Add RAR/CBR support

shard.lock

@@ -4,6 +4,10 @@ shards:
     github: crystal-ameba/ameba
     version: 0.12.0
 
+  archive:
+    github: hkalexling/archive.cr
+    commit: 64223b64d79afafcec67a127b92f21f6625ce5ce
+
   baked_file_system:
     github: schovi/baked_file_system
     version: 0.9.8

shard.yml

@@ -19,6 +19,8 @@ dependencies:
     github: crystal-lang/crystal-sqlite3
   baked_file_system:
     github: schovi/baked_file_system
+  archive:
+    github: hkalexling/archive.cr
 
 development_dependencies:
   ameba:

src/archive.cr

@@ -0,0 +1,53 @@
+require "zip"
+require "archive"
+
+# A unified class to handle all supported archive formats. It uses the ::Zip
+#   module in crystal standard library if the target file is a zip archive.
+#   Otherwise it uses `archive.cr`.
+class ArchiveFile
+  def initialize(@filename : String)
+    if [".cbz", ".zip"].includes? File.extname filename
+      @archive_file = Zip::File.new filename
+    else
+      @archive_file = Archive::File.new filename
+    end
+  end
+
+  def self.open(filename : String, &)
+    s = self.new filename
+    yield s
+    s.close
+  end
+
+  def close
+    if @archive_file.is_a? Zip::File
+      @archive_file.as(Zip::File).close
+    end
+  end
+
+  # Lists all file entries
+  def entries
+    ary = [] of Zip::File::Entry | Archive::Entry
+    @archive_file.entries.map do |e|
+      if (e.is_a? Zip::File::Entry && e.file?) ||
+         (e.is_a? Archive::Entry && e.info.file?)
+        ary.push e
+      end
+    end
+    ary
+  end
+
+  def read_entry(e : Zip::File::Entry | Archive::Entry) : Bytes?
+    if e.is_a? Zip::File::Entry
+      data = nil
+      e.open do |io|
+        slice = Bytes.new e.uncompressed_size
+        bytes_read = io.read_fully? slice
+        data = slice if bytes_read
+      end
+      data
+    else
+      e.read
+    end
+  end
+end

src/library.cr

@@ -1,8 +1,8 @@
-require "zip"
 require "mime"
 require "json"
 require "uri"
 require "./util"
+require "./archive"
 
 struct Image
   property data : Bytes
@@ -25,7 +25,7 @@ class Entry
     @title = File.basename path, File.extname path
     @encoded_title = URI.encode @title
     @size = (File.size path).humanize_bytes
-    file = Zip::File.new path
+    file = ArchiveFile.new path
     @pages = file.entries.count do |e|
       ["image/jpeg", "image/png"].includes? \
         MIME.from_filename? e.filename
@@ -68,7 +68,8 @@ class Entry
   end
 
   def read_page(page_num)
-    Zip::File.open @zip_path do |file|
+    img = nil
+    ArchiveFile.open @zip_path do |file|
       page = file.entries
         .select { |e|
           ["image/jpeg", "image/png"].includes? \
@@ -78,16 +79,13 @@ class Entry
           compare_alphanumerically a.filename, b.filename
         }
         .[page_num - 1]
-      page.open do |io|
-        slice = Bytes.new page.uncompressed_size
-        bytes_read = io.read_fully? slice
-        unless bytes_read
-          return nil
-        end
-        return Image.new slice, MIME.from_filename(page.filename),
-          page.filename, bytes_read
+      data = file.read_entry page
+      if data
+        img = Image.new data, MIME.from_filename(page.filename), page.filename,
+          data.size
       end
     end
+    img
   end
 end
 
@@ -115,12 +113,12 @@ class Title
         @title_ids << title.id
         next
       end
-      if [".zip", ".cbz"].includes? File.extname path
-        zip_exception = validate_zip path
-        unless zip_exception.nil?
-          Logger.warn "File #{path} is corrupted or is not a valid zip " \
-                      "archive. Ignoring it."
-          Logger.debug "Zip error: #{zip_exception}"
+      if [".zip", ".cbz", ".rar", ".cbr"].includes? File.extname path
+        archive_exception = validate_archive path
+        unless archive_exception.nil?
+          Logger.warn "File #{path} is corrupted or is not a valid archive. " \
+                      "Ignoring it."
+          Logger.debug "Archive error: #{archive_exception}"
           next
         end
         entry = Entry.new path, self, @id, storage

src/mangadex/downloader.cr

@@ -371,7 +371,7 @@ module MangaDex
         writer.close
         Logger.debug "cbz File created at #{zip_path}"
 
-        zip_exception = validate_zip zip_path
+        zip_exception = validate_archive zip_path
         if !zip_exception.nil?
           @queue.add_message "The downloaded archive is corrupted. " \
                              "Error: #{zip_exception}", job

src/util.cr

@@ -85,12 +85,8 @@ def compare_alphanumerically(a : String, b : String)
   compare_alphanumerically split_by_alphanumeric(a), split_by_alphanumeric(b)
 end
 
-# When downloading from MangaDex, the zip/cbz file would not be valid
-#   before the download is completed. If we scan the zip file,
-#   Entry.new would throw, so we use this method to check before
-#   constructing Entry
-def validate_zip(path : String) : Exception?
-  file = Zip::File.new path
+def validate_archive(path : String) : Exception?
+  file = ArchiveFile.new path
   file.close
   return
 rescue e