# This is a combination of 3 commits.

# This is the 1st commit message:

Add formatter and parser for standards ISO8601, RFC1123, RFC2822

# The commit message #2 will be skipped:

# Prefer RFC 3339 instead of ISO 8601
#
# see https://stackoverflow.com/questions/522251/whats-the-difference-between-iso-8601-and-rfc-3339-date-formats and http://docs.diesel.rs/chrono/struct.DateTime.html#method.parse_from_rfc3339

# The commit message crystal-lang#3 will be skipped:

# Remove RFC 1123 in favour of RFC 2822

spec/std/time/time_spec.cr

@@ -360,6 +360,14 @@ describe Time do
     t.to_s("%s").should eq("1388631845")
   end
 
+  it "formats standard formats" do
+    time = Time.new(2016, 2, 15, kind: Time::Kind::Utc)
+    time.to_rfc3339.should eq "2016-02-15T00:00:00+00:00"
+    Time.parse_rfc3339(time.to_rfc3339).should eq time
+    time.to_rfc2822.should eq "Mon, 15 Feb 2016 00:00:00 +0000"
+    Time.parse_rfc2822(time.to_rfc2822).should eq time
+  end
+
   it "parses empty" do
     t = Time.parse("", "")
     t.year.should eq(1)

src/http/common.cr

@@ -237,6 +237,7 @@ module HTTP
   # ```
   # HTTP.rfc1123_date(Time.new(2016, 2, 15)) # => "Sun, 14 Feb 2016 21:00:00 GMT"
   # ```
+  # DEPRECATED: Use `Time#to_rfc2822` instead.
   def self.rfc1123_date(time : Time) : String
     Time::Format::HTTP_DATE.format(time)
   end

src/http/cookie.cr

@@ -31,7 +31,7 @@ module HTTP
         header << "#{URI.escape @name}=#{URI.escape value}"
         header << "; domain=#{domain}" if domain
         header << "; path=#{path}" if path
-        header << "; expires=#{HTTP.rfc1123_date(expires)}" if expires
+        header << "; expires=#{expires.to_utc.to_rfc2822}" if expires
         header << "; Secure" if @secure
         header << "; HttpOnly" if @http_only
         header << "; #{@extension}" if @extension

src/time.cr

@@ -435,6 +435,56 @@ struct Time
     Format.new(format).format(self, io)
   end
 
+  # Format this time using the format specified by [RFC 3339](https://tools.ietf.org/html/rfc3339) ([ISO 8601](http://xml.coverpages.org/ISO-FDIS-8601.pdf) profile).
+  #
+  # ```
+  # Time.new(2016, 2, 15).to_rfc3339 # => "2016-02-15T00:00:00+00:00"
+  # ```
+  #
+  # ISO 8601 allows some freedom over the syntax and RFC 3339 exercises that
+  # freedom to rigidly define a fixed format intended for use in internet
+  # protocols and standards.
+  def to_rfc3339
+    Format::RFC_3339.format(to_utc)
+  end
+
+  # Format this time using the format specified by [RFC 3339](https://tools.ietf.org/html/rfc3339) ([ISO 8601](http://xml.coverpages.org/ISO-FDIS-8601.pdf) profile).
+  # into the given *io*.
+  def to_rfc3339(io : IO)
+    Format::RFC_3339.format(to_utc, io)
+  end
+
+  # Parse time in format specified by [RFC 3339](https://tools.ietf.org/html/rfc3339) ([ISO 8601](http://xml.coverpages.org/ISO-FDIS-8601.pdf) profile).
+  def self.parse_rfc3339(time : String)
+    Format::RFC_3339.parse(time)
+  end
+
+  # Format this time using the format specified by [RFC 2822](https://www.ietf.org/rfc/rfc2822.txt).
+  #
+  # ```
+  # Time.new(2016, 2, 15).to_rfc2822 # => "Mon, 15 Feb 2016 00:00:00 -0400"
+  # ```
+  #
+  # This is also compatible to [RFC 882](https://tools.ietf.org/html/rfc882) and [RFC 1123](https://tools.ietf.org/html/rfc1123#page-55).
+  def to_rfc2822
+    Format::RFC_2822.format(to_utc)
+  end
+
+  # Format this time using the format specified by [RFC 2822](https://www.ietf.org/rfc/rfc2822.txt)
+  # into the given *io*.
+  #
+  # This is also compatible to [RFC 882](https://tools.ietf.org/html/rfc882) and [RFC 1123](https://tools.ietf.org/html/rfc1123#page-55).
+  def to_rfc2822(io : IO)
+    Format::RFC_2822.format(to_utc, io)
+  end
+
+  # Parse time in format specified by [RFC 2822](https://www.ietf.org/rfc/rfc2822.txt).
+  #
+  # This is also compatible to [RFC 882](https://tools.ietf.org/html/rfc882) and [RFC 1123](https://tools.ietf.org/html/rfc1123#page-55).
+  def self.parse_rfc2822(time : String)
+    Format::RFC_2822.parse(time)
+  end
+
   # Parses a Time in the given *time* string, using the given *pattern* (see
   # `Time::Format`).
   #

src/time/format.cr

@@ -59,6 +59,15 @@ struct Time::Format
   # :nodoc:
   DAY_NAMES = %w(Sunday Monday Tuesday Wednesday Thursday Friday Saturday)
 
+  # The [RFC 3339](https://tools.ietf.org/html/rfc3339)/[ISO 8601](http://xml.coverpages.org/ISO-FDIS-8601.pdf) datetime format.
+  # This is just `"%FT%X%:z"`.
+  RFC_3339 = new "%FT%X%:z"
+
+  # The [RFC 2822](https://tools.ietf.org/html/rfc2822) datetime format.
+  #
+  # This is also compatible to [RFC 882](https://tools.ietf.org/html/rfc882) and [RFC 1123](https://tools.ietf.org/html/rfc1123#page-55).
+  RFC_2822 = new "%a, %d %b %Y %H:%M:%S %z"
+
   # Error raised when an invalid pattern is used.
   class Error < ::Exception
   end