lakka

lakka. An asynchronous request accelerator.

lakka is an accelerator for asyncronous requests. It works by caching the request's response in your users local storage. It caches JSON, text and HTML requests and considers the Cache-Control and Expires Headers of your requests and responses. Usualy, the content of an AJAX-request does not change so often. In the best case, the backend-environemnt either caches them or responds with a "not-modified"-like header. But the client still need to wait for this response and the network roundtrip + response time + connection speed makes your website feels "slow". This is where lakka enhances your website's snappiness: no more waiting, instant responses!

Installation

Install from npm $ yarn add lakka

Quick start

Add dist/wrapper/lakka.js to your project.

Core Concept

Basically you need to call two functions:

• before() with the uri before making your request
• after() with the response afterwards

.before()

Call this function before the actual request. It checks the cache and returns a fresh cache item or throws an error.

.after()

Call this after the actual request. Checks the response and store it at the cache. Returns the cache item or throws an error.

UMD-Module: lakka

This is an UMD-Module working in your browser, server, requirejs, browserify, commonjs or nodejs setup. Load ./dist/lakka.js to use the lakka accelerator in your code. This will give you access to the complete lakka-API. It exposes window.lakkafor your convienence.

Examples

Take a look example folder:

example/xmlhttprequest.js

For a simple example how to use lakka with window.XMLHTTPRequest()

example/fetch.js

For a simple example how to use lakka with window.fetch()

Configuration

Lakka let's you define basic options:

• exclude: Adds a regular-expressions to ignore certain URIs. This can be part of the configuration object or directly set using ``.ignore(). If an URI matches anexcludeandincludepattern, theexclude```pattern takes precedence and the URI will be ignored. Default: empty
• include: Adds a regular-expressions to include certain URIs. This can be part of the configuration object or directly set using ``.recognize()```. If this is set, all non-matching URIs will be ignored. Default: empty
• minutes: sets the time a cache item is considered "fresh" if the response does not contain a Cache-Control Header or Expires Header. Default: 60 minutes

API

ignore(String|RegEx)

Adds an ignore pattern (a string / RegEx) to the existing / default configuration. URIs matching this pattern will be ignored by lakka and passed throught to the remote location.

Arguments

• String|RegEx: The pattern to look for

recognize(String|RegEx)

Adds an include pattern (a string / RegEx) to the existing / default configuration. URIs matching this pattern will be recognized and handled by lakka. If none is set, all URIs will be handled.

Arguments

• String|RegEx: The pattern to look for

time(Number)

Sets the minutes (Number) we should cache items for. Defaut value is 60 minutes. It will be overwritten by the max-age - value of the response's Cache-Control Header or the response's Expires Header.

Arguments

• Number: The value the default caching time

configuration(Object)

Dynamically merge a configuration object into the current / default configuration object. include and exclude will be merged, minutes will be replaced.

Arguments

• Object: A configuration object

{
  "include":["/include-me/"],
  "exclude":["/exclude-me/"],
  "minutes": 120
}

after()

Call this after the actual request. Checks the response and store it at the cache. Returns the cache item or an error.

• Checks the status code for success or throws an error.
• Checks the includeand excludepatterns to see if this should be handled by lakka or throws an error.
• Checks for a cachable Cache-Control Header or throws an error.
  • Cachable: public, private, Immutable, proxy-revalidate
  • Non-cachable must-revalidate, no-cache, no-store,
• Checks the "Content-Type" or throws an error.
  • Valid content types are: application/json, text/x-json, text/plain, text/html
• Checks the Expires Header and the Cache-Control Header to see if the content is not already stale or throws an error.
• Creates and saves the cache item
• Returns the cache item or the thrown error

Arguments

Returns

Returns the cache item or an error if there's no cache-item for this request.

before()

Call this before the actual request. Checks for and returns a fresh cache item or an error.

• Checks the includeand excludepatterns to see if this should be handled by lakka or throws an error.
• Checks the Cache-Control Header or throws an Error
  • Cachable: public, private, Immutable, proxy-revalidate
  • Non-cachable must-revalidate, no-cache, no-store,
• Checks the Accept Header or throws an Error
  • Valid content types are: application/json, text/x-json, text/plain, ```text/html``
• Checks the Content Type Header or throws an Error
  • Valid content types are: application/json, text/x-json, text/plain, text/html
• Checks there's a fresh item for this URI or throws an Error.
• Returns the cache item or an error if there's no cache-item for this request.

Arguments

Returns

Returns a fresh cache item or an error if there's no cache-item for this request.

remove(String)

Force clear an item from lakka. Removes all stored content for this URI.

Arguments

• String: The URI to clear from lakka

flush()

Flush the lakka cache. Remove all items.

Tech Stack

• Writen in ECMAScript 2018 on ```nodejs v9.0.0``
• Transpiledbabel v6.26.0
• Bundled with webpack v3.10.0
• 100% code coverage using mocha v3.5.0, chai v4.1.1 and nyc v11.2.1

License

Licensed under the MIT license.

Copyright (c) 2016, 2017, 2018 Martin Krause [e-mail] http://martinkr.github.io)