Catch books with missing dates

.gitignore

@@ -4,4 +4,5 @@
 /.shards/
 *.dwarf
 *.pdf
-*.o
+*.o
+muse-dl-static*

spec/book_spec.cr

@@ -72,4 +72,10 @@ describe Muse::Dl::Book do
     book.formats.should contain :pdf
     book.formats.should contain :html
   end
+
+  it "should note both formats for book/57833" do
+    html = File.new("spec/fixtures/book-57833.html").gets_to_end
+    book = Muse::Dl::Book.new html
+    book.formats.should contain :pdf
+  end
 end

src/infoparser.cr

@@ -39,7 +39,11 @@ module Muse::Dl
     end
 
     def self.date(myhtml : Myhtml::Parser)
-      myhtml.css("#book_about_info .date").map(&.inner_text).to_a[0].strip
+      begin
+        myhtml.css("#book_about_info .date").map(&.inner_text).to_a[0].strip
+      rescue e : Exception
+        nil
+      end
     end
 
     def self.publisher(myhtml : Myhtml::Parser)

src/thing.cr

@@ -6,7 +6,7 @@ module Muse::Dl
     @info = Hash(String, String).new
     @title : String
     @author : String
-    @date : String
+    @date : String | Nil
     @publisher : String
     @summary : String
     @summary_html : String