Add support for multi-dimensional arrays in $input with a $config->wireInputArrayDepth setting. This was requested in prior feature requests and in PR #161 but ended up writing it in a different way than the PR to allow for control over the allowed max dimension and consistency with multidimensional arrays in $_GET or $_POST. To enable multi-dimensional array support add $config->wireInputArrayDepth = 2; to /site/config.php and use a value of 2 (or higher) to indicate the number of dimensions you want to support.

Co-authored-by: porl <porl42@gmail.com>

wire/config.php

@@ -1031,6 +1031,26 @@ $config->wireInputOrder = 'get post';
  */
 $config->wireInputLazy = false;
 
+/**
+ * Maximum depth for input variables accessed from $input
+ * 
+ * A value of 1 (or less) means only single dimensional arrays are allowed. For instance, `$a['foo']`
+ * would be allowed (since it is one dimension), but `$a['foo']['bar']` would not because it is 
+ * multi-dimensional to a depth of 2.
+ * 
+ * A value of 2 or higher enables multi-dimensional arrays to that depth. For instance, a value of 2 
+ * would allow `$a['foo']['bar']` and a value of 3 or higher would enable `$a['foo']['bar']['baz']`.
+ * 
+ * Note: if your use case requires multi-dimensional input arrays and you do not have control over
+ * this setting (like if you are a 3rd party module author), or are using a version of PW prior to 
+ * 3.0.178 you can always still access multi-dimensional arrays directly from `$_GET` or `$_POST`. 
+ *
+ * @var int
+ * @since 3.0.178
+ * 
+ */
+$config->wireInputArrayDepth = 1;
+
 /**
  * Options for setting cookies from $input->cookie()->set(...)
  * 

wire/core/Config.php

@@ -92,6 +92,7 @@
  * @property int $maxUrlDepth Maximum URL/path slashes (depth) for request URLs. (Min=10, Max=60) #pw-group-URLs
  * @property string $wireInputOrder Order that variables with the $input API var are handled when you access $input->var. #pw-group-HTTP-and-input
  * @property bool $wireInputLazy Specify true for $input API var to load input data in a lazy fashion and potentially use less memory. Default is false. #pw-group-HTTP-and-input
+ * @property int $wireInputArrayDepth Maximum multi-dimensional array depth for input variables accessed from $input or 1 to only allow single dimension arrays. (3.0.178+). #pw-group-HTTP-and-input
  * @property array $cookieOptions Options for setting cookies from $input->cookie #pw-group-HTTP-and-input
  * 
  * @property bool $advanced Special mode for ProcessWire system development. Not recommended for regular site development or production use. #pw-group-system

wire/core/WireInputData.php

@@ -330,19 +330,43 @@ class WireInputData extends Wire implements \ArrayAccess, \IteratorAggregate, \C
 	/**
 	 * Clean an array of data
 	 * 
-	 * Removes multi-dimensional arrays and slashes (if applicable) 
+	 * Support multi-dimensional arrays consistent with `$config->wireInputArrayDepth` 
+	 * setting (3.0.178+) and remove slashes if applicable/necessary. 
 	 * 
 	 * @param array $a
 	 * @return array
 	 * 
 	 */
 	protected function cleanArray(array $a) {
+		static $depth = 1;
+
+		$maxDepth = (int) $this->wire()->config->wireInputArrayDepth;
+		if($maxDepth < 1) $maxDepth = 1;
+		
 		$clean = array();
+		
 		foreach($a as $key => $value) {
-			if(is_array($value)) continue; // we only allow one dimensional arrays
+			if(is_array($value)) {
-			if(is_string($value) && $this->stripSlashes) $value = stripslashes($value);
+				if($depth >= $maxDepth) {
-			$clean[$key] = $value;
+					// max dimension reached
+					$value = null; 
+				} else {
+					// allow another dimension
+					$depth++;
+					$value = $this->cleanArray($value);
+					$depth--;
+					// empty arrays not possible in input vars past 1st dimension
+					if(!count($value)) $value = null; 
+				}
+			} else if(is_string($value)) {
+				if($this->stripSlashes) $value = stripslashes($value);
+			}
+			
+			if($value !== null) {
+				$clean[$key] = $value;
+			}
 		}
+		
 		return $clean;
 	}