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redisCacheMiddleware.js
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redisCacheMiddleware.js
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const loadAppends = require('./appenderLoad');
const {responseAndCacheFactory, responseFromCache} = require('./responseFactory');
const race = require('./race');
const DEFAULT_EXPIRE = 3600;
const defaultKeyGenerate = (req) => req.originalUrl || req.url;
const defaultCacheDisable = (req) => !!req.cacheEnable;
const defaultShouldCache = (req, res, next) => {
const statusCode = res.statusCode;
if (statusCode >= 200 && statusCode < 400) {
return true;
}
return false;
};
const getFromFaster = (appenders, key, callback) => race(appenders, (appender, cb) => appender.get(key, cb), callback);
const cacheMiddlewareFactory = (configList) => {
const appenders = loadAppends(configList);
return (expire = DEFAULT_EXPIRE, {
cacheKeyGen = defaultKeyGenerate,
cacheDisable = defaultCacheDisable,
shouldCache = defaultShouldCache
} = {}) => (req, res, next) => {
if (cacheDisable.call(req, req, res, next)) {
return next();
}
const key = cacheKeyGen.call(req, req, res, next);
getFromFaster(appenders, key, (err, cache) => {
if (err) {
return next();
} else if (!cache) {
return responseAndCacheFactory(expire, shouldCache, (cacheObj) => {
for (const appender of appenders) {
appender.set(key, cacheObj, expire);
}
})(req, res, next);
}
return responseFromCache(cache, res);
});
};
};
module.exports = {
cacheMiddlewareFactory,
defaultKeyGenerate,
defaultShouldCache,
defaultCacheDisable
};