Curb - Libcurl bindings for Ruby

Curb (probably CUrl-RuBy or something) provides Ruby-language bindings for the libcurl(3), a fully-featured client-side URL transfer library. cURL and libcurl live at http://curl.haxx.se/ .

Curb is a work-in-progress, and currently only supports libcurl's 'easy' and 'multi' modes.

License

You will need

A working Ruby installation (1.8+, tested with 1.8.6, 1.8.7, 1.9.1, and 1.9.2)
A working (lib)curl installation, with development stuff (7.5+, tested with 7.19.x)
A sane build environment (e.g. gcc, make)

Installation...

... will usually be as simple as:

$ gem install curb

Or, if you downloaded the archive:

$ rake install

If you have a wierd setup, you might need extconf options. In this case, pass them like so:

$ rake install EXTCONF_OPTS='--with-curl-dir=/path/to/libcurl --prefix=/what/ever'

Curb is tested only on GNU/Linux x86 and Mac OSX - YMMV on other platforms. If you do use another platform and experience problems, or if you can expand on the above instructions, please report the issue at http://github.com/taf2/curb/issues

On Ubuntu, the dependencies can be satisfied by installing the following packages:

$ sudo apt-get install libcurl3 libcurl3-gnutls libcurl4-openssl-dev

Curb has fairly extensive RDoc comments in the source. You can build the documentation with:

$ rake doc

Usage & examples

Curb provides two classes:

Curl::Easy - simple API, for day-to-day tasks.
Curl::Multi - more advanced API, for operating on multiple URLs simultaneously.

Simple fetch via HTTP:

c = Curl::Easy.perform("http://www.google.co.uk")
puts c.body_str

Same thing, more manual:

c = Curl::Easy.new("http://www.google.co.uk")
c.perform
puts c.body_str

Additional config:

Curl::Easy.perform("http://www.google.co.uk") do |curl| 
  curl.headers["User-Agent"] = "myapp-0.0"
  curl.verbose = true
end

Same thing, more manual:

c = Curl::Easy.new("http://www.google.co.uk") do |curl| 
  curl.headers["User-Agent"] = "myapp-0.0"
  curl.verbose = true
end

c.perform

HTTP basic authentication:

c = Curl::Easy.new("http://github.com/")
c.http_auth_types = :basic
c.username = 'foo'
c.password = 'bar'
c.perform

Supplying custom handlers:

c = Curl::Easy.new("http://www.google.co.uk")

c.on_body { |data| print(data) }
c.on_header { |data| print(data) }

c.perform

Reusing Curls:

c = Curl::Easy.new

["http://www.google.co.uk", "http://www.ruby-lang.org/"].map do |url|
  c.url = url
  c.perform
  c.body_str
end

HTTP POST form:

c = Curl::Easy.http_post("http://my.rails.box/thing/create",
                         Curl::PostField.content('thing[name]', 'box'),
                         Curl::PostField.content('thing[type]', 'storage'))

HTTP POST file upload:

c = Curl::Easy.new("http://my.rails.box/files/upload")
c.multipart_form_post = true
c.http_post(Curl::PostField.file('myfile.rb'))

Multi Interface (Basic HTTP GET):

# make multiple GET requests
easy_options = {:follow_location => true}
multi_options = {:pipeline => true}

Curl::Multi.get('url1','url2','url3','url4','url5', easy_options, multi_options) do|easy|
  # do something interesting with the easy response
  puts easy.last_effective_url
end

Multi Interface (Basic HTTP POST):

# make multiple POST requests
easy_options = {:follow_location => true, :multipart_form_post => true}
multi_options = {:pipeline => true}

url_fields = [
  { :url => 'url1', :post_fields => {'f1' => 'v1'} },
  { :url => 'url2', :post_fields => {'f1' => 'v1'} },
  { :url => 'url3', :post_fields => {'f1' => 'v1'} }
]

Curl::Multi.post(url_fields, easy_options, multi_options) do|easy|
  # do something interesting with the easy response
  puts easy.last_effective_url
end

Multi Interface (Advanced):

responses = {}
requests = ["http://www.google.co.uk/", "http://www.ruby-lang.org/"]
m = Curl::Multi.new
# add a few easy handles
requests.each do |url|
  responses[url] = ""
  c = Curl::Easy.new(url) do|curl|
    curl.follow_location = true
    curl.on_body{|data| responses[url] << data; data.size }
    curl.on_success {|easy| puts "success, add more easy handles" }
  end
  m.add(c)
end

m.perform do
  puts "idling... can do some work here"
end

requests.each do|url|
  puts responses[url]
end

Easy Callbacks

on_success: is called when the response code is 20x on_failure: is called when the response code is not success, including redirects e.g. 30x on_complete: is called in all cases.

rthbound/curb