Custom validator created with some functions

src/validator.php

@@ -0,0 +1,160 @@
+<?php
+
+function fieldExistsInData($data, $key)
+{
+    $keys = explode('.', $key);
+    foreach ($keys as $k) {
+        if (is_array($data) && array_key_exists($k, $data)) {
+            $data = $data[$k];
+        } else {
+            return false;
+        }
+    }
+    return true;
+}
+
+function getDataValue($data, $key)
+{
+    $keys = explode('.', $key);
+
+    foreach ($keys as $k) {
+        if (is_array($data) && array_key_exists($k, $data)) {
+            $data = $data[$k];
+        } else {
+            return null;
+        }
+    }
+
+    return $data;
+}
+
+function validate($data, $rules)
+{
+    $errors = [];
+
+    foreach ($rules as $field => $ruleString) {
+        $value = getDataValue($data, $field);
+        $ruleList = explode('|', $ruleString);
+
+        $hasSometimes = in_array('sometimes', $ruleList, true);
+        if ($hasSometimes && !fieldExistsInData($data, $field)) {
+            continue;
+        }
+
+        foreach ($ruleList as $ruleItem) {
+            if ($ruleItem === 'sometimes') {
+                continue; // already handled
+            }
+
+            $param = null;
+            if (strpos($ruleItem, ':') !== false) {
+                $exploded = explode(':', $ruleItem, 2);
+                $rule = $exploded[0];
+                $param = isset($exploded[1]) ? $exploded[1] : null;
+            } else {
+                $rule = $ruleItem;
+            }
+
+            $validator = 'validate_' . $rule;
+
+            if (function_exists($validator)) {
+                $result = $validator($field, $value, $param, $data);
+
+                if ($result !== true) {
+                    $errors[$field][] = $result;
+                }
+            } else {
+                $errors[$field][] = "Rule '$rule' is not supported.";
+            }
+        }
+    }
+
+    return ['valid' => !empty($errors) ? false : true, 'errors' => $errors];
+}
+
+function validate_array($field, $value, $param = null, $data = [])
+{
+    if (!is_array($value)) {
+        return "The field '$field' must be an array.";
+    }
+    return true;
+}
+
+function validate_integer($field, $value, $param = null, $data = [])
+{
+    if (!is_int($value)) {
+        return "The field '$field' must be an integer.";
+    }
+    return true;
+}
+
+function validate_max($field, $value, $param, $data = [])
+{
+    if (is_string($value) && strlen($value) > $param) {
+        return "The field '$field' must have at most $param characters.";
+    }
+    if (is_integer($value) && $value > $param) {
+        return "The value of '$field' must be at most $param.";
+    }
+    return true;
+}
+
+function validate_min($field, $value, $param, $data = [])
+{
+    if (is_string($value) && strlen($value) < $param) {
+        return "The field '$field' must have at least $param characters.";
+    }
+    if (is_numeric($value) && $value < $param) {
+        return "The value of '$field' must be at least $param.";
+    }
+    return true;
+}
+
+function validate_prohibited_with($field, $value, $param, $data = [])
+{
+    $otherFields = explode(',', $param);
+
+    foreach ($otherFields as $other) {
+        $other = trim($other);
+        if (!empty($data[$other])) {
+            if (!empty($value)) {
+                return "The field '$field' is not allowed when '$other' is present.";
+            }
+        }
+    }
+
+    return true;
+}
+
+function validate_required($field, $value, $param = null, $data = [])
+{
+    if ($value === null || $value === '') {
+        return "The field '$field' is required.";
+    }
+    return true;
+}
+
+function validate_required_with($field, $value, $param, $data = [])
+{
+    $relatedFields = explode(',', $param);
+
+    foreach ($relatedFields as $related) {
+        $related = trim($related);
+
+        if (isset($data[$related]) && $data[$related] !== '') {
+            if ($value === null || $value === '') {
+                return "The field '$field' is required when '$related' is present.";
+            }
+        }
+    }
+
+    return true;
+}
+
+function validate_string($field, $value, $param = null, $data = [])
+{
+    if (!is_string($value)) {
+        return "The field '$field' must be a string.";
+    }
+    return true;
+}