find you need a tool, When a GUI's more trouble than it's worth, The command line is waiting there for you, All it takes is a little Ruby love, Movin' the mouse And then clickin' And then typin' All of that to do just one little thing... Automation We do it for the world, So why don't we do it for ourselves? A CLA (Command Line Application) will solve the problem, No need to fumble or stumble with a mouse And then you will come to find, A whole new peace of mind, As you use your newfound productivity.
length would be closer to 50 minutes So: • much content will be mentioned only briefly • much source code will be passed over, left for you to view later If something interests you, feel free to: • ask about it during the Q&A • contact me afterwards
differentiate between names with and without leading spaces: SSID BSSID RSSI CHANNEL HT CC SECURITY (auth/unicast/group) freebox_19CDE1 e4:9e:12:19:cd:e2 -92 13 Y -- WPA(PSK/AES,TKIP/TKIP) FreeWifi 68:a3:78:80:fb:c8 -76 2 Y -- NONE FreeWifi_secure 68:a3:78:80:fb:c9 -77 2 Y -- WPA2(802.1x/AES,TKIP/TKIP) freebox_KZLFCE 14:0c:76:f8:9c:4c -86 5 N -- WEP FreeWifi 14:0c:76:f8:9c:4d -86 5 Y -- NONE We cannot even know if the 2 “FreeWifi” entries refer to the same network.
access points • show, clear, or set nameservers • get WiFi detailed status information • show network name (SSID) • show the password for a saved network • show wifi on/off and Internet on/off status
using utilities simplifies implementation • no need to write native code • using utilities complicates implementation • need to parse human readable output into objects • text formats may change over time • must deal with utility oddities, e.g. airport often returns no data • locales!
command line expertise • easily installable • provides a shell • installable without additional gems, with caveats: • `pry` is only required if/when running in shell mode • `awesome_print` is optional, fallback is `pretty_print` • support using models without command line execution, i.e. can be used as CLA or not • Support YAML & JSON
your Ruby code without using the CommandLineInterface class. Here is a script ‘public_ip’: #!/usr/bin/env ruby require 'wifi-wand' require 'awesome_print' ap WifiWand::MacOsModel.new.public_ip_address_info When we run it, we get:
with every command • returned data as Ruby objects, enabling: • composite commands • custom behavior • storing data in variables/constants for later use
one can access other shell commands using the dot ('.') prefix (e.g. ‘.ping google.com’) • Pry commands such as `ls` can be accessed using '%' prefix (e.g. ‘%ls')
directly related to the DSL commands, with both abbreviated and complete names. For example: So that it can be used in the shell like this: def fancy_puts(object) puts fancy_string(object) end alias_method :fp, :fancy_puts
foo Creating gem 'foo'... MIT License enabled in config create foo/Gemfile create foo/lib/foo.rb create foo/lib/foo/version.rb create foo/foo.gemspec create foo/Rakefile create foo/README.md create foo/bin/console create foo/bin/setup create foo/.gitignore create foo/.travis.yml create foo/.rspec create foo/spec/spec_helper.rb create foo/spec/foo_spec.rb create foo/LICENSE.txt Initializing git repo in /Users/kbennett/temp/foo As with any gem, the easiest way to create it is with bundler:
Ruby Gem • In your gemspec file, you specify the location of your executable(s): spec.executables = spec.files.grep(%r{^exe/}) { |f| File.basename(f) } # or: spec.executables = [‘wifi-wand’] • The executable can be (and probably should be) a simple wrapper around your other code, e.g.: #!/usr/bin/env ruby require_relative '../lib/wifi-wand/main' WifiWand::Main.new.call
providing richly functional interactive shell (REPL) • awesome_print - gem that outputs simple Ruby objects in a clear, logical, and attractive format • Ruby’s built-in json and yaml support • open - Mac OS command to open a resource identifier with the default application for that resource type, e.g. `open https://www.whatismyip.com/` (Linux: xdg- open, Windows: start)
(first) wireless network hardware port in the system, e.g. en0 or en1 # This may not detect wifi ports with nonstandard names, such as USB wifi devices. def detect_wifi_port lines = run_os_command("networksetup -listallhardwareports”).split("\n") # Produces something like this: # —————————————————————————————————————————————————————————— # Hardware Port: Wi-Fi # Device: en0 # Ethernet Address: ac:bc:32:b9:a9:9d # # Hardware Port: Bluetooth PAN # Device: en3 # Ethernet Address: ac:bc:32:b9:a9:9e # —————————————————————————————————————————————————————————— wifi_port_line_num = (0...lines.size).detect do |index| /: Wi-Fi$/.match(lines[index]) end if wifi_port_line_num.nil? raise Error.new(%Q{Wifi port (e.g. "en0") not found in output of: } + "networksetup -listallhardwareports”) else lines[wifi_port_line_num + 1].split(': ').last end
method_name.to_s action = find_command_action(method_name) if action action.(*method_args) else puts(%Q{"#{method_name}" is not a valid command or option. } \ << 'If you intend for this to be a string literal, ' \ << 'use quotes or %q{}/%Q{}.') end end
cmd.max_string.start_with?(command_string) \ && \ command_string.length >= cmd.min_string.length # e.g. 'c' by itself should not work because # there are ‘ci’, ‘co’, and ‘cy’ commands end result ? result.action : nil end
(command 2>&1) • Use their exit codes (`$?`, which is threadlocal, not global) • Provide a way for the user to see the commands and their output • Centralize calling the OS in a single method, even if you think you'll never need it. Here’s mine:
data • can be edited with the user’s favorite text editor • can be version controlled with git et al., • providing an audit log with date, author, & content changes • diffs are human readable • printable for archival purposes (practical in small quantities)
require any software (e.g. data base software) other than built-in software available on any OS • more likely to be readable in the distant future than other formats • editing can be faster for power users, no need to move hands away from the keyboard • can be implemented on even the smallest systems, eliminating the need for network connectivity • local or client/server
@doc_type: chart_of_accounts @title: Chart of Accounts - 2017 @entity: XYZ Consulting, Inc. # Assets ck.hsbc A HSBC Checking paypal A Paypal accts.rec A Accounts Receivable # Liabilities cc.hsbc.visa L Visa Credit Card loan.to.sh L Loan Payable to Shareholder
@doc_type: journal @title: HSBC Checking Disbursements Journal - 2017 @account_code: ck.hsbc @debit_or_credit: debit @short_name: ck.hsbc.disb @date_prefix: 2017- 01-01 -5000.00 own.equity Initial Deposit from Shareholder # To specify further comments about this transaction that will # not be included in reports, specify them as comments # (like this one), that is, lines starting with ‘#’ 01-05 2000.00 cc.hsbc.visa 01-07 -10000.00 sls.cons Invoice #437, Dec. 2016 work, ABC, Inc.
classes! reports = OpenStruct.new(book_set.all_reports($filter)) # add hash methods for convenience def reports.keys; to_h.keys.map(&:to_s); end def reports.values; to_h.values; end # to access as array, e.g. `a.at(1)` def reports.at(index); self.public_send(keys[index]);
filter to include only a subset of all transactions. For example: jan_cowork_filter = all( month(2017, 1), account_code('cowork.fees')) filtered_entries = filter(all_entries, jan_cowork_filter) puts filtered_entries.size 1 puts filtered_entries.first.description New Work City coworking fee for the month of January Receipt: 01/2017-01-02-nwc.pdf
->(entry) do entry.date.year == target_year && \ entry.date.month == target_month end end # A compound filter combining multiple other filters def all(*filters) ->(entry) { filters.all? { |filter| filter.(entry) } } end # The method that filters the Enumerable of journal entries def filter(entries, entry_filter) entries.select { |entry| entry_filter.(entry) } end
[10] pry> File.write('bs0.yaml', bs0.to_yaml); nil nil [11] pry> bs1 = YAML.load_file('bs0.yaml'); nil nil [12] pry> bs0 == bs1 true The entire RockBooks data set can be backed up and restored using YAML in the shell:
suite • interactive shell with data filters • option to specify options in an environment variable • directory specifications with reasonable defaults • output directories are created if nonexistent • use of $filter global
an obstacle to non-Rubyists (unlike, e.g., go) • + (As stated previously) it’s a great DSL language! • + Interpreted, not compiled • + Rich toolset • + In addition to MRI, JRuby can be used. • Can drive JVM code/libraries written in Java, Scala, Clojure, Kotlin, etc. • Can be installed where native code cannot be installed but Java libraries are permitted.
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