Add ability to hide unwanted fields.

.rubocop.yml

@@ -2,13 +2,13 @@ AllCops:
     NewCops: enable
     TargetRubyVersion: 2.0
 Metrics/AbcSize:
-    Max: 26
+    Max: 35
 Metrics/BlockLength:
-    Max: 45
+    Max: 53
 Metrics/CyclomaticComplexity:
     Max: 12
 Metrics/MethodLength:
-    Max: 28
+    Max: 35
 Naming/MethodParameterName:
     Enabled: false
 Metrics/PerceivedComplexity:

README.md

@@ -165,6 +165,26 @@ b25f8815-007f-40f7-a700-ce058ac05435  hotp   Mason     WWE         5VAML3X35THCE
 5b11ae3b-6fc3-4d46-8ca7-cf0aea7de920  steam  Sophia    Boeing      JRZCL47CMXVOQMNPZR2F7J4RGI  30           5                          SHA1
 ```
 
+### Hiding unwanted fields
+
+When the `-f / --format` option is set to `csv` or `pretty`, you can use the `-e / --except` option to hide unwanted fields.
+
+```bash
+# Enter the above password when prompted
+ruby lib/decrypt.rb test/encrypted_test.json -f pretty -e icon,info.counter,uuid
+```
+
+```csv
+type   name      issuer      info.secret                 info.period  info.digits  info.algo
+totp   Mason     Deno        4SJHB4GSD43FZBAI7C2HLRJGPQ  30           6            SHA1
+totp   James     SPDX        5OM4WOOGPLQEF6UGN3CPEOOLWU  20           7            SHA256
+totp   Elijah    Airbnb      7ELGJSGXNCCTV3O6LKJWYFV2RA  50           8            SHA512
+hotp   James     Issuu       YOOMIXWS5GN6RTBPUFFWKTW5M4               6            SHA1
+hotp   Benjamin  Air Canada  KUVJJOM753IHTNDSZVCNKL7GII               7            SHA256
+hotp   Mason     WWE         5VAML3X35THCEBVRLV24CGBKOY               8            SHA512
+steam  Sophia    Boeing      JRZCL47CMXVOQMNPZR2F7J4RGI  30           5            SHA1
+```
+
 ## Testing
 
 ```bash

lib/decrypt.rb

@@ -226,33 +226,41 @@ def decrypt_vault(filename)
 #
 def main
   formats = %i[json csv pretty]
-  options = { :format => :json }
+  options = { :format => :json, :except => [] }
 
   parser = OptionParser.new do |opts|
     opts.banner = "Usage: #{$PROGRAM_NAME} <filename> [options]"
     opts.on('-f FORMAT', '--format FORMAT', formats,
             "Plaintext vault output format; pick one from #{formats.map(&:to_s)}") do |f|
       options[:format] = f
     end
-    opts.on('-h', '--help', 'Show this message') do
+    opts.on('-e', '--except x,y,z', Array, 'Specify fields to hide; for example, `-e icon,info.counter,uuid`') do |e|
+      options[:except] = e
+    end
+    opts.on_tail('-h', '--help', 'Show this message') do
       puts opts
       exit 0
     end
   end
 
   begin
     parser.parse! ARGV
-    raise StandardError,  "invalid number of arguments: expected 1, got #{ARGV.length}" if ARGV.length != 1
+    raise StandardError, "invalid number of arguments: expected 1, got #{ARGV.length}" if ARGV.length != 1
+
+    if options[:format] == :json && !options[:except].empty?
+      raise StandardError,
+            'hiding fields is only supported for `csv` and `pretty` formats'
+    end
   rescue StandardError => e
     terminate "#{e}\n#{parser}"
   end
 
   plain_text = decrypt_vault(ARGV[0])
   $stdout.write case options[:format]
                 when :pretty
-                  beautify entries_to_csv plain_text
+                  beautify remove_fields(entries_to_csv(plain_text), options[:except])
                 when :csv
-                  entries_to_csv plain_text
+                  remove_fields(entries_to_csv(plain_text), options[:except])
                 else
                   plain_text
                 end

lib/pretty.rb

@@ -70,6 +70,22 @@ def entries_to_csv(plain_text)
   end
 end
 
+#
+# Remove specified fields from a CSV string. Non-existent fields are silently ignored.
+#
+# @param [String] raw_csv CSV String
+# @param [Array<String>] fields_to_remove Field names to be removed from the CSV String
+#
+# @return [String] CSV String with specified fields removed
+#
+def remove_fields(raw_csv, fields_to_remove)
+  csv_data = CSV.parse(raw_csv, :headers => true)
+  fields_to_remove.each do |field_name|
+    csv_data.delete field_name
+  end
+  csv_data.to_s
+end
+
 #
 # Make a beautiful CSV-like String padded with spaces.
 #

spec/decrypt_spec.rb

@@ -139,6 +139,14 @@ def decryption_test(args, expected_plaintext_filename)
       end
     end
   end
+  it 'Terminates if format is `json` and `--except` fields are included' do
+    silence do
+      ARGV.replace [ENCRYPTED_TEST_VAULT, '-f', 'json', '-e', 'field']
+      expect { main }.to raise_error(SystemExit) do |error|
+        expect(error.status).to eq(1)
+      end
+    end
+  end
   it 'Shows help' do
     ARGV.replace ['--help']
     output = nil

spec/pretty_spec.rb

@@ -30,6 +30,12 @@
   end
 end
 
+describe 'remove_fields' do
+  it 'Removes fields from CSV String correctly' do
+    expect(CSV.parse(remove_fields("a,b,c\n1,2,3", %w[a c]), :headers => true).headers).to eq ['b']
+  end
+end
+
 describe 'beautify' do
   it 'Pretty prints plain text vault as a CSV-like String padded with spaces' do
     expect(beautify(entries_to_csv(File.read('test/plaintext_test.json',