Add API endpoint /combine_pdf to combine multiple pdfs into one single pdf

Gemfile

@@ -2,7 +2,7 @@
 
 source 'https://rubygems.org'
 
-ruby '2.6.10'
+ruby '3.3.0'
 
 gem 'haml', '~> 6.3'
 gem 'iso-639', '~> 0.3.8'
@@ -19,6 +19,7 @@ gem 'sidekiq-cron', '~> 1.9'
 gem 'sinatra', '~> 3.2'
 gem 'thin', '~> 1.8'
 gem 'unicorn', '~> 6.1'
+gem 'combine_pdf'
 
 group :development do
   gem 'byebug'

Gemfile.lock

@@ -3,6 +3,9 @@ GEM
   specs:
     base64 (0.2.0)
     byebug (11.1.3)
+    combine_pdf (1.0.29)
+      matrix
+      ruby-rc4 (>= 0.1.5)
     concurrent-ruby (1.3.4)
     connection_pool (2.4.1)
     csv (3.3.0)
@@ -35,6 +38,7 @@ GEM
       net-imap
       net-pop
       net-smtp
+    matrix (0.4.2)
     mime-types (3.6.0)
       logger
       mime-types-data (~> 3.2015)
@@ -88,6 +92,7 @@ GEM
       rspec-support (~> 3.13.0)
     rspec-support (3.13.2)
     ruby-filemagic (0.7.3)
+    ruby-rc4 (0.1.5)
     ruby2_keywords (0.0.5)
     sidekiq (6.5.12)
       connection_pool (>= 2.2.5, < 3)
@@ -125,10 +130,11 @@ GEM
     yard (0.9.37)
 
 PLATFORMS
-  ruby
+  arm64-darwin-23
 
 DEPENDENCIES
   byebug
+  combine_pdf
   haml (~> 6.3)
   iso-639 (~> 0.3.8)
   json (~> 2.7)
@@ -152,7 +158,7 @@ DEPENDENCIES
   yard
 
 RUBY VERSION
-   ruby 2.6.10p210
+   ruby 3.3.0p0
 
 BUNDLED WITH
    2.4.22

lib/app.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'haml'
+require 'combine_pdf'
 require 'net/http'
 require 'pathname'
 require 'pp'
@@ -168,6 +169,34 @@ class App < Sinatra::Base
       respond_with_error e
     end
 
+    #
+    # Combine Multiple PDF's into one single PDF
+    #
+    # POST params:
+    #  pdf1     - the first pdf to combine
+    #  pdf2     - the second pdf to combine
+    #  ...
+    #  pdf<n>   - the nth pdf to combine
+    post '/combine_pdf' do
+      pdf_param_prefix = 'pdf'
+      pdf_file_counter = 1
+
+      pdfs = []
+
+      while (pdf_param = params["#{pdf_param_prefix}#{pdf_file_counter}"])
+        pdfs << pdf_param[:tempfile].read
+        pdf_file_counter += 1
+      end
+
+      combine_pdfs = CombinePdfs.new
+      combined_pdf = combine_pdfs.call(pdfs)
+
+      content_type 'application/pdf'
+      combined_pdf
+    rescue StandardError => e
+      respond_with_error e
+    end
+
     #
     # Convert document
     #

lib/colore.rb

@@ -10,3 +10,4 @@
 require_relative 'heathen'
 require_relative 'sidekiq_workers'
 require_relative 'tika_config'
+require_relative 'combine_pdfs'

lib/combine_pdfs.rb

@@ -0,0 +1,9 @@
+class CombinePdfs
+  def call(pdfs)
+    combined_pdf = CombinePDF.new
+
+    pdfs.each {|pdf| combined_pdf << CombinePDF.parse(pdf) }
+
+    combined_pdf.to_pdf
+  end
+end

spec/lib/app_spec.rb

@@ -389,4 +389,19 @@ def show_backtrace(response)
       expect(body['error']).to eq 'File does not exist'
     end
   end
+
+  describe 'POST /combine_pdf' do
+    it 'combines the provided pdfs into one single pdf' do
+      sample_pdf_dir = "#{__dir__}/../fixtures/pdfs"
+      pdf1 = Rack::Test::UploadedFile.new("#{sample_pdf_dir}/1.pdf", 'application/pdf')
+      pdf2 = Rack::Test::UploadedFile.new("#{sample_pdf_dir}/2.pdf", 'application/pdf')
+      post '/combine_pdf', {
+        pdf1: pdf1,
+        pdf2: pdf2,
+      }
+      expect(last_response.status).to eq 200
+      expect(last_response.content_type).to eq 'application/pdf'
+      expect(last_response.body.include?('PDF')).to be(true)
+    end
+  end
 end

spec/lib/combine_pdfs_spec.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'app'
+
+RSpec.describe CombinePdfs do
+	subject(:combine_pdfs) { CombinePdfs.new.(pdfs) }
+	let(:pdfs) { [fixture('pdfs/1.pdf').read, fixture('pdfs/2.pdf').read] }
+
+  describe 'combine' do
+    it 'creates a new pdf' do
+    	expect {
+    		pdf = combine_pdfs
+    		expect(pdf.size).to be > 0
+    	}.not_to raise_error
+    end
+  end
+end