From a9652670b3299de278be003b7fb7432a8a8edc6e Mon Sep 17 00:00:00 2001
From: "argiro.kokogiannaki"
 <argiro.kokogiannaki@d315682c-612b-4755-9ff5-7f18f6832af3>
Date: Fri, 26 Jun 2020 13:33:35 +0000
Subject: [PATCH] [Cahce service]

Add:
const expireShort = 2 * 60 * 1000; //2mins
const expireLong = 24 * 60 * 60 * 1000; //24 hours
const cacheMaxSize =500;
const longCachingRequests = ["/communityFull/", "/pagehelpcontent","/provision/mvc/vocabularies/","/pages?page_route="];

-use expireLongTime for longCachingRequests
-add /clear request
-add timer to clean the cache on midnight
-when maxcachesize is reached clean the cache



git-svn-id: https://svn.driver.research-infrastructures.eu/driver/dnet40/modules/uoa-services-portal/trunk@59001 d315682c-612b-4755-9ff5-7f18f6832af3
---
 services/cache/mecache/cache.js | 90 +++++++++++++++++++++++++++++++--
 1 file changed, 86 insertions(+), 4 deletions(-)

diff --git a/services/cache/mecache/cache.js b/services/cache/mecache/cache.js
index 6fc10408..435be2d5 100644
--- a/services/cache/mecache/cache.js
+++ b/services/cache/mecache/cache.js
@@ -6,7 +6,10 @@ let mcache = require('memory-cache');
 const request = require('superagent');
 const prom = require('prom-client');
 const URL = require('url');
-
+const expireShort = 2 * 60 * 1000; //2mins
+const expireLong = 24 * 60 * 60 * 1000; //24 hours
+const cacheMaxSize =500;
+const longCachingRequests = ["/communityFull/", "/pagehelpcontent","/provision/mvc/vocabularies/","/pages?page_route="];
 let cors = require('cors');
 app.use(cors());
 
@@ -34,10 +37,15 @@ const histogram = new prom.Histogram({
     buckets: [0.1, 0.2, 0.5, 1, 2]
 });
 
-let cache = (duration) => {
+let cache = () => {
     return (req, res, next) => {
         if(req.query.url) {
+            if(mcache.size() > cacheMaxSize){
+                console.debug("Max cache size reached!"+cacheMaxSize);
+                clearCache();
+            }
             let key = '__express__' + req.query.url;
+            let longCache = checkForLongCachedRequests(req.query.url);
             let cachedBody = mcache.get(key);
             const url = new URL.parse(req.query.url);
             const target = url.host + '/' + url.pathname.split('/')[1];
@@ -58,7 +66,8 @@ let cache = (duration) => {
                         end();
                     }
                     if (res.statusCode === 200) {
-                        mcache.put(key, body, duration * 1000, () => {
+                        // console.log("Expire in " +(longCache?expireLong:expireShort) + " " +req.query.url);
+                        mcache.put(key, body,longCache?expireLong:expireShort, () => {
                             entries.set(mcache.size());
                         });
                     }
@@ -72,12 +81,54 @@ let cache = (duration) => {
     };
 };
 
+app.get('/clear', (req, res) => {
+    let c = mcache.size();
+    const url = req.query.url;
+    let message ="";
+    if(url){
+        let key = '__express__' + req.query.url;
+        mcache.del(key);
+        message = "Delete entry with key "+ url;
+        entries.set(mcache.size());
+    }else{
+        clearCache();
+         message ="Delete "+c + " entries. Now there are: "+mcache.size()
+     }
+    res.header("Access-Control-Allow-Headers", "Origin, Content-Type,  Content-Length");
+    res.header("Access-Control-Allow-Methods", "GET,  OPTIONS");
+    res.header("Access-Control-Allow-Methods", "GET,  OPTIONS");
+    res.header("Content-Type", "application/json");
+    res.status(200).send(getResponse(200,message));
 
+});
 app.get('/metrics', (req, res) => {
     res.set('Content-Type', register.contentType);
     res.end(register.metrics());
 });
 
+app.get('/get', cache(), cors(), (req, res) => {
+    setTimeout(() => {
+        const url = (req.query) ? req.query.url : null;
+        if (!url) {
+            res.status(404).send(getResponse(404, "Not Found ")) //not found
+        } else {
+            request.get(url, function (err, response) {
+                // res.header("Access-Control-Allow-Origin", "http://localhost:3000");
+                res.header("Access-Control-Allow-Headers", "Origin, Content-Type,  Content-Length");
+                res.header("Access-Control-Allow-Methods", "GET,  OPTIONS");
+                res.header("Access-Control-Allow-Methods", "GET,  OPTIONS");
+                res.header("Content-Type", "application/json");
+                if (!response && err) {
+                    res.status(500).send(getResponse(500, "An error occurred for " + url))
+                } else {
+                    res.status(response.status).send(response.body);
+                }
+            })
+        }
+    })
+});
+
+
 app.get('/get', cache(30), cors(), (req, res) => {
     setTimeout(() => {
         const url = (req.query) ? req.query.url : null;
@@ -99,7 +150,6 @@ app.get('/get', cache(30), cors(), (req, res) => {
         }
     })
 });
-
 app.use((req, res) => {
     res.status(404).send(getResponse(404, "Not Found")); //not found
 });
@@ -115,3 +165,35 @@ function getResponse(code, message) {
     return response;
 
 }
+function clearCache(){
+    console.debug("cache is cleared!");
+    mcache.clear();
+    entries.set(mcache.size());
+}
+function checkForLongCachedRequests(url){
+    let long =false;
+    longCachingRequests.forEach(partUrl => {
+        if(url.indexOf(partUrl) !==-1){
+            long = true;
+        }
+    });
+    return long;
+}
+//run the timer
+resetAtMidnight();
+function resetAtMidnight() {
+    console.debug("Run Reset timer");
+    var now = new Date();
+    var night = new Date(
+        now.getFullYear(),
+        now.getMonth(),
+        now.getDate() + 1 , //  the next day, ...
+         0, 0, 0 // ...at 00:00:00 hours
+    );
+    var msToMidnight = night.getTime() - now.getTime();
+
+    setTimeout(function() {
+        clearCache();              //      <-- This is the function being called at midnight.
+        resetAtMidnight();    //      Then, reset again next midnight.
+    }, msToMidnight);
+}