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DNS Cache Resolver (dcr)

dcr is a simple library to resolve and cache URLs from hostbased naming convention to IP based one. For instance, if you have an URL like http://www.google.com and would like to resolve it into IP based URL this library will help you, e.g.

// set DNSManager
var mgr DNSManager
host := "www.google.com"
rurl := fmt.Sprintf("http://%s/", host)

// resolve given URL
ipUrl := mgr.Resolve(rurl)

// print existing cache content
fmt.Println(mgr.String())

{"http://www.google.com/":["http://172.217.6.228/","http://[2607:f8b0:4006:802::2004]/"]}

Use-cases

In service like applications where code needs to deal with lots of similart URLs it is handy to define local cache of their IP representations without going through DNS server. For example, in web server where you need to handle multiple URLs at high rate and all of those URLs have a small set of unique hostnames, it is beneficial to resolve and cache theose URLs to avoid flood of requests to DNS server