add get_file_info method and MovieHasher to search for movies based o…

…n the OpenSubtitles file hash

lib/tmdb_party.rb

@@ -1,6 +1,6 @@
 require 'httparty'
 
-%w[extras/httparty_icebox extras/attributes video genre person image country studio cast_member movie].each do |class_name|
+%w[extras/httparty_icebox extras/attributes video genre person image country studio cast_member movie extras/movie_hasher].each do |class_name|
   require "tmdb_party/#{class_name}"
 end
 
@@ -49,7 +49,19 @@ def get_info(id, lang = @default_lang)
       data = self.class.get(method_url('Movie.getInfo', lang, id)).parsed_response
       Movie.new(data.first, self)
     end
-
+
+    def get_file_info(file, lang=@default_lang)
+      hash = TMDBParty::MovieHasher.compute_hash(file)
+      bytesize = file.size
+      data = self.class.get(method_url('Media.getInfo', lang, hash, bytesize)).parsed_response
+
+      if data.class != Array || data.first == "Nothing found."
+        []
+      else
+        data.collect { |movie| Movie.new(movie, self) }
+      end
+    end
+
     def get_person(id, lang = @default_lang)
       data = self.class.get(method_url('Person.getInfo', lang, id)).parsed_response
       Person.new(data.first, self)

lib/tmdb_party/extras/movie_hasher.rb

@@ -0,0 +1,32 @@
+# MovieHasher based on the one found here:
+# http://trac.opensubtitles.org/projects/opensubtitles/wiki/HashSourceCodes
+#
+# This will compute a unique hash for the movie that can be used for lookups on TMDB
+# The algorithm calculates size + 64bit chksum of the first and last 64k (even if they overlap because the file is smaller than 128k).
+# Make sure to uncomment and run the tests for this before making any changes
+module TMDBParty
+  module MovieHasher
+    CHUNK_SIZE = 64 * 1024 # in bytes
+
+    def self.compute_hash(file)
+      filesize = file.size
+      hash = filesize
+
+      # Read 64 kbytes, divide up into 64 bits and add each
+      # to hash. Do for beginning and end of file.
+      # Q = unsigned long long = 64 bit
+      file.read(CHUNK_SIZE).unpack("Q*").each do |n|
+        hash = hash + n & 0xffffffffffffffff # to remain as 64 bit number
+      end
+
+      file.seek([0, filesize - CHUNK_SIZE].max, IO::SEEK_SET)
+
+      # And again for the end of the file
+      file.read(CHUNK_SIZE).unpack("Q*").each do |n|
+        hash = hash + n & 0xffffffffffffffff
+      end
+
+      sprintf("%016x", hash)
+    end
+  end
+end

spec/lib/tmdb_party/extras/movie_hasher_spec.rb

@@ -0,0 +1,21 @@
+require 'spec_helper'
+
+# Download the sample files from here:
+# http://trac.opensubtitles.org/projects/opensubtitles/wiki/HashSourceCodes
+# and uncomment these tests before making any changes
+describe TMDBParty::MovieHasher do
+  # Not sure the best way to have tests for this without having real files to work with.
+  it "should compute hash" do
+    pending
+    File.open('breakdance.avi') do |file|
+      TMDBParty::MovieHasher.compute_hash(file).should == "8e245d9679d31e12"
+    end
+  end
+
+  it "should compute hash on large file" do
+    pending
+    File.open('dummy.bin') do |file|
+      TMDBParty::MovieHasher.compute_hash(file).should == "61f7751fc2a72bfb"
+    end
+  end
+end

spec/lib/tmdb_party_spec.rb

@@ -65,6 +65,24 @@
       tmdb.get_info(1858, 'sv').should_not be_nil
     end
   end
+
+  describe "#get_info with file" do
+    it "should return a movie instance" do
+      file = mock("file")
+      file.should_receive(:size).and_return(742086656)
+      TMDBParty::MovieHasher.should_receive(:compute_hash).with(file).and_return("907172e7fe51ba57")
+      stub_get('/Media.getInfo/en/json/key/907172e7fe51ba57/742086656', 'transformers.json')
+      tmdb.get_file_info(file).should have(1).movies
+    end
+
+    it "should return empty array when no movie found" do
+      file = mock("file")
+      file.should_receive(:size).and_return("fake")
+      TMDBParty::MovieHasher.should_receive(:compute_hash).with(file).and_return("fake")
+      stub_get('/Media.getInfo/en/json/key/fake/fake', 'nothing_found.json')
+      tmdb.get_file_info(file).should == []
+    end
+  end
 
   describe "#search_person" do
     it "should return empty array when no people was found" do
@@ -114,4 +132,4 @@
       tmdb.get_genres('sv').first.name.should == 'Action'
     end
   end
-end
+end