Class: Webby::File

Inherits:
File
  • Object
show all
Defined in:
lib/webby/file.rb

Overview

The Webby::File class is identical to the core Ruby file class except for YAML meta-data stored at the top of the file. This meta-data is made available through the meta_data and meta_data= functions.

The meta-data data must be found between two YAML block separators “—”, each on their own line.

Example:

---
layout: blog
filter: markdown
tags:
  - ruby
  - web development
---
This is a blog entry formatted using MarkDown and tagged as "ruby" and
"web development". The layout being used is the "blog" format.

Constant Summary collapse

META_SEP =

:nodoc:

%r/\A---\s*\r?\n\z/o

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ File

call-seq:

Webby::File.new( filename, mode = "r" )          => file
Webby::File.new( filename [, mode [, perm]] )    => file

Opens the file named by filename according to mode (default is ‘r’) and returns a new Webby::File object. See the description of class IO for a description of mode. The file mode may optionally be specified as a Fixnum by or-ing together the flags (O_RDONLY etc, again described under IO). Optional permission bits may be given in perm. These mode and permission bits are platform dependent; on Unix systems, see open(2) for details. 

f = File.new("testfile", "r")
f = File.new("newfile",  "w+")
f = File.new("newfile", File::CREAT|File::TRUNC|File::RDWR, 0644)



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# File 'lib/webby/file.rb', line 90

def initialize( *args )
  super
  @meta_end = end_of_meta_data
end

Class Method Details

.meta_data(name) ⇒ Object

call-seq:

Webby::File.meta_data( name )    => object or nil

Reads the meta-data from the file specified by name. meta_data ensures the files is closed before returning.



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# File 'lib/webby/file.rb', line 66

def meta_data( name )
  fd = new name, 'r'
  fd.meta_data
ensure
  fd.close
end

.read(name, *args) ⇒ Object

call-seq:

Webby::File.read( name [, length [, offset]])    => string

Opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file). read ensures the file is closed before returning.



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# File 'lib/webby/file.rb', line 39

def read( name, *args )
  fd = new name, 'r'
  fd.read *args
ensure
  fd.close
end

.readlines(name, sep = $/) ⇒ Object

call-seq:

Webby::File.readlines( name, sep_string = $/ )    => array

Reads the entire file specified by name as individual lines, and returns those lines in an array. Lines are separated by sep_string. readlines ensures the file is closed before returning.



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# File 'lib/webby/file.rb', line 53

def readlines( name, sep = $/ )
  fd = new name, 'r'
  fd.readlines sep
ensure
  fd.close
end

Instance Method Details

#meta_data ⇒ Object

call-seq:

meta_data

Returns the meta-data defined at the top of the file. Returns nil if no meta-data is defined. The meta-data is returned as Ruby objects

Meta-data is stored in YAML format between two YAML separators “—” on their own lines.



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# File 'lib/webby/file.rb', line 104

def meta_data
  return if @meta_end.nil?

  cur, meta_end, @meta_end = tell, @meta_end, nil
  seek 0
  return YAML.load(self)

ensure
  @meta_end = meta_end if defined? meta_end and meta_end
  seek cur if defined? cur and cur
end

#meta_data=(data) ⇒ Object

call-seq

meta_data = object

Stores the given object as meta-data in YAML format at the top of the file. If the objectc is nil, then the meta-data section will be removed from the file.

Meta-data is stored in YAML format between two YAML separators “—” on their own lines.



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# File 'lib/webby/file.rb', line 126

def meta_data=( data )
  return if data.nil? and @meta_end.nil?

  seek 0
  lines = readlines

  truncate 0
  unless data.nil?
    write YAML.dump(data)
    write "--- #$/"
  end
  lines.each {|line| write line}
ensure
  @meta_end = end_of_meta_data
  seek 0, IO::SEEK_END
end