I'm debugging a program, and it's not executing the new puts in the loaded files. The main file is running, and changes on that file are executed. So I'm skeptical any changes are loaded.
What could I be doing wrong?
The first file works fine. its the second file... the newmods.rb file that the prompt isn't changing when run, and any new 'puts' statements are not taking.
I'm using load instead of require_relative. the file doesn't compile with require_relative.
File 1
#!/usr/bin/env ruby
load "/Users/abcde/Ruby/learning/shorterZork/monsters.rb"
load "/Users/abcde/Ruby/learning/shorterZork/room.rb"
load "/Users/abcde/Ruby/learning/shorterZork/avatar.rb"
load "/Users/abcde/Ruby/learning/shorterZork/newmods.rb"
load "/Users/abcde/Ruby/learning/shorterZork/items.rb"
def main()
game_loop(avatar)
end
def game_loop(avatar)
puts "You are in the: #{#room_name}"
puts "#{avatar.name} has #{avatar.life}!"
health_bar(avatar)
# Check for avatar's life.
#avatar_life(avatar)
#puts #room_monsters.to_s
monster = #room_monsters
test_encounter(avatar, monster)
# need to put the meat of the game here.
# puts "I need something here."
#puts "--------------------------------------------This is the main loop."
prompt; action = gets.chomp
if action.downcase == "help"
help()
..etc...etc.
end
main()
File 2 newmods.rb
# This includes any modules that might be nice to use.
load "/Users/abcde/Ruby/learning/shorterZork/monsters.rb"
load "/Users/abcde/Ruby/learning/shorterZork/room.rb"
load "/Users/abcde/Ruby/learning/shorterZork/avatar.rb"
load "/Users/abcde/Ruby/learning/shorterZork/items.rb"
#require 'items'
#require 'monsters'
#require 'avatar'
#require 'room'
#require 'shortZork'
def prompt()
print ">> "
end
From my experience, common mistakes in such cases are
The edit displayed on the editor/IDE is not saved to the file.
There are different versions of a file, and the edit is made on the version that is not used.
Joy. Just when you reach out for help the answer slaps you in the face.
The ruby load is loading a file from a different path than the current expected path. The username is different, so...
Related
Yes, I know I can just use load instead of require. But that is not a good solution for my use case:
When the app boots, it requires a config file. Each environment has its own config. The config sets constants.
When the app boots, only one environment is required. However, during testing, it loads config files multiple times to make sure there are no syntax errors.
In the testing environment, the same config file may be loaded more than once. But I don't want to change the require to load because every time the a spec runs, it reloads the config. This should be done via require, because if the config has already been loaded, it raises already initialized constant warnings.
The cleanest solution I can see is to manually reset the require flag for the config file after any config spec.
Is there a way to do that in Ruby?
Edit: adding code.
When the app boots it calls the init file:
init.rb:
require "./config/environments/#{ ENV[ 'RACK_ENV' ]}.rb"
config/environments/test.rb:
APP_SETTING = :foo
config/environments/production.rb:
APP_SETTING = :bar
spec/models/config.rb: # It's not a model spec...
describe 'Config' do
specify do
load './config/environments/test.rb'
end
specify do
load './config/environments/production.rb'
end
Yes it can be done. You must know the path to the files that you want to reload. There is a special variable $LOADED_FEATURES which stores what has been loaded, and is used by require to decide whether to load a file when it is requested again.
Here I am assuming that the files you want to re-require all have the unique path /myapp/config/ in their name. But hopefully you can see that this would work for any rule about the path name you can code.
$LOADED_FEATURES.reject! { |path| path =~ /\/myapp\/config\// }
And that's it . . .
Some caveats:
require does not store or follow any kind of dependency tree, to know what it "should" have loaded. So you need to ensure the full chain of requires starting with the require command you run in the spec to re-load the config, and including everything you need to be loaded, is covered by the removed paths.
This will not unload class definitions or constants, but simply re-load the files. In fact that is literally what require does, it just calls load internally. So all the warning messages about re-defining constants will also need to be handled by un-defining the constants you expect to see defined in the files.
There is probably a design of your config and specs that avoids the need to do this.
if you really want to do this, here's one approach that doesn't leak into your test process. Fork a process for every config file you want to test, communicate the status back to the test process via IO.pipe and fail/succeed the test based on the result.
You can go as crazy as you want with the stuff you send down the pipe...
Here's some quick and dirty example to show you what I mean.
a config
# foo.rb
FOO = "from foo"
another config
# bar.rb
FOO = "from bar"
some faulty config
# witherror.rb
asdf
and your "test"
# yourtest.rb
def load_config(writer, config_file)
fork do
begin
require_relative config_file
writer.write "success: #{FOO}\n"
rescue
writer.write "fail: #{$!.message}\n"
end
writer.close
exit # maybe this is even enough to NOT make it run your other tests...
end
end
rd, writer = IO.pipe
load_config(writer, "foo.rb")
load_config(writer, "bar.rb")
load_config(writer, "witherror.rb")
writer.close
puts rd.read
puts rd.read
puts rd.read
puts FOO
The output is:
success: from foo
success: from bar
fail: undefined local variable or method `asdf' for main:Object
yourtest.rb:24:in `<main>': uninitialized constant FOO (NameError)
as you can see, the FOO constant doesn't leak into your test process etc.
Of course you're only through half way because there's more to it like, making sure only one process runs the test etc.
Frankly, I don't think this is a good idea, no matter what approach you chose because you'll open a can of worms and imho there's no really clean way to do this.
I am using Ruby 2.1.0p0 on Mac OS.
I'm parsing a CSV file and grabbing all the URLs, then using Nokogiri and OpenURI to scrape them which is where I'm getting stuck.
When I try to use an each loop to run through the URLs array, I get this error:
initialize': No such file or directory # rb_sysopen - URL (Errno::ENOENT)
When I manually create an array, and then run through it I get no error. I've tried to_s, URI::encode, and everything I could think of and find on Stack Overflow.
I can copy and paste the URL from the CSV or from the terminal after using puts on the array and it opens in my browser no problem. I try to open it with Nokogiri it's not happening.
Here's my code:
require 'rubygems'
require 'nokogiri'
require 'open-uri'
require 'uri'
require 'csv'
events = Array.new
CSV.foreach('productfeed.csv') do |row|
events.push URI::encode(row[0]).to_s
end
events.each do |event|
page = Nokogiri::HTML(open("#{event}"))
#eventually, going to find info on the page, and scrape it, but not there yet.
#something to show I didn't get an error
puts "open = success"
end
Please help! I am completely out of ideas.
It looks like you're processing the header row, where on of those values is literally "URL". That's not a valid URI so open-uri won't touch it.
There's a headers option for the CSV module that will make use of the headers automatically. Try turning that on and referring to row["URL"]
I tried doing the same thing and found it to work better using a text file.
Here is what I did.
#!/usr/bin/python
#import webbrowser module and time module
import webbrowser
import time
#open text file as "dataFile" and verify there is data in said file
dataFile = open('/home/user/Desktop/urls.txt','r')
if dataFile > 1:
print("Data file opened successfully")
else:
print("!!!!NO DATA IN FILE!!!!")
exit()
#read file line by line, remove any spaces/newlines, and open link in chromium-browser
for lines in dataFile:
url = str(lines.strip())
print("Opening " + url)
webbrowser.get('chromium-browser').open_new_tab(url)
#close file and exit
print("Closing Data File")
dataFile.close()
#wait two seconds before printing "Data file closed".
#this is purely for visual effect.
time.sleep(2)
print("Data file closed")
#after opener has run, user is prompted to press enter key to exit.
raw_input("\n\nURL Opener has run. Press the enter key to exit.")
exit()
Hope this helps!
Here I have two files:
file.rb
def method
puts "This won't be outputted."
end
puts "This will be outputted."
main.rb
require "./file"
When running main.rb it will load all the code inside file.rb so I will get "This will be outputted." on the screen.
Is it possible to load a file without having it to run the code?
Cause I want to load all the methods (in modules and classes too) without having to execute code outside these scopes.
Is it possible to load a file without having it to run the code?
No, everything in a ruby file is executable code, including class and method definitions (you can see this when you try to define a method inside an if-statement for example, which works just fine). So if you wouldn't execute anything in the file, nothing would be defined.
You can however tell ruby that certain code shall only execute if the file is run directly - not if it is required. For this simply put the code in question inside an if __FILE__ == $0 block. So for your example, this would work:
file.rb
def method
puts "This won't be outputted."
end
if __FILE__ == $0
puts "This will not be outputted."
end
main.rb
require "./file"
the if __FILE__ == $0 is nice, but a way more in keeping with ruby's Object Oriented approach is to put all the methods you want access to in a class (as class methods), and then call them from main.rb.
e.g.
file.rb
class MyUtils
def self.method
puts "this won't be outputted"
end
end
and then in main.rb
require "/.file.rb"
and when you want to use your utility methods:
MyUtils.method
I don't think modifying file is good idea - there are could be a lot of files like this one or these files belong to customer and a ton of another reasons.
Ruby is good at metaprogramming so why don't use this feature?
It could be like this.
Create file with fake module and put here the file.
File.open("mfile.rb","w") do |f|
f.write "module FakeModule
"
f.write File.open("file.rb").read
f.write "
end"
end
Then load this file:
require "/.mfile.rb
and accessing to the method:
FakeModule::method
I'm trying to create an application that will primarily consist of ruby scripts that will be run from the command-line (cron, specifically). I want to have a libs folder, so I can put encapsulated, reusable classes/modules in there, and be able to access them from any script.
I want to be able to put my scripts into a "bin" folder.
What is the best way to give them access to the libs folder? I know I can add to the load path via command-line argument, or at the top of each command-line script. In PHP, it sometimes made more sense to create a custom .ini file and point the cli to the ini file, so you got them all in one pop.
Anything similar for ruby? Based on your experience, what's the best way to go here?
At the top of each bin/executable, you can put this at the top
#!/usr/bin/env ruby
$:.unshift(File.join(File.dirname(__FILE__), '..', 'lib')
require 'libfile'
[etc.]
Were you looking for something different?
If you turn your application into a Ruby gem and install the gem on your system, you don't even need to put this stuff at the top. The require statement would suffice in that case.
Sean,
There is no way to not have to require a library, that I know of. I guess if you want to personalize your Ruby so much you could "roll your own" using eval.
The script below basically works as the interpreter. You can add your own functions and include libraries. Give the file executable permissions and put it in /usr/bin if you really want. Then just use
$ myruby <source>
Here's the code for a very minimal one. As an example I've included the md5 digest library and created a custom function called md5()
#!/usr/bin/ruby -w
require 'digest/md5';
def executeCode(file)
handle = File.open(file,'r');
for line in handle.readlines()
line = line.strip();
begin
eval(line);
rescue Exception => e
print "Problem with script '" + file + "'\n";
print e + "\n";
end
end
end
def checkFile(file)
if !File.exists?(file)
print "No such source file '" + file + "'\n";
exit(1);
elsif !File.readable?(file)
print "Cannot read from source file '" + file + "'\n";
exit(1);
else
executeCode(file);
end
end
# My custom function for our "interpreter"
def md5(key=nil)
if key.nil?
raise "md5 requires 1 parameter, 0 given!\n";
else
return Digest::MD5.hexdigest(key)
end
end
if ARGV[0].nil?
print "No input file specified!\n"
exit(1);
else
checkFile(ARGV[0]);
end
Save that as myruby or myruby.rb and give it executable permissions (755). Now you're ready to create a normal ruby source file
puts "I will now generate a md5 digest for mypass using the md5() function"
puts md5('mypass')
Save that and run it as you would a normal ruby script but with our new interpreter. You'll notice I didn't need to include any libraries or write the function in the source code because it's all defined in our interpreter.
It's probably not the most ideal method, but it's the only one I can come up with.
Cheers
There is a RUBYLIB environment variable that can be set to any folder on the system
If you want to use your classes/modules globally, why not just move them to your main Ruby lib directory? eg: /usr/lib/ruby/1.8/ ?
Eg:
$ cat > /usr/lib/ruby/1.8/mymodule.rb
module HelloWorld
def hello
puts("Hello, World!");
end
end
We have our module in the main lib directory - should be able to
require it from anywhere in the system now.
$ irb
irb(main):001:0> require 'mymodule'
=> true
irb(main):002:0> include HelloWorld
=> Object
irb(main):003:0> hello
Hello, World!
=> nil
Is there a shorter way to require a file located in the same directory (as the script being executed)?
require File.expand_path(File.dirname(__FILE__) + '/some_other_script')
I read that require "my_script" and require "./my_script" will actually load the script twice (ruby will not recognize that it is actually the same script), and this is the reason why File.expand_path is recommended: if it is used every time the script is required, then it will only be loaded once.
It seems weird to me that a concise language like Ruby does not seem to have a shorter solution. For example, python simply has this:
import .some_other_module_in_the_same_directory
I guess I could monkey-patch require... but that's just evil! ;-)
Since ruby 1.9 you can use require_relative.
Check the latest doc for require_relative or another version of the Core API.
Just require filename.
Yes, it will import it twice if you specify it as filename and ./filename, so don't do that. You're not specifying the .rb, so don't specify the path. I usually put the bulk of my application logic into a file in lib, and then have a script in bin that looks something like this:
#!/usr/bin/env ruby
$: << File.join(File.dirname(__FILE__), "/../lib")
require 'app.rb'
App.new.run(ARGV)
Another advantage is that I find it easier to do unit testing if the loading the application logic doesn't automatically start executing it.
The above will work even when you're running the script from some other directory.
However, inside the same directory the shorter forms you refer to work as expected and at least for ruby 1.9 won't result in a double-require.
testa.rb
puts "start test A"
require 'testb'
require './testb'
puts "finish test A"
testb.rb
puts "start test B"
puts "finish test B"
running 'ruby testa.rb' will result in:
start test A
start test B
finish test B
finish test A
However, the longer form will work even from another directory (eg. ruby somedir/script.rb)
Put this in a standard library directory (somewhere that's already in your default loadpath $:):
# push-loadpath.rb
if caller.first
$: << File.expand_path(File.dirname(caller.first))
end
Then, this should work
% ls /path/to/
bin.rb lib1.rb lib2.rb #...
% cat /path/to/bin.rb
load 'push-loadpath.rb'
require 'lib1'
require 'lib2'
#...
caller gives you access to the current callstack, and tells you what file and where, so push-loadpath.rb uses that to add the file that load'd it to the loadpath.
Note that you should load the file, rather than require it, so the body can be invoked multiple times (once for each time you want to alter the loadpath).
Alternately, you could wrap the body in a method,
# push-loadpath.rb
def push_loadpath
$: << File.expand_path(File.dirname(caller.first))
end
This would allow you to require it, and use it this way:
% ls /path/to/
bin.rb lib1.rb lib2.rb #...
% cat /path/to/bin.rb
require 'push-loadpath'
push_loadpath
require 'lib1'
require 'lib2'
#...