Allow user to specify key fingerprint with --fingerprint or -f, or th…

lib/dotgpg/cli.rb

@@ -7,6 +7,8 @@ class Cli < Thor
     desc "init [DIRECTORY]", "create a new dotgpg directory"
     option :"new-key", type: :boolean, desc: "Force creating a new key", aliases: ["-n"]
     option :email, type: :string, desc: "Use a specific email address", aliases: ["-e"]
+    # User can supply fingerprint with --fingerprint or -f, but if GPGKEY env variable is set use that.
+    option :fingerprint, type: :string, desc: "Search for a specific fingerprint", aliases: ["-f"], default: if ENV.has_key?('GPGKEY'); ENV['GPGKEY']; else nil; end
     def init(directory=".")
       return if helped?
 
@@ -16,7 +18,7 @@ def init(directory=".")
         fail "#{directory}/.gpg already exists"
       end
 
-      key = Dotgpg::Key.secret_key(options[:email], options[:"new-key"])
+      key = Dotgpg::Key.secret_key(options[:email], options[:"new-key"], options[:fingerprint])
 
       info "Initializing new dotgpg directory"
       info "  #{directory}/README.md" unless File.exist? 'README.md'

lib/dotgpg/key.rb

@@ -7,12 +7,12 @@ def self.read(file)
       end.flatten.first
     end
 
-    def self.secret_key(email=nil, force_new=nil)
-      new.secret_key(email, force_new)
+    def self.secret_key(email=nil, force_new=nil, fingerprint=nil)
+      new.secret_key(email, force_new, fingerprint)
     end
 
-    def secret_key(email=nil, force_new=nil)
-      existing = existing_key(email)
+    def secret_key(email=nil, force_new=nil, fingerprint=nil)
+      existing = existing_key(email, fingerprint)
       if existing && !force_new
         existing
       else
@@ -22,9 +22,24 @@ def secret_key(email=nil, force_new=nil)
 
     private
 
-    def existing_key(email=nil)
-      existing_private_keys.detect do |k|
-        email.nil? || k.email == email
+    def existing_key(email=nil, fingerprint=nil)
+      # User can specify an Email address or a fingerprint on the command line, to
+      # use in searching for a matching GPG key.  If finterprint is specified
+      # it takes priority as it is more specific.  Must handle either or both
+      # search parameters being nil.
+      #
+      if ! fingerprint.nil?
+        existing_private_keys.detect do |k|
+          # Match user-supplied fingerprint at END of key's fingerprint string,
+          # as users often use a shortened fingerprint.
+          /#{fingerprint}$/.match(k.fingerprint)
+        end
+      elsif ! email.nil?
+        existing_private_keys.detect do |k|
+          k.email == email
+        end
+      else
+        nil
       end
     end