Gemcutter recently added a sweet search call to its API. With gemcutter’s API and boson, we’ll see how to search gems, get a gem’s information and compare multiple gems on the commandline. Also, I’ll explain how some of this was done so you’re able to make commands for any API.

If you’re more interested in how this library is built, skip to here.

To use this boson library:

$ gem install boson boson-more $ echo "require 'boson/more'" >> ~/.bosonrc $ boson install https://github.com/cldwalker/irbfiles/raw/master/boson/commands/public/site/gemcutter.rb

Usage

This gemcutter CLI comes with three commands. The first command is gem_search :

# basic search bash> boson gem_search command +---------------------+-----------+---------------------------------------------------------------------------------------+---------------------------------------------------------------+ | name | downloads | info | authors | +---------------------+-----------+---------------------------------------------------------------------------------------+---------------------------------------------------------------+ | rubyforge | 70823 | A script which automates a limited set of rubyforge operations.



* Run 'rubyforg... | Ryan Davis, Eric Hodel, Ara T Howard, Tom Copeland | | gemcutter | 69607 | Adds several commands to RubyGems for managing gems and more on Gemcutter.org. | Nick Quaranto | | hoe | 68058 | Hoe is a rake/rubygems helper for project Rakefiles. It helps you

manage and main... | Ryan Davis | | capistrano | 55740 | Capistrano is a utility and framework for executing commands in parallel on multip... | Jamis Buck, Lee Hambley | # ... 30 rows in set # Let's go the second page of the previous query bash> boson gem_search command -p2 +--------------+-----------+------------------------------------------------------------------------------------------+--------------------------------------------------------------+ | name | downloads | info | authors | +--------------+-----------+------------------------------------------------------------------------------------------+--------------------------------------------------------------+ | vlad | 2173 | Vlad the Deployer is pragmatic application deployment automation,

without mercy. Muc... | Ryan Davis, Eric Hodel, Wilson Bilkovich | | sys-uname | 2161 | The sys-uname library provides an interface for gathering information

about ... | Daniel J. Berger | | cmdparse | 1943 | cmdparse provides classes for parsing commands on the command line; command line opti... | Thomas Leitner | | backup | 1862 |

Backup is a Ruby Gem written for Unix and Rails environ... | Michael van Rooijen | # ... 30 rows in set # multi word search bash> boson gem_search rails plugin +--------------------------------+-----------+--------------------------------------------------------------------------------+--------------------------------------------------------------------------------+ | name | downloads | info | authors | +--------------------------------+-----------+--------------------------------------------------------------------------------+--------------------------------------------------------------------------------+ | will_paginate | 42886 | The will_paginate library provides a simple, yet powerful and extensible AP... | Mislav Marohnić, PJ Hyett | | aasm | 7638 | AASM is a continuation of the acts as state machine rails plugin, built for... | Scott Barron, Scott Petersen, Travis Tilley | | after_commit | 7016 |

A Ruby on Rails plugin to add an after_commit callback. This can be u... | Nick Muerdter, David Yip, Pat Allan | | rails_datamapper | 2124 | Rails Plugin for DataMapper | Tom Malone | # ... 30 rows in set # with no search term, defaults to all-time top-downloaded gems # no surprises here bash> boson gem_search +-----------------+-----------+----------------------------------------------------------------------------------------+----------------------------------------------------+ | name | downloads | info | authors | +-----------------+-----------+----------------------------------------------------------------------------------------+----------------------------------------------------+ | activesupport | 319341 | Utility library which carries commonly used classes and goodies from the Rails fram... | David Heinemeier Hansson | | activerecord | 293266 | Implements the ActiveRecord pattern (Fowler, PoEAA) for ORM. It ties database table... | David Heinemeier Hansson | | actionpack | 287332 | Eases web-request routing, handling, and response as a half-way front, half-way pag... | David Heinemeier Hansson | | rails | 287005 | Rails is a framework for building web-application using CGI, FCGI, mod_ruby, or... | David Heinemeier Hansson | | rack | 285612 | Rack provides minimal, modular and adaptable interface for developing

web applicat... | Christian Neukirchen | # ... 30 rows in set

If you’re not familiar with boson, you may be surprised with how many options are available by default to control how and what you see:

# Only see the name and info fields bash> boson gem_search tag -f=n,i # or --fields=name,info +---------------------+------------------------------------------------------------------------------------------------------------------------------+ | name | info | +---------------------+------------------------------------------------------------------------------------------------------------------------------+ | haml | Haml (HTML Abstraction Markup Language) is a layer on top of XHTML or XML

that's designed to express the str... | | libxml-ruby | The Libxml-Ruby project provides Ruby language bindings for the GNOME Libxml2 XML toolkit. It is free software, released ... | | win32-api | The Win32::API library is meant as a replacement for the Win32API

library that ships as part of the standard... | | haml-edge | Haml (HTML Abstraction Markup Language) is a layer on top of XHTML or XML

that's designed to express the str... | # ... 30 rows in set # Sort by authors bash> boson gem_search tag -s=a # or --sort=authors +---------------------+-----------+--------------------------------------------------------+--------------------------------------------------------+ | name | downloads | info | authors | +---------------------+-----------+--------------------------------------------------------+--------------------------------------------------------+ | calais | 489 | A Ruby interface to the Calais Web Service | Abhay Kumar | | stage | 506 | Code template generator for Rails and Merb that DRY... | Andrew Stone | | tagz | 779 | tagz.rb is generates html, xml, or any sgml... | Ara T. Howard | | dm-tags | 1985 | This package brings tagging to DataMapper. It is i... | Bobby Calderwood | | libxml-ruby | 21789 | The Libxml-Ruby project provides Ruby language bind... | Charlie Savage | | win32-api | 14810 | The Win32::API library is meant as a replacem... | Daniel J. Berger, Park Heesob | # ... 30 rows in set # Show all fields, displaying a paged vertical table bash> boson gem_search tag -f=* -V ************************* 1. row ************************* authors: Nathan Weizenbaum, Hampton Catlin dependencies: {"development"=>[{"name"=>"maruku", "requirements"=>">= 0.5.9"}, {"name"=>"yard", "requirements"=>">= 0.4.0"}], "runtime"=>[]} downloads: 85590 gem_uri: http://gemcutter.org/gems/haml-2.2.17.gem info: Haml (HTML Abstraction Markup Language) is a layer on top of XHTML or XML that's designed to express the structure of XHTML or XML documents in a non-repetitive, elegant, easy way, using indentation rather than closing tags and allowing Ruby to be embedded with ease. It was originally envisioned as a plugin for Ruby on Rails, but it can function as a stand-alone templating engine. name: haml project_uri: http://gemcutter.org/gems/haml version: 2.2.17 version_downloads: 25104 ************************* 2. row ************************* # Remaining records are paged ... # To get more help on this command bash> boson gem_search -hv # ...

The second command we’ll look at is cut , which displays gemcutter’s information on a gem:

bash> boson cut rails +-------------------+--------------------------------------------------------------------------------------------------------------------------------+ | field | value | +-------------------+--------------------------------------------------------------------------------------------------------------------------------+ | name | "rails" | | downloads | 287086 | | info | " Rails is a framework for building web-application using CGI, FCGI, mod_ruby, or WEBrick

on top of either MySQL, P... | | version | "2.3.5" | | project_uri | "http://gemcutter.org/gems/rails" | | gem_uri | "http://gemcutter.org/gems/rails-2.3.5.gem" | | version_downloads | 189219 | | authors | "David Heinemeier Hansson" | | dependencies | {"development"=>[], "runtime"=>[{"name"=>"activeresource", "requirements"=>"= 2.3.5"}, {"name"=>"actionmailer", "requiremen... | +-------------------+--------------------------------------------------------------------------------------------------------------------------------+ 9 rows in set

The third command is cuts , which lists multiple gems. This command is perfect for comparing gems i.e. mocking gems:

bash> boson cuts rr mocha flexmock facon Fetching gem 'rr' Fetching gem 'mocha' Fetching gem 'flexmock' Fetching gem 'facon' +----------+-----------+------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------+ | name | downloads | project_uri | info | +----------+-----------+------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------+ | rr | 4973 | http://gemcutter.org/gems/rr | RR (Double Ruby) is a double framework that features a rich selection of double techniques and a terse syntax. http://xunitpatterns.com/Test%2... | | mocha | 19703 | http://gemcutter.org/gems/mocha | Mocking and stubbing library with JMock/SchMock syntax, which allows mocking and stubbing of methods on real (non-mock) classes.

| | flexmock | 4527 | http://gemcutter.org/gems/flexmock | FlexMock is a extremely simple mock object class compatible with the Test::Unit framework. Although the FlexMock's interface is simple, it i... | | facon | 291 | http://gemcutter.org/gems/facon | A mocking library in the spirit of the Bacon spec library. Small, compact, and works with Bacon. | +----------+-----------+------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------+ 4 rows in set

Now, if you want to use these commands but with shorter command names or different default fields displayed, you should read up on boson.

So how hard was it to create this CLI? Not hard at all …

To understand this console interface to gemcutter, let’s look at creating the gem_search command.

First, as gemcutter’s api docs explain, a search request looks like /api/v1/search.(json|xml)?query=[QUERY] . Let’s consider what we’ll do with this api call:

1. Make a get request to get back a string.

2. Convert the string into a ruby object by parsing the format (xml or json).

3. Display the ruby object in a well-formatted, useful way.

Step 1 can be done with the standard library net/http i.e. Net::HTTP.get(URI.parse(url)) . We’ll just use boson’s get() command which wraps around this. For step 2, we’ll parse json using JSON.parse . If you’re on 1.9, you should already have the json library. Otherwise, sudo gem install json should set you up. For step 3, we’ll use hirb’s handy tables which integrate nicely with boson.

Taking the first two steps, the boson command looks like this:

require 'json' module Gemcutter def gem_search ( query ) JSON . parse get ( "http://gemcutter.org/api/v1/search.json?query= #{ query } " ) end end

Pretty straightforward. To try this command, drop it in a local Bosonfile and …

# Knowing nothing about the returned data structure, boson attempts to format it bash> boson gem_search tag +---------------------------+---------------------------+-----------+---------------------------+---------------------------+---------------------+---------------------------+-----------+-------------------+ | authors | dependencies | downloads | gem_uri | info | name | project_uri | version | version_downloads | +---------------------------+---------------------------+-----------+---------------------------+---------------------------+---------------------+---------------------------+-----------+-------------------+ | Nathan Weizenbaum, Ham... | developmentnamemarukur... | 85521 | http://gemcutter.org/g... | Haml (HTML Abstr... | haml | http://gemcutter.org/g... | 2.2.17 | 25048 | | Charlie Savage | developmentruntime | 21769 | http://gemcutter.org/g... | The Libxml-Ruby projec... | libxml-ruby | http://gemcutter.org/g... | 1.1.3 | 18167 | | Daniel J. Berger, Park... | developmentnametest-un... | 14794 | http://gemcutter.org/g... | The Win32::API l... | win32-api | http://gemcutter.org/g... | 1.4.5 | 3973 | # ... # It's a mess. # Knowing that we're supposed to be getting back an array of gems # let's inspect one of the results bash> boson -e "p gem_search('tag')[0]" {"name"=>"haml", "downloads"=>85525, "info"=>" Haml (HTML Abstraction Markup Language) is a layer on top of XHTML or XML

that's designed to express the structure of XHTML or XML documents

in a non-repetitive, elegant, easy way,

using indentation rather than closing tags

and allowing Ruby to be embedded with ease.

It was originally envisioned as a plugin for Ruby on Rails,

but it can function as a stand-alone templating engine.

", "version"=>"2.2.17", "project_uri"=>"http://gemcutter.org/gems/haml", "gem_uri"=>"http://gemcutter.org/gems/haml-2.2.17.gem", "version_downloads"=>25052, "authors"=>"Nathan Weizenbaum, Hampton Catlin", "dependencies"=>{"development"=>[{"name"=>"maruku", "requirements"=>">= 0.5.9"}, {"name"=>"yard", "requirements"=>">= 0.4.0"}], "runtime"=>[]}} # Ok, a gem is a hash. But with what fields? bash> boson -e "p gem_search('tag')[0].keys" ["name", "downloads", "info", "version", "project_uri", "gem_uri", "version_downloads", "authors", "dependencies"]

Now for the third step. Let’s configure the table fields rendered for our api call with render_options() . In keeping with boson’s philosophy, we’ll write it in commented form:

require 'json' module Gemcutter # @render_options :fields=>{:default=>%w{name downloads info authors}, # :values=>%w{name authors version_downloads info project_uri gem_uri version downloads dependencies} }, # :filters=>{:default=>{'dependencies'=>:inspect}} # Search gemcutter def gem_search ( query ) JSON . parse get ( "http://gemcutter.org/api/v1/search.json?query= #{ query } " ) end end

Note that we passed two keys to render_options : :fields and :filters. For :fields we pass :default to specify default fields and :values to specify all values for :fields. Now let’s give this command a test drive:

bash> boson gem_search tagging +---------------------------------+-----------+---------------------------------------------------------------------+--------------------------------+ | name | downloads | info | authors | +---------------------------------+-----------+---------------------------------------------------------------------+--------------------------------+ | dm-tags | 1989 | This package brings tagging to DataMapper. It is inspired by Ac... | Bobby Calderwood | | sup | 1840 | Sup is a console-based email client for people with a lot of ema... | William Morgan | | tagomatic | 634 | = tagomatic



Simple command-line mp3 tagger based on mp3info g... | Daniel Lukic | | CachedSupermodel | 610 | Based on cached_model by <a href="http://dev.robotcoop.c... | adocca Entertainment AB | # ... 30 rows in set # Having specified available fields above, we can use aliased versions of fields # when referring to them. # Let's only see the numerical fields bash> boson gem_search tag -f=n,do,version_d,v # or --fields=name,downloads,version_downloads,version +---------------------+-----------+-------------------+-----------+ | name | downloads | version_downloads | version | +---------------------+-----------+-------------------+-----------+ | haml | 85579 | 25097 | 2.2.17 | | libxml-ruby | 21784 | 18180 | 1.1.3 | | win32-api | 14809 | 3978 | 1.4.5 | | haml-edge | 11241 | 3555 | 2.3.100 | # ... 30 rows in set

Success! How about the pagination option and multi-word search we saw above? Source code says it all.

Wrap Up

As we’ve seen with the gemcutter API, boson makes it dead easy to interface to an API from the commandline. If you’re interested in more boson-wrapped APIs, I’d recommend github or anything under here. And if you don’t already know, we can use any of these api commands in irb thanks to boson’s shell/irb duality.