I am working through the event_manager intro to ruby lessons, and need to load a file called
event_attendees.csv from my event_manager.rb.
I cannot figure out where to put the event_attendees.csv file. I know that it needs to go in the root directory but I cannot figure out where that is.
When I look at the Dir.pwd for my ruby document, I get:
C:/Ruby_Documents/event_manger/event_manager/lib
Does it matter that windows uses \ instead of / when I call the doc? This is where I am:
puts "EventManager initialized"
contents = File.read "event_attendees.csv"
puts contents
according to event_manager instructions you just need one event_manager directory and you need to put your event_attendees.csv in the same directory.
Related
I want to display all the .conf files in the computer using ruby. I have written the below code, however, its not printing anything.
Dir.glob("**/*.conf") {|file| puts file}
What am I doing wrong?
You're almost there. Your code will show you all the conf files, but it will start checking in the folder where you're currently located, not the whole computer. To achieve that, try with:
Dir.glob("/**/*.conf") {|file| puts file}
I've got a project structure as follows:
info.config (just a JSON file w/ prefs+creds)
main.rb
tasks/
test.rb
In both main.rb (at the root of the project), and test.rb (under the tasks folder), I want to be able to read and parse the info.config file. I've figured out how to do that in main.rb with the following:
JSON.parse(File.read('info.config'))
Of course, that doesn't work in test.rb.
Question: How can I read the file from a test.rb even though it's one level deeper in the hierarchy?
Appreciate any guidance I can get! Thanks!
Use relative path:
path = File.join(
File.dirname(File.dirname(File.absolute_path(__FILE__))),
'info.config'
)
JSON.parse(File.read(path))
File.dirname(File.absolute_path(__FILE__)) will give you the directory where test.rb resides. -> (1)
File.dirname(File.dirname(File.absolute_path(__FILE__))) will give you parent directory of (1).
Reference: File::absolute_path, File::dirname
UPDATE
Using File::expand_path is more readable.
path = File.expand_path('../../info.config', __FILE__)
JSON.parse(File.read(path))
What I usually do is:
Create file called environment or similar in your project root. This file has only one purpose - to extend load path:
require 'pathname'
ROOT_PATH = Pathname.new(File.dirname(__FILE__))
$:.unshift ROOT_PATH
Require this file at the beginning of your code. From now on every time you call require, you can use relative_path to you root directory, without worrying where file you are requiring it from is located.
When using File, you can simple do:
File.open(ROOT_PATH.join 'task', 'test.rb')
You can do as below using File::expand_path :
path = File.expand_path("info.config","#{File.dirname(__FILE__)}/..")
JSON.parse(File.read(path))
File.dirname(__FILE__) will give you the path as "root_path_of_your_projet/tasks/".
"#{File.dirname(__FILE__)}/.." will give you the path as "root_path_of_your_projet/". .. means go one level up from the current directory.
File.expand_path("info.config","root_path_of_your_projet/") will give you the actual path to the file as "root_path_of_your_projet/info.config".
You can also use __dir__ instead of File.dirname(__FILE__).
__dir__ : Returns the canonicalized absolute path of the directory of the file from which this method is called.
Hope that explanation helps.
I'm trying to move files from one folder to another via Ruby, but I'm stuck trying to get Pathname.new to work. For reference the files are being held in array as an inbetween from their normal dir. I know I could move it via CLI but I'd like the program to do it for me. This is what I have so far. I know it's wrong; I just don't get how to fix it.
temp_array.each {|song| song.path(Pathname.new("/Users/tsiege/Desktop/#{playlist_name}"))}
Have a look at FileUtils.mv:
require 'fileutils'
temp_array.each do |song|
FileUtils.mv song.path, "/Users/tsiege/Desktop/#{playlist_name}"
end
Be sure that the directory #{playlist_name} exists before you do, though:
FileUtils.mkdir_p "/Users/tsiege/Desktop/#{playlist_name}"
To move files you can use FileUtils.mv:
require 'fileutils'
FileUtils.mv 'from.ext', 'to.ext'
http://ruby-doc.org/stdlib-1.9.3/libdoc/fileutils/rdoc/FileUtils.html#method-c-mv
And if you want a list of files in a directory you can use:
Dir['/path/to/dir/*']
http://ruby-doc.org/core-1.9.3/Dir.html
Lastly, you may also want to check if you have a file or directory:
File.file? file
File.directory? dir
http://ruby-doc.org/core-1.9.3/File.html#method-c-file-3F
I'm trying to write a Sinatra app that reads in a list from a file, and then spits back a random item from that list.
I'm having trouble figuring out the path to the file to read it, though. Sinatra says 'no such file or directory' when I try to load an item in my browser:
Errno::ENOENT at /wod
No such file or directory - http://localhost:4567/listing.txt
Here is the code:
require 'sinatra'
#list
get /item
puts read_list[rand(#list.size)]
end
def read_list
File.open('listing.txt', 'r').readlines
end
I have the file in /public, which the Sinatra README says is the default location for hosting static files. Furthermore, if I put it in /public I can navigate to localhost:4567/listing.txt and read the file in the browser.
A couple things I noticed:
get /item
isn't correct, it should be:
get '/item' do
If you start your code inside the same directory the Ruby code is in, the current working-directory will be ".", which is where Ruby will look when trying to:
File.open('listing.txt', 'r').readlines
Ruby will actually use './listing.txt' as the path. That's OK if you manually launch the code from the root directory of the application, but that doesn't work well if you try to launch it from anywhere else.
It's better to be explicit about the location of the file when you're actually trying to load something for use with a web server. Instead of relying on chance, there are a couple things you can do to help make it more bullet-proof. Consider this:
def read_list
running_dir = File.dirname(__FILE__)
running_dir = Dir.pwd if (running_dir == '.')
File.open(running_dir + '/public/listing.txt', 'r').readlines
end
File.dirname gets the path information from __FILE__, which is the absolute path and name of the current file running. If the application was started from the same directory as the file, that will be ., which isn't what we want. In that case, we want the absolute path of the current working-directory, which Dir.pwd returns. Then we can append that to the path of the file you want, from the root of the application.
You'll need to do File.read('public/listing.txt', 'r') to get what you want here.
File.open isn't part of Sinatra and doesn't know to look in a specific place for static files, so it just looks in the current working directory.
I'm just working on my first gem (pretty new to ruby as well), entire code so far is here;
https://github.com/mikeyhogarth/tablecloth
One thing I've tried to do is to create a yaml file which the gem can access as a lookup (under lib/tablecloth/yaml/qty.yaml). This all works great and the unit tests all pass, hwoever when I build and install the gem and try to run under irb (from my home folder) I am getting;
Errno::ENOENT: No such file or directory - lib/tablecloth/yaml/qty.yaml
The code is now looking for the file in ~/lib/tablecloth... rather than in the directory the gem is installed to. So my questions are;
1) How should i change line 27 of recipe.rb such that it is looking in the folder that the gem is installed to?
2) Am I in fact approaching this whole thing incorrectly (is it even appropriate to use static yaml files within gems in this way)?
Well first of all you should refer to the File in the following way:
file_path = File.join(File.dirname(__FILE__),"yaml/qty.yaml")
units_hash = YAML.load_file(filepath)
File.dirname(__FILE__) gives you the directory in which the current file (recipe.rb) lies.
File.join connects filepaths in the right way. So you should use this to reference the yaml-file relative to the recipe.rb folder.
If using a YAML-file in this case is a good idea, is something which is widely discussed. I, myself think, this is an adequate way, especially in the beginning of developing with ruby.
A valid alternative to yaml-files would be a rb-File (Ruby Code), in which you declare constants which contain your data. Later on you can use them directly. This way only the ruby-interpreter has to work and you save computing time for other things. (no parser needed)
However in the normal scenario you should also take care that reading in a YAML file might fail. So you should be able to handle that:
file_path = File.join(File.dirname(__FILE__),"yaml/qty.yaml")
begin
units_hash = YAML.load_file(filepath)
rescue Psych::SyntaxError
$stderr.puts "Invalid yaml-file found, at #{file_path}"
exit 1
rescue Errno::EACCES
$stderr.puts "Couldn't access file due to permissions at #{file_path}"
exit 1
rescue Errno::ENOENT
$stderr.puts "Couldn't access non-existent file #{file_path}"
exit 1
end
Or if you don't care about the details:
file_path = File.join(File.dirname(__FILE__),"yaml/qty.yaml")
units_hash =
begin
YAML.load_file(filepath)
rescue Psych::SyntaxError, Errno::EACCES, Errno::ENOENT
{}
end