Unable to parse JSON web service response with json_decode() - php

Question

I'm struggling with parsing a web service response JSON in cases where the service returns an error.
Example JSON - success flow:
{
"Response": [{
"iconPath" : "/img/theme/destiny/icons/icon_psn.png",
"membershipType": 2,
"membershipId": "4611686018429261138",
"displayName": "Spuff_Monkey"
}],
"ErrorCode": 1,
"ThrottleSeconds": 0,
"ErrorStatus": "Success",
"Message": "Ok",
"MessageData":{}
}
Example JSON - error flow:
{
"ErrorCode": 7,
"ThrottleSeconds": 0,
"ErrorStatus": "ParameterParseFailure",
"Message": "Unable to parse your parameters. Please correct them, and try again.",
"MessageData": {}
}
Now my PHP:
function hitWebservice($endpoint) {
$curl = curl_init($endpoint);
curl_setopt($curl, CURLOPT_HEADER, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_HTTPHEADER, array("Content-type: application/json"));
$json_response = curl_exec($curl);
if(curl_exec($curl) === false) {
echo "Curl error: " . curl_error($curl);
}
curl_close($curl);
$array_response = json_decode($json_response, true);
$function_response = array();
if (!isset($array_response['Response'])) {
$function_response = $array_response;
} else {
$function_response = $array_response['Response'];
}
return $function_response;
}
What I'm trying to achieve is when the JSON includes the "Response" block I put that in a new array and return only that detail from the function, where "Response" isn't present I want to return the full JSON as an array.
However at present, where there is no "Response" I get an empty array.
There's something wrong with my logic and I can't get past it in my tiny mind, so it's time to reach out for help!

Answer 1

Judging from the fact that Response is an array of objects in the JSON, I suspect that the error-flow response may also contain a Response-field, but with an empty array as value ([]). That would explain your current result.
Therefore, do not check for the existence of Response. It may just be an empty array. Instead, check for the ErrorCode, ErrorStatus or ErrorMessage (whichever you think is most suitable). For example:
if ($array_response['ErrorStatus'] != "Success") {
$function_response = $array_response;
} else {
if (!isset($array_response['Response'])) {
$function_response = null;
} else {
$function_response = $array_response['Response'];
}
}
In the Success-case, you want to check for existence of Response, so that if it does not exist (but it is expected), you can raise some error).
Another possible solution is to count the number of responses:
if (!isset($array_response['Response'])) {
$function_response = $array_response;
} else {
if (count($array_response['Response']) > 0) {
$function_response = $array_response['Response'];
} else {
$function_response = $array_response;
}
}

Answer 2

If you notice, both a good and a bad response contain an ErrorCode
You would be better designing your code to work from this field rather than test a field that may or may not exist.
So try this instead :-
$array_response = json_decode($json_response, true);
switch ( $array_response['ErrorCode'] ) {
case 1 :
do_errorCode_1_processing($array_response)
break;
case 2 :
do_errorCode_2_processing($array_response)
break;
// etc etc
}

Answer 3

isset () is not the right function for checking if the key in an array is present or not.
Use array_key_exists () instead.
http://php.net/manual/en/function.array-key-exists.php
so your code should look like this:
$array_response = json_decode($json_response, true);
$function_response = array();
if (array_key_exists('Response', $array_response)) {
$function_response = $array_response['Response'];
} else {
$function_response = $array_response;
}
return $function_response;
The above should do the trick.