Route to validate user existence in workspace. (#7456)

* Route to validate user existence in workspace.

* Case insensitive check

* io-ts and using resources

* Nits

front/pages/api/v1/w/[wId]/members/validate.ts

@@ -0,0 +1,82 @@
+import type { WithAPIErrorResponse } from "@dust-tt/types";
+import { isLeft } from "fp-ts/lib/Either";
+import * as t from "io-ts";
+import * as reporter from "io-ts-reporters";
+import type { NextApiRequest, NextApiResponse } from "next";
+
+import { withPublicAPIAuthentication } from "@app/lib/api/wrappers";
+import type { Authenticator } from "@app/lib/auth";
+import { MembershipResource } from "@app/lib/resources/membership_resource";
+import { UserResource } from "@app/lib/resources/user_resource";
+import { apiError } from "@app/logger/withlogging";
+
+export type ValidateMemberResponseBody = {
+  valid: boolean;
+};
+
+/**
+ * @ignoreswagger
+ * Validates an email corresponds to an active member in a specific workspace. For Dust managed apps only - undocumented.
+ */
+
+export const PostValidateMemberRequestBodySchema = t.type({
+  email: t.string,
+});
+
+async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse<WithAPIErrorResponse<ValidateMemberResponseBody>>,
+  auth: Authenticator
+): Promise<void> {
+  const bodyValidation = PostValidateMemberRequestBodySchema.decode(req.body);
+
+  if (isLeft(bodyValidation)) {
+    const pathError = reporter.formatValidationErrors(bodyValidation.left);
+
+    return apiError(req, res, {
+      status_code: 400,
+      api_error: {
+        type: "invalid_request_error",
+        message: `Invalid request body: ${pathError}`,
+      },
+    });
+  }
+
+  const { email } = bodyValidation.right;
+
+  switch (req.method) {
+    case "POST":
+      const user = await UserResource.fetchByEmail(email);
+
+      const workspace = auth.getNonNullableWorkspace();
+
+      if (!user) {
+        return res.status(200).json({
+          valid: false,
+        });
+      }
+
+      const workspaceMembership =
+        await MembershipResource.getActiveMembershipOfUserInWorkspace({
+          user,
+          workspace,
+        });
+
+      const valid = !!workspaceMembership;
+
+      return res.status(200).json({
+        valid,
+      });
+
+    default:
+      return apiError(req, res, {
+        status_code: 405,
+        api_error: {
+          type: "method_not_supported_error",
+          message: "The method passed is not supported, POST is expected.",
+        },
+      });
+  }
+}
+
+export default withPublicAPIAuthentication(handler);