Provide a public variable "NEXT_PUBLIC_KEYSTATIC_STORAGE_KIND" to allow Keystatic to detect the storage client-side. This is fundamental to make the Admin work.

packages/cms/keystatic/src/keystatic-storage.ts

@@ -0,0 +1,67 @@
+import { CloudConfig, GitHubConfig, LocalConfig } from '@keystatic/core';
+import { z } from 'zod';
+
+type ZodOutputFor<T> = z.ZodType<T, z.ZodTypeDef, unknown>;
+
+/**
+ * @name STORAGE_KIND
+ * @description The kind of storage to use for the Keystatic reader.
+ *
+ * This can be provided through the `KEYSTATIC_STORAGE_KIND` environment variable or 'NEXT_PUBLIC_KEYSTATIC_STORAGE_KIND'.
+ * The previous environment variable `KEYSTATIC_STORAGE_KIND` is deprecated - as Keystatic may need this to be available in the client-side.
+ *
+ */
+const STORAGE_KIND = process.env.NEXT_PUBLIC_KEYSTATIC_STORAGE_KIND ??
+    /* @deprecated */
+    process.env.KEYSTATIC_STORAGE_KIND ??
+    'local';
+
+const PROJECT = process.env.KEYSTATIC_STORAGE_PROJECT;
+const REPO = process.env.KEYSTATIC_STORAGE_REPO;
+const BRANCH_PREFIX = process.env.KEYSTATIC_STORAGE_BRANCH_PREFIX;
+const PATH_PREFIX = process.env.KEYSTATIC_PATH_PREFIX;
+
+/**
+ * @name local
+ * @description The configuration for the local storage.
+ */
+const local = z.object({
+  kind: z.literal('local'),
+}) satisfies ZodOutputFor<LocalConfig['storage']>;
+
+/**
+ * @name cloud
+ * @description The configuration for the cloud storage.
+ */
+const cloud = z.object({
+  kind: z.literal('cloud'),
+  project: z.string({
+    description: `The Keystatic Cloud project. Please provide the value through the "KEYSTATIC_STORAGE_PROJECT" environment variable.`,
+  }).min(1),
+  branchPrefix: z.string().optional(),
+  pathPrefix: z.string().optional(),
+}) satisfies ZodOutputFor<CloudConfig['storage']>;
+
+/**
+ * @name github
+ * @description The configuration for the GitHub storage.
+ */
+const github = z.object({
+  kind: z.literal('github'),
+  repo: z.custom<`${string}/${string}`>(),
+  branchPrefix: z.string().optional(),
+  pathPrefix: z.string().optional(),
+}) satisfies ZodOutputFor<GitHubConfig['storage']>;
+
+/**
+ * @name KeystaticStorage
+ * @description The configuration for the Keystatic storage. This is used to determine where the content is stored.
+ * This configuration is validated through Zod to ensure that the configuration is correct.
+ */
+export const KeystaticStorage = z.union([local, cloud, github]).parse({
+  kind: STORAGE_KIND,
+  project: PROJECT,
+  repo: REPO,
+  branchPrefix: BRANCH_PREFIX,
+  pathPrefix: PATH_PREFIX,
+});