Automatically cast/encode statement parameters

Statement parameters are automatically cast to values expected by postgres, including encoding arrays.

lib/Internal/functions.php

@@ -2,13 +2,15 @@
 
 namespace Amp\Postgres\Internal;
 
+use function Amp\Postgres\cast;
+
 const STATEMENT_PARAM_REGEX = <<<'REGEX'
 ~(["'`])(?:\\(?:\\|\1)|(?!\1).)*+\1(*SKIP)(*F)|(\$(\d+)|\?)|:([a-zA-Z_]+)~ms
 REGEX;
 
 /**
- * @param string $sql SQL statement with named placeholers.
- * @param array $names Array of parameter positions mapped to names.
+ * @param string $sql SQL statement with named and unnamed placeholders.
+ * @param array $names Array of parameter positions mapped to names and/or indexed locations.
  *
  * @return string SQL statement with Postgres-style placeholders
  */
@@ -35,8 +37,8 @@ function parseNamedParams(string $sql, array &$names = null): string {
 }
 
 /**
- * @param mixed[] $params
- * @param mixed[] $names
+ * @param mixed[] $params User-provided array of statement parameters.
+ * @param mixed[] $names Array generated by parseNamedParams.
  *
  * @return mixed[]
  *
@@ -45,7 +47,7 @@ function parseNamedParams(string $sql, array &$names = null): string {
 function replaceNamedParams(array $params, array $names): array {
     $values = [];
     foreach ($names as $index => $name) {
-        if (!isset($params[$name])) {
+        if (!\array_key_exists($name, $params)) {
             if (\is_int($name)) {
                 $message = \sprintf("Value for unnamed parameter at position %s missing", $name);
             } else {
@@ -55,7 +57,7 @@ function replaceNamedParams(array $params, array $names): array {
             throw new \Error($message);
         }
 
-        $values[$index] = $params[$name];
+        $values[$index] = cast($params[$name]);
     }
 
     return $values;

lib/functions.php

@@ -37,3 +37,72 @@ function connect(string $connectionString, CancellationToken $token = null): Pro
 function pool(string $connectionString, int $maxConnections = Pool::DEFAULT_MAX_CONNECTIONS): Pool {
     return new Pool($connectionString, $maxConnections);
 }
+
+/**
+ * Casts a PHP value to a representation that is understood by Postgres, including encoding arrays.
+ *
+ * @param mixed $value
+ *
+ * @return string|int|float|null
+ *
+ * @throws \Error If $value is an object without a __toString() method, a resource, or an unknown type.
+ */
+function cast($value) {
+    switch ($type = \gettype($value)) {
+        case "NULL":
+        case "integer":
+        case "double":
+        case "string":
+            return $value; // No casting necessary for numerics, strings, and null.
+
+        case "boolean":
+            return $value ? 't' : 'f';
+
+        case "array":
+            return encode($value);
+
+        case "object":
+            if (!\method_exists($value, "__toString")) {
+                throw new \Error("Object without a __toString() method included in parameter values");
+            }
+
+            return (string) $value;
+
+        default:
+            throw new \Error("Invalid value type '$type' in parameter values");
+    }
+}
+
+/**
+ * Encodes an array into a PostgreSQL representation of the array.
+ *
+ * @param array $array
+ *
+ * @return string The serialized representation of the array.
+ *
+ * @throws \Error If $array contains an object without a __toString() method, a resource, or an unknown type.
+ */
+function encode(array $array): string {
+    $array = \array_map(function ($value) {
+        switch (\gettype($value)) {
+            case "NULL":
+                return "NULL";
+
+            case "object":
+                if (!\method_exists($value, "__toString")) {
+                    throw new \Error("Object without a __toString() method in array");
+                }
+
+                $value = (string) $value;
+                // no break
+
+            case "string":
+                return '"' . \str_replace(['\\', '"'], ['\\\\', '\\"'], $value) . '"';
+
+            default:
+                return cast($value); // Recursively encodes arrays and errors on invalid values.
+        }
+    }, $array);
+
+    return '{' . \implode(',', $array) . '}';
+}

test/EncodeTest.php

@@ -0,0 +1,79 @@
+<?php
+
+namespace Amp\Postgres\Test;
+
+use Amp\PHPUnit\TestCase;
+use function Amp\Postgres\encode;
+
+class EncodeTest extends TestCase {
+    public function testSingleDimensionalStringArray() {
+        $array = ["one", "two", "three"];
+        $string = '{"one","two","three"}';
+
+        $this->assertSame($string, encode($array));
+    }
+
+    public function testMultiDimensionalStringArray() {
+        $array = ["one", "two", ["three", "four"], "five"];
+        $string = '{"one","two",{"three","four"},"five"}';
+
+        $this->assertSame($string, encode($array));
+    }
+
+    public function testQuotedStrings() {
+        $array = ["one", "two", ["three", "four"], "five"];
+        $string = '{"one","two",{"three","four"},"five"}';
+
+        $this->assertSame($string, encode($array));
+    }
+
+    public function testEscapedQuoteDelimiter() {
+        $array = ['va"lue1', 'value"2'];
+        $string = '{"va\\"lue1","value\\"2"}';
+
+        $this->assertSame($string, encode($array));
+    }
+
+    public function testNullValue() {
+        $array = ["one", null, "three"];
+        $string = '{"one",NULL,"three"}';
+
+        $this->assertSame($string, encode($array));
+    }
+
+    public function testSingleDimensionalIntegerArray() {
+        $array = [1, 2, 3];
+        $string = '{' . \implode(',', $array) . '}';
+
+        $this->assertSame($string, encode($array));
+    }
+
+    public function testIntegerArrayWithNull() {
+        $array = [1, 2, null, 3];
+        $string = '{1,2,NULL,3}';
+
+        $this->assertSame($string, encode($array));
+    }
+
+    public function testMultidimensionalIntegerArray() {
+        $array = [1, 2, [3, 4], [5], 6, 7, [[8, 9], 10]];
+        $string = '{1,2,{3,4},{5},6,7,{{8,9},10}}';
+
+        $this->assertSame($string, encode($array));
+    }
+
+    public function testEscapedBackslashesInQuotedValue() {
+        $array = ["test\\ing", "esca\\ped\\"];
+        $string = '{"test\\\\ing","esca\\\\ped\\\\"}';
+
+        $this->assertSame($string, encode($array));
+    }
+
+    /**
+     * @expectedException \Error
+     * @expectedExceptionMessage Object without a __toString() method in array
+     */
+    public function testObjectWithoutToStringMethod() {
+        encode([new \stdClass]);
+    }
+}