I have a decent amount of knowledge about Ruby code, but I do have an issue with my current project. I use Gosu to make 2D games (and once I figure out how, simple 3D games), so I need a resolution.
And this is where my question comes in, why does Ruby keep giving me an error when seeing if the settings file exists? I've been trying to get it working with the file not existing, which keeps giving me the error, "'initialize': No such file or directory # rb_sysopen - ./settings.set (Errno::ENOENT)" which has been annoying me for the last few days. The file gives no issues and actually works as intended when I leave the file created, but I want it to be where if the file gets deleted off of someone's computer, it rebuilds the file and creates a new one using default values.
Here's the area that it keeps crashing at:
settings = []
settings_file_existance = File.file?("settings.set")
if settings_file_existance == true
File.open("settings.set").readlines.each do |line|
settings.push line
end
else
settings_file = File.open("settings.set")
settings_file.write "800"
settings_file.write "\n"
settings_file.write "600"
settings_file.close
end
I have tried looking for fixes on this site, along with many others, but no one so far has been able to help.
You could try this:
settings = []
if File.file?("settings.set")
settings = File.read("settings.set").split("\n")
else
File.open("settings.set", "w") do |file|
file.write "800\n600"
end
end
As a side note, consider that the above code will set settings only if settings.set file exits, otherwise it will remain in an empty array (i.e. []).
If you wish to avoid that, just define settings with the default values, for example:
settings = [800, 600]
Now if settings.set file doesn't exist, then settings will be [800, 600], otherwise it will be overwritten with the values from settings.set.
To avoid writing 800 and 600 twice, you could use settings variable to get the values to be written in the new file, for example:
file.write(settings.join("\n"))
Putting it all together, your code would look like this:
settings = [800, 600]
if File.file?("settings.set")
settings = File.read("settings.set").split("\n")
else
File.open("settings.set", "w") do |file|
file.write(settings.join("\n"))
end
end
Related
I want to ask for user input, but I only want to do it once (possibly save the information within the program), meaning, something like this:
print "Enter your name (you will only need to do this once): "
name = gets.chomp
str = "Hello there #{name}" #<= As long as the user has put their name in the very first
# time the program was run, I want them to never have to put thier name in again
How can I got about doing this within a Ruby program?
This program will be run by multiple users throughout the day on multiple systems. I've attempted to store it into memory, but obviously that failed because from my understand that memory is wiped everytime a Ruby program stops executing.
My attempts:
def capture_user
print 'Enter your name: '
name = gets.chomp
end
#<= works but user has to put in name multiple times
def capture_name
if File.read('name.txt') == ''
print "\e[36mEnter name to appear on email (you will only have to do this once):\e[0m "
#esd_user = gets.chomp
File.open('name.txt', 'w') { |s| s.puts(#esd_user) }
else
#esd_user = File.read('name.txt')
end
end
#<= works but there has to be a better way to do this?
require 'tempfile'
def capture_name
file = Tempfile.new('user')
if File.read(file) == ''
print "\e[36mEnter name to appear on email (you will only have to do this once):\e[0m "
#esd_user = gets.chomp
File.open(file, 'w') { |s| s.puts(#esd_user) }
else
#esd_user = File.read(file)
end
end
#<= Also used a tempfile, this is a little bit over kill I think,
# and doesn't really help because the users can't access their Appdata
You will want to store the username in a file on the local file system. Ruby provides many ways to do this, and we'll explore one in this answer: YAML files.
YAML files are a structured storage file that can store all kinds of different data, and is a good place to store config data. In fact, YAML configuration files are key parts of the largest Ruby projects in existence. YAML gives you a good starting point for supporting future configuration needs, beyond the current one, which is a great way to plan feature development.
So, how does it work? Let's take a look at your requirement using a YAML config:
require 'yaml'
config_filename = "config.yml"
config = {}
name = nil
if file_exists(config_filename)
begin
config = YAML.load_file(config_filename)
name = config["name"]
rescue ArgumentError => e
puts "Unable to parse the YAML config file."
puts "Would you like to proceed?"
proceed = gets.chomp
# Allow the user to type things like "N", "n", "No", "nay", "nyet", etc to abort
if proceed.length > 0 && proceed[0].upcase == "N"
abort "User chose not to proceed. Aborting!"
end
end
end
if name.nil? || (name.strip.length == 0)
print "Enter your name (you will only need to do this once): "
name = gets.chomp
# Store the name in the config (in memory)
config["name"] = name
# Convert config hash to a YAML config string
yaml_string = config.to_yaml
# Save the YAML config string to the config file
File.open(config_filename, "w") do |out|
YAML.dump(config, out)
end
end
Rather than show you the bare minimum to meet your needs, this code includes a little error handling and some simple safety checks on the config file. It may well be robust enough for you to use immediately.
The very first bit simply requires the YAML standard library. This makes the YAML functions work in your program. If you have a loader file or some other common mechanism like that, simply place the require 'yaml' there.
After that, we initialize some variables that get used in this process. You should note that the config_filename has no path information in it, so it will be read from the current directory. You will likely want to store the config file in a common place, such as in ~/.my-program-name/config.yml or C:\Documents and Settings\MyUserName\Application Data\MyProgramName\. This can be done pretty easily, and there's plenty to help, such as this Location to Put User Config Files in Windows and Location of ini/config files in linux/unix.
Next, we check to see if the file actually exists, and if so, we attempt to read the YAML contents from it. The YAML.load_file() method handles all the heavy lifting here, so you just have to ask the config hash that's returned for the key that you're interested in, in this case, the "name" key.
If an error occurs while reading the YAML file, it indicates that the file might possibly be corrupted, so we try to deal with that. YAML files are easy to edit by hand, but when you do that, you can also easily introduce an error that will make loading the YAML file fail. The error handling code here will allow the user to abort the program and go back to fix the YAML file, so that it doesn't simply get overwritten.
After that, we try to see if we've been had a valid name from the YAML config, and if not, we go ahead and accept it from the user. Once they've entered a name, we add it to the config hash, convert the hash to a YAML-formatted string, and then write that string to the config file.
And that's all it takes. Just about anything that you can store in a Ruby hash, you can store in a YAML file. That's a lot of power for storing config information, and if you later need to add more config options, you have a versatile container that you can use exactly for that purpose.
If you want to do any further reading on YAML, you can find some good information here:
YAML in Ruby Tutorial on Robot Has No Heart
Jamming with Ruby YAML on Juixe Techknow
YAML on Struggling with Ruby
While some of these articles are a bit older, they're still very relevant and will give you a jumping off point for further reading. Enjoy!
If you need the name to persist across the user running the script several times, you're going to need to use some sort of data store. As much as I hate flat files, if all you're storing is the user's name, I think this is a valid option.
if File.exist?('username.txt')
name = File.open( 'username.txt', 'r' ) do |file|
name = file.gets
end
else
print "Enter your name (you will only need to do this once): "
name = gets.chomp
File.open( 'username.txt', 'w' ) do |file|
file.puts name
end
end
str = "Hello there #{name}"
I have an input file and a batch file. When the batch file is executed using the System command,
a corresponding outfile is generated.
Now I want a particular text (position 350 to 357) from that outfile to be displayed on to my lineedit widget
Here is that part of my code:
system("C:/ORG_Class0178.bat")
Now the outfile will be generated
File.open("C:/ORG_Class0178_out.txt", 'r').each do |line|
var = line[350..357]
puts var
# To test whether the file is being read.
#responseLineEdit = Qt::LineEdit.new(self)
#responseLineEdit.setFont Qt::Font.new("Times NEw Roman", 12)
#responseLineEdit.resize 100,20
#responseLineEdit.move 210,395
#responseLineEdit.setText("#{var}")
end
When I do test whether the file is being read using puts statement, I get the exact required output in editor. However, the same text is not being displayed on LineEdit. Suggestions are welcome.
EDIT: A wired observation here. It works fine when I try to read the input file and display it , however it does not work with the output file. The puts statement does give the answer in editor confirming that output file does contain the required text. I am confused over this scenario.
There is nothing wrong with the code fragments shown.
Note that var is a local variable. Are the second and third code fragments in the same context? If they are in the same method, and var is not touched in-between, it will work.
If the fragments belong to different methods of the same class, than an instance variable (#var) will solve the problem.
If all that does not help, use Pry to chase the problem. Follow the link to find the pre-requisites and how to use. Place binding.pry in your code, and your program will stop at that line. Then inspect what your variables are doing.
try 'rb' instead of 'r'
File.open("C:/ORG_Class0178_out.txt", 'rb').each do |line|
var = line[350..357]
puts var
In my application, the user must upload a text document, the contents of which are then parsed by the receiving controller action. I've gotten the document to upload successfully, but I'm having trouble reading its contents.
There are several threads on this issue. I've tried more or less everything recommended on these threads, and I'm still unable to resolve the problem.
Here is my code:
file_data = params[:file]
contents = ""
if file_data.respond_to?(:read)
contents = file_data.read
else
if file_data.respond_to?(:path)
File.open(file_data, 'r').each_line do |line|
elts = line.split
#
#
end
end
end
So here are my problems:
file_data doesn't 'respond_to?' either :read or :path. According to some other threads on the topic, if the uploaded file is less than a certain size, it's interpreted as a string and will respond to :read. Otherwise, it should respond to :path. But in my code, it responds to neither.
If I try to take out the if statements and straight away attempt File.open(file_data, 'r'), I get an error saying that the file wasn't found.
Can someone please help me find out what's wrong?
PS, I'm really sorry that this is a redundant question, but I found the other threads unhelpful.
Are you actually storing the file? Because if you are not, of course it can't be found.
First, find out what you're actually getting for file_data by adding debug output of file_data.inspect. It maybe something you don't expect, especially if form isn't set up correctly (i.e. :multipart => true).
Rails should enclose uploaded file in special object providing uniform interface, so that something as simple as this should work:
file_data.read.each_line do |line|
elts = line.split
#
#
end
So, I wrote a simple Ruby class, and put it in my rails /lib directory. This class has the following method:
def Image.make_specific_image(paths, newfilename)
puts "making specific image"
#new_image = File.open(newfilename, "w")
puts #new_image.inspect
##blank.each(">") do |line|
puts line + "~~~~~"
#new_image.puts line
if line =~ /<g/
paths.each do |p|
puts "adding a path"
puts p
#new_image.puts p
end
end
end
end
Which creates a new file, and copies a hardcoded string (##blank) to this file, adding custom content at a certain location (after a g tag is found).
If I run this code from ruby, everything is just peachy.
HOWEVER, if I run this code from rails, the file gets CREATED, but is then empty. I've inspected each line of the code: nothing I'm trying to write to the file is nil, but the file is empty nonetheless.
I'm really stumped here. Is it a permissions thing? If so, why on EARTH would Rails have the permissions necessary to MAKE a file, but then not WRITE to the file it made?
Does File I/O somehow work differently in rails?
Specifically, I have a model method that calls:
Image.make_specific_image(paths, creature.id.to_s + ".svg")
which succesfully makes a file of the type "47.svg" that is empty.
Have you tried calling close on the file after you're done writing it? (You could also use the block-based File.open syntax, which will automatically close once the block is complete). I'm guessing the problem is that the writes aren't getting flushed to disk.
So.
Apparently File I/0 DOES work in Rails...just very, very slowly. In Ruby, as soon as I go to look at the file, it's there, it works, everything is spiffy.
Before, after seeing blank files from Rails, I would get frustrated, then delete the file, and change some code and try again (so as not to be full of spam, since each file is genearted on creature creation, so I would soon end up with a lot of files like "47.svg" and "48.svg", etc.
....So. I took my lunch break, came back to see if I could tell if the permissions of the rails generated file were different from the ruby generated file...and noticed that the RAILS file is no longer blank.
Seems to take about five minutes for rails to finally write to the file, even AFTER it claims it's done processing that whole call. Ruby takes a few seconds. Not really sure WHY they are so different, but at least now I know it's not a permissions thing.
Edit: Actually, on some files take so long, others are instant...
trying to get my head around Feedzirra here.
I have it all setup and everything, and can even get results and updates, but something odd is going on.
I came up with the following code:
def initialize(feed_url)
#feed_url = feed_url
#rssObject = Feedzirra::Feed.fetch_and_parse(#feed_url)
end
def update_from_feed_continuously()
#rssObject = Feedzirra::Feed.update(#rssObject)
if #rssObject.updated?
puts #rssObject.new_entries.count
else
puts "nil"
end
end
Right, what I'm doing above, is starting with the big feed, and then only getting updates. I'm sure I must be doing something stupid, as even though I'm able to get the updates, and store them on the same instance variable, after the first time, I'm never able to get those again.
Obviously this happens because I'm overwriting my instance variable with only updates, and lose the full feed object.
I then thought about changing my code to this:
def update_from_feed_continuously()
feed = Feedzirra::Feed.update(#rssObject)
if feed.updated?
puts feed.new_entries.count
else
puts "nil"
end
end
Well, I'm not overwriting anything and that should be the way to go right?
WRONG, this means I'm doomed to always try to get updates to the same static feed object, as although I get the updates on a variable, I'm never actually updating my "static feed object", and newly added items will be appended to my "feed.new_entries" as they in theory are new.
I'm sure I;m missing a step here, but I'd really appreciate if someone could shed me a light on it. I've been going through this code for hours, and can't get to grips with it.
Obviously it should work fine, if I did something like:
if feed.updated?
puts feed.new_entries.count
#rssObject = initialize(#feed_url)
else
Because that would reinitialize my instance variable with a brand new feed object, and the updates would come again.
But that also means that any new update added on that exact moment would be lost, as well as massive overkill, as I'd have to load the thing again.
Thanks in advance!
How to do updates is a bit counterintuitive with the current API. This example shows the best way to do it:
# I'm using Atom here, but it could be anything. You don't need to know ahead of time.
# It will parse out to the correct format when it updates.
feed_to_update = Feedzirra::Parser::Atom.new
feed_to_update.feed_url = some_stored_feed_url
feed_to_update.etag = some_stored_feed_etag
feed_to_update.last_modified = some_stored_feed_last_modified
last_entry = Feedzirra::Parser::AtomEntry.new
last_entry.url = the_url_of_the_last_entry_for_a_feed
feed_to_update.entries = [last_entry]
updated_feed = Feedzirra::Feed.update(feed_to_update)
updated_feed.updated? # => nil if there is nothing new
updated_feed.new_entries # => [] if nothing new otherwise a collection of feedzirra entries
updated_feed.etag # => same as before if nothing new. although could change with comments added to entries.
updated_feed.last_modified # => same as before if nothing new. although could change with comments added to entries.
Basically, you'll have to save off four pieces of data (feed_url,
last_modified, etag, and the url of the most recent entry). Then when you
want to do updates you construct a new feed object and call update on
that.
I think a more obvious solution would be to add :if_modified_since option to fetch_and_parse method of class Feed, see https://github.com/pauldix/feedzirra/blob/master/lib/feedzirra/feed.rb#L116 and https://github.com/pauldix/feedzirra/blob/master/lib/feedzirra/feed.rb#L206
You can reset #rssObject to the updated feed.
feed = Feedzirra::Feed.update(#rssObject)
if feed.updated?
puts feed.new_entries.count
#rssObject = feed
else
puts 'nil'
end
The number of entries in #rssObject will keep growing as new entries are found. So if the first fetch finds 10 entries, and then next finds 10 new entries, #rssObject.entries.size will be 20.
Note that you can do this regardless of whether update finds new entries. If feed.updated? is false, feed will be the original feed object, #rssObject.