Class: K8::Util::TemporaryFile

Inherits:
Object
  • Object
show all
Defined in:
lib/keight.rb

Overview

Temporary file which is removed automatically at end of response.

Example:

def do_download_csv()
  ## generate temporary filepath
  tmpfile = K8::Util::TemporaryFile.new
  p tmpfile.path      #=> ex: '/var/tmp/tmp-0372042668525.tmp'
  p File.exist?(tmpfile.path)   #=> false
  ## create temporary file and content
  sql = "select * from table1"
  system("psql dbname -A -F',' -c \"#{sql}\" | gzip > #{tmpfile.path}")
  p File.exist?(tmpfile.path)   #=> true
  ## set resonse headers
  @resp.headers['Content-Type']        = 'text/csv;charset=UTF-8'
  @resp.headers['Content-Length']      = File.size(tmpfile.path)
  @resp.headers['Content-Disposition'] = 'attachment;filename="file1.csv"'
  @resp.headers['Content-Encoding']    = "gzip"
  ## return temporary file
  return tmpfile  # will be removed automatically at end of response!!
end

Constant Summary collapse

TMPDIR = 
(ENV['TMPDIR'] || proc {require 'etc'; Etc.systmpdir}.call || '/tmp').chomp('/')
CHUNK_SIZE =

8KB

8 * 1024

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path = nil, tmpdir: nil, chunk_size: nil) ⇒ TemporaryFile

Returns a new instance of TemporaryFile.



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# File 'lib/keight.rb', line 447

def initialize(path=nil, tmpdir: nil, chunk_size: nil)
  #; [!ljilm] generates temporary filepath automatically when filepath is not specified.
  @path       = path || self.class.new_path(tmpdir)
  @tmpdir     = tmpdir if tmpdir
  @chunk_size = chunk_size if chunk_size
end

Instance Attribute Details

#path ⇒ Object (readonly)

Returns the value of attribute path.



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# File 'lib/keight.rb', line 454

def path
  @path
end

Class Method Details

.new_path(tmpdir = nil) ⇒ Object 



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# File 'lib/keight.rb', line 439

def self.new_path(tmpdir=nil)
  #; [!hvnzd] generates new temorary filepath under temporary directory.
  #; [!ulb2e] uses default temporary directory path if tmpdir is not specified.
  tmpdir ||= TMPDIR
  randstr = rand().to_s[2..14]
  return "#{tmpdir}/tmp-#{randstr}.tmp"
end

Instance Method Details

#each ⇒ Object 



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# File 'lib/keight.rb', line 456

def each
  #; [!d9suq] opens temporary file with binary mode.
  #; [!68xdj] reads chunk size data from temporary file per iteration.
  size = @chunk_size || CHUNK_SIZE
  File.open(@path, 'rb') do |f|
    yield f.read(size)
  end
ensure
  #; [!i0dmd] removes temporary file automatically at end of loop.
  #; [!347an] removes temporary file even if error raised in block.
  File.unlink @path
  self
end