Safe Access Inline — PHP

PHP library for safe nested data access with security validation on by default — JSON, YAML, XML, INI, ENV, NDJSON, arrays and objects. Includes a full PathQuery engine with filters, wildcards, slices, and projections. Zero production dependencies.

The problem

Reading nested data from external sources requires more than null-safe access. You also need to defend against XXE in XML, anchor bombs in YAML, PHP magic method injection, stream wrapper abuse, superglobal access, and payload size attacks. Without a tool for this, that validation is boilerplate you write manually for every format and every endpoint.

Without this library (XML from an external API):

libxml_disable_entity_loader(true);
$xml = simplexml_load_string($input, 'SimpleXMLElement', LIBXML_NOENT);
if ($xml === false) {
    throw new RuntimeException('Invalid XML');
}
// validate keys against magic methods, superglobals, stream wrappers...
// enforce depth and key count limits...
$host = isset($xml->database->host) ? (string) $xml->database->host : null;

With this library:

$host = Inline::fromXml($input)->get('database.host');
// XXE blocked, forbidden keys validated, depth enforced — by default

Installation

composer require safeaccess/inline

Requirements: PHP 8.2+, extensions: json, simplexml, libxml

Optional: ext-yaml for improved YAML parsing performance (a built-in minimal parser is used by default).

Quick start

use SafeAccess\Inline\Inline;

$accessor = Inline::fromJson('{"user": {"name": "Alice", "age": 30}}');

$accessor->get('user.name');           // 'Alice'
$accessor->get('user.email', 'N/A');   // 'N/A' (default when missing)
$accessor->has('user.age');            // true
$accessor->getOrFail('user.name');     // 'Alice' (throws if missing)

// Immutable writes - original is never modified
$updated = $accessor->set('user.email', 'alice@example.com');
$updated->get('user.email');           // 'alice@example.com'
$accessor->has('user.email');          // false (original unchanged)

Security

All public entry points validate input by default. Every key passes through SecurityGuard and SecurityParser before being accessible.

What gets blocked

Category	Examples	Reason
PHP magic methods	`__construct`, `__destruct`, `__wakeup`, `__sleep`, `__toString`, ...	Prevent PHP magic behavior via data keys
Prototype pollution	`__proto__`, `constructor`, `prototype`	Prevent prototype pollution attacks
PHP superglobals	`GLOBALS`, `_GET`, `_POST`, `_COOKIE`, `_SERVER`, `_ENV`, ...	Prevent superglobal variable access
Stream wrapper URIs	`php://input`, `phar://...`, `data://...`, `file://...`	Prevent stream wrapper injection

Format-specific protections

Format	Protection
XML	Rejects `<!DOCTYPE` — prevents XXE (XML External Entity) attacks
YAML	Blocks unsafe tags, anchors (`&`), aliases (`*`), and merge keys (`<<`)
All	Forbidden key validation on every parsed key

Structural limits

Limit	Default	Description
`maxPayloadBytes`	10 MB	Maximum raw string input size
`maxKeys`	10,000	Maximum total key count
`maxDepth`	512	Maximum structural nesting depth
`maxResolveDepth`	100	Maximum recursion for path resolution
`maxCountRecursiveDepth`	100	Maximum recursion when counting keys

Custom forbidden keys

$guard = new SecurityGuard(extraForbiddenKeys: ['secret', 'internal_token']);
$accessor = Inline::withSecurityGuard($guard)->fromJson($data);

Disabling validation for trusted input

$accessor = Inline::withStrictMode(false)->fromJson($trustedPayload);

Warning: Disabling strict mode skips all validation. Only use with application-controlled input.

For vulnerability reports, see SECURITY.md.

Dot notation syntax

Basic syntax

Syntax	Example	Description
`key.key`	`user.name`	Nested key access
`key.0.key`	`users.0.name`	Numeric key (array index)
`key\.with\.dots`	`config\.db\.host`	Escaped dots in key names
`$` or `$.path`	`$.user.name`	Optional root prefix (stripped)

$data = Inline::fromJson('{"users": [{"name": "Alice"}, {"name": "Bob"}]}');
$data->get('users.0.name'); // 'Alice'
$data->get('users.1.name'); // 'Bob'

Advanced PathQuery

Syntax	Example	Description
`[0]`	`users[0]`	Bracket index access
`` or `[]`	`users.*`	Wildcard — expand all children
`..key`	`..name`	Recursive descent — find key at any depth
`..['a','b']`	`..['name','age']`	Multi-key recursive descent
`[0,1,2]`	`users[0,1,2]`	Multi-index selection
`['a','b']`	`['name','age']`	Multi-key selection
`[0:5]`	`items[0:5]`	Slice — indices 0 through 4
`[::2]`	`items[::2]`	Slice with step
`[::-1]`	`items[::-1]`	Reverse slice
`[?expr]`	`users[?age>18]`	Filter predicate expression
`.{fields}`	`.{name, age}`	Projection — select fields
`.{alias: src}`	`.{fullName: name}`	Aliased projection

Filter expressions

$data = Inline::fromJson('[
    {"name": "Alice", "age": 25, "role": "admin"},
    {"name": "Bob",   "age": 17, "role": "user"},
    {"name": "Carol", "age": 30, "role": "admin"}
]');

// Comparison: ==, !=, >, <, >=, <=
$data->get('[?age>18]');                          // Alice and Carol

// Logical: && and ||
$data->get('[?age>18 && role==\'admin\']');       // Alice and Carol

// Built-in functions: starts_with, contains, values
$data->get('[?starts_with(@.name, \'A\')]');      // Alice
$data->get('[?contains(@.name, \'ob\')]');        // Bob

// Arithmetic: +, -, *, /
$orders = Inline::fromJson('[{"price": 10, "qty": 5}, {"price": 3, "qty": 2}]');
$orders->get('[?@.price * @.qty > 20]');          // first order only

Supported formats

JSON

$accessor = Inline::fromJson('{"users": [{"name": "Alice"}, {"name": "Bob"}]}');
$accessor->get('users.0.name'); // 'Alice'

YAML

$yaml = <<<YAML
database:
  host: localhost
  port: 5432
  credentials:
    user: admin
YAML;

$accessor = Inline::fromYaml($yaml);
$accessor->get('database.credentials.user'); // 'admin'

XML

$xml = '<config><database><host>localhost</host></database></config>';
$accessor = Inline::fromXml($xml);
$accessor->get('database.host'); // 'localhost'

// Also accepts SimpleXMLElement
$accessor = Inline::fromXml(simplexml_load_string($xml));

INI

$accessor = Inline::fromIni("[database]\nhost=localhost\nport=5432");
$accessor->get('database.host'); // 'localhost'

ENV (dotenv)

$accessor = Inline::fromEnv("APP_NAME=MyApp\nAPP_DEBUG=true\nDB_HOST=localhost");
$accessor->get('DB_HOST'); // 'localhost'

NDJSON

Each line is parsed as an independent JSON object and indexed from 0 by its position in the input. Blank lines and trailing newlines are skipped. Security validation is applied to each line individually.

$ndjson = '{"id":1,"name":"Alice"}' . "\n" . '{"id":2,"name":"Bob"}';
$accessor = Inline::fromNdjson($ndjson);
$accessor->get('0.name'); // 'Alice'
$accessor->get('1.name'); // 'Bob'

Array / Object

$accessor = Inline::fromArray(['users' => [['name' => 'Alice'], ['name' => 'Bob']]]);
$accessor->get('users.0.name'); // 'Alice'

$accessor = Inline::fromObject((object) ['name' => 'Alice']);
$accessor->get('name'); // 'Alice'

Any (custom format via integration)

use SafeAccess\Inline\Contracts\ParseIntegrationInterface;

// Requires implementing ParseIntegrationInterface
$accessor = Inline::withParserIntegration(new MyCsvIntegration())->fromAny($csvString);
$accessor->get('0.column_name');

Dynamic (by TypeFormat enum)

use SafeAccess\Inline\Enums\TypeFormat;
$accessor = Inline::from(TypeFormat::Json, '{"key": "value"}');
$accessor->get('key'); // 'value'

Reading & writing

$accessor = Inline::fromJson('{"a": {"b": 1, "c": 2}}');

// Read
$accessor->get('a.b');                  // 1
$accessor->get('a.missing', 'default'); // 'default'
$accessor->getOrFail('a.b');            // 1 (throws PathNotFoundException if missing)
$accessor->has('a.b');                  // true
$accessor->all();                       // ['a' => ['b' => 1, 'c' => 2]]
$accessor->count();                     // 1 (root keys)
$accessor->count('a');                  // 2 (keys under 'a')
$accessor->keys();                      // ['a']
$accessor->keys('a');                   // ['b', 'c']
$accessor->getMany([
    'a.b' => null,
    'a.x' => 'fallback',
]);                                     // ['a.b' => 1, 'a.x' => 'fallback']
$accessor->getRaw();                    // original JSON string

// Write (immutable - every write returns a new instance)
$updated = $accessor->set('a.d', 3);
$updated = $updated->remove('a.c');
$updated = $updated->merge('a', ['e' => 4]);
$updated = $updated->mergeAll(['f' => 5]);
$updated->all();                        // ['a' => ['b' => 1, 'd' => 3, 'e' => 4], 'f' => 5]

// Readonly mode - block all writes
$readonly = $accessor->readonly();
$readonly->get('a.b');                  // 1 (reads work)
$readonly->set('a.b', 99);             // throws ReadonlyViolationException

Configure

Builder pattern

use SafeAccess\Inline\Inline;
use SafeAccess\Inline\Security\SecurityGuard;
use SafeAccess\Inline\Security\SecurityParser;

$accessor = Inline::withSecurityGuard(new SecurityGuard(extraForbiddenKeys: ['secret']))
    ->withSecurityParser(new SecurityParser(maxDepth: 5))
    ->withStrictMode(true)
    ->fromJson($untrustedInput);

Builder methods

Method	Description
`withSecurityGuard($guard)`	Custom forbidden-key rules and depth limits
`withSecurityParser($parser)`	Custom payload size and structural limits
`withPathCache($cache)`	Path segment cache for repeated lookups
`withParserIntegration($integration)`	Custom format parser for `fromAny()`
`withStrictMode(false)`	Disable security validation (trusted input only)

Error handling

All exceptions extend AccessorException:

use SafeAccess\Inline\Exceptions\AccessorException;
use SafeAccess\Inline\Exceptions\InvalidFormatException;
use SafeAccess\Inline\Exceptions\SecurityException;
use SafeAccess\Inline\Exceptions\PathNotFoundException;
use SafeAccess\Inline\Exceptions\ReadonlyViolationException;

try {
    $accessor = Inline::fromJson($untrustedInput);
    $value = $accessor->getOrFail('config.key');
} catch (InvalidFormatException $e) {
    // Malformed JSON, XML, INI, or NDJSON
} catch (SecurityException $e) {
    // Forbidden key, payload too large, depth/key-count exceeded
} catch (PathNotFoundException $e) {
    // Path does not exist
} catch (ReadonlyViolationException $e) {
    // Write on readonly accessor
} catch (AccessorException $e) {
    // Catch-all for any library error
}

Exception hierarchy

Exception	Extends	When
`AccessorException`	`RuntimeException`	Root — catch-all
`SecurityException`	`AccessorException`	Forbidden key, payload, structural limits
`InvalidFormatException`	`AccessorException`	Malformed JSON, XML, INI, NDJSON
`YamlParseException`	`InvalidFormatException`	Unsafe or malformed YAML
`PathNotFoundException`	`AccessorException`	`getOrFail()` on missing path
`ReadonlyViolationException`	`AccessorException`	Write on readonly accessor
`UnsupportedTypeException`	`AccessorException`	Unknown accessor class in `make()`
`ParserException`	`AccessorException`	Internal parser errors

Advanced usage

Strict mode

// Disable all security validation for trusted input
$accessor = Inline::withStrictMode(false)->fromJson($trustedPayload);

Warning: Disabling strict mode skips all validation. Only use with application-controlled input.

Path cache

// Implement PathCacheInterface for repeated lookups
$cache = new MyPathCache();
$accessor = Inline::withPathCache($cache)->fromJson($data);
$accessor->get('deeply.nested.path'); // parses path
$accessor->get('deeply.nested.path'); // cache hit

Custom format integration

// Implement ParseIntegrationInterface for custom formats
class CsvIntegration implements ParseIntegrationInterface
{
    public function assertFormat(mixed $raw): bool
    {
        return is_string($raw) && str_contains($raw, ',');
    }

    public function parse(mixed $raw): array
    {
        // Parse CSV to associative array
        return $parsed;
    }
}

$accessor = Inline::withParserIntegration(new CsvIntegration())->fromAny($csvString);

API reference

`Inline` facade

Static factory methods

Method	Input	Returns
`fromArray($data)`	`array<array-key, mixed>`	`ArrayAccessor`
`fromObject($data)`	`object`	`ObjectAccessor`
`fromJson($data)`	JSON `string`	`JsonAccessor`
`fromXml($data)`	XML `string` or `SimpleXMLElement`	`XmlAccessor`
`fromYaml($data)`	YAML `string`	`YamlAccessor`
`fromIni($data)`	INI `string`	`IniAccessor`
`fromEnv($data)`	dotenv `string`	`EnvAccessor`
`fromNdjson($data)`	NDJSON `string`	`NdjsonAccessor`
`fromAny($data, $integration?)`	`mixed`	`AnyAccessor`
`from($typeFormat, $data)`	`TypeFormat` enum	`AccessorsInterface`
`make($class, $data)`	`class-string`	`AbstractAccessor`

Accessor read methods

Method	Returns
`get($path, $default?)`	Value at path, or default
`getOrFail($path)`	Value or throws `PathNotFoundException`
`getAt($segments, $default?)`	Value at key segments
`has($path)`	`bool`
`hasAt($segments)`	`bool`
`getMany($paths)`	`array<string, mixed>`
`all()`	`array<string, mixed>`
`count($path?)`	`int`
`keys($path?)`	`list<string>`
`getRaw()`	`mixed`

Accessor write methods (immutable)

Method	Description
`set($path, $value)`	Set at path
`setAt($segments, $value)`	Set at key segments
`remove($path)`	Remove at path
`removeAt($segments)`	Remove at key segments
`merge($path, $value)`	Deep-merge at path
`mergeAll($value)`	Deep-merge at root

Modifier methods

Method	Description
`readonly($flag?)`	Block all writes
`strict($flag?)`	Toggle security validation

TypeFormat enum

Array · Object · Json · Xml · Yaml · Ini · Env · Ndjson · Any

Contributing

See CONTRIBUTING.md for development setup, commit conventions, and pull request guidelines.

Name		Name	Last commit message	Last commit date
Latest commit History 18 Commits
scripts		scripts
src		src
tests		tests
.gitattributes		.gitattributes
.gitkeep		.gitkeep
.php-cs-fixer.dist.php		.php-cs-fixer.dist.php
CHANGELOG.md		CHANGELOG.md
LICENSE		LICENSE
README.md		README.md
composer.json		composer.json
composer.lock		composer.lock
infection.json		infection.json
phpstan.neon		phpstan.neon
phpunit.xml.dist		phpunit.xml.dist

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