I'm new to Ruby
MakModule.rb
module Display
class Multiply
def Multiply.mul(first, second)
return first * second
end
end
end
MakRequire1.rb
require "Display"
puts Multiply.mul 5,6
MakRequire2.rb
require "MakModule.rb"
puts Multiply.mul 5,6
both file give me the error below
ruby: No such file or directory -- makRequire (LoadError)
How should I correct my code?
It is simply impossible that the code you posted here generates that error message. The error message says that you tried to require a file named makRequire, but that filename doesn't appear anywhere in the code you posted.
Without the actual code that is generating the actual error, it is impossible to answer your question. However, here are a few general tips:
Whenever the computer tells you that it cannot find something, in 99% of the cases, the problem is that the thing the computer tells it couldn't find isn't actually there.
So, in this case, the computer tells you that it cannot find a file named makRequire.rb, and the most likely explanation for that is that makRequire.rb doesn't actually exist. So, the first thing you need to check is: does makRequire.rb (note the capitalization and the file extension) actually exist? Because if it doesn't exist, then the reason why the computer cannot find it, should be rather obvious.
In 99% of the rest of the cases, the problem is that the thing the computer is looking for does exist, but the computer is looking in the wrong place. So, after you have verified that makRequire.rb actually does exist, you need to make sure that the directory the file is in, is in Ruby's $LOAD_PATH, and if it isn't, you need to add that directory to Ruby's $LOAD_PATH. Alternatively, if you want to require the file relative to the path of the file that is doing the requiring, you need to use require_relative instead of require.
The third thing to check for, is whether the user who own the ruby process has sufficient privileges to access the file makRequire.rb, the directory it is in and all of its parent directories.
Try this,
require File.join(File.dirname(__FILE__),'MarkModule')
Try require './MakModule', because the . is the current directory.
require 'MakModule'
You can require a file that is in the same directory. To use a module you would typically include the module inside a class definition. So you would never require Display, you would require the file that contains Display (without the .rb extension, usually).
Related
OK SO I Am just picking Ruby up pretty much for the kicks and giggles... and Believe me when I say I'm stumped.
I want to create a bot for my Twitch stream and do it in Ruby because I found a fairly easy tut to follow along with, along with my reasoning skills. However I'm having a very hard time getting my command prompt or pry to load the file.
Here is my file JUST IN CASE
require 'socket'
TWITCH_HOST = "irc.twitch.tv"
TWITCH_PORT = 6667
class Fox
def initialize
#nickname = "mybotsname"
#password = "I have the proper oauth here"
#channel = "mytwitchchannel"
#socket = TCPSocket.open(TWITCH_HOST, TWITCH_PORT)
write_to_system "PASS #{#password}"
write_to_system "NICK #{#nickname}"
write_to_system "USER #{#nickname} 0 * #{#nickname}"
write_to_system "JOIN ##{#Channel}"
end
def write_to_system(message)
#socket.puts message
end
def write_to_chat(message)
write_to_system "PRIVMSG ##{#channel} :{message}"
end
end
Now, From what I gathered, I should beable to go into my command prompt and type pry
I get this.
Pry
Now, I want to run my program which is located in a dropbox (Private use)
I'm Still very new to the concept of Repl's as I've been working with Java mostly along with very LITTLE Experience in other languages. What am I doing wrong here? Why can I not get my file to load properly? I've also tried filepathing and got this.FilePathing
I'm sorry if this is a stupid question. It's just driving me absolutely bat-brain crazy. The reason this is driving me bonkers is the video I was watching, he didn't do anything different other than my guess is he was using Terminal instead of Command Prompt. I Wanted originally to do this through Cygwin but upon install of Pry I lost a bunch of Cygwin files and can no longer load Cygwin, I will re-install the over all program later and see what I can from there.
Sorry for no embedded pics.
Also, any easier way to do this I'm all ears. I've tried Komodo Edit 10 but it's not playing nice ether.
Require from LOAD_PATH
A Ruby module or class file needs to be in the LOAD_PATH to require it with Kernel#require. For example, if your file is named just_in_case.rb, you can use:
$LOAD_PATH.unshift '/path/to/dropbox/directory'
# Leave off the path and .rb extension.
require 'just_in_case'
Load from an absolute path
If you need to provide an absolute path, then you should use Kernel#load instead. For example:
# Use the absolute path and the .rb extension.
load '/path/to/dropbox/just_in_case.rb'
Caveats
There are some other differences in behavior between require, require_relative, and load, but they probably don't really matter within the limited scope of the question you asked except that there have historically been issues with Kernel#require_relative within the REPL. It may or may not work as expected now, but I would still recommend require or load for your specific use case.
I have a block of code that executes a zip command from another class:
def zip_up_contents path name
Zipper.new path name
end
The problem is that it zips blank copies of all the files passed to it. But when I put a binding before the zip command like so:
def zip_up_contents path name
binding.pry
Zipper.new path name
binding.pry
end
it zips the files successfully. I know this by checking the resulting file's byte size from within pry on the second binding point with and without the first binding present. Without the binding, the zip archive's byte size is half what it should be, and with the binding it's the size I would expect.
The "Zipper" class simply calls the system zip with backticks. I don't think that's the problem because I've used that class without trouble in other contexts. The zip utility is Zip 3.0 on Ubuntu 10.04.
I have no idea why the presence of the binding makes a difference. If anyone has encountered anything similar, or has thoughts about how to better debug the issue, I'd appreciate hearing about it.
EDIT: For anyone encountering anything similar, I resolved this by calling fsync on the files prior to zipping them: http://www.ruby-doc.org/core-2.0.0/IO.html#method-i-fsync
I had this problem with some Rspec tests last week -- turned out to be a race condition. Is there any chance that the file hasn't been saved when you pass it to be zipped? I mean, maybe the binding.pry is just giving it a chance to catch up.
I had the impression that I should use require 'some_path' to get a file or a library I want to use, but I couldn't get it to work, and load 'some_path' worked.
When are the different times when I should use these?
Also, is it possible to import a directory with the load or require commmands? I am trying to use a whole directory, but so far I could only get one file at a time with load.
You can use Dir to list all the files ending with .rb and require/load them
Dir["/path/to/dir/*.rb"].each { |file| load_your_file_here(file) }
I recommend requiring file and then including the module that file loads... If you are not using module or class inside your file than maybe you should reconsider your structure.
load might have some unintended consequences and it's not performant.
Once you call require for a file further calls of require will no longer require it again(i.e. will have no effect), while load will reload it every time you call it. As far as I know there is no way to load a whole directory.
im trying to figure out what exactly these methods are doing.
$:.unshift(File.join(APP_ROOT, 'lib'))
I know its for file paths but if this piece of code were to broken down into segments how would you describe each one?
So far I under stand the File.join part, which takes two arguments (the APP_ROOT variable, and the 'lib' directory.) It then unshifts something?
Thanks in advance.
$: is Ruby shorthand to the load path array, i.e. an array full of the paths that Ruby uses to look up external files when asked to require one (try running it in IRB).
In Ruby, .unshift is a method that takes the given path (in this case, whatever File.join(APP_ROOT, 'lib') resolves to), and prepends it to the beginning of the load path array.
This way Ruby will know to check the APP_ROOT/lib path the next time you do a require 'myfile' line elsewhere in the app.
I'm writing some code that at run time may create or delete directories within the project path. I haven't really used ruby for file processing so i'm really uneasy about having code that, with a few mistypes weeks down the line, could result in wiping other directories outside of my project path.
Is there anyway to make it impossible for the program to delete files outside of its own path regardless of whats typed in destructive calls?
Pathname is a wrapper class for almost any file operations.
require "pathname"
path= Pathname.new("/home/johannes")
path.directory? # => true
path.children # => [#<Pathname:.bash_history>, #<Pathname:Documents>, #<Pathname:Desktop>]
path.children.each do |p|
p.delete if p.file?
end
Pathname#children does not contain . or .. so you don't accidently walk up the tree instead of down. If you still don't trust in the code, you can even check if on path is contained in another
Pathname.new("test") <=> Pathname.new("test/123") # => -1
You might want to create a wrapper method around your favourite delete method (or, perhaps, around whole class, because not only deleting files is potentially destructive file operation), which would expand all the submitted paths and check whether they begin with your "sandbox" path). You can also try to redefine delete method, if you are willing to cripple it through whole application.
And maybe the cleanest solution of them all would be to create a new user on your system and run your program as him.
On a POSIX system, you can use Dir.chroot to change the root that your application sees. Then ALL actions, not just delete ones, will be limited to the project directory. This does mean that external commands will be unavailable unless you make them part of your project directory as well.
This is the standard 'sandboxing' method used in Unix based systems. It can be difficult to setup (eliminating all external dependancies is sometimes hard), but affords significant protection when configured properly.
You could generate an Array of filenames in your project directory using
my_files = Dir["/bla/bla/your/directory/**/*"]
and then simply check if the filename passed to your "delete" function exist in your my_files array.
I'm sure there is a more elegant solution, but this could work ^_^
You could use File.expand_path and File.dirname on the input, and check that against __FILE__. So something like this might work:
File.delete(path) if File.dirname(File.expand_path(path)).include? File.dirname(File.expand_path(__FILE__))
I've got automated tests that routinely create and wipe out directories. I've taken two approaches:
Use /tmp as much as possible. The 'tmpdir' standard library module will create temporary directories which will be destroyed when your program exits. Or,
When the code creates a directory that it will later be deleting, it drops a marker file into the directory. When it comes time to delete the directory, if the marker file is not found, the code refuses to delete the directory. A marker file might be called ".ok_to_delete", for example.