md5_file

  • There are generally two different ways in Ruby to generate a cryptographic hash of a file. The first and easiest way is to use File.read to read the entire file contents into memory. We can then use the same MD5.hexdigest method on the contents to generate the hash.

    PHP

    print md5_file("my_file.jpg");
// => 14b6a00b1a4eb40542cfecdc4d64940d

    Ruby

    require "digest"
 
print Digest::MD5.hexdigest(File.read("my_file.jpg"))
# => 14b6a00b1a4eb40542cfecdc4d64940d

    The code above works for many cases but for larger files, there’s a risk of consuming large amounts of memory. For these cases, we can initialize a new digest with Digest::MD5.new and then read the file in smaller chunks, incrementally building the digest with MD5#update.

    Ruby

    require "digest"
 
digest = Digest::MD5.new
File.open("my_file.jpg", "r") do |f|
  digest.update f.read(8192) until f.eof
end
 
print digest.hexdigest
# => 14b6a00b1a4eb40542cfecdc4d64940d

    see also

← md5 metaphone →

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