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PORuby zlib deflate and inflate not working as intended
 

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  1. PORuby zlib deflate and inflate not working as intended
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    <p>I have been trying to get a (relatively) simple compression and decompression functionality working on any sort of object (images, csv files, docs etc) and have had no success whatsoever. </p> <p>I have tried many things and currently I think this code is close to it (not my code) however I have been having trouble getting it to work.</p> <p>Hoge.txt content:</p> <pre><code>blahblah123 </code></pre> <p>Ruby deflate class titled rubyfiletest.rb:</p> <pre><code>require "zlib" file_name = "hoge.txt" compressed_file = File.open(file_name +".gz", "w+") zd = Zlib::Deflate.new(Zlib::BEST_COMPRESSION, 15, Zlib::MAX_MEM_LEVEL, Zlib::HUFFMAN_ONLY) compressed_file &lt;&lt; zd.deflate(File.read(file_name)) compressed_file.close zd.close </code></pre> <p>So with this code what it does is create a .gz file entitled hoge.txt.gz which generates this in the command prompt </p> <pre><code>rubyfiletest.rb:9:in `read': No such file or directory - hoge.txt (Errno::ENOEN) </code></pre> <p>Also if I try to open the newly created file with winrar/7zip it will give me this error:</p> <pre><code>The archive is either in unknown format or damaged. </code></pre> <p>Ruby inflate class titled rubyinflate.rb:</p> <pre><code>require 'zlib' File.open('hoge.txt.gz', 'rb') do |compressed| File.open('hoge.txt', 'w') do |decompressed| gz = Zlib::GzipReader.new(compressed) result = gz.read decompressed.write(result) gz.close end end </code></pre> <p>I am guessing the compression is not working correctly since I cannot even open the compressed file and have been having so many problems with this. I think it is worth while to mention I am new to ruby. I also would like to know if the way this is implemented would enable images and all types of files to be compressed/decompressed fine.</p> <p><strong>* Update *</strong></p> <p>I was getting the error for wrong path because hoge was saved as hoge.txt.txt (doh!) and it was looking for hoge.txt in that path. So now I changed the ruby compression code a little so that the output creates a valid gzip file as pointed out by Matthew T. </p> <p>This is what it looks like now</p> <pre><code>require "zlib" file_name = "hoge.txt" compressed_file = File.open(file_name +".gz", "w+b") zd = Zlib::GzipWriter.new(compressed_file) zd &lt;&lt; File.read(file_name) compressed_file.close zd.close </code></pre> <p>With this as the new rubyfiletest.rb class to decompress using GzipWriter I receive this error when I run this class:</p> <pre><code>rubyfiletest.rb:8 in 'write': closed stream (IOError) </code></pre> <p>This will still generate the .gz file (and I can now open it in winrar/7zip without any problems however it is empty, should contain 'blahblah123'). After I compress it and run the rubyinflate.rb I receive this error from rubyinflate.rb:</p> <pre><code>rubyinflate.rb:6 in 'read': unecpected end of file (Zlib::GzipFile::Error) </code></pre> <p>I think these errors may be causing the data to not be copied over? If I used an image would that data be copied over assuming this code worked?</p>
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    1. COuse File.expand_path('', __FILE__) to print if you're in the right directory/path
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      1. PORuby zlib deflate and inflate not working as intended
      1. USRodrigo Dias
    2. COI used Dir.pwd and I was indeed in the right path (desktop) where all the files (ruby and text files) are located.
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      1. PORuby zlib deflate and inflate not working as intended
      1. USSurep
    3. COSince you seem to be on Windows, is there a chance that you have extensions for known file types hidden? That would cause your hoge.txt file (as you see it on the desktop) to actually be named hoge.txt.txt.
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      1. PORuby zlib deflate and inflate not working as intended
      1. USMatthew T. Staebler
 

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