Patron is a Ruby HTTP client library based on libcurl. It does not try to expose
the full “power” (read complexity) of libcurl but instead tries to provide a
sane API while taking advantage of libcurl under the hood.

Usage

First, you instantiate a Session object. You can set a few
default options on the Session instance that will be used by all subsequent
requests:

sess = Patron::Session.new
sess.timeout = 10
sess.base_url = “http://myserver.com:9900”
sess.headers[‘User-Agent’] = ‘myapp/1.0’

You can set options with a hash in the constructor:

sess = Patron::Session.new({ :timeout => 10,
:base_url => ‘http://myserver.com:9900’,
:headers => {'User-Agent’ => ‘myapp/1.0’} } )

Or the set options in a block:

sess = Patron::Session.new do |patron|
patron.timeout = 10
patron.base_url = ‘http://myserver.com:9900’
patron.headers = {'User-Agent’ => ‘myapp/1.0’}
end

Output debug log:

sess.enable_debug “/tmp/patron.debug”

The Session is used to make HTTP requests.

resp = sess.get(“/foo/bar”)

Requests return a Response object:

if resp.status < 400
puts resp.body
end

The GET, HEAD, PUT, POST and DELETE operations are all supported.

sess.put(“/foo/baz”, “some data”)
sess.delete(“/foo/baz”)

You can ship custom headers with a single request:

sess.post(“/foo/stuff”, “some data”, {“Content-Type” => “text/plain”})

Known issues

Currently, an issue is at play with OSX builds of curl which use Apple’s SecureTransport. Such builds (which Patron is linking to), are causing segfaults when performing HTTPS requests in forked subprocesses. If you need to check whether your
system is affected, run the Patron test suite by performing

$ bundle install && bundle exec rspec

in the Patron install directory. Most default curl configurations on OSX (both
the Apple-shipped version and the version available via Homebrew) are linked to
SecureTransport and are likely to be affected. This issue may also manifest in
forking webserver implementations (such as Unicorn or Passenger) and in forking
job execution engines (such as resque), so even though you may not be using
fork() directly your server engine might be doing it for you.

To circumvent the issue, you need to build curl with OpenSSL via homebrew.
When doing so, curl will use openssl as it’s SSL driver. You also need to
change the Patron compile flag:

$ brew install curl –with-openssl && \
gem install patron –with-curl-config=/usr/local/opt/curl/bin/curl-config

You can also save this parameter for all future Bundler-driven gem installs by
setting this flag in Bundler proper:

$ bundle config build.patron –with-curl-config=/usr/local/opt/curl/bin/curl-config

Threading

By itself, the Patron::Session objects are not thread safe (each Session holds a single curl_state pointer
during the request/response cycle). At this time, Patron has no support for curl_multi_* family of functions
for doing concurrent requests. However, the actual code that interacts with libCURL does unlock the RVM GIL,
so using multiple Session objects in different threads is possible with a high degree of concurrency.
For sharing a resource of sessions between threads we recommend using the excellent connection_pool gem by Mike Perham.

patron_pool = ConnectionPool.new(size: 5, timeout: 5) { Patron::Session.new }
patron_pool.with do |session|
session.get(…)
end

Requirements

Patron uses encoding features of Ruby, so you need at least Ruby 1.9. Also, a
recent version of libCURL is required. We recommend at least 7.19.4 because
it supports limiting the protocols,
and that is very important for security - especially if you follow redirects.

On OSX the provided libcurl is sufficient. You will have to install the libcurl
development packages on Debian or Ubuntu. Other Linux systems are probably
similar. For Windows we do not have an established build instruction at the moment, unfortunately.

Installation

sudo gem install patron

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