Add Language Detection endpoint

Close #247

README.md

@@ -342,6 +342,28 @@ Response:
 
       ... PDF document body ...
 
+### Detect language
+
+This is a foreground document language detection request. The detected language
+will be returned as the response body.
+
+    POST /detect-language
+
+Params *(suggest using `multipart/form-data`)*:
+
+* `file`      - the file to convert
+
+#### Example:
+
+    POST /detect-language
+      file=... foo.docx ...
+
+Response:
+
+      Content-Type: text/plain
+
+      en
+
 ## Callbacks
 
 When a document conversion is completed, an attempt will be made to POST a

lib/app.rb

@@ -207,6 +207,30 @@ class App < Sinatra::Base
       end
     end
 
+    #
+    # Detect document language
+    #
+    # POST params:
+    #  file     - the file to detect language
+    post '/detect-language' do
+      begin
+        unless params[:file]
+          return respond 400, "missing file parameter"
+        end
+
+        unless params[:file].respond_to?(:fetch) and params[:file].fetch(:tempfile, nil).respond_to?(:read)
+          return respond 400, "invalid file parameter"
+        end
+
+        body = params[:file][:tempfile].read
+        content = Converter.new(logger: @logger).convert_file('detect_language', body)
+        content_type content.mime_type
+        content
+      rescue StandardError => e
+        respond_with_error e
+      end
+    end
+
     # Legacy method to convert files
     # Brought over from Heathen
     #

lib/heathen/processor_methods/detect_language.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module Heathen
+  class Processor
+    def detect_language
+      expect_mime_type 'application/pdf'
+
+      executioner.execute(
+        Colore::C_.tika_path,
+        '--language',
+        job.content_file,
+        binary: true
+      )
+
+      job.content = executioner.stdout
+    end
+  end
+end

spec/heathen/processor_methods/detect_language_spec.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Heathen::Processor do
+  let(:content) { File.read(fixture('heathen/quickfox.pdf')) }
+  let(:job) { Heathen::Job.new 'foo', content, 'en' }
+  let(:processor) { described_class.new job: job, logger: Logger.new($stderr) }
+
+  after do
+    processor.clean_up
+  end
+
+  context '#detect_language' do
+    it 'detects input file language' do
+      processor.detect_language
+      expect(job.content).to eq 'en'
+    end
+  end
+end