<?php
namespace Aws\DynamoDb;
use Psr\Http\Message\StreamInterface;
/**
* Marshals and unmarshals JSON documents and PHP arrays into DynamoDB items.
*/
class Marshaler
{
/** @var array Default options to merge into provided options. */
private static $defaultOptions = [
'ignore_invalid' => false,
'nullify_invalid' => false,
'wrap_numbers' => false,
];
/** @var array Marshaler options. */
private $options;
/**
* Instantiates a DynamoDB Marshaler.
*
* The following options are valid.
*
* - ignore_invalid: (bool) Set to `true` if invalid values should be
* ignored (i.e., not included) during marshaling.
* - nullify_invalid: (bool) Set to `true` if invalid values should be set
* to null.
* - wrap_numbers: (bool) Set to `true` to wrap numbers with `NumberValue`
* objects during unmarshaling to preserve the precision.
*
* @param array $options Marshaler options
*/
public function __construct(array $options = [])
{
$this->options = $options + self::$defaultOptions;
}
/**
* Creates a special object to represent a DynamoDB binary (B) value.
*
* This helps disambiguate binary values from string (S) values.
*
* @param mixed $value A binary value compatible with Guzzle streams.
*
* @return BinaryValue
* @see GuzzleHttp\Stream\Stream::factory
*/
public function binary($value)
{
return new BinaryValue($value);
}
/**
* Creates a special object to represent a DynamoDB number (N) value.
*
* This helps maintain the precision of large integer/float in PHP.
*
* @param string|int|float $value A number value.
*
* @return NumberValue
*/
public function number($value)
{
return new NumberValue($value);
}
/**
* Creates a special object to represent a DynamoDB set (SS/NS/BS) value.
*
* This helps disambiguate set values from list (L) values.
*
* @param array $values The values of the set.
*
* @return SetValue
*
*/
public function set(array $values)
{
return new SetValue($values);
}
/**
* Marshal a JSON document from a string to a DynamoDB item.
*
* The result is an array formatted in the proper parameter structure
* required by the DynamoDB API for items.
*
* @param string $json A valid JSON document.
*
* @return array Item formatted for DynamoDB.
* @throws \InvalidArgumentException if the JSON is invalid.
*/
public function marshalJson($json)
{
$data = json_decode($json);
if (!($data instanceof \stdClass)) {
throw new \InvalidArgumentException(
'The JSON document must be valid and be an object at its root.'
);
}
return current($this->marshalValue($data));
}
/**
* Marshal a native PHP array of data to a DynamoDB item.
*
* The result is an array formatted in the proper parameter structure
* required by the DynamoDB API for items.
*
* @param array|\stdClass $item An associative array of data.
*
* @return array Item formatted for DynamoDB.
*/
public function marshalItem($item)
{
return current($this->marshalValue($item));
}
/**
* Marshal a native PHP value into a DynamoDB attribute value.
*
* The result is an associative array that is formatted in the proper
* `[TYPE => VALUE]` parameter structure required by the DynamoDB API.
*
* @param mixed $value A scalar, array, or `stdClass` value.
*
* @return array Attribute formatted for DynamoDB.
* @throws \UnexpectedValueException if the value cannot be marshaled.
*/
public function marshalValue($value)
{
$type = gettype($value);
// Handle string values.
if ($type === 'string') {
if ($value === '') {
return $this->handleInvalid('empty strings are invalid');
}
return ['S' => $value];
}
// Handle number values.
if ($type === 'integer'
|| $type === 'double'
|| $value instanceof NumberValue
) {
return ['N' => (string) $value];
}
// Handle boolean values.
if ($type === 'boolean') {
return ['BOOL' => $value];
}
// Handle null values.
if ($type === 'NULL') {
return ['NULL' => true];
}
// Handle set values.
if ($value instanceof SetValue) {
if (count($value) === 0) {
return $this->handleInvalid('empty sets are invalid');
}
$previousType = null;
$data = [];
foreach ($value as $v) {
$marshaled = $this->marshalValue($v);
$setType = key($marshaled);
if (!$previousType) {
$previousType = $setType;
} elseif ($setType !== $previousType) {
return $this->handleInvalid('sets must be uniform in type');
}
$data[] = current($marshaled);
}
return [$previousType . 'S' => array_unique($data)];
}
// Handle list and map values.
$dbType = 'L';
if ($value instanceof \stdClass) {
$type = 'array';
$dbType = 'M';
}
if ($type === 'array' || $value instanceof \Traversable) {
$data = [];
$index = 0;
foreach ($value as $k => $v) {
if ($v = $this->marshalValue($v)) {
$data[$k] = $v;
if ($dbType === 'L' && (!is_int($k) || $k != $index++)) {
$dbType = 'M';
}
}
}
return [$dbType => $data];
}
// Handle binary values.
if (is_resource($value) || $value instanceof StreamInterface) {
$value = $this->binary($value);
}
if ($value instanceof BinaryValue) {
return ['B' => (string) $value];
}
// Handle invalid values.
return $this->handleInvalid('encountered unexpected value');
}
/**
* Unmarshal a document (item) from a DynamoDB operation result into a JSON
* document string.
*
* @param array $data Item/document from a DynamoDB result.
* @param int $jsonEncodeFlags Flags to use with `json_encode()`.
*
* @return string
*/
public function unmarshalJson(array $data, $jsonEncodeFlags = 0)
{
return json_encode(
$this->unmarshalValue(['M' => $data], true),
$jsonEncodeFlags
);
}
/**
* Unmarshal an item from a DynamoDB operation result into a native PHP
* array. If you set $mapAsObject to true, then a stdClass value will be
* returned instead.
*
* @param array $data Item from a DynamoDB result.
*
* @return array|\stdClass
*/
public function unmarshalItem(array $data)
{
return $this->unmarshalValue(['M' => $data]);
}
/**
* Unmarshal a value from a DynamoDB operation result into a native PHP
* value. Will return a scalar, array, or (if you set $mapAsObject to true)
* stdClass value.
*
* @param array $value Value from a DynamoDB result.
* @param bool $mapAsObject Whether maps should be represented as stdClass.
*
* @return mixed
* @throws \UnexpectedValueException
*/
public function unmarshalValue(array $value, $mapAsObject = false)
{
list($type, $value) = each($value);
switch ($type) {
case 'S':
case 'BOOL':
return $value;
case 'NULL':
return null;
case 'N':
if ($this->options['wrap_numbers']) {
return new NumberValue($value);
} else {
// Use type coercion to unmarshal numbers to int/float.
return $value + 0;
}
case 'M':
if ($mapAsObject) {
$data = new \stdClass;
foreach ($value as $k => $v) {
$data->$k = $this->unmarshalValue($v, $mapAsObject);
}
return $data;
}
// NOBREAK: Unmarshal M the same way as L, for arrays.
case 'L':
foreach ($value as &$v) {
$v = $this->unmarshalValue($v, $mapAsObject);
}
return $value;
case 'B':
return new BinaryValue($value);
case 'SS':
case 'NS':
case 'BS':
foreach ($value as &$v) {
$v = $this->unmarshalValue([$type[0] => $v]);
}
return new SetValue($value);
}
throw new \UnexpectedValueException("Unexpected type: {$type}.");
}
/**
* Handle invalid value based on marshaler configuration.
*
* @param string $message Error message
*
* @return array|null
*/
private function handleInvalid($message)
{
if ($this->options['ignore_invalid']) {
return null;
} elseif ($this->options['nullify_invalid']) {
return ['NULL' => true];
}
throw new \UnexpectedValueException("Marshaling error: {$message}.");
}
}
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