implement object storage

1 files changed, 62 insertions, 0 deletions

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);
+}
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