Simple MODX Spamfilter

checkWeekday.snippet.php

<?php
/*
Really primitive, but oddly efficient, anti-spambot validator for formit
 
1. Add weekday selectfield:

        <div class="form-group [[!+fi.error.weekday:notempty=`has-error`]]">
            <label for="weekday" class="col-sm-3 control-label">I'm not a robot! <sup>*</sup></label>
            <div class="col-sm-9">
                <select class="form-control" name="weekday" required>
                    <option value="">What day is it?</option>
                    <option value="Monday"     [[!+fi.wochentag:FormItIsSelected=`Monday`]]     >Monday</option>
                    <option value="Tuesday"   [[!+fi.wochentag:FormItIsSelected=`Tuesday`]]   >Tuesday</option>
                    <option value="Wednesday"   [[!+fi.wochentag:FormItIsSelected=`Wednesday`]]   >Wednesday</option>
                    <option value="Thursday" [[!+fi.wochentag:FormItIsSelected=`Thursday`]] >Thursday</option>
                    <option value="Friday"    [[!+fi.wochentag:FormItIsSelected=`Friday`]]    >Friday</option>
                    <option value="Saturday"    [[!+fi.wochentag:FormItIsSelected=`Saturday`]]    >Saturday</option>
                    <option value="Sunday"    [[!+fi.wochentag:FormItIsSelected=`Sunday`]]    >Sunday</option>
                </select>
                <span class="help-block">[[!+fi.error.weekday]]</span>
            </div>
        </div>     

2. Add formit parameters:

    &customValidators=`checkWeekday`
    
    &validate=`message:required,
      weekday:checkWeekday:required,
      email:email:required,
      name:required`
*/

$weekdays = array(
    'Sunday' => 0,
    'Monday' => 1,
    'Tuesday' => 2,
    'Wednesday' => 3,
    'Thursday' => 4,
    'Friday' => 5,
    'Saturday' => 6
);

if(!array_key_exists($value, $weekdays)){
    /* Should only be possible if something messed with the selectfield */
    $validator->addError('weekday','Please check your input');
    return false;  
}

$weekday = $value;

$w = date('w'); 

if($weekdays[$weekday] == $w) {
    return true;
}
else {
    $validator->addError('weekday',"Today isn't <strong>" . $weekday . "</strong>. <br>Please check your calendar");
    return false;
}