implement remote object fetching!

this is most of the tricky parts of inbound federation :3

1 files changed, 78 insertions, 0 deletions

diff --git a/WpfTest/Model/FetchableModel.php b/WpfTest/Model/FetchableModel.php
new file mode 100644
index 0000000..44106d4
--- /dev/null
+++ b/WpfTest/Model/FetchableModel.php
@@ -0,0 +1,78 @@
+<?php
+namespace WpfTest\Model;
+
+use WpfTest\Model;
+use WpfTest\RemoteFetchable;
+
+abstract class FetchableModel extends Model implements RemoteFetchable {
+    private static \JsonMapper $mapper;
+
+    public static function __initStatic() {
+        self::$mapper = new \JsonMapper();
+        // this is unfortunately necessary to parse DateTime(Immutable)s properly
+        self::$mapper->bStrictObjectTypeChecking = false;
+    }
+
+    private static function fetchFromRemote(string $uri, bool $autoSave): ?static {
+        // fetch the object
+        $data = @file_get_contents($uri, context: stream_context_create(['http' => [
+            'header' => 'Accept: application/json'
+        ]]));
+        if ($data === false)
+            return null;
+        $data = json_decode($data);
+        if ($data === false)
+            return null;
+        // default everything nullable to null
+        $obj = new static();
+        $reflProps = (new \ReflectionClass(static::class))->getProperties();
+        foreach ($reflProps as $reflProp) {
+            assert($reflProp instanceof \ReflectionProperty); // for intellisense lmao
+            if ($reflProp->getType()->allowsNull()) {
+                $obj->{$reflProp->getName()} = null;
+            }
+        }
+        // rename 'self' to 'uri' because of reasons
+        if (property_exists($data, 'self')) {
+            $data->uri = $data->self;
+            unset($data->self);
+        }
+        // map all present fields
+        self::$mapper->map($data, $obj);
+        // (hopefully) recursively fetch any other fetchable models contained in this one
+        foreach ($reflProps as $reflProp) {
+            assert($reflProp instanceof \ReflectionProperty);
+            $reflType = $reflProp->getType();
+            $propName = $reflProp->getName();
+            if (!($reflType instanceof \ReflectionNamedType))
+                continue;
+            $type = $reflType->getName();
+            if (is_subclass_of($type, FetchableModel::class) && is_string($data->{$propName})) {
+                // try to avoid recursion
+                // TODO: make a better effort at avoiding recursion (e.g. when it's more than one step nested)
+                if ($data->{$propName} == $uri) {
+                    $obj->{$propName} = $obj;
+                } else {
+                    $obj->{$propName} = $type::findByUri($data->{$propName}, $autoSave);
+                }
+            }
+        }
+
+        if ($autoSave) {
+            $obj->save();
+        }
+
+        return $obj;
+    }
+
+    public static function findByUri(string $uri, bool $autoSave = true, bool $forceRefetch = false): ?static {
+        if (!$forceRefetch) {
+            $obj = static::findWhere('uri = ?', [$uri]);
+            if ($obj != null)
+                return $obj;
+        }
+        return static::fetchFromRemote($uri, $autoSave);
+    }
+}
+
+FetchableModel::__initStatic();
\ No newline at end of file