implement object storage

3 files changed, 221 insertions, 0 deletions

diff --git a/Digitigrade/Model/StorageObject.php b/Digitigrade/Model/StorageObject.php
new file mode 100644
index 0000000..333b5b1
--- /dev/null
+++ b/Digitigrade/Model/StorageObject.php
@@ -0,0 +1,107 @@
+<?php
+namespace Digitigrade\Model;
+
+use Digitigrade\Model;
+use Digitigrade\StorageProvider;
+
+class StorageObject extends Model {
+    public string $oid;
+    public string $provider;
+    public string $token;
+    public string $filename;
+    public string $mimetype;
+    public \DateTimeImmutable $created;
+
+    /**
+     * Creates a new storage object on the given provider by consuming a local file
+     * @param string $provider class name of the storage provider to use
+     * @param string $path path to local file (will be deleted)
+     * @param bool $checkIsUpload if true, ensures that the local file was uploaded via HTTP
+     * @return self
+     */
+    public static function createFromFile(string $provider, string $path, string $filename, bool $checkIsUpload = false): self {
+        if (!is_file($path)) {
+            throw new \RuntimeException('local file does not exist');
+        }
+        $mimetype = mime_content_type($path);
+        $p = new $provider();
+        assert($p instanceof StorageProvider);
+        $token = $p->storeFile($path, $checkIsUpload);
+
+        $obj = new self();
+        $obj->oid = random_printable_bytes();
+        $obj->provider = $p::class;
+        $obj->token = $token;
+        $obj->filename = $filename;
+        $obj->mimetype = $mimetype;
+        $obj->created = new \DateTimeImmutable();
+
+        $obj->save();
+        return $obj;
+    }
+
+    public static function findByOid(string $oid): ?self {
+        return self::findWhere('oid = ?', [$oid]);
+    }
+
+    public static function findByProviderTokenPair(string $provider, string $token): ?self {
+        return self::findWhere('provider = ? AND token = ?', [$provider, $token]);
+    }
+
+    protected function getUpdateWhereClause(\PDO $db): ?string {
+        if (isset($this->oid) && self::findByOid($this->oid) != null) {
+            return 'oid = ' . $db->quote($this->oid);
+        }
+        if (self::findByProviderTokenPair($this->provider, $this->token) != null) {
+            return 'provider = ' . $db->quote($this->provider) . ' AND token = ' . $db->quote($this->token);
+        }
+        return null;
+    }
+
+    private function getProvider(): StorageProvider {
+        return new $this->provider();
+    }
+
+    /**
+     * Deletes this object from the storage backend and removes it from the database.
+     * @return void
+     */
+    public function delete() {
+        $this->getProvider()->delete($this->token);
+        $this->remove();
+    }
+
+    /**
+     * Gets the entire content of this object.
+     * @return string
+     */
+    public function retrieve(): string {
+        return $this->getProvider()->retrieve($this->token);
+    }
+
+    /**
+     * Streams the content of this object to the web client (stdout).
+     * @return void
+     */
+    public function passthrough() {
+        $this->getProvider()->passthrough($this->token, $this->mimetype);
+    }
+
+    /**
+     * Gets a direct public URL to this object, if one exists.
+     * @return ?string the URL or null if none is available
+     */
+    public function getDirectUrl(): ?string {
+        return $this->getProvider()->directUrl($this->token);
+    }
+
+    public function getUrl(bool $allowDirect = true): string {
+        if ($allowDirect) {
+            $url = $this->getDirectUrl();
+            if ($url != null) {
+                return $url;
+            }
+        }
+        return path_to_uri("/storage/$this->oid");
+    }
+}
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diff --git a/Digitigrade/StorageProvider.php b/Digitigrade/StorageProvider.php
new file mode 100644
index 0000000..53b3549
--- /dev/null
+++ b/Digitigrade/StorageProvider.php
@@ -0,0 +1,62 @@
+<?php
+namespace Digitigrade;
+
+abstract class StorageProvider {
+    public function __construct() {
+    }
+
+    /**
+     * Moves a file from the local filesystem to the storage backend. Deletes
+     * the file from the local filesystem.
+     * @param string $path the path to the file to store
+     * @param bool $checkIsUpload if true, verifies that the local file was
+     * uploaded via PHP's HHTP upload mechanism before doing anything with it
+     * @return ?string a token that uniquely identifies the new object on this
+     * provider, or null if it could not be stored for any reason
+     */
+    public function storeFile(string $path, bool $checkIsUpload = false): ?string {
+        if ($checkIsUpload && !is_uploaded_file($path)) {
+            return null;
+        }
+        return $this->storeFileInternal($path);
+    }
+
+    abstract protected function storeFileInternal(string $path): ?string;
+
+    /**
+     * @param string $token the token of the object to look for
+     * @return bool whether the requested object exists or not
+     */
+    abstract public function exists(string $token): bool;
+
+    /**
+     * Retrieves an object's contents from the storage backend.
+     * @param string $token the token of the object to retrieve
+     * @return ?string the entire content, or null if not found
+     */
+    abstract public function retrieve(string $token): ?string;
+
+    /**
+     * Gets a direct, public URL to the given object, if possible.
+     * @param string $token the token of the object to look up
+     * @return ?string the URL or null if one is not available
+     */
+    abstract public function directUrl(string $token): ?string;
+
+    /**
+     * Streams the data of an object to the web client (stdout).
+     * @param string $token the token of the object to retrieve
+     * @param ?string $mimetype value of the Content-Type header to send (if
+     * null, will try to figure it out anyway)
+     * @return void
+     */
+    abstract public function passthrough(string $token, ?string $mimetype = null);
+
+    /**
+     * Deletes an object from the backend. If the object doesn't exist, does
+     * nothing.
+     * @param string $token the token of the object to delete
+     * @return void
+     */
+    abstract public function delete(string $token);
+}
\ No newline at end of file
diff --git a/Digitigrade/StorageProvider/FilesystemStorage.php b/Digitigrade/StorageProvider/FilesystemStorage.php
new file mode 100644
index 0000000..8f67653
--- /dev/null
+++ b/Digitigrade/StorageProvider/FilesystemStorage.php
@@ -0,0 +1,52 @@
+<?php
+namespace Digitigrade\StorageProvider;
+
+use Digitigrade\StorageProvider;
+
+class FilesystemStorage extends StorageProvider {
+    private const BASE_PATH = __DIR__ . '/../../upload/';
+
+    private static function tokenToPath(string $token): string {
+        return self::BASE_PATH . $token;
+    }
+
+    protected function storeFileInternal(string $path): ?string {
+        $token = hash_file('sha256', $path);
+        rename($path, self::tokenToPath($token));
+        return $token;
+    }
+
+    public function exists(string $token): bool {
+        return is_file(self::tokenToPath($token));
+    }
+
+    public function retrieve(string $token): ?string {
+        $path = self::tokenToPath($token);
+        if (!is_readable($path)) {
+            return null;
+        }
+        return file_get_contents($path);
+    }
+
+    public function directUrl(string $token): ?string {
+        return path_to_uri("/upload/$token");
+    }
+
+    public function passthrough(string $token, ?string $mimetype = null) {
+        if (!$this->exists($token)) {
+            throw new \RuntimeException('requested object does not exist');
+        }
+        $path = self::tokenToPath($token);
+        if (!headers_sent()) {
+            header('Content-Type: ' . ($mimetype ?? (mime_content_type($path) ?: 'application/octet-stream')));
+        }
+        readfile($path);
+    }
+
+    public function delete(string $token) {
+        $path = self::tokenToPath($token);
+        if (is_file($path)) {
+            unlink($path);
+        }
+    }
+}
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