PHP - Checking an array for required keys and setting optional key-values

Question

I’m building a web API which takes an array of data. I want to check this array for certain keys and if a required key doesn’t exist, return false and if an optional key doesn’t exist, set that key-value pair in the array.

The confusion comes from my input array having potentially arrays as values. For example, let’s say I input an array like this:

$input_array = array(
    ’name’ => ‘Adam’,
    ‘address’ => array(
        ‘number’ => 12,
        ‘street’ => ‘My Street’
    )
);

I have required keys:

$required_keys = array(
    ‘name’,
    ‘address’ => array(
        ‘number’,
        ‘street’
    )
);

Optional keys:

$optional_keys = array(
    ‘address’ = array(
        ‘postcode’ => ‘WA1'
    )
);

I’m struggling of a way to test my input array against these two types of test arrays (input and optional).

What should happen is: 1) All of the required keys should be matched. 2) If any optional keys don’t exist, set them to the key-value pair from the optional keys array.

I know of (but am not experienced with) regular expressions. However, I do know that PHP has a function called http_build_query(mixed $array); which takes an array and turns it in to a URL query string. My thoughts are maybe I could turn the input array into a URL string then compare it against a regular expression made of my two test arrays (required and optional). Would/could this work?

If anyone has any other ideas I’d love to know. Thanks

Update: Attached unsuspected output

enter image description here

Update 2: Attached new output

enter image description here

Update 3: Current code:

static public function static_test_required_keys(Array $required_keys_array, Array $input_array)
{
    $missing = array();

    foreach ($required_keys_array as $key => $value)
    {
        if (empty($input_array[$key]))
        {
            $missing[] = $key;
        }
        else if (isset($input_array[$key]) && is_array($input_array[$key]))
        {
            $missing = array_merge(Inputter::static_test_required_keys($value, $input_array[$key]), $missing);
        }
    }

    return $missing;
}

Update 4: New code.

tatic public function static_test_required_keys(Array $required_keys_array, Array $input_array)
{
    $missing = array();

    foreach ($required_keys_array as $key => $value)
    {
        if (! isset($input_array[$key]))
        {
            $missing[] = $key;
        }
        else if (isset($input_array[$key]) && is_array($input_array[$key]))
        {
            $missing = array_merge(Inputter::static_test_required_keys($value, $input_array[$key]), $missing);
        }
    }

    return $missing;
}

Changed the code from isempty() to isset(). This page gives the differences between the two. https://www.virendrachandak.com/techtalk/php-isset-vs-empty-vs-is_null/

Check the manual php.net/manual/en/ref.array.php and take a look to diff, intersect, and merge functions. — Maks3w
– Maks3w, Commented Feb 6, 2015 at 14:54
Don't forget to mark an answer as correct (assuming there was one) — designosis
– designosis, Commented Jul 25, 2016 at 14:31

Community · Accepted Answer · 2020-06-20 09:12:55Z

Required fields

You can use array_diff for check if any of the required field is missing on the input.

Optional fields

You can use array_merge for set default values for missing fields.

Code

$requiredKeys = [
   'foo',
   'baz',
];

// Take the keys from input
$inputKeys = array_keys($input);

$missingRequiredKeys = array_diff($requiredKeys, $inputKeys)
if (!empty($missingRequiredKeys)) {
    throw new InvalidArgumentException(...);
}

// Setup default values for missing optional keys
$defaultValues = [
   'bar' => 'bas',
];

$result = array_merge($defaultValues, $input);

Child arrays

For check required fields or set default values the thing is to repeat the code above in individual functions.

function validateInput(array $input) {
   // Above code

   // Validate field subkeys from a parent required field.
   // or optional field with default value.
   validateFoo($input['foo']);

   // Validate field subkeys from a parent optional field without default value.
   if (array_key_exists('optional_input_without_default', $input)) {
       validateAnotherFooInput($input['optional_input_without_default']);
   }
}

Other options

You can play with array intersection, diff and merge in multiple ways checking for those family of functions in the Array Book

array_diff_assoc — Computes the difference of arrays with additional index check

array_diff_key — Computes the difference of arrays using keys for comparison

array_diff_uassoc — Computes the difference of arrays with additional index check which is performed by a user supplied callback function

array_diff_ukey — Computes the difference of arrays using a callback function on the keys for comparison

array_diff — Computes the difference of arrays

array_intersect_assoc — Computes the intersection of arrays with additional index check

array_intersect_key — Computes the intersection of arrays using keys for comparison

array_intersect_uassoc — Computes the intersection of arrays with additional index check, compares indexes by a callback function

array_intersect_ukey — Computes the intersection of arrays using a callback function on the keys for comparison

array_intersect — Computes the intersection of arrays

array_udiff_assoc — Computes the difference of arrays with additional index check, compares data by a callback function

array_udiff_uassoc — Computes the difference of arrays with additional index check, compares data and indexes by a callback function

array_udiff — Computes the difference of arrays by using a callback function for data comparison

array_uintersect_assoc — Computes the intersection of arrays with additional index check, compares data by a callback function

array_uintersect_uassoc — Computes the intersection of arrays with additional index check, compares data and indexes by a callback functions

array_uintersect — Computes the intersection of arrays, compares data by a callback function

Worth noting: short array syntax only works on php >= 5.4, you also have some undefined variables in your answer $input, $inpuKeys and a fatal error on your if statement.. no closing )

designosis · Accepted Answer · 2015-02-06 16:17:10Z

1

New improved version with symmetrical input+required keys...

$input_array = array(
    'name' => 'Adam',
    'address' => array(
        'number' => 12,
        'street' => '',
        'phones' => array('home_phone'=>'','fax'=>'555-1212')
    )
);

$required_keys = array(
    'name' => '',
    'address' => array(
        'number' => '',
        'street' => '',
        'phones' => array('home_phone'=>'')
    )
);


function check_required( $input, $required ){
    $missing = array();
    foreach ($required as $k=>$v) {
        if (empty($input[$k])) {
            $missing[] = $k;
        } else if (is_array($v)) {
            $missing = array_merge( check_required( $input[$k], $v ), $missing );
        }
    }
    return $missing;
}

$missing = check_required( $input_array, $required_keys );
if (!empty($missing)) echo 'Please enter your '. implode(', ', $missing);

See sandbox here ... http://sandbox.onlinephpfunctions.com/code/23b908b873b053aefb37770f636b63bba2db960b

edited Feb 6, 2015 at 16:17

answered Feb 6, 2015 at 14:50

designosis

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20 Comments

Adam Carter Over a year ago

My input array has to be multidimensional. The input array comes from JSON POST and can be multidimensional.

designosis Over a year ago

updated answer for infinite depth of multidimensional array checking

Adam Carter Over a year ago

Thanks for your help. This does work, but I’ve just realised that it’s possible for my data (being JSON encoded) to contain an indexed array. For example,

‘addresses’ => array( ‘address’ => array(‘number’ => 13, ’street’ => ‘My Street’), ‘address’ => array(‘number’ => 14, ‘street’ => ‘My Street’))

designosis Over a year ago

as long as the structure of the $input_array is mirrored by $required_keys (sort of, since keys and values are swapped), it'll work

Adam Carter Over a year ago

Yeah, you’re right. My ‘addressed’ should have been in an indexed array in my required_keys during testing. Thanks a lot for your help. Where optional_keys is concerned, would a simple array_merge work (as @Maks3w suggested)?

|

matthias · Accepted Answer · 2015-02-06 14:55:15Z

// Check if required keys exist
foreach( $required_keys as $req_key => $req_val )
{
    if( !array_key_exists( $req_key, $input_array )
    {
        // if key exists check if it has values set in an array and if 
        // these are also in $input_array
        if( is_array( $req_val ) )
        {
            foreach( $req_val as $inner_req_key )
            {
                if( !isset( $input_array[$req_val][$inner_req_key] )
                {
                    echo "Required key '$req_key' is missing value '$inner_req_key'.";
                }
            }
        }
        echo "Required key '$req_key' is missing.";
    }
}

// Check if optional keys are defined
foreach( $optional_keys as $opt_key => $opt_val )
{
    // Check if key exists, if not copy optional key=>value as whole
    if( !array_key_exists( $opt_key, $input_array )
    {
        $input_array[ $opt_key ] = $opt_val;
    }
    else // key exists
    {
        // if key exists check if it is an array and if optional elements
        // exist, else add them
        if( is_array( $opt_key ) )
        {
            foreach( $opt_key as $inner_opt_key => $inner_opt_val )
            {
                // key is not set, so get from %optional_keys
                if( !isset( $input_array[$opt_key][$inner_opt_key] )
                {
                    $input_array[$opt_key][$inner_opt_key] = $inner_opt_val;
                }
            }
        }
    }
}

Long time no PHP, but maybe this helps. PS: Not tested and added some interpretation. HTH

Adam Carter · Accepted Answer · 2015-02-06 17:25:00Z

So here is my final code for anyone who stumbles upon this/wants to know how I did it. Feel free to submit ideas for improvement.

static protected function static_test_required_keys(Array $required_keys_array, Array $input_array, &$error)
{
    //  Loop through each required key and value
    //
    foreach ($required_keys_array as $key => $value)
    {
        //  Check the corresponding value in the input array is not set
        //
        if (! isset($input_array[$key]))
        {
            //  If it isn't set return false with a missing error
            //
            $error = Error::withDomain(INPUTTER_ERROR_DOMAIN,
                                       INPUTTER_ERROR_CODE_KEY_MISSING,
                                       'Missing a required key: ' . $key);

            return false;
        }
        //
        //  Check corresponding value in the input array is set and is an array
        //
        else if (isset($input_array[$key]) && is_array($input_array[$key]))
        {
            //  Recurse the function for sub arrays
            //
            if (! Inputter::static_test_required_keys($value, $input_array[$key], $error))
            {
                //  If we return false from this one, we've found at least one error and don't need to continue
                //
                return false;
            }
        }
    }

    //  If we get here then it must be valid
    //
    return true;
}

static protected function static_set_optional_key_values(Array $optional_dictionary, Array &$input_array, &$error)
{
    //  Loop through each optional key/value
    //
    foreach ($optional_dictionary as $key => $value)
    {
        //  Check the key doesn't exist in the input array OR the corresponding value in the input array is not set
        //
        if (! array_key_exists($key, $input_array) || ! isset($input_array[$key]))
        {
            //  Set the new key/value
            //              
            $input_array[$key] = $value;
        }
        //
        //  Check corresponding value in the input array is set and is an array
        //
        else if (isset($input_array[$key]) && is_array($input_array[$key]))
        {
            //  Recurse the function for sub arrays
            //
            Inputter::static_set_optional_key_values($value, $input_array[$key], $error);
        }
    }
}

Community · Accepted Answer · 2017-04-13 12:40:33Z

I don't know where you want to run this code.

If it is in the browser or in Javascript.

Since I am in doubt, I've made this:

function array_extend() {

    //Detects if we are running in Javascript or PHP
    //In PHP, this will be false because PHP only parses
    //escape sequences in double-quoted strings (except the sequence \')
    $javascript = '\0' == "\0";

    //PHP arrays support 'key=>value' pairs, JS arrays don't.
    $result = $javascript ? new Object() : array();

    $arguments = $javascript? arguments : func_get_args();

    $get_keys = function($elem){
        if('\0' == "\0")//PHP complains if I use the var $javascript
        {
            $object = Object;
            return $object['keys']($elem); //PHP doesn't like the Object.keys syntax
        }
        else
        {
            return array_keys($elem);
        }
    };


    for($j = 0, $length_args = $javascript? $arguments['length']: count($arguments); $j < $length_args; $j++)
    {
        $keys = $get_keys( $arguments[$j] );

        for($i = 0, $length_keys = $javascript? $keys['length']: count($keys); $i < $length_keys; $i++)
        {
            $result[$keys[$i]] = $arguments[$j][$keys[$i]];
        }
    }

    return $result;
}

It runs both in PHP and Javascript.

Currently, I have an opened question on another website, showcasing the function.

You can go on https://codereview.stackexchange.com/questions/79804/polyglot-array-extend-function-for-javascript-and-php to check it.

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