I want to check if a directory has a ".ogg" or ".m4a" file. In every case the dir is empty before starting a download session. So it just can have one "ogg" or one "m4a" file.
I tried out this code to fetch the filename:
def self.get_filename
if File.exists?('*.ogg')
file = Dir.glob('*.ogg')
#testfile = file[0]
#filename = File.basename(#testfile,File.extname(#testfile))
end
if File.exists?('*.m4a')
file = Dir.glob('*.m4a')
#testfile = file[0]
#filename = File.basename(#testfile,File.extname(#testfile))
end
end
Sadly the filename is actual empty. Maybe anyone knows why?
I think that you need Dir.glob instead.
Dir.glob('/path/to/dir/*.ogg') do |ogg_file|
#testfile = ogg_file
#filename = File.basename(#testfile,File.extname(#testfile))
end
File#exists? does not support regular expressions.
You can do this instead:
if Dir["*.rb"].any?
#....
Related
Below is the piece of code that is supposed read the directory and for each file entry prints the first row of the file. The issue is x is not visible so file is not being parsed.
Dir.foreach("C:/fileload/src") do |file_name|
x = file_name
puts x
f = File.open("C:/fileload/src/" +x)
f.readlines[1..1].each do |line|
puts line
end
end
Why are you assigning x to file_name? You can use file_name directly. And if you are only reading the first line of the file, why not try this?
#!/usr/bin/ruby
dir = "C:/fileload/src"
Dir.foreach(dir) do |file_name|
full = File.join(dir, file_name)
if File.file?(full)
f = File.open(full)
puts f.first
f.close
end
end
You should use File.join to safely combine paths in Ruby. I also checked that you are opening a file using the File.file? method.
You have no visibility issue with x. You should be using File::join or Pathname#+ to build your file paths. You should exclude non-files from consideration. You're selecting the second line, not the first with [1..1]. Here's a cleaner correct replacement for your sample code.
dir = "C:/fileload/src"
Dir.foreach(dir).
map { |fn| File.join(dir,fn) }.
select { |fn| File.file?(fn) }.
each { |fn| puts File.readlines(fn).first }
I have a gem that has code like this inside:
def read(file)
#file = File.new file, "r"
end
Now the problem is, say you have a directory structure like so:
app/main.rb
app/templates/example.txt
and main.rb has the following code:
require 'mygem'
example = MyGem.read('templates/example.txt')
It comes up with File Not Found: templates/example.txt. It would work if example.txt was in the same directory as main.rb but not if it's in a directory. To solve this problem I've added an optional argument called relative_to in read(). This takes an absolute path so the above could would need to be:
require 'mygem'
example = MyGem.read('templates/example.txt', File.dirname(__FILE__))
That works fine, but I think it's a bit ugly. Is there anyway to make it so the class knows what file read() is being called in and works out the path based on that?
There is an interesting library - i told you it was private. One can protect their methods with it from being called from outside. The code finds the caller method's file and removes it. The offender is found using this line:
offender = caller[0].split(':')[0]
I guess you can use it in your MyGem.read code:
def read( file )
fpath = Pathname.new(file)
if fpath.relative?
offender = caller[0].split(':')[0]
fpath = File.join( File.dirname( offender ), file )
end
#file = File.new( fpath, "r" )
end
This way you can use paths, relative to your Mygem caller and not pwd. Exactly the way you tried in your app/main.rb
Well, you can use caller, and a lot more reliably than what the other people said too.
In your gem file, outside of any class or module, put this:
c = caller
req_file = nil
c.each do |s|
if(s =~ /(require|require_relative)/)
req_file = File.dirname(File.expand_path(s.split(':')[0])) #Does not work for filepaths with colons!
break
end
end
REQUIRING_FILE_PATH = req_file
This will work 90% of the time, unless the requiring script executed a Dir.chdir. The File.expand_path depends on that. I'm afraid that unless your requirer passes their __FILE__, there's nothing you can do if they change the working dir.
Also you may check for caller:
def read(file)
if /^(?<file>.+?):.*?/ =~ caller(1).first
caller_dir, caller_file = Pathname.new(Regexp.last_match[:file]).split
file_with_path = File.join caller_dir, file
#file = File.new "#{file_with_path}", "r"
end
end
I would not suggest you to do so (the code above will break being called indirectly, because of caller(1), see reference to documentation on caller). Furthermore, the regex above should be tuned more accurately if the caller path is intended to contain colons.
This should work for typical uses (I'm not sure how resistant it is to indirect use, as mentioned by madusobwa above):
def read_relative(file)
#file = File.new File.join(File.dirname(caller.first), file)
end
On a side note, consider adding a block form of your method that closes the file after yielding. In the current form you're forcing clients to wrap their use of your gem with an ensure.
Accept a file path String as an argument. Convert to a Pathname object. Check if the path is relative. If yes, then convert to absolute.
def read(file)
fpath = Pathname.new(file)
if fpath.relative?
fpath = File.expand_path(File.join(File.dirname(__FILE__),file))
end
#file = File.new(fpath,"r")
end
You can make this code more succinct (less verbose).
To determine the file type of an attached file, I used the OS "file" utility:
class AttachedFileTypeValidator < ActiveModel::Validator
def validate(record)
file = record.resource.uploaded_file
attached_file = Rails.root + file.path
file_type = `file #{attached_file}`
Rails.logger.info "Attached file type determined to be: #{file_type}"
unless file_type.split(',').first =~ /ASCII|UTF/
record.errors[:resource_content_type] << "Attachment does not appear to be a text CSV file, please ensure it was saved correctly."
end
end
end
Unfortunately brakeman suggests its a command line injection opportunity. I'm assuming this means someone figures out a clever name for a file like:
; rm -rf /;
And away we go. Whats a good way to sanitize filenames?
Use IO#popen to call the external command:
file_type = IO.popen(['file', attached_file]).read
This will handle proper escaping of funny characters in the filename for you.
I want to copy the contents of one file to another using Ruby's file methods.
How can I do it using a simple Ruby program using file methods?
There is a very handy method for this - the IO#copy_stream method - see the output of ri copy_stream
Example usage:
File.open('src.txt') do |f|
f.puts 'Some text'
end
IO.copy_stream('src.txt', 'dest.txt')
For those that are interested, here's a variation of the IO#copy_stream, File#open + block answer(s) (written against ruby 2.2.x, 3 years too late).
copy = Tempfile.new
File.open(file, 'rb') do |input_stream|
File.open(copy, 'wb') do |output_stream|
IO.copy_stream(input_stream, output_stream)
end
end
As a precaution I would recommend using buffer unless you can guarantee whole file always fits into memory:
File.open("source", "rb") do |input|
File.open("target", "wb") do |output|
while buff = input.read(4096)
output.write(buff)
end
end
end
Here my implementation
class File
def self.copy(source, target)
File.open(source, 'rb') do |infile|
File.open(target, 'wb') do |outfile2|
while buffer = infile.read(4096)
outfile2 << buffer
end
end
end
end
end
Usage:
File.copy sourcepath, targetpath
Here is a simple way of doing that using ruby file operation methods :
source_file, destination_file = ARGV
script = $0
input = File.open(source_file)
data_to_copy = input.read() # gather the data using read() method
puts "The source file is #{data_to_copy.length} bytes long"
output = File.open(destination_file, 'w')
output.write(data_to_copy) # write up the data using write() method
puts "File has been copied"
output.close()
input.close()
You can also use File.exists? to check if the file exists or not. This would return a boolean true if it does!!
Here's a fast and concise way to do it.
# Open first file, read it, store it, then close it
input = File.open(ARGV[0]) {|f| f.read() }
# Open second file, write to it, then close it
output = File.open(ARGV[1], 'w') {|f| f.write(input) }
An example for running this would be.
$ ruby this_script.rb from_file.txt to_file.txt
This runs this_script.rb and takes in two arguments through the command-line. The first one in our case is from_file.txt (text being copied from) and the second argument second_file.txt (text being copied to).
You can also use File.binread and File.binwrite if you wish to hold onto the file contents for a bit. (Other answers use an instant copy_stream instead.)
If the contents are other than plain text files, such as images, using basic File.read and File.write won't work.
temp_image = Tempfile.new('image.jpg')
actual_img = IO.binread('image.jpg')
IO.binwrite(temp_image, actual_img)
Source: binread,
binwrite.
I have this little program I write in ruby. I found a nice piece of code here, on SO, to find and replace something in a file, but it doesn't seems to work.
Here's the code:
#!/usr/bin/env ruby
DOC = "test.txt"
FIND = /,,^M/
SEP = "\n"
#make substitution
File.read(DOC).gsub(FIND, SEP)
#Check if the line already exist
unique_lines = File.readlines(DOC).uniq
#Save the result in a new file
File.open('test2.txt', 'w') { |f| f.puts(unique_lines) }
Thanks everybody !
I skip the check you make to see if the line already exists and usually go with something like this (here I want to replace 'FOO' with 'BAR'):
full_path_to_read = File.expand_path('~/test1.txt')
full_path_to_write = File.expand_path('~/test2.txt')
File.open(full_path_to_read) do |source_file|
contents = source_file.read
contents.gsub!(/FOO/, 'BAR')
File.open(full_path_to_write, "w+") { |f| f.write(contents) }
end
The use of expand_path is also probably a bit pedantic here, but I like it just so that I don't accidentally clobber some file I didn't mean to.