🎉 Add plugable storages abstraction layer (with support for fs, s3 and db).

backend/src/app/storage/impl.clj

@@ -0,0 +1,181 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+;;
+;; This Source Code Form is "Incompatible With Secondary Licenses", as
+;; defined by the Mozilla Public License, v. 2.0.
+;;
+;; Copyright (c) 2020-2021 UXBOX Labs SL
+
+(ns app.storage.impl
+  "Storage backends abstraction layer."
+  (:require
+   [app.common.exceptions :as ex]
+   [app.common.spec :as us]
+   [app.common.uuid :as uuid]
+   [clojure.java.io :as io]
+   [buddy.core.codecs :as bc])
+  (:import
+   java.nio.ByteBuffer
+   java.util.UUID
+   java.io.ByteArrayInputStream
+   java.io.InputStream
+   java.nio.file.Path
+   java.nio.file.Files))
+
+;; --- API Definition
+
+(defmulti put-object (fn [cfg _ _] (:type cfg)))
+
+(defmethod put-object :default
+  [cfg _ _]
+  (ex/raise :type :internal
+            :code :invalid-storage-backend
+            :context cfg))
+
+(defmulti get-object (fn [cfg _] (:type cfg)))
+
+(defmethod get-object :default
+  [cfg _]
+  (ex/raise :type :internal
+            :code :invalid-storage-backend
+            :context cfg))
+
+(defmulti get-object-url (fn [cfg _ _] (:type cfg)))
+
+(defmethod get-object-url :default
+  [cfg _ _]
+  (ex/raise :type :internal
+            :code :invalid-storage-backend
+            :context cfg))
+
+
+(defmulti del-objects-in-bulk (fn [cfg _] (:type cfg)))
+
+(defmethod del-objects-in-bulk :default
+  [cfg _]
+  (ex/raise :type :internal
+            :code :invalid-storage-backend
+            :context cfg))
+
+
+;; --- HELPERS
+
+(defn uuid->hex
+  [^UUID v]
+  (let [buffer (ByteBuffer/allocate 16)]
+    (.putLong buffer (.getMostSignificantBits v))
+    (.putLong buffer (.getLeastSignificantBits v))
+    (bc/bytes->hex (.array buffer))))
+
+(defn id->path
+  [id]
+  (let [tokens (->> (uuid->hex id)
+                    (re-seq #"[\w\d]{2}"))
+        prefix (take 2 tokens)
+        suffix (drop 2 tokens)]
+    (str (apply str (interpose "/" prefix))
+         "/"
+         (apply str suffix))))
+
+(defn coerce-id
+  [id]
+  (cond
+    (string? id) (uuid/uuid id)
+    (uuid? id) id
+    :else (ex/raise :type :internal
+                    :code :invalid-id-type
+                    :hint "id should be string or uuid")))
+
+
+(defprotocol IContentObject)
+
+(defn- path->content-object
+  [path]
+  (let [size (Files/size path)]
+    (reify
+      IContentObject
+      io/IOFactory
+      (make-reader [_ opts]
+	    (io/make-reader path opts))
+      (make-writer [_ opts]
+        (throw (UnsupportedOperationException. "not implemented")))
+      (make-input-stream [_ opts]
+        (io/make-input-stream path opts))
+      (make-output-stream [_ opts]
+        (throw (UnsupportedOperationException. "not implemented")))
+      clojure.lang.Counted
+      (count [_] size))))
+
+(defn string->content-object
+  [^String v]
+  (let [data (.getBytes v "UTF-8")
+        bais (ByteArrayInputStream. ^bytes data)]
+    (reify
+      IContentObject
+      io/IOFactory
+      (make-reader [_ opts]
+	    (io/make-reader bais opts))
+      (make-writer [_ opts]
+        (throw (UnsupportedOperationException. "not implemented")))
+      (make-input-stream [_ opts]
+        (io/make-input-stream bais opts))
+      (make-output-stream [_ opts]
+        (throw (UnsupportedOperationException. "not implemented")))
+
+      clojure.lang.Counted
+      (count [_]
+        (alength data)))))
+
+(defn- input-stream->content-object
+  [^InputStream is size]
+  (reify
+    IContentObject
+    io/IOFactory
+    (make-reader [_ opts]
+	  (io/make-reader is opts))
+    (make-writer [_ opts]
+      (throw (UnsupportedOperationException. "not implemented")))
+    (make-input-stream [_ opts]
+      (io/make-input-stream is opts))
+    (make-output-stream [_ opts]
+      (throw (UnsupportedOperationException. "not implemented")))
+
+      clojure.lang.Counted
+      (count [_] size)))
+
+(defn content-object
+  ([data] (content-object data nil))
+  ([data size]
+   (cond
+     (instance? java.nio.file.Path data)
+     (path->content-object data)
+
+     (instance? java.io.File data)
+     (path->content-object (.toPath ^java.io.File data))
+
+     (instance? String data)
+     (string->content-object data)
+
+     (instance? InputStream data)
+     (do
+       (when-not size
+         (throw (UnsupportedOperationException. "size should be provided on InputStream")))
+       (input-stream->content-object data size))
+
+     :else
+     (throw (UnsupportedOperationException. "type not supported")))))
+
+(defn content-object?
+  [v]
+  (satisfies? IContentObject v))
+
+(defn slurp-bytes
+  [content]
+  (us/assert content-object? content)
+  (with-open [input  (io/input-stream content)
+              output (java.io.ByteArrayOutputStream. (count content))]
+    (io/copy input output)
+    (.toByteArray output)))
+
+