feat(server): add generic url upload provider

server/providers/uploads/url/index.ts

@@ -0,0 +1,24 @@
+import { Provider } from '../../../uploads/provider'
+
+interface UrlProviderOptions {
+  templateUrl: string;
+}
+
+// assumes URL will always resolve to a file
+// uploaders should interact with the storage provider directly
+export default class UrlProvider implements Provider {
+  private templateUrl: string
+
+  constructor (_options: Partial<UrlProviderOptions>) {
+    const options: Required<UrlProviderOptions> = {
+      templateUrl: _options.templateUrl || 'https://storageaccount.blob.core.windows.net/uploads/{{name}}'
+    }
+
+    this.templateUrl = options.templateUrl
+  }
+
+  upload = async (data: Buffer): Promise<string> => data.toString()
+  getUrl = async (sha256: string, name: string): Promise<string|null> => this.templateUrl
+    .replace('{{sha256}}', sha256)
+    .replace('{{name}}', name)
+}