When I type ri at the command prompt it returns nothing:
Classes and Modules known to ri:
How do I set this up properly?
Many thanks.
You can type gem rdoc --all --overwrite to have gem recreate ri and rdocs for all gems.
You don't say what version of Ruby you have installed, but 1.8.7 seemed to have problems remembering whether it had docs for the core and standard libraries. There was a gem called something like core-data that helped. If I can remember the real name I'll update this.
1.9.2 is better about its docs but I've seen times where I have to force the rebuild using the command above. A gem can act up, causing RDoc to puke, which ends up keeping all the docs from being generated so watch its progress and compare it to what gem list outputs as a sanity check. If that happens I have a shell script I use to walk through all the gems and rebuild their docs one by one. It's an easy piece of code to write and steps around the problem of a single gem killing the processing of everything.
I think you don't have the path to your ruby install folder in your PATH variable.
You have to do it to be allowed to launch ri in your command prompt.
Otherwise you can use the entire path : C:\Ruby\bin\ri.bat
Related
In our Rails application we do require 'RRD' at some point, but that results in a cannot load such file -- RRD. So obviously I used homebrew to install rrdtool, but the error remains.
The docs at https://oss.oetiker.ch/rrdtool/prog/rrdruby.en.html provide two options:
Either:
$: << '/path/to/rrdtool/lib/ruby/1.8/i386-linux'
require "RRD"
In my /opt/homebrew/Cellar/rrdtool/1.8.0/lib directory there's no mention of ruby, which is because of the --disable-ruby-site-install flag in the formula, because when I skip that flag I do actually get something: /opt/homebrew/Cellar/rrdtool/1.8.0/lib/ruby/2.6.0/universal-darwin21. However replacing the path/to string with this path still gives the error.
Or:
If you use the --ruby-site-install configure option you can drop the $: line since the RRDtool module will be found automatically.
Which is a little confusing (and probably outdated) because here it seems that ruby site install is disabled by default and you have to enable it proactively, whereas in the formula it's actually actively disabled.
Either way: both options didn't do the trick for me and if there's a solution without homebrew that's also fine.
For good measure: I'm on macOS Monterey
TL;DR
For the most part, I'd say that using a non-standard gem without a Ruby version manager is your main issue. There are instructions on the rrdruby site for installing it, but they don't follow typical conventions, so your mileage will vary.
Some Practical Suggestions
The require keyword is for gems, not binaries. You need to have an rrdtool-related gem installed, available to your Ruby instance (usually through a Bundler Gemfile or gemspec, or via the RUBYOPTS environment variable or your in-process Ruby $LOAD_PATH), and then require the correct name of the gem in your code. For example, using the older rrd-ffi gem:
# use sudo if you're installing it to the system,
# but I would strongly recommend a ruby version
# manager instead
gem install rrd-ffi
# in your Ruby class/module file
require "rrd"
For the gem you seem to be using, you have to compile the gem first to make it usable, and then ensure it's available in your Ruby $LOAD_PATH (or other gem lookup mechanism) before trying to require it. The error message you're seeing is basically telling you that a gem with that name is not available as called within any of the standard lookup locations.
Again, I'd suggest reading the build documentation for your gem, and then seeing if you can install it as part of a Bundler bundle, RVM gemset, or other non-system approach if you can. Otherwise, follow the directions for the rrdruby tool, which is not available as a standard Rubygems.org gem, in order to make it available before trying to require it.
Beware of Outdated or Non-Standard Gems
Most of the RRD gems I found were quite old; most were 7-8 years old or older, so their compatibility with current Rubies is potentially suspect. The gem-builder you're using is newer, but doesn't seem to be designed as a standard gem, so you need to build it and install it in a suitable lookup path before it can be required. Installing gems as system gems is almost always a bad idea, so I'd strongly recommend building it from source and using a ruby version manager rather than following the rrdtool author's atypical suggestions. YMMV.
I would like to run gem commands, such as gem install, with a different ruby version than what is listed in gem env. The Ruby version I want to use is a pre-compiled version which I have the path for, so installing and using another version from RVM or similar would not solve my problem.
I do not want to change the RUBY EXECUTABLE permanently, just for one command at a time. I have tried to set GEM_HOME, GEM_PATH, PATH, RUBY and more. I have tried firing up gem with specific/version/of/ruby/path/ruby path/to/gem env, but I still get the default Ruby in my RUBY EXECUTABLE variable.
I even tried settingRUBY_EXECUTABLE=/path/to/correct/ruby, which also did not work.
What really surprised me was that when I edited the shebang in the path/to/gem file itself so it pointed to the correct Ruby, it still did not work! What is up with that?!
How can I change this variable so I can use gem goodness with my custom compiled Ruby?
This one is really beating me. I have now updated my rbconfig.rb to point to the desired Ruby path. I have looked at the rubygems source and replaced every single instance of the default ruby , in all the files I could find, with the path to the one I want. Even this did not set the environment correctly. Is this somehow hard-coded into the compiled ruby? If that is the case, why the star*4 is this done?
Try using rbenv (https://github.com/sstephenson/rbenv) or RVM to manage Ruby versions (https://rvm.io/). When you switch Ruby versions with rbenv, gem env will use use the new Ruby version. The following command can be used to change the Ruby version for a single shell:
$ rbenv shell 2.1.2
After hours and hours of research, stepping through the Ruby source with Pry, reading source code and more I figured out that this is not possible to do because it is hard-coded into ruby at compile time (wtf?). Anyway, the way to solve this is to simply recompile Ruby. Yeah.
There is also apparently a compile flag which you can set which removes this hard-coded environment: --enable-load-relative
After struggling with this for way to long I finally got this project working, where I have made an easy to use portable version of Ruby. Simply put, a folder with Ruby on it which you can move about, put on a USB stick or whatever, and it still works :)
When I pass CSV to ri I get this output
Nothing known about CSV
I thought all ruby classes are documented with ri.
CSV is a part of standard library and is fully documented. That issue may be linked wit rvm using. Try to prepare rvm docs generate command.
If RI returns "NOTHING KNOWN ABOUT..." the documentation may be missing.
RI documentation isn't included when Ruby is installed.
It must be manually generated - ideally, immediately after installing EACH VERSION of Ruby (before the downloaded installation files are cleaned up).
To generate it:
$ rvm docs generate
If that doesn't work, check this RVM.io page for command options & scenarios.
With Jeweler I created a gem folder structure with ease.
However, I still have some questions:
Why are params like --gemcutter and --rubyforge still available for Jeweler. Aren't these replaced by RubyGems? Do I have to specify anything to create a gem for RubyGems?
In the Rakefile I have information about the gem, and when I run "rake install" it created a gemspec. Why is the same information in two places?
What is a manifest? Just read about it, haven't seen such file.
How do I make my gem callable from the shell once I have installed it, like rails. Cause right now it's just accessible through a Ruby script using require.
Should I use "jeweler release" or "gem push" to push my gem to RubyGems.org?
I have to specify "handle" when signing up in RubyGems. What is that?
Thanks.
jeweler was created before RubyGems became what it is, so it still reflects the split. I'm not sure when jeweler was last updated, either. (I think it also still recognizes building gems on Github, which is now disabled.)
I'm not sure I follow what you're saying. The specification in the Rakefile details what the spec that gets written should look like. The spec that gets written details what should be installed and how, I believe.
A manifest is a list of all the files that your gem should ship with. Not everyone uses one. See the hoe documentation for some pro-manifest discussion.
Many Ruby gems are only libraries. If you want yours to also have a program like jeweler or rake or rails that you can call, you have to write the callable program, put it in bin in your gem's layout and specify (in your gemspec) that it should be packaged and installed. See the Gem::Specification reference under files and executable.
Not sure. Consult both jeweler's docs and the docs for RubyGems.
You can give an email address or use a name (a 'handle', like I use Telemachus here), which is all they mean by 'handle'.
For the record, if you are just learning how to write gems, you do not need to upload your first attempts using RubyGems or anything like it. You can simply install the gem on your machine only.
Sometimes I have seen following code.
gem 'factory_girl','= 1.2.3'
require 'factory_girl'
I tried to look at gem doc but could not find answer to the question of what does the first line do in code above?
What you're looking for in the gem docs is about Coding with Rubygems.
The first line basically says "Hey, go get this gem with this version" from the install directory for gems and load it into the environment. This is mainly to help you add version dependencies to your requires instead of just doing require 'factory_girl' by itself.
Edit: To add on to Jörg's point below, I thought that Ryan Tomayko had a pretty good short and sweet article about why doing this is "wrong".
As #theIV already explained, this activates the factory_girl gem, using exactly (because of the = sign) version 1.2.3.
Note, however, that this is very bad practice and should never be done. If you activate gems manually inside your code, it means that people who do not use RubyGems can no longer use your code.
RubyGems is a package manager. Your code should never care about what package manager was used to install it. Some people prefer RubyGems, some dpkg/APT, some RPM/YUM, some RPM/APT, some RPM/URPMI, some RPM/YaST2, Portage, FreeBSD ports, pkgsrc, MacPorts, slashpackage, CoAPP, Conary, Slackware. There's tons of them. Some people like not to use any package manager at all. Or, they use RubyGems just for downloading, but then unpack the gem into their vendor directory.
All of this cannot possibly work, if you use the gem method in your code.