JSON element returning NULL - php

Question

I am new to JSON and having a problem with checking at getting the error message when there is an error. My code works fine when the result is not an error, so I do somewhat understand what I am doing.
This is the error JSON that I am trying to parse:
{
"error": {
"message": "Unsupported get request.",
"type": "GraphMethodException",
"code": 100
}
}
Here is my code that fails:
$jsonurl = "http://graph.facebook.com/JubilationDanceMinistry";
//valid $jsonurl = "http://graph.facebook.com/WhitworthACM";
$json = file_get_contents($jsonurl,0,null,null);
$json_output = json_decode($json);
var_dump($json_output);
// This returns NULL
if (property_exists($json_output->error)) {
echo "<p>error: $json_output->error->{'message'} </p>";
} else {
echo "<p>no error :(</p>";
}
$facebook_id = $json_output->{'id'};
$facebook_name = $json_output->{'name'};
$facebook_link = $json_output->{'link'};

Answer 1

Because the url returns the 400 Bad Request.
By default, you can't use file_get_contents function to get the response content when the http status code is 400.
You need to set ignore_errors options to true.
$opts = array(
'http'=>array(
'ignore_errors' => true
)
);
$context = stream_context_create($opts);
$jsonurl = "http://graph.facebook.com/JubilationDanceMinistry";
$json = file_get_contents($jsonurl, false, $context);
var_dump($json);

Answer 2

You can't chain multiple ->'s with string interpolation.
You'll have resort to passing multiple arguments to echo or to string concatenation:
echo "<p>error: ", $json_output->error->{'message'}, " </p>";