@themost/cache

MOST Web Framework Data Caching

@themost/cache implements the default data caching strategy that is going to be used by any @themost data application

Important note: This module has been separated from @themost/data even if it exports the default caching strategy.

Installation

npm i @themost/cache

Configuration

@themost/cache/platform-server#DefaultDataCachingStrategy is being registered by @themost/data#DataConfiguration:

{
    "services": [
        {
            "serviceType": "@themost/cache#DataCacheStrategy",
            "strategyType": "@themost/cache/platform-server#DefaultDataCacheStrategy"
        }
    ]
}
    

Configure absolute expiration timeout by setting absoluteExpiration under settings/cache section:

{
    "settings": {
        "cache": {
            "absoluteExpiration": 900
        }
    }
}

This setting is going to be used by node-cache which is the caching engine initiated by @themost/cache#DefaultDataCacheStrategy strategy.

@themost/cache/platform-server#IndexedCacheStrategy is an alternative caching strategy which uses disk for caching items.

{
    "services": [
        {
            "serviceType": "@themost/cache#DataCacheStrategy",
            "strategyType": "@themost/cache/platform-server#IndexedCacheStrategy"
        }
    ]
}

Configure disk cache root under settings/cache section (the default value is .cache/diskCache):

{
    "settings": {
        "cache": {
            "absoluteExpiration": 900,
            "rootDir": ".cache/diskCache"
        }
    }
}

and the interval -in seconds- of validating the expiration of cached items:

{
    "settings": {
        "cache": {
            "absoluteExpiration": 900,
            "rootDir": ".cache/diskCache",
            "checkingPeriod": 60
        }
    }
}

Checkout other data caching strategies like @themost/memcached, @themost/redis etc.

Output caching

@themost/cache#OutputCaching enables caching mechanisms on expressjs application based on pre-defined cache profiles

e.g.

const clientCacheProfile = {
    location: 'client',
    duration: 60 * 60, // 1 hour
    varyByHeader: [
        'accept',
        'accept-encoding',
        'accept-language',
        'accept-profile'
    ],
    varyByParam: [
        '*' // use any query param
    ],
    varyByCallback: async (req) => {
        if (req.headers.authorization) {
            return `context=${MD5(req.headers.authorization).toString()}`
        }
        return null;
    } 
}

...

// setup cache
app.use(OutputCaching.setup({
    rootDir: '.cache/indexedCache',
    absoluteExpiration: 20 * 60 // 20 minutes,
    checkingPeriod: 60 * 1000 // 1 minute
}));

...

app.use('/api/hello', OutputCaching.cache(clientCacheProfile), (req, res, next) => {
    return res.json({
        message: 'Hello World'
    });
});

where /api/hello response will be cached on client side based on several parameters defined in clientCacheProfile.

OutputCaching.cache(PreOutputCacheConfiguration)

Caches response based on cache profile parameters

duration

int

Gets or sets the time duration in seconds during which the response is cached.

location

string

Gets or sets the output cache location.

| | | |---|---| | client | The output cache is located on the browser | server | The output cache is located on the server | serverAndClient | The output cache is located both on the client and server | none | The output cache is disabled | any | The output cache is located both on the client and server

varyByHeader

string[]

Gets or sets an array of headers used to vary the cached output

varyByParam

string[]

Gets or sets an array of query string params used to vary the cached output

varyByContentEncoding

string

Gets or sets a content encoding which will be used to vary the cached output

varyByCallback

function(): Promise<string>

varyByCallback() method may used to programmatically vary the cached output.