Add rate limit to isochrone calculation

Caddyfile

@@ -1,7 +1,13 @@
 https://localhost:443
 
 root * /usr/share/caddy
-reverse_proxy /api/* http://server:8080
+route /api/* {
+    # global rate limit
+    rate_limit {host} 100r/m
+    # rate limit per "client"
+    rate_limit {remote.host} 25r/m
+    reverse_proxy http://server:8080
+}
 encode gzip
 file_server {
     precompressed br

fastreach-ui/src/lib/IsochroneConfig.svelte

@@ -53,7 +53,11 @@
         });
 
         if (res.status !== 200) {
-            error = `HTTP request failed, status code: ${res.status}`;
+            if (res.status === 429) {
+                error = "Please try again later.";
+            } else {
+                error = `HTTP request failed, status code: ${res.status}.`;
+            }
             return;
         }
         const result = (await res.json()) as IsochroneResponse;

ui.Dockerfile

@@ -1,7 +1,11 @@
-FROM node:18-alpine as build
+FROM node:18-alpine as ui-build
 WORKDIR /app/fastreach-ui
 COPY . /app
 RUN npm install && npm run build
 
+FROM caddy:2.7-builder-alpine AS caddy-build
+RUN xcaddy build --with github.com/RussellLuo/caddy-ext/ratelimit
+
 FROM caddy:2.7-alpine
-COPY --from=build /app/fastreach-ui/dist /usr/share/caddy
+COPY --from=caddy-build /usr/bin/caddy /usr/bin/caddy
+COPY --from=ui-build /app/fastreach-ui/dist /usr/share/caddy