ruby 39 lines · 8 steps

Compress-and-encode payloads in Ruby

A module that gzips data into a Base64 string, reverses the trip safely, and reports how much space it saved.

Explained by highlit
Intermediate compression encoding io-streams error-handling
1require "zlib"
2require "stringio"
3require "base64"
4 
5module PayloadCodec
6 module_function
7 
8 def pack(data)
9 io = StringIO.new
10 io.set_encoding(Encoding::BINARY)
11 gz = Zlib::GzipWriter.new(io, Zlib::BEST_COMPRESSION)
12 begin
13 gz.write(data.to_s)
14 ensure
15 gz.close
16 end
17 Base64.strict_encode64(io.string)
18 end
19 
20 def unpack(encoded)
21 raw = Base64.strict_decode64(encoded)
22 gz = Zlib::GzipReader.new(StringIO.new(raw))
23 begin
24 gz.read
25 ensure
26 gz.close
27 end
28 rescue Zlib::GzipFile::Error, ArgumentError => e
29 raise ArgumentError, "corrupt payload: #{e.message}"
30 end
31 
32 def ratio(data)
33 original = data.to_s.bytesize
34 return 0.0 if original.zero?
35 
36 compressed = Base64.strict_decode64(pack(data)).bytesize
37 (1.0 - compressed.fdiv(original)).round(4)
38 end
39end
01 / 01
STEP 01

Walkthrough

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Three takeaways
  1. 1Wrapping stream writes in begin/ensure guarantees the gzip footer is flushed even if writing fails.
  2. 2Base64 turns raw binary gzip output into a safe transportable string for JSON, URLs, or headers.
  3. 3Rescuing library-specific errors lets you present a single, meaningful failure to callers.

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