bumped versions; added in-memory-cache plugin; updated README

Dockerfile

@@ -1,15 +1,17 @@
-FROM node:9.4-alpine
+FROM node:10.11.0-alpine
 
-ENV CHROMIUM_VERSION 63.0.3239.108-r0
-ENV PRERENDER_VERSION 5.2.0
+ENV CHROMIUM_VERSION 68.0.3440.106-r0
+ENV PRERENDER_VERSION 5.4.4
+ENV PRERENDER_MEMORY_VERSION 1.0.2
 ENV DISPLAY :99.0
 
 WORKDIR /app
 
 RUN addgroup -S prerender && adduser -S -g prerender prerender  && \
     apk add --no-cache ca-certificates && \
-    apk add chromium=$CHROMIUM_VERSION --no-cache --repository http://nl.alpinelinux.org/alpine/edge/community && \
-    npm install [email protected]  && \
+    apk add chromium=${CHROMIUM_VERSION} --no-cache --repository http://nl.alpinelinux.org/alpine/edge/community && \
+    npm install prerender@${PRERENDER_VERSION}  && \
+    npm install prerender-memory-cache@${PRERENDER_MEMORY_VERSION} && \
     rm -rf /var/cache/apk/*
 
 COPY server.js /app/server.js

README.md

@@ -1,29 +1,51 @@
-Docker Image for Prerender
-==========================
+# Docker Image for Prerender
 
 Dockerized Prerender + Chrome Headless (chromium-browser on Alpine Linux)
 
-Example
--------
+https://prerender.io is an open-source nodeJS based web server that servers HTML for web crawlers like Google, Twitter, Slack preview bots and so on. It is used to make SEO for single page web apps built with any framework: React, Angular, VueJS ...
 
+You can secure prerender in 3 ways:
+* make it public and use the whitelist/blacklist options
+* expose the port to the localhost but binding it only to local interface: `-p 127.0.0.1:3000:3000`
+* do not expose the port and put it in a docker network
+
+Docker run: https://docs.docker.com/engine/reference/run/
+Prerender: https://prerender.io/documentation
+In-memory cache plugin:  https://github.com/prerender/prerender-memory-cache
+
+### Examples
+
+Run it with default settings, and expose the port to public:
+```bash
+docker run --detach \
+    --name prerender \
+    -it \
+    -p 3000:3000
+    bgadrian/docker-prerender
 ```
-docker container run --name prerender --rm -it -p 3000:3000 ball6847/prerender
+
+Run it with 7 days cache, 10.000 pages limit and in a docker network, the instance can be accesed by its container name by any other container running in the same network.
+
+```bash
+docker run --detach \
+    --name prerender \
+    -it \
+    --network my-net
+    -e "CACHE_MAXSIZE=10000" \
+    -e "CACHE_TTL=604800" \
+    bgadrian/docker-prerender
 ```
 
-To run with docker-compose
+### Cache
 
-```yml
-version: '3'
+You can see the cache in action by reading the logs, eg from multiple calls of `curl localhost:3000/https://twitter.com` you may get <15ms subsequent responses:
 
-services:
-  prerender:
-    image: ball6847/prerender:latest
-    restart: unless-stopped
-    ports:
-      - 3000:3000
+```bash
+2018-10-06T19:58:42.354Z got 200 in 2910ms for https://twitter.com/
+2018-10-06T19:59:08.905Z getting https://twitter.com/
+2018-10-06T19:59:08.917Z got 200 in 12ms for https://twitter.com/
+2018-10-06T19:59:11.551Z getting https://twitter.com/
+2018-10-06T19:59:11.557Z got 200 in 6ms for https://twitter.com/
 ```
 
-Author
-------
-
-Porawit Poboonma <[email protected]>
+Because the cache is in memory, to purge it (for example at each big release) you can just restart the container: `docker restart prerender`

server.js

@@ -1,8 +1,10 @@
 #!/usr/bin/env node
-var prerender = require("prerender");
+const prerender = require("prerender");
+const cache = require('prerender-memory-cache');
 
+//got from https://github.com/ball6847/docker-prerender who
 // borrow from https://github.com/prerender/prerender/blob/master/server.js
-var server = prerender({
+const server = prerender({
   chromeLocation: "/usr/lib/chromium/chrome",
   chromeFlags: [
     "--headless",
@@ -17,5 +19,6 @@ server.use(prerender.sendPrerenderHeader());
 server.use(prerender.blockResources());
 server.use(prerender.removeScriptTags());
 server.use(prerender.httpHeaders());
+server.use(cache);
 
 server.start();