hopjs/lib/cacheredis.js

A RESTful declarative API framework, with stub generators for Shell, and Android

var Hop = require('./cache');
var crypto = require('crypto');


var redis = require("redis");
if(Hop.cacheOptions.redisClient==undefined){
  var  client = redis.createClient();
} else {
  var client = Hop.cacheOptions.redisClient;
}

client.on("error", function (err) {
    Hop.log("Error " + err);
});

Hop.Cache.clear=function(onComplete){
  onComplete=onComplete||function(){}
  client.flushdb(onComplete);
}

Hop.cacheLog=function(){
  if(Hop.cacheOptions.log){
    var args = Array.prototype.slice.call(arguments);
    args.unshift("Cache:");
    Hop.log.apply(null,args);
  }
}

Hop.Cache.store=function(cacheId,duration,req,input,err,result,next,force){
  var entry = {
    expiresAt: (duration*1000)+(new Date()).getTime(),
    cachedAt: new Date().getTime(),
    err: err,
    result: result
  };

  var md5 = crypto.createHash('md5');
  md5.update(cacheId+":"+entry.cachedAt);
  entry.etag = md5.digest('hex');
  req.getResponse().set('ETag',entry.etag);
  if(force)
    req.getResponse().set('Cache-Control','max-age='+Math.floor((entry.expiresAt - (new Date()).getTime())/1000.0));
  Hop.cacheLog("Saving object in cache with:",cacheId)
  client.setex(cacheId,duration,JSON.stringify(entry));
  next();
}

Hop.Cache.fetch=function(cacheId,duration,req,input,onComplete,next,force){
  client.get(cacheId,function(err,data){
    if(!err && data){
      try {
        Hop.cacheLog("Cache: hit ",cacheId,JSON.parse(data));
        var entry = JSON.parse(data.toString());
        if(entry.expiresAt > (new Date()).getTime()){
            
          var md5 = crypto.createHash('md5');
          md5.update(cacheId+":"+entry.cachedAt);
          entry.etag = md5.digest('hex');
          req.getResponse().set('ETag',entry.etag);
          if(force)
            req.getResponse().set('Cache-Control','max-age='+Math.floor((entry.expiresAt - (new Date()).getTime())/1000.0));
          
          if(req.get('If-None-Match') == entry.etag){
            return req.getResponse().send("Not modified",304);
          } else {
            return onComplete(entry.err,entry.result);
          }
        } else return next();
      } catch(e){
        Hop.error(e);
        return next();
      }
    } else return next();
  });
}

Hop.Cache.invalidate=function(cacheId){
  Hop.cacheLog("deleting",cacheId);
  client.del(cacheId);
}