Merge pull request #32 from square/mommy-daddy

Set parent relations

src/Json.php

@@ -18,6 +18,12 @@ class Json
 {
     protected array $path;
 
+    /**
+     * Sometimes we want to link back to the parent object.
+     * This is a reference to the parent objects available for such cases.
+     */
+    protected static array $parentStack = [];
+
     protected string $type;
 
     protected bool $omit_empty;
@@ -64,11 +70,39 @@ public function forProperty(ReflectionProperty $prop): Json
         return $this;
     }
 
+    /**
+     * Adds a parent in the stack of parents that we use to be able to link parents
+     * from the children objects.
+     */
+    public static function withParent(mixed $parent, callable $cb): mixed
+    {
+        static::$parentStack[] = $parent;
+        try {
+            return $cb();
+        } finally {
+            array_pop(static::$parentStack);
+        }
+    }
+
+    /**
+     * Whether or not we marked this property as linking back to the parent object.
+     * This is done via a separate attribute JsonParent
+     */
+    public function linksToParentObject(): bool
+    {
+        return false;
+    }
+
     /**
      * Builds the PHP value from the json data and a type if available
      */
     public function retrieveValue(?array $data, ReflectionNamedType|ReflectionUnionType|null $type = null)
     {
+        if ($this->linksToParentObject()) {
+            end(static::$parentStack);
+
+            return prev(static::$parentStack);
+        }
         foreach ($this->path as $pathBit) {
             if (! array_key_exists($pathBit, $data)) {
                 return $this->handleMissingValue($data);

src/JsonParent.php

@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Square\Pjson;
+
+use Attribute;
+
+/**
+ * Allows linking a deserialized json item to its parent
+ * There is no intention for this library to handle more complex backwards lookign paths than
+ * this one.
+ * Those more complex paths can easily be handled by methods that traverse the entire
+ * data structure once it is in memory once the parent is available.
+ * So encoding something like parent->property->parent->parent->property->property is left to be
+ * implemented in client code
+ */
+#[Attribute(Attribute::TARGET_PROPERTY)]
+class JsonParent extends Json
+{
+    /**
+     * No constructor params are made available in this case as we do not allow customizing how we link
+     * to the parent object. There is only one parent object available, that is the one we are linking to
+     * and that's it.
+     */
+    public function __construct()
+    {
+        $this->path = [];
+        $this->omit_empty = false;
+    }
+
+    public function linksToParentObject(): bool
+    {
+        return true;
+    }
+}

src/JsonSerialize.php

@@ -1,16 +1,20 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 namespace Square\Pjson;
 
+use const JSON_THROW_ON_ERROR;
+
 use ReflectionAttribute;
 use Square\Pjson\Internal\RClass;
-use const JSON_THROW_ON_ERROR;
 
 trait JsonSerialize
 {
-    public function toJson(int $flags = 0, int $depth = 512) : string
+    public function toJson(int $flags = 0, int $depth = 512): string
     {
         $flags |= JSON_THROW_ON_ERROR;
+
         return json_encode($this->toJsonData(), flags: $flags, depth: $depth);
     }
 
@@ -33,14 +37,15 @@ public function toJsonData()
         return $d;
     }
 
-    public static function toJsonListData(array $data) : array
+    public static function toJsonListData(array $data): array
     {
         return array_map(fn ($d) => $d->toJsonData(), $data);
     }
 
-    public static function toJsonList(array $data, int $flags = 0, int $depth = 512) : string
+    public static function toJsonList(array $data, int $flags = 0, int $depth = 512): string
     {
         $flags |= JSON_THROW_ON_ERROR;
+
         return json_encode(static::toJsonListData($data), flags: $flags, depth: $depth);
     }
 
@@ -49,9 +54,10 @@ public static function fromJsonString(
         array|string $path = [],
         int $depth = 512,
         int $flags = 0,
-    ) : static {
+    ): static {
         $flags |= JSON_THROW_ON_ERROR;
         $jd = json_decode($json, associative: true, flags: $flags, depth: $depth);
+
         return self::fromJsonData($jd, $path);
     }
 
@@ -60,24 +66,26 @@ public static function listFromJsonString(
         array|string $path = [],
         int $depth = 512,
         int $flags = 0,
-    ) : array {
+    ): array {
         $flags |= JSON_THROW_ON_ERROR;
         $jd = json_decode($json, associative: true, flags: $flags, depth: $depth);
+
         return static::listfromJsonData($jd, $path);
     }
 
-    public static function listfromJsonData(array $json, array|string $path = []) : array
+    public static function listfromJsonData(array $json, array|string $path = []): array
     {
         if (is_string($path)) {
             $path = [$path];
         }
         foreach ($path as $pathBit) {
             $json = $json[$pathBit];
         }
+
         return array_map(fn ($d) => static::fromJsonData($d), $json);
     }
 
-    public static function fromJsonData($jd, array|string $path = []) : static
+    public static function fromJsonData($jd, array|string $path = []): static
     {
         if (is_string($path)) {
             $path = [$path];
@@ -97,13 +105,14 @@ public static function fromJsonData($jd, array|string $path = []) : static
             $a = $attrs[0];
 
             $type = $prop->getType();
-            $v = $a->newInstance()->forProperty($prop)->retrieveValue($jd, $type);
-            if (is_null($v) && $type && !$type->allowsNull()) {
+            $v = Json::withParent($return, fn () => $a->newInstance()->forProperty($prop)->retrieveValue($jd, $type));
+            if (is_null($v) && $type && ! $type->allowsNull()) {
                 continue;
             }
 
             $prop->setValue($return, $v);
         }
+
         return $return;
     }
 }

tests/DeSerializationTest.php

@@ -16,6 +16,7 @@
 use Square\Pjson\Tests\Definitions\Category;
 use Square\Pjson\Tests\Definitions\Collection;
 use Square\Pjson\Tests\Definitions\Collector;
+use Square\Pjson\Tests\Definitions\LinkParent;
 use Square\Pjson\Tests\Definitions\MenuList;
 use Square\Pjson\Tests\Definitions\Privateer;
 use Square\Pjson\Tests\Definitions\Schedule;
@@ -672,4 +673,26 @@ public function testUnionTypesUsingArrayAndCustomObject()
             ],
         ]);
     }
+
+    public function testLinkToParent()
+    {
+        $d = LinkParent::fromJsonString('{
+            "name": "Millie",
+            "child": {
+                "name": "bob"
+            },
+            "children": [
+                {"name": "Alice"},
+                {"name": "Caroline"}
+            ]
+        }');
+
+        $this->assertEquals($d->name, 'Millie');
+        $this->assertEquals($d->child->name, 'bob');
+        $this->assertEquals($d->child->parent, $d);
+        $this->assertEquals($d->children[0]->name, 'Alice');
+        $this->assertEquals($d->children[0]->parent, $d);
+        $this->assertEquals($d->children[1]->name, 'Caroline');
+        $this->assertEquals($d->children[1]->parent, $d);
+    }
 }

tests/Definitions/LinkChild.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Square\Pjson\Tests\Definitions;
+
+use Square\Pjson\Json;
+use Square\Pjson\JsonParent;
+use Square\Pjson\JsonSerialize;
+
+class LinkChild
+{
+    use JsonSerialize;
+
+    #[Json]
+    public string $name;
+
+    #[JsonParent]
+    public LinkParent $parent;
+}

tests/Definitions/LinkParent.php

@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Square\Pjson\Tests\Definitions;
+
+use Square\Pjson\Json;
+use Square\Pjson\JsonSerialize;
+
+class LinkParent
+{
+    use JsonSerialize;
+
+    #[Json]
+    public LinkChild $child;
+
+    #[Json(type: LinkChild::class)]
+    public array $children;
+
+    #[Json]
+    public string $name;
+}

tests/SerializationTest.php

@@ -1,9 +1,12 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
+
 namespace Square\Pjson\Tests;
 
 use PHPUnit\Framework\TestCase;
-use Square\Pjson\JsonSerialize;
 use Square\Pjson\Json;
+use Square\Pjson\JsonSerialize;
 use Square\Pjson\Tests\Definitions\BigCat;
 use Square\Pjson\Tests\Definitions\BigInt;
 use Square\Pjson\Tests\Definitions\CatalogCategory;
@@ -12,6 +15,7 @@
 use Square\Pjson\Tests\Definitions\Category;
 use Square\Pjson\Tests\Definitions\Child;
 use Square\Pjson\Tests\Definitions\Collector;
+use Square\Pjson\Tests\Definitions\LinkParent;
 use Square\Pjson\Tests\Definitions\MenuList;
 use Square\Pjson\Tests\Definitions\Privateer;
 use Square\Pjson\Tests\Definitions\Schedule;
@@ -44,7 +48,7 @@ public function testNullableProperty()
     public function testSerializeAcceptsJsonFlags()
     {
         $c = new Category;
-        $expected = <<<JSON
+        $expected = <<<'JSON'
         {
             "identifier": "myid",
             "category_name": "Clothes",
@@ -54,13 +58,13 @@ public function testSerializeAcceptsJsonFlags()
         }
         JSON;
 
-
         $this->assertEquals($expected, $c->toJson(flags: JSON_PRETTY_PRINT));
     }
 
     public function testSerializeThrowsOnJsonError()
     {
-        $c = new class {
+        $c = new class
+        {
             use JsonSerialize;
 
             public function __construct(
@@ -239,7 +243,7 @@ public function testList()
     public function testClassToScalar()
     {
         $stats = new Stats;
-        $stats->count = new BigInt("123456789876543234567898765432345678976543234567876543212345678765432");
+        $stats->count = new BigInt('123456789876543234567898765432345678976543234567876543212345678765432');
         $this->assertEquals(
             '{"count":"123456789876543234567898765432345678976543234567876543212345678765432"}',
             $stats->toJson()
@@ -306,14 +310,32 @@ public function testMissingParent()
     {
         // Ensure that while the `parent` object is null, we can still serialize the parent.id property which is
         // nested under `parent`.
-        $data = new Child();
+        $data = new Child;
         $json = '{"identifier":null,"parent":{"id":null}}';
 
         $this->assertEquals($this->comparableJson($json), $data->toJson());
     }
 
-    protected function comparableJson(string $json) : string
+    protected function comparableJson(string $json): string
     {
         return json_encode(json_decode($json));
     }
+
+    public function testLinkedParents()
+    {
+        $d = LinkParent::fromJsonString('{
+            "name": "Millie",
+            "child": {
+                "name": "bob"
+            },
+            "children": [
+                {"name": "Alice"},
+                {"name": "Caroline"}
+            ]
+        }');
+
+        $this->assertEquals(json_encode(json_decode(
+            '{"child":{"name":"bob"},"children":[{"name":"Alice"},{"name":"Caroline"}],"name":"Millie"}'
+        )), $d->toJson());
+    }
 }