class Zip::InputStream
InputStream is the basic class for reading zip entries in a zip file. It is possible to create a InputStream object directly, passing the zip file name to the constructor, but more often than not the InputStream will be obtained from a File (perhaps using the ZipFileSystem interface) object for a particular entry in the zip archive.
A InputStream inherits IOExtras::AbstractInputStream in order to provide an IO-like interface for reading from a single zip entry. Beyond methods for mimicking an IO-object it contains the method #get_next_entry for iterating through the entries of an archive. #get_next_entry returns a Entry object that describes the zip entry the InputStream is currently reading from.
Example that creates a zip archive with ZipOutputStream and reads it back again with a InputStream.
require 'zip' Zip::OutputStream.open("my.zip") do |io| io.put_next_entry("first_entry.txt") io.write "Hello world!" io.put_next_entry("adir/first_entry.txt") io.write "Hello again!" end Zip::InputStream.open("my.zip") do |io| while (entry = io.get_next_entry) puts "Contents of #{entry.name}: '#{io.read}'" end end
java.util.zip.ZipInputStream is the original inspiration for this class.
Public Class Methods
Opens the indicated zip file. An exception is thrown if the specified offset in the specified filename is not a local zip entry header.
@param context [String||IO||StringIO] file path or IO/StringIO object @param offset [Integer] offset in the IO/StringIO
# File lib/zip/input_stream.rb, line 50 def initialize(context, offset = 0, decrypter = nil) super() @archive_io = get_io(context, offset) @decompressor = ::Zip::NullDecompressor @decrypter = decrypter || ::Zip::NullDecrypter.new @current_entry = nil end
Same as initialize but if a block is passed the opened stream is passed to the block and closed when the block returns.
# File lib/zip/input_stream.rb, line 95 def open(filename_or_io, offset = 0, decrypter = nil) zio = new(filename_or_io, offset, decrypter) return zio unless block_given? begin yield zio ensure zio.close if zio end end
# File lib/zip/input_stream.rb, line 105 def open_buffer(filename_or_io, offset = 0) puts 'open_buffer is deprecated!!! Use open instead!' open(filename_or_io, offset) end
Public Instance Methods
# File lib/zip/input_stream.rb, line 58 def close @archive_io.close end
# File lib/zip/input_stream.rb, line 85 def eof @output_buffer.empty? && @decompressor.eof end
Returns a Entry object. It is necessary to call this method on a newly created InputStream before reading from the first entry in the archive. Returns nil when there are no more entries.
# File lib/zip/input_stream.rb, line 66 def get_next_entry @archive_io.seek(@current_entry.next_header_offset, IO::SEEK_SET) if @current_entry open_entry end
Rewinds the stream to the beginning of the current entry
# File lib/zip/input_stream.rb, line 72 def rewind return if @current_entry.nil? @lineno = 0 @pos = 0 @archive_io.seek(@current_entry.local_header_offset, IO::SEEK_SET) open_entry end
Modeled after IO.sysread
# File lib/zip/input_stream.rb, line 81 def sysread(number_of_bytes = nil, buf = nil) @decompressor.sysread(number_of_bytes, buf) end
Protected Instance Methods
# File lib/zip/input_stream.rb, line 142 def get_decompressor case when @current_entry.nil? ::Zip::NullDecompressor when @current_entry.compression_method == ::Zip::Entry::STORED ::Zip::PassThruDecompressor.new(@archive_io, @current_entry.size) when @current_entry.compression_method == ::Zip::Entry::DEFLATED header = @archive_io.read(@decrypter.header_bytesize) @decrypter.reset!(header) ::Zip::Inflater.new(@archive_io, @decrypter) else raise ::Zip::CompressionMethodError, "Unsupported compression method #{@current_entry.compression_method}" end end
# File lib/zip/input_stream.rb, line 113 def get_io(io_or_file, offset = 0) if io_or_file.respond_to?(:seek) io = io_or_file.dup io.seek(offset, ::IO::SEEK_SET) io else file = ::File.open(io_or_file, 'rb') file.seek(offset, ::IO::SEEK_SET) file end end
# File lib/zip/input_stream.rb, line 162 def input_finished? @decompressor.input_finished? end
# File lib/zip/input_stream.rb, line 125 def open_entry @current_entry = ::Zip::Entry.read_local_entry(@archive_io) if @current_entry && @current_entry.gp_flags & 1 == 1 && @decrypter.is_a?(NullEncrypter) raise Error, 'password required to decode zip file' end if @current_entry && @current_entry.gp_flags & 8 == 8 && @current_entry.crc == 0 && @current_entry.compressed_size == 0 && @current_entry.size == 0 && !@internal raise GPFBit3Error, 'General purpose flag Bit 3 is set so not possible to get proper info from local header.' 'Please use ::Zip::File instead of ::Zip::InputStream' end @decompressor = get_decompressor flush @current_entry end
# File lib/zip/input_stream.rb, line 158 def produce_input @decompressor.produce_input end