This might be due to AppArmor denying the MySQL server access to most of the filesystem. You can instead use
LOAD DATA LOCAL INFILE ...
to pipe data through the MySQL client, which can read everything the executing user can.

Backtick quoting alone does not prevent MySQL column-name injection when SQL fragments are built from user input. Removing backticks before quoting makes malformed identifiers fail safely.

Checking response status in Cucumber can verify error handling and redirects during acceptance tests. Webrat and Capybara expose status information for custom step definitions.

Cucumber step for HTTP basic auth in Capybara, Rack::Test, or Selenium when visiting protected admin pages via path_to.

Offline RubyGem documentation becomes available when rubydoc.info is unavailable or slow. gem server provides a local browser for installed gems and generated docs.

I love ETags, but there’s something that annoys me: most implementations revolve around pulling a record out of a data store and only “rendering” the response if it hasn’t been modified. 

The problem with this approach is that request has already gone through most of your application stack–parsing params, authentication, authorization, a few database lookups–so ETags are only saving you render time and some bandwidth.

While working on a Sinatra-based JSON web service that gets very heavy traffic, I wanted to find a way to short-circuit...

Cucumber failures can open the current page in a browser automatically, avoiding repeated "Then show me the page" reruns and speeding up debugging.

From time to time we're convinced that an error must be very close to the network card, OS IP stack or compiler. In reality this is quite rare, so before continuing, triple-check that the issue is not located between chair and keyboard...

If you're still convinced that a in-depth analysis of network traffic might help you, go on:

• Find out the IP address the client causing trouble will come from.

• Replace 147.0.0.123 with the client address, log into your web server and run:

  `remote$ sudo tcpdump host 147.0.0.123 and port 80 -s 0 -w...

It's that simple to allow one of your Linux users to run a single command as UID 0:

1. sudo visudo
2. Add the line below to allow user 'deploy' to run /usr/bin/bundle with root privileges

deploy  ALL=NOPASSWD: /usr/bin/bundle

Ruby gem installation can fail with LoadError for mkmf when Ruby header files are missing, often resolved by installing the platform’s Ruby development package.

Convert an existing OpenSSL certificate and private key into a Java keystore for Tomcat HTTPS, avoiding JSSE configuration errors and alias mismatches.

Apache development servers can accept connections from other machines on the network. Binding Listen to 127.0.0.1 limits access to the local computer.

Mobile pages need a dedicated stylesheet and viewport settings so iPhone, iPad, and Android layouts fit small screens without awkward scaling.

Remove unused and unnecessary files from a project root with geordi clean, a cleanup command in the Geordi gem.

Deferred Ruby garbage collection can speed up RSpec examples by reducing GC overhead, though gains vary and may be negligible in newer Ruby versions.

In January this year (2010), Gmail switched to using HTTPS for everything by default. Previously it had been introduced as an option, but now all of our users use HTTPS to secure their email between their browsers and Google, all the time. In order to do this we had to deploy no additional machines and no special hardware. On our production frontend machines, SSL/TLS accounts for less than 1% of the CPU load, less than 10KB of memory per connection and less than 2% of network overhead. Many people believe that SSL takes a lot of CPU time and...

Deprecated Ruby tests can flood RSpec output with warning noise. A narrower way to quiet them avoids hiding warnings from dependencies.

Use Range#step to visit every n-th value in a Ruby range, useful for date sequences such as weekly Mondays. Rails and ActiveSupport return an array when no block is given.

Rails 2.3.8 to 2.3.10 upgrades can reduce bugs and security risk in older applications.

Apache logs behind a reverse proxy show the proxy IP instead of the original client IP, complicating troubleshooting and traffic statistics.

Check a download or page response by its MIME type in Cucumber, using Webrat or Capybara; the Selenium webdriver does not support this approach.

Exact form-field matching in Cucumber prevents false positives from partial values, while wildcards allow flexible contains-style checks.

Ruby 1.8.6 and 1.8.7 do not support default block arguments; a lambda workaround uses *args and assigns missing values manually.