feat: add backend function versioning support

- Add extractSnapshotIdFromHost utility to detect environment from URL
- Include Base44-Functions-Version header in function calls
- Support functionsVersion parameter in client configuration
- Automatically route function calls to correct deployment based on URL pattern

This ensures backend functions work correctly with app versioning,
calling the right deployment for production, preview, and checkpoint environments.

Author: GabiGrin

src/client.ts

@@ -22,20 +22,29 @@ export function createClient(config: {
   token?: string;
   serviceToken?: string;
   requiresAuth?: boolean;
+  functionsVersion?: string;
 }) {
   const {
     serverUrl = "https://base44.app",
     appId,
     token,
     serviceToken,
     requiresAuth = false,
+    functionsVersion
   } = config;
 
+  const headers = {
+    "X-App-Id": String(appId),
+  }
+
+  const functionHeaders = functionsVersion ? {
+    ...headers,
+    "Base44-Functions-Version": functionsVersion
+  } : headers;
+
   const axiosClient = createAxiosClient({
     baseURL: `${serverUrl}/api`,
-    headers: {
-      "X-App-Id": String(appId),
-    },
+    headers,
     token,
     requiresAuth,
     appId,
@@ -44,9 +53,7 @@ export function createClient(config: {
 
   const functionsAxiosClient = createAxiosClient({
     baseURL: `${serverUrl}/api`,
-    headers: {
-      "X-App-Id": String(appId),
-    },
+    headers: functionHeaders,
     token,
     requiresAuth,
     appId,
@@ -56,19 +63,15 @@ export function createClient(config: {
 
   const serviceRoleAxiosClient = createAxiosClient({
     baseURL: `${serverUrl}/api`,
-    headers: {
-      "X-App-Id": String(appId),
-    },
+    headers,
     token: serviceToken,
     serverUrl,
     appId,
   });
 
   const serviceRoleFunctionsAxiosClient = createAxiosClient({
     baseURL: `${serverUrl}/api`,
-    headers: {
-      "X-App-Id": String(appId),
-    },
+    headers: functionHeaders,
     token: serviceToken,
     serverUrl,
     appId,
@@ -160,6 +163,7 @@ export function createClientFromRequest(request: Request) {
   );
   const appId = request.headers.get("Base44-App-Id");
   const serverUrlHeader = request.headers.get("Base44-Api-Url");
+  const functionsVersion = request.headers.get("Base44-Functions-Version");
 
   if (!appId) {
     throw new Error(
@@ -190,5 +194,6 @@ export function createClientFromRequest(request: Request) {
     appId,
     token: userToken,
     serviceToken: serviceRoleToken,
+    functionsVersion: functionsVersion ?? undefined
   });
 }

src/modules/functions.ts

@@ -1,4 +1,5 @@
 import { AxiosInstance } from "axios";
+import { extractSnapshotIdFromHost } from "../utils/extract-snapshot-id-from-host.js";
 
 /**
  * Creates the functions module for the Base44 SDK
@@ -41,10 +42,18 @@ export function createFunctionsModule(axios: AxiosInstance, appId: string) {
         contentType = "application/json";
       }
 
+      // Extract functions version from the current URL host
+      const functionsVersion = extractSnapshotIdFromHost();
+
       return axios.post(
         `/apps/${appId}/functions/${functionName}`,
         formData || data,
-        { headers: { "Content-Type": contentType } }
+        { 
+          headers: { 
+            "Content-Type": contentType,
+            "X-Functions-Version": functionsVersion
+          } 
+        }
       );
     },
   };

src/utils/extract-snapshot-id-from-host.ts

@@ -0,0 +1,34 @@
+/**
+ * Extracts the snapshot ID or environment type from the current hostname
+ * Used to determine which backend function deployment to call
+ *
+ * @returns {string} The snapshot ID for checkpoints, 'preview' for preview URLs, or 'prod' for production
+ */
+export function extractSnapshotIdFromHost(): string {
+  if (typeof window === "undefined") {
+    return "prod";
+  }
+
+  const hostname = window.location.hostname;
+
+  // Check if it's a checkpoint URL
+  if (hostname.startsWith("checkpoint--")) {
+    // Format: checkpoint--{app_id}--{snapshot_id}.domain
+    const parts = hostname.split("--");
+    if (parts.length >= 3) {
+      // Extract snapshot_id (last part before the domain)
+      const snapshotPart = parts[2];
+      // Remove domain extension if present
+      const snapshotId = snapshotPart.split(".")[0];
+      return snapshotId;
+    }
+  }
+
+  // Check if it's a preview URL
+  if (hostname.startsWith("preview--")) {
+    return "preview";
+  }
+
+  // Production URLs - return "prod"
+  return "prod";
+}