module ENV

Overview

ENV is a hash-like accessor for environment variables.

Note: All keys and values are strings. You must take care to cast other types at runtime, e.g. integer port numbers.

Example

# Set env var PORT to a default if not already set
ENV["PORT"] ||= "5000"
# Later use that env var.
puts ENV["PORT"].to_i

Defined in:

env.cr

Class Method Summary

Class Method Detail

def self.[](key : String) : String #

Retrieves the value for environment variable named key as a String. Raises KeyError if the named variable does not exist.


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def self.[]=(key : String, value : String | Nil) #

Sets the value for environment variable named key as value. Overwrites existing environment variable if already present. Returns value if successful, otherwise raises an exception. If value is nil, the environment variable is deleted.


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def self.[]?(key : String) : String | Nil #

Retrieves the value for environment variable named key as a String?. Returns nil if the named variable does not exist.


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def self.clear #

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def self.delete(key : String) : String | Nil #

Removes the environment variable named key. Returns the previous value if the environment variable existed, otherwise returns nil.


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def self.each(&block) #

Iterates over all KEY=VALUE pairs of environment variables, yielding both the key and value.

ENV.each do |key, value|
  puts "#{key} => #{value}"
end

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def self.fetch(key : String, &block : String -> String | Nil | NoReturn) #

Retrieves a value corresponding to a key. Return the value of the block if the key does not exist.


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def self.fetch(key) : String #

Retrieves a value corresponding to the given key. Raises a KeyError exception if the key does not exist.


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def self.fetch(key, default) #

Retrieves a value corresponding to the given key. Return the second argument's value if the key does not exist.


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def self.has_key?(key : String) : Bool #

Returns true if the environment variable named key exists and false if it doesn't.


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def self.inspect(io) #

Writes the contents of the environment to io.


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def self.keys : Array(String) #

Returns an array of all the environment variable names.


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def self.values : Array(String) #

Returns an array of all the environment variable values.


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