Query packagist for the latest version

config/config.rb.example

@@ -4,5 +4,6 @@ CONFIG = {
   remote_path: 'example.com:/srv/httpd/some/path',
   download_url: 'https://example.com/some/path',
   branch: 'user/nick/updates',
-  gh_token: ''
+  gh_token: '',
+  repository: '../slackbuilds'
 }.freeze

lib/up2date.rb

@@ -9,6 +9,15 @@ require 'json'
 require_relative '../config/config'
 
 module SlackBuilder
+  # Remote repository for a single package.
+  class Repository
+    # Request the latest tag in the given repository.
+    def latest
+      raise NotImplementedError
+    end
+  end
+
+  class GitHub < Repository
     GITHUB_QUERY = <<~GQL
       query ($name: String!, $owner: String!) {
         repository(name: $name, owner: $owner) {
@@ -23,11 +32,17 @@ module SlackBuilder
     GQL
     private_constant :GITHUB_QUERY
 
-  # Request the latest tag in the given repository.
-  def self.github_latest_tag(owner, name)
+    def initialize(owner, name)
+      super()
+
+      @owner = owner
+      @name = name
+    end
+
+    def latest
       post_data = {
         'query' => GITHUB_QUERY,
-      'variables' => { 'name' => name, 'owner' => owner }
+        'variables' => { 'name' => @name, 'owner' => @owner }
       }
       uri = URI('https://api.github.com/graphql')
       response = Net::HTTP.post uri, post_data.to_json, {
@@ -37,3 +52,36 @@ module SlackBuilder
       JSON.parse(response.body)['data']['repository']['refs']['nodes'].first['name']
     end
   end
+
+  class Packagist < Repository
+    def initialize(vendor, name)
+      super()
+
+      @vendor = vendor
+      @name = name
+    end
+
+    # Request the latest version from the packagist API.
+    def latest
+      full_name = [@vendor, @name].join '/'
+      uri = URI "https://repo.packagist.org/p2/#{full_name}.json"
+      response = Net::HTTP.get uri, {
+        'content-type' => 'application/json'
+      }
+      JSON.parse(response)['packages'][full_name].first['version']
+    end
+  end
+
+  def self.check_for_latest(package_name, repository)
+    package_path = Pathname.new Dir.glob("#{CONFIG[:repository]}/*/#{package_name}").first
+    package_category = package_path.dirname.basename.to_s
+    package = Package.parse("#{package_category}/#{package_name}", File.read("#{package_path}/#{package_name}.info"))
+    latest_version = repository.latest
+
+    if package.version == latest_version
+      puts "#{package_name} is up to date."
+    else
+      puts "#{package_name}: Current version is #{package.version}, #{latest_version} is available."
+    end
+  end
+end