Impl. file domain layer

[Re #1543]

* Also added a generic function in the gpml.domain.types namespace to
generate the Malli schema for a given type. Which comes in handy as we
always endup writing the same code for enums.

backend/src/gpml/domain/file.clj

@@ -0,0 +1,70 @@
+(ns gpml.domain.file
+  (:require [clojure.string :as str]
+            [gpml.domain.miscellaneous :as dom.misc]
+            [gpml.domain.types :as dom.types]
+            [gpml.util :as util]
+            [malli.core :as m])
+  (:import [java.io File]))
+
+(def ^:const object-key-pattern
+  "Pattern to define the object key of the file in the object storage.
+  Example:
+
+  - event/images/12fd5c76-7f12-4084-a9ca-a834d030977d"
+  "ENTITY-KEY/FILE-KEY/FILE-ID")
+
+(def file-schema
+  (m/schema
+   [:map
+    {:closed true}
+    [:id uuid?]
+    [:object-key
+     [:string
+      {:min 1}]]
+    [:name
+     [:string
+      {:min 1}]]
+    [:alt-desc
+     {:optional true}
+     [:maybe
+      [:string
+       {:min 1}]]]
+    [:type
+     [:string
+      {:min 1}]]
+    [:extension
+     {:optional true}
+     [:maybe
+      [:string]]]
+    [:visibility
+     (dom.types/get-type-schema :file-visibility)]
+    [:content
+     {:optional true}
+     [:or
+      dom.misc/base64-schema
+      [:fn #(instance? File %)]]]
+    [:created-at inst?]
+    [:last-updated-at
+     {:optional true}
+     inst?]]))
+
+(defn create-file-object-key
+  [entity-key file-key file-id]
+  (-> object-key-pattern
+      (str/replace #"ENTITY-KEY" (name entity-key))
+      (str/replace #"FILE-KEY" (name file-key))
+      (str/replace #"FILE-ID" (str file-id))))
+
+(defn base64->file
+  [payload entity-key file-key visibility]
+  (let [[_ ^String content-type ^String content] (re-find #"^data:(\S+);base64,(.*)$" payload)
+        [_ extension] (str/split content-type #"\/")
+        file-id (util/uuid)]
+    {:id file-id
+     :object-key (create-file-object-key entity-key file-key file-id)
+     :name (format "%s-%s" (name entity-key) (util/uuid))
+     :alt-desc nil
+     :type content-type
+     :extension extension
+     :visibility visibility
+     :content content}))

backend/src/gpml/domain/miscellaneous.clj

@@ -0,0 +1,12 @@
+(ns gpml.domain.miscellaneous
+  (:require [malli.core :as m]))
+
+(def base64-schema
+  (m/schema
+   [:and
+    [:string]
+    [:or
+     [:= ""]
+     [:and
+      [:re #"[0-9a-zA-Z+/]+={0,2}"]
+      [:fn #(= 0 (rem (count %) 4))]]]]))

backend/src/gpml/domain/types.clj

@@ -1,6 +1,7 @@
 (ns gpml.domain.types
   "Well-known domain global types definitions. These types are used
-  across the domain model by several entities.")
+  across the domain model by several entities."
+  (:require [malli.core :as m]))
 
 ;; TODO: Refactor enums to be keywords instead of strings.
 (def ^:const review-statuses
@@ -77,3 +78,26 @@
     "financing_resource"
     "technical_resource"
     "action_plan"})
+
+(def ^:const file-visibility
+  "Informs about a file's accessability privilegies."
+  #{:private
+    :public})
+
+(def ^:const enum-types
+  {:review-status review-statuses
+   :reviewer-status reviewer-review-statuses
+   :geo-coverage-type geo-coverage-types
+   :association-type association-types
+   :resource-source resource-source-types
+   :topic-entity-table topic-entity-tables
+   :topic-type topic-types
+   :resource-type resources-types
+   :file-visibility file-visibility})
+
+(defn get-type-schema
+  [type-name]
+  (m/schema
+   [:and
+    [:keyword]
+    (apply conj [:enum] (get enum-types type-name))]))