subdomains_from(host, tld_length) — ActionDispatch::Http::URL::DomainExtractor

subdomains_from(host, tld_length)

Extracts the subdomain components from a host string as an Array.

Returns all the components that come before the domain and TLD parts. The +tld_length+ parameter is used to determine where the domain begins so that everything before it is considered a subdomain.

==== Parameters

[+host+] The host string to extract subdomains from.

[+tld_length+] The number of domain components that make up the TLD. This affects where the domain boundary is calculated.

==== Examples

# Standard TLD (tld_length = 1) DomainExtractor.subdomains_from(“www.example.com”, 1) # => [“www”]

# Country-code TLD (tld_length = 2) DomainExtractor.subdomains_from(“api.staging.example.co.uk”, 2) # => [“api”, “staging”]

# No subdomains DomainExtractor.subdomains_from(“example.com”, 1) # => []

# Single subdomain with complex TLD DomainExtractor.subdomains_from(“www.mysite.co.uk”, 2) # => [“www”]

# Multiple levels of subdomains DomainExtractor.subdomains_from(“dev.api.staging.example.com”, 1) # => [“dev”, “api”, “staging”]

Parameters

host req
tld_length req

Source

# File actionpack/lib/action_dispatch/http/url.rb, line 104
        def subdomains_from(host, tld_length)
          parts = host.split(".")
          parts[0..-(tld_length + 2)]
        end

Defined in actionpack/lib/action_dispatch/http/url.rb line 104 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActionDispatch::Http::URL::DomainExtractor

Signature

Parameters