then encode back to json:
$data = json_decode($data_string);
$data['message']=1;
$data_string = json_encode($data);
How to maintain object state after JSON Encode/Decode in PHP
From json-decode documentation:
When TRUE, returned objects will be converted into associative arrays
You using it so the object are convert into array - if you want it to be object (aka {}
) just remove the true
from the line:
$decodeData = json_decode($encodeData,true);
To:
$decodeData = json_decode($encodeData);
And by the way, json-encode doesn't get true
as second argument, I think you wanted JSON_FORCE_OBJECT
JSON encode and decode on PHP
Don't have enough rep to comment on other peoples comments
To get the info out after you've processed it with
$decoded = json_decode( $responseJSON, TRUE );
You can access all the information inside of it as normal.
do a
var_dump($decoded);
just incase it add's levels you wouldn't expect
Then just proceed as usual
echo $decoded['status']
echo $decoded['content']['sessionid']
How to prevent json_encode to encode existing json
I'd recommend decoding the json when appending it to data key in the array and later encode everything to json. Like this:
$json = '{ some already encoded json }';
$data = [
'success' => $this->isSuccess(),
'message' => $this->getMessage(),
'statusCode' => (string)$this->getStatusCode(),
'data' => json_decode($json)
];
json_encode($data);
How to extract and access data from JSON with PHP?
Intro
First off you have a string. JSON is not an array, an object, or a data structure. JSON is a text-based serialization format - so a fancy string, but still just a string. Decode it in PHP by using json_decode()
.
$data = json_decode($json);
Therein you might find:
- scalars: strings, ints, floats, and bools
- nulls (a special type of its own)
- compound types: objects and arrays.
These are the things that can be encoded in JSON. Or more accurately, these are PHP's versions of the things that can be encoded in JSON.
There's nothing special about them. They are not "JSON objects" or "JSON arrays." You've decoded the JSON - you now have basic everyday PHP types.
Objects will be instances of stdClass, a built-in class which is just a generic thing that's not important here.
Accessing object properties
You access the properties of one of these objects the same way you would for the public non-static properties of any other object, e.g. $object->property
.
$json = '
{
"type": "donut",
"name": "Cake"
}';
$yummy = json_decode($json);
echo $yummy->type; //donut
Accessing array elements
You access the elements of one of these arrays the same way you would for any other array, e.g. $array[0]
.
$json = '
[
"Glazed",
"Chocolate with Sprinkles",
"Maple"
]';
$toppings = json_decode($json);
echo $toppings[1]; //Chocolate with Sprinkles
Iterate over it with foreach
.
foreach ($toppings as $topping) {
echo $topping, "\n";
}
Glazed
Chocolate with Sprinkles
Maple
Or mess about with any of the bazillion built-in array functions.
Accessing nested items
The properties of objects and the elements of arrays might be more objects and/or arrays - you can simply continue to access their properties and members as usual, e.g. $object->array[0]->etc
.
$json = '
{
"type": "donut",
"name": "Cake",
"toppings": [
{ "id": "5002", "type": "Glazed" },
{ "id": "5006", "type": "Chocolate with Sprinkles" },
{ "id": "5004", "type": "Maple" }
]
}';
$yummy = json_decode($json);
echo $yummy->toppings[2]->id; //5004
Passing true
as the second argument to json_decode()
When you do this, instead of objects you'll get associative arrays - arrays with strings for keys. Again you access the elements thereof as usual, e.g. $array['key']
.
$json = '
{
"type": "donut",
"name": "Cake",
"toppings": [
{ "id": "5002", "type": "Glazed" },
{ "id": "5006", "type": "Chocolate with Sprinkles" },
{ "id": "5004", "type": "Maple" }
]
}';
$yummy = json_decode($json, true);
echo $yummy['toppings'][2]['type']; //Maple
Accessing associative array items
When decoding a JSON object to an associative PHP array, you can iterate both keys and values using the foreach (array_expression as $key => $value)
syntax, eg
$json = '
{
"foo": "foo value",
"bar": "bar value",
"baz": "baz value"
}';
$assoc = json_decode($json, true);
foreach ($assoc as $key => $value) {
echo "The value of key '$key' is '$value'", PHP_EOL;
}
Prints
The value of key 'foo' is 'foo value'
The value of key 'bar' is 'bar value'
The value of key 'baz' is 'baz value'
Don't know how the data is structured
Read the documentation for whatever it is you're getting the JSON from.
Look at the JSON - where you see curly brackets {}
expect an object, where you see square brackets []
expect an array.
Hit the decoded data with a print_r()
:
$json = '
{
"type": "donut",
"name": "Cake",
"toppings": [
{ "id": "5002", "type": "Glazed" },
{ "id": "5006", "type": "Chocolate with Sprinkles" },
{ "id": "5004", "type": "Maple" }
]
}';
$yummy = json_decode($json);
print_r($yummy);
and check the output:
stdClass Object
(
[type] => donut
[name] => Cake
[toppings] => Array
(
[0] => stdClass Object
(
[id] => 5002
[type] => Glazed
)
[1] => stdClass Object
(
[id] => 5006
[type] => Chocolate with Sprinkles
)
[2] => stdClass Object
(
[id] => 5004
[type] => Maple
)
)
)
It'll tell you where you have objects, where you have arrays, along with the names and values of their members.
If you can only get so far into it before you get lost - go that far and hit that with print_r()
:
print_r($yummy->toppings[0]);
stdClass Object
(
[id] => 5002
[type] => Glazed
)
Take a look at it in this handy interactive JSON explorer.
Break the problem down into pieces that are easier to wrap your head around.
json_decode()
returns null
This happens because either:
- The JSON consists entirely of just that,
null
. - The JSON is invalid - check the result of
json_last_error_msg
or put it through something like JSONLint. - It contains elements nested more than 512 levels deep. This default max depth can be overridden by passing an integer as the third argument to
json_decode()
.
If you need to change the max depth you're probably solving the wrong problem. Find out why you're getting such deeply nested data (e.g. the service you're querying that's generating the JSON has a bug) and get that to not happen.
Object property name contains a special character
Sometimes you'll have an object property name that contains something like a hyphen -
or at sign @
which can't be used in a literal identifier. Instead you can use a string literal within curly braces to address it.
$json = '{"@attributes":{"answer":42}}';
$thing = json_decode($json);
echo $thing->{'@attributes'}->answer; //42
If you have an integer as property see: How to access object properties with names like integers? as reference.
Someone put JSON in your JSON
It's ridiculous but it happens - there's JSON encoded as a string within your JSON. Decode, access the string as usual, decode that, and eventually get to what you need.
$json = '
{
"type": "donut",
"name": "Cake",
"toppings": "[{ \"type\": \"Glazed\" }, { \"type\": \"Maple\" }]"
}';
$yummy = json_decode($json);
$toppings = json_decode($yummy->toppings);
echo $toppings[0]->type; //Glazed
Data doesn't fit in memory
If your JSON is too large for json_decode()
to handle at once things start to get tricky. See:
- Processing large JSON files in PHP
- How to properly iterate through a big json file
How to sort it
See: Reference: all basic ways to sort arrays and data in PHP.
PHP json_encode json_decode UTF-8
This is an encoding issue. It looks like at some point, the data gets represented as ISO-8859-1.
Every part of your process needs to be UTF-8 encoded.
The database connection
The database tables
Your PHP file (if you are using special characters inside that file as shown in your example above)
The
content-type
headers that you output
PHP decoding and encoding json with unicode characters
Judging from everything you've said, it seems like the original Odómetro
string you're dealing with is encoded with ISO 8859-1, not UTF-8.
Here's why I think so:
json_encode
produced parseable output after you ran the input string throughutf8_encode
, which converts from ISO 8859-1 to UTF-8.- You did say that you got "mangled" output when using
print_r
after doingutf8_encode
, but the mangled output you got is actually exactly what would happen by trying to parse UTF-8 text as ISO 8859-1 (ó is\x63\xb3
in UTF-8, but that sequence isó
in ISO 8859-1. - Your
htmlentities
hackaround solution worked.htmlentities
needs to know what the encoding of the input string to work correctly. If you don't specify one, it assumes ISO 8859-1. (html_entity_decode
, confusingly, defaults to UTF-8, so your method had the effect of converting from ISO 8859-1 to UTF-8.) - You said you had the same problem in Python, which would seem to exclude PHP from being the issue.
PHP will use the \uXXXX
escaping, but as you noted, this is valid JSON.
So, it seems like you need to configure your connection to Postgres so that it will give you UTF-8 strings. The PHP manual indicates you'd do this by appending options='--client_encoding=UTF8'
to the connection string. There's also the possibility that the data currently stored in the database is in the wrong encoding. (You could simply use utf8_encode
, but this will only support characters that are part of ISO 8859-1).
Finally, as another answer noted, you do need to make sure that you're declaring the proper charset, with an HTTP header or otherwise (of course, this particular issue might have just been an artifact of the environment where you did your print_r
testing).
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