Add DeJureIntegrator filter.

Signed-off-by: Thomas Hochstein <thh@inter.net>

README.md

@@ -2,7 +2,7 @@
 
 *[nanoc](http://nanoc.ws/)* is a popular *static site generator*.
 
-I'll add some little extensions for *nanoc* here.
+I'll add some little extensions for *nanoc* (v3) here.
 
 ## filters
 
@@ -34,3 +34,14 @@ from being rendered and compiled, i.e. like this:
     route %r{/_} do
       nil
     end
+
+### dejure.rb
+
+*nanoc* filter implementation of the *dejure.org*
+[legal integration service](https://dejure.org/vernetzung.html).
+
+    filter :dejure,
+      format: 'weit',
+      buzer: 1,
+      target: '_blank',
+      class: 'dejure'

lib/filters/dejure.rb

@@ -0,0 +1,104 @@
+# dejure.rb
+# a nanoc filter for dejure.org legal integration service
+# see <https://dejure.org/vernetzung.html>
+#
+# adapted from PHP reference implementation
+# at <https://dejure.org/vernetzung/vernetzungsfunktion.zip>
+#
+# (c) 2017 Thomas Hochstein <thh@inter.net>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+# 
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+# 
+#
+# params may be set as follows:
+# params[:format] -> [weit|schmal]          (weit)
+# params[:target] -> target for <a href>    ('')
+# params[:class]  -> CSS class for <a href> ('')
+# params[:buzer]  -> fallback to buzer.de?  (1)
+
+require 'net/http'
+
+module Nanoc::Filters
+  class DeJureIntegrator < Nanoc::Filter
+  	identifier :dejure
+  	type :text
+
+    def set_params (params)
+      # set default params
+      params[:version]            = '0.1'
+      if !@config[:base_url].nil?
+        params[:Anbieterkennung]  = @config[:base_url]
+      else
+        params[:Anbieterkennung] = 'http://unknown.nanoc.installation.invalid'
+      end
+      params[:format]           ||= 'weit'
+      params[:buzer]            ||= 1
+      return params
+    end
+
+    def run(content, params={})
+      if !(/§|&sect;|Art\.|\/[0-9][0-9](?![0-9\/])| [0-9][0-9]?[\/\.][0-9][0-9](?![0-9\.])|[0-9][0-9], / =~ content)
+        # nothing to replace
+        return content
+      else
+        params = set_params(params)
+        return DeJureIntegrator(content.strip, params)
+      end
+    end
+
+    def DeJureIntegrator (text, params={})
+      prot = 'http://'
+      host = 'rechtsnetz.dejure.org'
+      path = '/dienste/vernetzung/vernetzen'
+      uri  = URI(prot + host + path)
+
+      http     = Net::HTTP.new(uri.host, uri.port)
+      request  = Net::HTTP::Post.new(uri.request_uri)
+      request['User-Agent']   = params[:Anbieterkennung] + ' (DeJureIntegrator for nanoc ruby-' + params[:version] + ')'
+      request['Content-Type'] = 'application/x-www-form-urlencoded'
+
+      formdata = params
+      formdata['Originaltext'] = text
+      request.set_form_data(formdata)
+
+      response = http.request(request)
+
+      if (response.code != '200')  || response.body.nil? || (text.length > response.body.length)
+        # HTTP error, empty body or response body smaller than original text
+        printf("DeJureIntegrator HTTP error: %s\n", response.code)
+        return text
+      else
+        return IntegrityCheck(text,response.body.force_encoding('UTF-8'))
+      end
+    end
+
+  def IntegrityCheck (input,output)
+    # compare input and output text after removing all added links - texts should match!
+    regexp = /<a href="http:\/\/dejure.org\/[^>]*>([^<]*)<\/a>/i
+    if input.strip.gsub(regexp, '\\1') == output.strip.gsub(regexp, '\\1')
+      return output
+    else
+      # texts don't match 
+      puts "DeJureIntegrator integrity error\n"
+      return input
+    end
+  end
+
+  end
+end