Module: Cfruby::FileEdit

Defined in:
lib/libcfruby/fileedit.rb

Overview

Methods for line-based editing of files. Generally geared towards editing configuration files on POSIX-based systems.

Defined Under Namespace

Classes: AnchorNotFoundError, FileEditError

Constant Summary collapse

APPEND = 
"append"
PREPEND = 
"prepend"

Class Method Summary collapse

Class Method Details

.comment(filename, regex, options = {}) ⇒ Object

Comments out lines that match regex, which may also be given as a string Options:

:commentwith

(defaults to ‘#’) Use this at the front of the line to comment the line

:fuzzymatch

(defaults to true) If regex is given as a String, ignore whitespace



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# File 'lib/libcfruby/fileedit.rb', line 421

def FileEdit.comment(filename, regex, options = {})
	if(options[:fuzzymatch] == nil)
		options[:fuzzymatch] = true
	end

	if(!options[:commentwith])
		options[:commentwith] = '#'
	end

	if(!regex.kind_of?(Array))
		regex = Array.[](regex)
	end
	
	regex.each_index() { |i|
		if(!regex[i].kind_of?(Regexp))
			if(options[:fuzzymatch])
				regex[i] = convert_to_fuzzy_regex(regex[i], :partialstr => true)
			else
				regex[i] = Regexp.new(Regexp.escape(regex[i]))
			end
		end				
	}

	commented = Regexp.new("^\\s*#{Regexp.escape(options[:commentwith])}")

	changed = false
	Cfruby.controller.attempt("Commenting all lines matching \"#{regex.map() { |r| r.source() }.join(',')}\" in \"#{filename}\"", 'destructive') {
		lines = Array.new()
		File.open(filename, File::RDONLY) { |fp|
			lines = fp.readlines()
		}
	
		lines.each_index() { |i|
			regex.each() { |r|
				if(r.match(lines[i]) and !commented.match(lines[i]))
					lines[i] = options[:commentwith] + ' ' + lines[i]
					Cfruby.controller.inform('verbose', "Commented \"#{lines[i].strip()}\" in #{filename}")
					changed = true
				end						
			}
		}
	
		if(!changed)
			Cfruby.controller.attempt_abort("nothing commented")
		end

		FileEdit.open(filename, File::WRONLY | File::TRUNC) { |fp|
			lines.each() { |line|
				fp.write(line)
			}
		}				
	}
	
	return(changed)
end

.contains?(filename, pattern) ⇒ Boolean

Returns true if the given pattern (str or regular expression) is found in filename

Returns:

  • (Boolean) 


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# File 'lib/libcfruby/fileedit.rb', line 30

def FileEdit.contains?(filename, pattern)
	if(!pattern.kind_of?(Regexp))
		pattern = Regexp.new(Regexp.escape(pattern.to_s()))
	end
	
	File.open(filename, File::RDONLY) { |fp|
		fp.each_line() { |line|
			if(pattern.match(line))
				return(true)
			end
		}
	}
	
	return(false)
end

.file_append(filename, str) ⇒ Object

Appends str to the end of filename



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# File 'lib/libcfruby/fileedit.rb', line 276

def FileEdit.file_append(filename, str) 
	changed = false
	Cfruby.controller.attempt("appending \"#{str}\" to #{filename}", 'destructive') {
		changed = FileEdit.open(filename, File::WRONLY|File::APPEND) { |fp|
			fp.write(str)
		}
	}
	
	return(changed)
end

.file_must_contain(filename, str, options = {}) ⇒ Object

Ensures that filename contains str. If str is a single line, that line will be searched for. If str contains multiple lines then, by default, it will be split on /n/ and each line will be checked/added in turn. If :block => true is passed in then the first line of a multiline block will be searched for (or :regex if it is given), and the entire block will be added if it is not found. If str contains an array then file_must_contain will be called on each item in order.

Returns true if str (or any substr) was added, false if it was not (meaning everything passed was already in the file). Options:

:position

may be FileEdit::APPEND or FileEdit::PREPEND (or ‘append’ or ‘prepend’). Defaults to FileEdit::APPEND

:anchor

may be nil, a line number, or a regular expression. Used to determine where to append or prepend

:fuzzymatch

defaults to true - causes whitespace in str to be largely ignored for purposes of matching.

:regex

if given, then str will be added if regex matches no lines in the file

:block

defaults to false - determines whether multiline str’s will be treated as a single block

:allwaysadd

If true str will be added even if the given anchor cannot be found. Defaults to false.



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# File 'lib/libcfruby/fileedit.rb', line 60

def FileEdit.file_must_contain(filename, str, options={})
	if(!options[:position])
		options[:position] = APPEND
	elsif(options[:postion] == 'append')
		options[:position] = APPEND
	elsif(options[:position] == 'prepend')
		options[:position] = PREPEND
	end
	
	if(options[:fuzzymatch] == nil)
		options[:fuzzymatch] = true
	end
	
	if(str.kind_of?(Array))
		added = false
		str.each() { |substr|
			if(file_must_contain(filename, substr, options))
				added = true
			end
		}
		return(added)
	elsif(str =~ /\n./ and !options[:block])
		return(file_must_contain(filename, str.split(/\n/), options))
	end
	
	# add a newline to str if it wasn't passed in with one
	if(str !~ /\n$/)
		str = str + "\n"
	end

	regex = options[:regex]
	if(regex == nil)
		# if the str is multi-line, split it and use the first line
		matchstr = str
		if(str =~ /\n./)
			matchstr = str.split(/\n/)[0]
		end
		
		if(options[:fuzzymatch])
			regex = convert_to_fuzzy_regex(matchstr)
		else			
			regex = Regexp.new(Regexp.escape(matchstr))
		end
	end
			
	# don't call contains? here because we need to snag the last line in the file
	lastline = "\n"
	File.open(filename, File::RDONLY) { |fp|
		fp.each_line() { |line|
			if(regex.match(line))
				return(false)
			end
			lastline = line
		}
	}
	
	Cfruby.controller.attempt("adding \"#{str}\" to #{filename}", 'destructive') {
		begin
			# if we get here, it isn't in the file - stick it in
			if(options[:position] == APPEND)
				if(options[:anchor] == nil)
					FileEdit.open(filename, File::RDWR|File::APPEND) { |fp|
						if(lastline !~ /\n$/)
							fp.write("\n")
						end
						fp.write(str)
					}
				elsif(options[:anchor].kind_of?(Integer))
					lines = nil
					File.open(filename, File::RDONLY) { |fp|
						lines = fp.readlines()									
					}
					if(options[:anchor] < 0 or lines.length+1 < options[:anchor])
						raise(AnchorNotFoundError, "options[:anchor] is past the last line in the file \"#{filename}\"")
					end
					lines.insert(options[:anchor]+1, str)
					write_file(filename, lines)
				elsif(options[:anchor].respond_to?(:match))
					added = false
					lines = Array.new()
					File.open(filename, File::RDONLY) { |fp|
						fp.each_line() { |line|
							lines << line
							if(options[:anchor].match(line))
								lines << str
								added = true
							end				
						}
					}
					if(added)
						write_file(filename, lines)
					else
						raise(AnchorNotFoundError, "Anchor \"#{options[:anchor].source}\" not found in \"#{filename}\"")
					end
				else
					raise(ArgumentError, "options[:anchor] was not nil, a number, or a regular expression")
				end
			elsif(options[:position] == PREPEND)						
				if(options[:anchor] == nil)
					File.open(filename, File::RDWR) { |fp|
						lines = fp.readlines
						fp.seek(0, IO::SEEK_SET)
						fp.truncate(0)
						fp.write(str)
						lines.each() { |line|
							fp.write(line)
						}
					}
				elsif(options[:anchor].kind_of?(Integer))
					lines = nil
					File.open(filename, File::RDONLY) { |fp|
						lines = fp.readlines
					}
					if(options[:anchor] < 0 or lines.length < options[:anchor])
						raise(AnchorNotFoundError, "options[:anchor] is past the last line in the file \"#{filename}\"")
					end
					lines.insert(options[:anchor], str)
					write_file(filename, lines)
				elsif(options[:anchor].respond_to?(:match))
					added = false
					lines = Array.new()
					File.open(filename, File::RDONLY) { |fp|
						fp.each_line() { |line|
							if(options[:anchor].match(line))
								lines << str
								added = true
							end				
							lines << line
						}									
					}

					if(added)
						write_file(filename, lines)
					else
						raise(AnchorNotFoundError, "Anchor \"#{options[:anchor].source}\" not found in \"#{filename}\"")
					end
				else
					raise(ArgumentError, "options[:anchor] was not nil, a number, or a regular expression")
				end
			end
		rescue AnchorNotFoundError
			if(options[:allwaysadd])
				options[:anchor] = nil
				file_must_contain(filename, str, options)
			else
				raise($!)
			end
		end
	}
	
	return(true)
end

.file_must_not_contain(filename, pattern, options = {}) ⇒ Object

Ensures that filename does not contain lines matching pattern. Pattern may be a String, Regexp, or an Array of either. Options:

:fuzzymatch

defaults to true - causes whitespace in pattern (if passed as a String) to be largely ignored for purposes of matching.



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# File 'lib/libcfruby/fileedit.rb', line 217

def FileEdit.file_must_not_contain(filename, pattern, options={})
	if(pattern.kind_of?(Array))
		pattern.each() { |p|
			file_must_not_contain(filename, p)
		}
		return()
	elsif(!pattern.kind_of?(Regexp) and pattern.to_s() =~ /\n./)
		file_must_not_contain(filename, pattern.split("\n"))
	end
	
	if(options[:fuzzymatch] == nil)
		options[:fuzzymatch] = true
	end
	
	regex = pattern			
	# convert regex to a real Regexp if it isn't one
	if(!pattern.kind_of?(Regexp))
		if(options[:fuzzymatch])
			regex = convert_to_fuzzy_regex(regex)
		else
			regex = regex.to_s()
			if(regex !~ /\n$/)
				regex += "\n"
			end
			regex = Regexp.new("^#{Regexp.escape(regex.to_s)}$")
		end
	end
	
	# do this in two passes, one with the file open read only to check
	# for the existence of the line, then trunc and write out a new file
	# if it does
	lines = Array.new()
	rewrite = false
	FileEdit.open(filename, File::RDONLY) { |fp|
		fp.each_line() { |line|
			if(regex.match(line))
				rewrite = true
			else
				lines << line
			end
		}
	}
	
	changed = false
	if(rewrite == true)
		Cfruby.controller.attempt("removing \"#{regex.to_s()}\" from #{filename}", 'nonreversible', 'destructive') {
			changed = FileEdit.open(filename, File::TRUNC|File::WRONLY) { |fp|
				lines.each() { |line|
					fp.write(line)
				}
			}
		}
	end
	
	return(changed)
end

.file_prepend(filename, str) ⇒ Object

Prepends str to filename



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# File 'lib/libcfruby/fileedit.rb', line 289

def FileEdit.file_prepend(filename, str)
	changed = false
	Cfruby.controller.attempt("prepending \"#{str}\" to #{filename}", 'destructive') {
		lines = File.open(filename, File::RDONLY).readlines()
		changed = FileEdit.open(filename, File::WRONLY|File::TRUNC) { |fp|
			fp.write(str)
			if(str !~ /\n$/)
				fp.write("\n")
			end
			lines.each() { |line|
				fp.write(line)
			}
		}
	}
	
	return(changed)
end

.open(filename, mode, &block) ⇒ Object

Handles atomic editing by creating a temporary copy of filename and only writing it back if an actual change has been made. Yields a File object.



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# File 'lib/libcfruby/fileedit.rb', line 571

def FileEdit.open(filename, mode, &block)
	Cfruby.controller.attempt("Editing \"#{filename}\"") {
		newfile = Tempfile.new('fileedit')
		newfile.close(false)
		
		# attempt to chown the temp file - and set move based on our ability to do so
		move = false
		begin
			Cfruby::FileOps.chown(newfile.path, File.stat(filename).uid, File.stat(filename).gid)
			move = true
		rescue
			# we failed - do nothing
		end
		
		# chmod the temp file
		Cfruby::FileOps.chmod(newfile.path, File.stat(filename).mode)
		
		buffer = ''
		File.open(filename, File::RDONLY) { |orig|
			File.open(newfile.path, File::WRONLY|File::TRUNC) { |copy|
				while(orig.read(2048, buffer) != nil)
					copy.write(buffer)
				end
			}
		}

		File.open(newfile.path, mode) { |fp|
			yield(fp)
		}

		if(Cfruby::Checksum::Checksum.get_checksums(filename).sha1 != Cfruby::Checksum::Checksum.get_checksums(newfile.path).sha1)
			# backup the file
			FileOps.backup(filename)
			
			if(move)
				FileOps.move(newfile.path, filename, :force => true, :preserve => true)
			else
				File.open(newfile.path, File::RDONLY) { |orig|
					File.open(filename, File::WRONLY|File::TRUNC) { |copy|
						while(orig.read(2048, buffer) != nil)
							copy.write(buffer)
						end
					}
				}
			end
			
			return(true)
		else
			Cfruby.controller.attempt_abort("unchanged")
		end
	}
	
	return(false)
end

.replace(filename, regex, str, options = {}) ⇒ Object

Replaces all lines matching regex with str. Options:

:firstonly

if true then the first match is replaced and all other matching lines are removed from the file.

:fuzzymatch

(defaults to true) causes String whitespace to be ignored for matching purposes

:alwaysadd

(defaults to true) then the line will be added (by calling file_must_contain and passing

through options) to the end of the file even if no lines match regex.



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# File 'lib/libcfruby/fileedit.rb', line 348

def FileEdit.replace(filename, regex, str, options={})
	if(options[:fuzzymatch] == nil)
		options[:fuzzymatch] = true
	end

	if(options[:alwaysadd] == nil)
		options[:alwaysadd] = true
	end
	
	if(str !~ /\n$/)
		str << "\n"
	end
	
	if(!regex.kind_of?(Array))
		regex = Array.[](regex)
	end
	
	regex.each_index() { |i|
		if(!regex[i].kind_of?(Regexp))
			if(options[:fuzzymatch])
				regex[i] = convert_to_fuzzy_regex(regex[i], :partialstr => true)
			else
				regex[i] = Regexp.new(Regexp.escape(regex[i]))
			end
		end
	}
	
	replaced = false
	Cfruby.controller.attempt("Replacing #{regex[0].source}... with #{str} in \"#{filename}\"", 'destructive', 'nonreversible') {
		lines = Array.new()
		File.open(filename, File::RDONLY) { |fp|
			fp.each_line() { |line|
				regex.each() { |r|
					if(r.match(line))
						if(replaced && options[:firstonly])
							next
						else
							line = str
							replaced = true
						end
					end
				}
				lines << line
			}
		}
	
		if(!replaced and options[:alwaysadd])
			file_must_contain(filename, str, options)
			replaced = true
		elsif(replaced)
			changed = write_file(filename, lines)
			if(changed != true)
				replaced = false
				Cfruby.controller.attempt_abort("unchanged")
			end
		else
			replaced = false
			Cfruby.controller.attempt_abort("unchanged")
		end
	}
	
	if(replaced)
		return(true)
	else
		return(false)
	end
end

.set(filename, variable, value, options = {}) ⇒ Object

Sets variable to value in filename (as in hostname = “my.hostname.com”). Options:

:delimiter

(‘=’ by default) determines what delimiter to place between variable and value

:whitespace

(overrides delimiter) uses a special whitespace matching delimiter if true



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# File 'lib/libcfruby/fileedit.rb', line 543

def FileEdit.set(filename, variable, value, options={})
  replaced = false
	Cfruby.controller.attempt("Setting \"#{variable}\" to \"#{value}\" in \"#{filename}\"", 'destructive', 'nonreversible') {
		delimiter = '='
		replacement = delimiter
		if(options[:whitespace])
			delimiter = "\\s+"
			replacement = ' '
		elsif(options[:delimiter] != nil)
			replacement = options[:delimiter]
			delimiter = Regexp.escape(options[:delimiter])
		end
	
		regex = Regexp.new("^\\s*#{Regexp.escape(variable)}\\s*?#{delimiter}")
		str = "#{variable}#{replacement}#{value}\n"
	
		replaced = replace(filename, regex, str)
		if(replaced != true)
			Cfruby.controller.attempt_abort("unchanged")
		end
	}

	return(replaced)
end

.set_contents(filename, remove, add, options = {}) ⇒ Object

Atomically sets the contents of filename by first removing all lines in remove and then adding all lines in add using file_must_not_contain and file_must_contain



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# File 'lib/libcfruby/fileedit.rb', line 310

def FileEdit.set_contents(filename, remove, add, options={})
	filename = Pathname.new(filename).realpath

	newfile = Tempfile.new('fileedit')
	File.open(filename, File::RDONLY) { |fp|
		fp.each_line() { |line|
			newfile.write(line)
		}
	}
	newfile.close()
	
	changed = false
	if(remove)
		mustnotchanged = file_must_not_contain(newfile.path, remove, options)
		if(mustnotchanged)
			changed = true
		end
	end
	if(add)
		mustchanged = file_must_contain(newfile.path, add, options)
		if(mustchanged)
			changed = true
		end
	end
	
	if(changed)
		FileOps.move(newfile.path, filename, :force=>true, :preserve=>true)
	end
	
	return(changed)
end

.uncomment(filename, regex, options = {}) ⇒ Object

Uncomments lines that match regex, which may also be given as a string Options:

:commentwith

(defaults to ‘#’) Remove this from the front of the line to uncomment the line

:fuzzymatch

(defaults to true) If regex is given as a String, ignore whitespace



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# File 'lib/libcfruby/fileedit.rb', line 482

def FileEdit.uncomment(filename, regex, options = {})
	if(options[:fuzzymatch] == nil)
		options[:fuzzymatch] = true
	end

	if(!options[:commentwith])
		options[:commentwith] = '#'
	end

	if(!regex.kind_of?(Array))
		regex = Array.[](regex)
	end

	regex.each_index() { |i|
		if(!regex[i].kind_of?(Regexp))
			if(options[:fuzzymatch])
				regex[i] = convert_to_fuzzy_regex(regex[i], :partialstr => true)
			else
				regex[i] = Regexp.new(Regexp.escape(regex[i]))
			end
		end				
	}

	commented = Regexp.new("^\\s*#{Regexp.escape(options[:commentwith])}")

	changed = false
	Cfruby.controller.attempt("Uncommenting all lines matching \"#{regex.map() { |r| r.source() }.join(',')}\" in \"#{filename}\"", 'destructive') {
		lines = Array.new()
		File.open(filename, File::RDONLY) { |fp|
			lines = fp.readlines()
		}

		lines.each_index() { |i|
			regex.each() { |r|
				if(r.match(lines[i]) and commented.match(lines[i]))
					# use multiline match here to get the newline on the end
					lines[i] = lines[i][/^\s*#{Regexp.escape(options[:commentwith])}\s*(.*)$/m, 1]
					Cfruby.controller.inform('verbose', "Uncommented \"#{lines[i].strip()}\" in #{filename}")
					changed = true
				end						
			}
		}

		if(!changed)
			Cfruby.controller.attempt_abort("nothing uncommented")
		end

		FileEdit.open(filename, File::WRONLY | File::TRUNC) { |fp|
			lines.each() { |line|
				fp.write(line)
			}
		}
	}
	
	return(changed)
end