Merge pull request #14 from ninoseki/add-max_concurrency-option

feat: add max_concurrency option

lib/rangescan/cli.rb

@@ -12,6 +12,7 @@ class CLI < Thor
     method_option :timeout, type: :numeric, desc: "Timeout in seconds"
     method_option :user_agent, type: :string, desc: "User Agent"
     method_option :verify_ssl, type: :boolean, desc: "Whether to verify SSL or not"
+    method_option :max_concurrency, type: :numeric, desc: "Concurrency limit for HTTP requests to scan"
     def scan(ip_with_subnet_mask, regexp)
       symbolized_options = symbolize_hash_keys(options)
       range = Range.new(ip_with_subnet_mask)

lib/rangescan/scanner.rb

@@ -12,6 +12,7 @@ module RangeScan
   class Scanner
     attr_reader :context
     attr_reader :host
+    attr_reader :max_concurrency
     attr_reader :port
     attr_reader :processor_count
     attr_reader :scheme
@@ -20,7 +21,7 @@ class Scanner
     attr_reader :user_agent
     attr_reader :verify_ssl
 
-    def initialize(host: nil, port: nil, scheme: "http", verify_ssl: true, timeout: 5, user_agent: nil)
+    def initialize(host: nil, port: nil, scheme: "http", verify_ssl: true, timeout: 5, user_agent: nil, max_concurrency: nil)
       @host = host
       @port = port || (scheme == "http" ? 80 : 443)
       @timeout = timeout
@@ -32,7 +33,7 @@ def initialize(host: nil, port: nil, scheme: "http", verify_ssl: true, timeout:
       @ssl_context = OpenSSL::SSL::SSLContext.new
       @ssl_context.verify_mode = OpenSSL::SSL::VERIFY_NONE unless verify_ssl
 
-      @processor_count ||= Etc.nprocessors
+      @max_concurrency = max_concurrency || Etc.nprocessors * 2
     end
 
     def url_for(ipv4)
@@ -45,7 +46,7 @@ def scan(ipv4s)
       results = []
       Async do
         barrier = Async::Barrier.new
-        semaphore = Async::Semaphore.new(processor_count, parent: barrier)
+        semaphore = Async::Semaphore.new(max_concurrency, parent: barrier)
 
         ipv4s.each do |ipv4|
           semaphore.async do

spec/range_scan/scanner_spec.rb

@@ -2,6 +2,7 @@
 
 require "glint"
 require "webrick"
+require "etc"
 
 HOST = "127.0.0.1"
 
@@ -76,6 +77,18 @@ def server
     end
   end
 
+  describe "#max_concurrency" do
+    it do
+      scanner = described_class.new(scheme: "http")
+      expect(scanner.max_concurrency).to eq(Etc.nprocessors * 2)
+    end
+
+    it do
+      scanner = described_class.new(scheme: "https", max_concurrency: 3)
+      expect(scanner.max_concurrency).to eq(3)
+    end
+  end
+
   describe "#url_for" do
     it do
       scanner = described_class.new