THE EXPERTLS VOICE® IN OPEN SOURCE. Practical. Ruby Gems Using RubyGems in Your Code. □CHAPTER 21 Writing PDFs with pdf-writer. Practical Ruby Gems is a comprehensive guide to utilizing and creating Ruby Using RubyGems. Front Matter. Pages PDF · What Is RubyGems? Pages David Berube. Practical Ruby Gems . □CHAPTER 21 Writing PDFs with pdf- writer. . Updating Your RubyGems System After You've Installed It.

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Practical Ruby Gems. Each of these also comes complete with actual use cases and code examples that readers can immediately use in their own projects. Source code for 'Practical Ruby Gems' by David Berube - Apress/practical-ruby- gems. Practical Ruby Gems book. Read 3 reviews from the world's largest community for readers. Practical Ruby Gems is a comprehensive guide to utilizing and cr.

Practical Ruby Gems

As a result, such gems typically come in multiple varieties: a special binary distribution for Windows machines, and a source variety that is portable and will typically work on most Unix-like systems, such as Linux or Mac OS X.

Installing RDoc documentation for mongrel As you can see, the gem command presents you with a list of options.

The ruby versions work anywhere that has a C compiler; the mswin32 versions work only under Windows. The reason for this is that binary gems often require an extra step, such as running a postinstall. Since only Windows typically has difficulty compiling binary gems, the options are usually a Ruby version—which would contain the compilable source—and a Win32 version.

About this book

Under Win32 you would download the binary gem, uncompress it, and then use a command like this Rmagick install command see Chapter 25 for more details to install the gem from the file: gem install RMagick-winx. Binary gems may have other issues, since they are compiled for a certain version of Ruby.

Using source gems and compiling them yourself avoids such issues, and you should always compile from source if possible. If you have the MySQL client installed properly, the install should go smoothly. Cancel installation 2 Building native extensions.

This could take a while As you can see, the extension compiles without much difficulty.

Practical Ruby Gems

There are quite a few lines of output and a number of commands run automatically, but the only command we typed in was 2—selecting the pure Ruby source version. Debugging Source-Gem Problems Source gems can sometimes pose difficulties on any operating system. Typically, a missing system dependency will result in an error message being displayed; a quick Google search will often reveal the source of the difficulties.

There may also be a system compatibility issue; most source gems will not compile on every platform and environment.

Windows tends to be particularly tricky, even if a development environment is installed. If your platform supports it, you may be able to use a binary gem. In some cases, you may want to directly edit the gem source to work on your platform. Debugging RubyGems Sometimes a gem that was working with your code stops working.

Often this is a versioning issue: Did you update the gem involved? If not, did you update another gem that updated the first gem?

If so, you can roll back to the previous version. Alternatively, because RubyGems does not, by default, remove old versions of gems, you can instruct RubyGems to use an older version instead; see Chapter 1 for details.

Even if this is not the case, the gem involved may depend on another gem version; the latest version of Rails, for example, may have broken a plugin that your Rails application uses. You may also have an issue with locally patched or corrupted gems. RubyGems includes checksums on all gems, so you can see if something has changed. This display shows all gems are error-free, but if a gem source file had been edited or if a file had been corrupted, the alien check would have displayed an error, which you could correct by installing the gem again using the gem install command, which should rewrite all of the files with new versions.

Gem versioning is very useful—particularly because of the ever-changing nature of the Ruby community.

See a Problem?

Many gems are changing very fast, and sometimes interfaces change as well. In some ways, this is good—it means that software is improving.

Creating Graphical User Interfaces with fxruby Retrieving Stock Quotes with YahooFinance Parsing HTML with hpricot Parsing CSV with fastercsv Multiple Dispatch with multi Serving Web Applications with mongrel Transferring Files Securely with net-sftp Executing Commands on Remote Servers with net-ssh Validating Credit Cards with creditcard Writing PDFs with pdf-writer This book is ideal for Ruby programmers as well as web developers who use Rails and wish to extend the functionality of their projects.

You'll get a prime selection of 34 of the best and most useful Gems, which makes up the core of this book.

Each of these also comes complete with actual use cases and code examples that you can use immediately in your own projects. Skip to main content Skip to table of contents.

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Front Matter Pages i-xv. Front Matter Pages What Is RubyGems? Pages Installing RubyGems.

Practical Ruby Gems

Using RubyGems in Your Code. Managing Installed Gem Versions. Data Access with the ActiveRecord Gem. Creating Web Applications with Camping. Creating Command-Line Utilities with cmdparse.Zvr added it May 16, To find a gem that fits our criteria, we could do a Web search to determine if there are any gems with the functionality we need.

Those gems must be compiled before they are used. Parsing Feeds with feedtools. There are seven constraints, which are detailed in Table