feat: validate custom srcsets

src/Imgix/UrlBuilder.php

@@ -2,6 +2,8 @@
 
 namespace Imgix;
 
+use Imgix\Validator;
+
 class UrlBuilder {
 
     private $currentVersion = "3.2.0";
@@ -82,6 +84,7 @@ public function createSrcSet($path, $params=array(), $options=array()) {
         $widthsArray = isset($options['widths']) ? $options['widths'] : NULL;
 
         if (isset($widthsArray)) {
+            Validator::validateWidths($widthsArray);
             return $this->createSrcSetPairs($path, $params=$params, $widthsArray);
         }
 
@@ -130,6 +133,7 @@ public function targetWidths(
             return array((int) $start);
         }
 
+        Validator::validateMinMaxTol($start, $stop, $tol);
         $resolutions = array();
 
         while ($start < $stop && $start < self::MAX_WIDTH) {

src/Imgix/Validator.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace Imgix;
+
+class Validator {
+    const ONE_PERCENT = 0.01;
+
+    public static function validateMinWidth($start) {
+        if ($start < 0) {
+            throw new \InvalidArgumentException("`start` width value must be greater than zero");
+        }
+    }
+
+    public static function validateMaxWidth($end) {
+        if ($end < 0) {
+            throw new \InvalidArgumentException("`stop` width value must be greater than zero"); 
+        }
+    }
+
+    public static function validateRange($start, $stop) {
+        // Validate the minimum width, `begin`.
+        Validator::validateMinWidth($start);
+        // Validate the maximum width, `end`.
+        Validator::validateMaxWidth($stop);
+
+        // Ensure that the range is valid, ie. `begin <= end`.
+        if ($start > $stop) {
+            throw new \InvalidArgumentException("`start` width value must be less than `stop` width value"); 
+        }
+    }
+
+    public static function validateTolerance($tol) {
+        $msg = "`tol`erance value must be greater than, or equal to one percent, ie. >= 0.01";
+
+        if ($tol < self::ONE_PERCENT) {
+            throw new \InvalidArgumentException($msg);
+        }
+    }
+
+    public static function validateMinMaxTol($begin, $end, $tol) {
+        Validator::validateRange($begin, $end);
+        Validator::validateTolerance($tol);
+    }
+
+    public static function validateWidths($widths) {
+        if ($widths == NULL) {
+            throw new \InvalidArgumentException("`widths` array cannot be `null`");
+        }
+
+        if (count($widths) == 0) {
+            throw new \InvalidArgumentException("`widths` array cannot be empty");
+        }
+        foreach ($widths as &$w) {
+            if ($w < 0) {
+                throw new \InvalidArgumentException("width values in `widths` cannot be negative");
+            }
+        }
+    }
+}
+?>

tests/Imgix/Tests/ValidatorTest.php

@@ -0,0 +1,63 @@
+<?php
+
+use Imgix\Validator;
+
+class ValidatorTest extends \PHPUnit\Framework\TestCase {
+    const LESS_THAN_ZERO = -1;
+    /**
+     * Test `validateMinWidth` throws if passed a value less than
+     * zero.
+     */
+    public function testValidateMinWidth() {
+        $this->expectException(InvalidArgumentException::class);
+        Validator::validateMinWidth(self::LESS_THAN_ZERO);
+    }
+
+    /**
+     * Test `validateMaxWidth` throws if passed a value less than
+     * zero.
+     */
+    public function testValidateMaxWidth() {
+        $this->expectException(InvalidArgumentException::class);
+        Validator::validateMaxWidth(self::LESS_THAN_ZERO);
+    }
+
+    /**
+     * Test `validateRange` throws if passed an invalid range,
+     * ie. if `BEGIN > END`.
+     */
+    public function testValidateRange() {
+        $this->expectException(InvalidArgumentException::class);
+        $begin = 400;
+        $end = 100;
+        Validator::validateRange($begin, $end);
+    }
+
+    /**
+     * Test `validateTolerance` throws if passed a `tol`erance
+     * that is less than one percent.
+     */
+    public function testValidateTolerance() {
+        $this->expectException(InvalidArgumentException::class);
+        $lessThanOnePercent = 0.001;
+        Validator::validateTolerance($lessThanOnePercent);
+    }
+
+
+    /**
+     * Test `validateWidths` throws if passed a `null` array.
+     */
+    public function testValidateWidthsNullArray() {
+        $this->expectException(InvalidArgumentException::class);
+        Validator::validateWidths(NULL);
+    }
+
+    /**
+     * Test `validateWidths` throws if passed an empty array.
+     */
+    public function testValidateWidthsEmptyArray() {
+        $this->expectException(InvalidArgumentException::class);
+        Validator::validateWidths([]);
+    }
+}
+?>