Create an utils subdir in core, which will store all utility files that can be reloaded without quitting the bot, and move httputil and utils to it

1 files changed, 404 insertions, 0 deletions

diff --git a/lib/rbot/core/utils/httputil.rb b/lib/rbot/core/utils/httputil.rb
new file mode 100644
index 00000000..42b7fdb8
--- /dev/null
+++ b/lib/rbot/core/utils/httputil.rb
@@ -0,0 +1,404 @@
+module ::Irc
+module Utils
+
+require 'resolv'
+require 'net/http'
+require 'net/https'
+Net::HTTP.version_1_2
+
+# class for making http requests easier (mainly for plugins to use)
+# this class can check the bot proxy configuration to determine if a proxy
+# needs to be used, which includes support for per-url proxy configuration.
+class HttpUtil
+    BotConfig.register BotConfigBooleanValue.new('http.use_proxy',
+      :default => false, :desc => "should a proxy be used for HTTP requests?")
+    BotConfig.register BotConfigStringValue.new('http.proxy_uri', :default => false,
+      :desc => "Proxy server to use for HTTP requests (URI, e.g http://proxy.host:port)")
+    BotConfig.register BotConfigStringValue.new('http.proxy_user',
+      :default => nil,
+      :desc => "User for authenticating with the http proxy (if required)")
+    BotConfig.register BotConfigStringValue.new('http.proxy_pass',
+      :default => nil,
+      :desc => "Password for authenticating with the http proxy (if required)")
+    BotConfig.register BotConfigArrayValue.new('http.proxy_include',
+      :default => [],
+      :desc => "List of regexps to check against a URI's hostname/ip to see if we should use the proxy to access this URI. All URIs are proxied by default if the proxy is set, so this is only required to re-include URIs that might have been excluded by the exclude list. e.g. exclude /.*\.foo\.com/, include bar\.foo\.com")
+    BotConfig.register BotConfigArrayValue.new('http.proxy_exclude',
+      :default => [],
+      :desc => "List of regexps to check against a URI's hostname/ip to see if we should use avoid the proxy to access this URI and access it directly")
+    BotConfig.register BotConfigIntegerValue.new('http.max_redir',
+      :default => 5,
+      :desc => "Maximum number of redirections to be used when getting a document")
+    BotConfig.register BotConfigIntegerValue.new('http.expire_time',
+      :default => 60,
+      :desc => "After how many minutes since last use a cached document is considered to be expired")
+    BotConfig.register BotConfigIntegerValue.new('http.max_cache_time',
+      :default => 60*24,
+      :desc => "After how many minutes since first use a cached document is considered to be expired")
+    BotConfig.register BotConfigIntegerValue.new('http.no_expire_cache',
+      :default => false,
+      :desc => "Set this to true if you want the bot to never expire the cached pages")
+
+  def initialize(bot)
+    @bot = bot
+    @cache = Hash.new
+    @headers = {
+      'User-Agent' => "rbot http util #{$version} (http://linuxbrit.co.uk/rbot/)",
+    }
+    @last_response = nil
+  end
+  attr_reader :last_response
+  attr_reader :headers
+
+  # if http_proxy_include or http_proxy_exclude are set, then examine the
+  # uri to see if this is a proxied uri
+  # the in/excludes are a list of regexps, and each regexp is checked against
+  # the server name, and its IP addresses
+  def proxy_required(uri)
+    use_proxy = true
+    if @bot.config["http.proxy_exclude"].empty? && @bot.config["http.proxy_include"].empty?
+      return use_proxy
+    end
+
+    list = [uri.host]
+    begin
+      list.concat Resolv.getaddresses(uri.host)
+    rescue StandardError => err
+      warning "couldn't resolve host uri.host"
+    end
+
+    unless @bot.config["http.proxy_exclude"].empty?
+      re = @bot.config["http.proxy_exclude"].collect{|r| Regexp.new(r)}
+      re.each do |r|
+        list.each do |item|
+          if r.match(item)
+            use_proxy = false
+            break
+          end
+        end
+      end
+    end
+    unless @bot.config["http.proxy_include"].empty?
+      re = @bot.config["http.proxy_include"].collect{|r| Regexp.new(r)}
+      re.each do |r|
+        list.each do |item|
+          if r.match(item)
+            use_proxy = true
+            break
+          end
+        end
+      end
+    end
+    debug "using proxy for uri #{uri}?: #{use_proxy}"
+    return use_proxy
+  end
+
+  # uri:: Uri to create a proxy for
+  #
+  # return a net/http Proxy object, which is configured correctly for
+  # proxying based on the bot's proxy configuration.
+  # This will include per-url proxy configuration based on the bot config
+  # +http_proxy_include/exclude+ options.
+  def get_proxy(uri)
+    proxy = nil
+    proxy_host = nil
+    proxy_port = nil
+    proxy_user = nil
+    proxy_pass = nil
+
+    if @bot.config["http.use_proxy"]
+      if (ENV['http_proxy'])
+        proxy = URI.parse ENV['http_proxy'] rescue nil
+      end
+      if (@bot.config["http.proxy_uri"])
+        proxy = URI.parse @bot.config["http.proxy_uri"] rescue nil
+      end
+      if proxy
+        debug "proxy is set to #{proxy.host} port #{proxy.port}"
+        if proxy_required(uri)
+          proxy_host = proxy.host
+          proxy_port = proxy.port
+          proxy_user = @bot.config["http.proxy_user"]
+          proxy_pass = @bot.config["http.proxy_pass"]
+        end
+      end
+    end
+
+    h = Net::HTTP.new(uri.host, uri.port, proxy_host, proxy_port, proxy_user, proxy_port)
+    h.use_ssl = true if uri.scheme == "https"
+    return h
+  end
+
+  # uri::         uri to query (Uri object)
+  # readtimeout:: timeout for reading the response
+  # opentimeout:: timeout for opening the connection
+  #
+  # simple get request, returns (if possible) response body following redirs
+  # and caching if requested
+  # if a block is given, it yields the urls it gets redirected to
+  # TODO we really need something to implement proper caching
+  def get(uri_or_str, readtimeout=10, opentimeout=5, max_redir=@bot.config["http.max_redir"], cache=false)
+    if uri_or_str.kind_of?(URI)
+      uri = uri_or_str
+    else
+      uri = URI.parse(uri_or_str.to_s)
+    end
+    debug "Getting #{uri}"
+
+    proxy = get_proxy(uri)
+    proxy.open_timeout = opentimeout
+    proxy.read_timeout = readtimeout
+
+    begin
+      proxy.start() {|http|
+        yield uri.request_uri() if block_given?
+	req = Net::HTTP::Get.new(uri.request_uri(), @headers)
+	if uri.user and uri.password
+          req.basic_auth(uri.user, uri.password)
+	end
+	resp = http.request(req)
+        case resp
+        when Net::HTTPSuccess
+          if cache
+	    debug "Caching #{uri.to_s}"
+	    cache_response(uri.to_s, resp)
+          end
+          return resp.body
+        when Net::HTTPRedirection
+          if resp.key?('location')
+            new_loc = URI.join(uri, resp['location'])
+            debug "Redirecting #{uri} to #{new_loc}"
+            yield new_loc if block_given?
+            if max_redir > 0
+              # If cache is an Array, we assume get was called by get_cached
+              # because of a cache miss and that the first value of the Array
+              # was the noexpire value. Since the cache miss might have been
+              # caused by a redirection, we want to try get_cached again
+              # TODO FIXME look at Python's httplib2 for a most likely
+              # better way to handle all this mess
+              if cache.kind_of?(Array)
+                return get_cached(new_loc, readtimeout, opentimeout, max_redir-1, cache[0])
+              else
+                return get(new_loc, readtimeout, opentimeout, max_redir-1, cache)
+              end
+            else
+              warning "Max redirection reached, not going to #{new_loc}"
+            end
+          else
+            warning "Unknown HTTP redirection #{resp.inspect}"
+          end
+        else
+          debug "HttpUtil.get return code #{resp.code} #{resp.body}"
+        end
+        @last_response = resp
+        return nil
+      }
+    rescue StandardError, Timeout::Error => e
+      error "HttpUtil.get exception: #{e.inspect}, while trying to get #{uri}"
+      debug e.backtrace.join("\n")
+    end
+    @last_response = nil
+    return nil
+  end
+
+  # just like the above, but only gets the head
+  def head(uri_or_str, readtimeout=10, opentimeout=5, max_redir=@bot.config["http.max_redir"])
+    if uri_or_str.kind_of?(URI)
+      uri = uri_or_str
+    else
+      uri = URI.parse(uri_or_str.to_s)
+    end
+
+    proxy = get_proxy(uri)
+    proxy.open_timeout = opentimeout
+    proxy.read_timeout = readtimeout
+
+    begin
+      proxy.start() {|http|
+        yield uri.request_uri() if block_given?
+	req = Net::HTTP::Head.new(uri.request_uri(), @headers)
+	if uri.user and uri.password
+          req.basic_auth(uri.user, uri.password)
+	end
+	resp = http.request(req)
+        case resp
+        when Net::HTTPSuccess
+          return resp
+        when Net::HTTPRedirection
+          debug "Redirecting #{uri} to #{resp['location']}"
+          yield resp['location'] if block_given?
+          if max_redir > 0
+            return head( URI.parse(resp['location']), readtimeout, opentimeout, max_redir-1)
+          else
+            warning "Max redirection reached, not going to #{resp['location']}"
+          end
+        else
+          debug "HttpUtil.head return code #{resp.code}"
+        end
+        @last_response = resp
+        return nil
+      }
+    rescue StandardError, Timeout::Error => e
+      error "HttpUtil.head exception: #{e.inspect}, while trying to get #{uri}"
+      debug e.backtrace.join("\n")
+    end
+    @last_response = nil
+    return nil
+  end
+
+  def cache_response(k, resp)
+    begin
+      if resp.key?('pragma') and resp['pragma'] == 'no-cache'
+	debug "Not caching #{k}, it has Pragma: no-cache"
+	return
+      end
+      # TODO should we skip caching if neither last-modified nor etag are present?
+      now = Time.new
+      u = Hash.new
+      u = Hash.new
+      u[:body] = resp.body
+      u[:last_modified] = nil
+      u[:last_modified] = Time.httpdate(resp['date']) if resp.key?('date')
+      u[:last_modified] = Time.httpdate(resp['last-modified']) if resp.key?('last-modified')
+      u[:expires] = now
+      u[:expires] = Time.httpdate(resp['expires']) if resp.key?('expires')
+      u[:revalidate] = false
+      if resp.key?('cache-control')
+	# TODO max-age
+	case resp['cache-control']
+	when /no-cache|must-revalidate/
+	  u[:revalidate] = true
+	end
+      end
+      u[:etag] = ""
+      u[:etag] = resp['etag'] if resp.key?('etag')
+      u[:count] = 1
+      u[:first_use] = now
+      u[:last_use] = now
+    rescue => e
+      error "Failed to cache #{k}/#{resp.to_hash.inspect}: #{e.inspect}"
+      return
+    end
+    @cache[k] = u
+    debug "Cached #{k}/#{resp.to_hash.inspect}: #{u.inspect_no_body}"
+    debug "#{@cache.size} pages (#{@cache.keys.join(', ')}) cached up to now"
+  end
+
+  # For debugging purposes
+  class ::Hash
+    def inspect_no_body
+      temp = self.dup
+      temp.delete(:body)
+      temp.inspect
+    end
+  end
+
+  def expired?(uri, readtimeout, opentimeout)
+    k = uri.to_s
+    debug "Checking cache validity for #{k}"
+    begin
+      return true unless @cache.key?(k)
+      u = @cache[k]
+
+      # TODO we always revalidate for the time being
+
+      if u[:etag].empty? and u[:last_modified].nil?
+	# TODO max-age
+	return true
+      end
+
+      proxy = get_proxy(uri)
+      proxy.open_timeout = opentimeout
+      proxy.read_timeout = readtimeout
+
+      proxy.start() {|http|
+	yield uri.request_uri() if block_given?
+	headers = @headers.dup
+	headers['If-None-Match'] = u[:etag] unless u[:etag].empty?
+	headers['If-Modified-Since'] = u[:last_modified].rfc2822 if u[:last_modified]
+        debug "Cache HEAD request headers: #{headers.inspect}"
+	# FIXME TODO We might want to use a Get here
+	# because if a 200 OK is returned we would get the new body
+	# with one connection less ...
+	req = Net::HTTP::Head.new(uri.request_uri(), headers)
+	if uri.user and uri.password
+	  req.basic_auth(uri.user, uri.password)
+	end
+	resp = http.request(req)
+	debug "Checking cache validity of #{u.inspect_no_body} against #{resp.inspect}/#{resp.to_hash.inspect}"
+	case resp
+	when Net::HTTPNotModified
+	  return false
+	else
+	  return true
+	end
+      }
+    rescue => e
+      error "Failed to check cache validity for #{uri}: #{e.inspect}"
+      return true
+    end
+  end
+
+  # gets a page from the cache if it's still (assumed to be) valid
+  # TODO remove stale cached pages, except when called with noexpire=true
+  def get_cached(uri_or_str, readtimeout=10, opentimeout=5,
+                 max_redir=@bot.config['http.max_redir'],
+                 noexpire=@bot.config['http.no_expire_cache'])
+    if uri_or_str.kind_of?(URI)
+      uri = uri_or_str
+    else
+      uri = URI.parse(uri_or_str.to_s)
+    end
+    debug "Getting cached #{uri}"
+
+    if expired?(uri, readtimeout, opentimeout)
+      debug "Cache expired"
+      bod = get(uri, readtimeout, opentimeout, max_redir, [noexpire])
+      bod.instance_variable_set(:@cached,false)
+    else
+      k = uri.to_s
+      debug "Using cache"
+      @cache[k][:count] += 1
+      @cache[k][:last_use] = Time.now
+      bod = @cache[k][:body]
+      bod.instance_variable_set(:@cached,true)
+    end
+    unless noexpire
+      remove_stale_cache
+    end
+    unless bod.respond_to?(:cached?)
+      def bod.cached?
+        return @cached
+      end
+    end
+    return bod
+  end
+
+  # We consider a page to be manually expired if it has no
+  # etag and no last-modified and if any of the expiration
+  # conditions are met (expire_time, max_cache_time, Expires)
+  def manually_expired?(hash, time)
+    auto = hash[:etag].empty? and hash[:last_modified].nil?
+    # TODO max-age
+    manual = (time - hash[:last_use] > @bot.config['http.expire_time']*60) or
+             (time - hash[:first_use] > @bot.config['http.max_cache_time']*60) or
+	     (hash[:expires] < time)
+    return (auto and manual)
+  end
+
+  def remove_stale_cache
+    debug "Removing stale cache"
+    debug "#{@cache.size} pages before"
+    begin
+    now = Time.new
+    @cache.reject! { |k, val|
+       manually_expired?(val, now)
+    }
+    rescue => e
+      error "Failed to remove stale cache: #{e.inspect}"
+    end
+    debug "#{@cache.size} pages after"
+  end
+end
+end
+end