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Net::HTTP provides a rich library which can be used to build HTTP user-agents. For more details about HTTP see [RFC2616](www.ietf.org/rfc/rfc2616.txt)
Net::HTTP is designed to work closely with URI. URI::HTTP#host, URI::HTTP#port and URI::HTTP#request_uri are designed to work with Net::HTTP.
If you are only performing a few GET requests you should try OpenURI.
All examples assume you have loaded Net::HTTP with:
require 'net/http'
This will also require ‘uri’ so you don’t need to require it separately.
The Net::HTTP methods in the following section do not persist connections. They are not recommended if you are performing many HTTP requests.
Net::HTTP.get('example.com', '/index.html') # => String
uri = URI('http://example.com/index.html?count=10') Net::HTTP.get(uri) # => String
uri = URI('http://example.com/index.html') params = { :limit => 10, :page => 3 } uri.query = URI.encode_www_form(params) res = Net::HTTP.get_response(uri) puts res.body if res.is_a?(Net::HTTPSuccess)
uri = URI('http://www.example.com/search.cgi') res = Net::HTTP.post_form(uri, 'q' => 'ruby', 'max' => '50') puts res.body
uri = URI('http://www.example.com/search.cgi') res = Net::HTTP.post_form(uri, 'q' => ['ruby', 'perl'], 'max' => '50') puts res.body
The following example code can be used as the basis of a HTTP user-agent which can perform a variety of request types using persistent connections.
uri = URI('http://example.com/some_path?query=string') Net::HTTP.start(uri.host, uri.port) do |http| request = Net::HTTP::Get.new uri.request_uri response = http.request request # Net::HTTPResponse object end
Net::HTTP.start immediately creates a connection to an HTTP server which is kept open for the duration of the block. The connection will remain open for multiple requests in the block if the server indicates it supports persistent connections.
The request types Net::HTTP supports are listed below in the section “HTTP Request Classes”.
If you wish to re-use a connection across multiple HTTP requests without automatically closing it you can use ::new instead of ::start. request will automatically open a connection to the server if one is not currently open. You can manually close the connection with finish.
uri = URI('http://example.com/index.html') res = Net::HTTP.get_response(uri) # Headers res['Set-Cookie'] # => String res.get_fields('set-cookie') # => Array res.to_hash['set-cookie'] # => Array puts "Headers: #{res.to_hash.inspect}" # Status puts res.code # => '200' puts res.message # => 'OK' puts res.class.name # => 'HTTPOK' # Body puts res.body if res.response_body_permitted?
Each Net::HTTPResponse object belongs to a class for its response code.
For example, all 2XX responses are instances of a Net::HTTPSuccess subclass, a 3XX response is an instance of a Net::HTTPRedirection subclass and a 200 response is an instance of the Net::HTTPOK class. For details of response classes, see the section “HTTP Response Classes” below.
Using a case statement you can handle various types of responses properly:
def fetch(uri_str, limit = 10) # You should choose a better exception. raise ArgumentError, 'too many HTTP redirects' if limit == 0 response = Net::HTTP.get_response(URI(uri_str)) case response when Net::HTTPSuccess then response when Net::HTTPRedirection then location = response['location'] warn "redirected to #{location}" fetch(location, limit - 1) else response.value end end print fetch('http://www.ruby-lang.org')
A POST can be made using the Net::HTTP::Post request class. This example creates a urlencoded POST body:
uri = URI('http://www.example.com/todo.cgi') req = Net::HTTP::Post.new(uri.path) req.set_form_data('from' => '2005-01-01', 'to' => '2005-03-31') res = Net::HTTP.start(uri.hostname, uri.port) do |http| http.request(req) end case res when Net::HTTPSuccess, Net::HTTPRedirection # OK else res.value end
At this time Net::HTTP does not support multipart/form-data. To send multipart/form-data use Net::HTTPGenericRequest#body= and Net::HTTPHeader#content_type=:
req = Net::HTTP::Post.new(uri.path) req.body = multipart_data req.content_type = 'multipart/form-data'
Other requests that can contain a body such as PUT can be created in the same way using the corresponding request class (Net::HTTP::Put).
The following example performs a conditional GET using the If-Modified-Since header. If the files has not been modified since the time in the header a Not Modified response will be returned. See RFC 2616 section 9.3 for further details.
uri = URI('http://example.com/cached_response') file = File.stat 'cached_response' req = Net::HTTP::Get.new(uri.request_uri) req['If-Modified-Since'] = file.mtime.rfc2822 res = Net::HTTP.start(uri.hostname, uri.port) {|http| http.request(req) } open 'cached_response', 'w' do |io| io.write res.body end if res.is_a?(Net::HTTPSuccess)
Basic authentication is performed according to [RFC2617](www.ietf.org/rfc/rfc2617.txt)
uri = URI('http://example.com/index.html?key=value') req = Net::HTTP::Get.new(uri.request_uri) req.basic_auth 'user', 'pass' res = Net::HTTP.start(uri.hostname, uri.port) {|http| http.request(req) } puts res.body
By default Net::HTTP reads an entire response into memory. If you are handling large files or wish to implement a progress bar you can instead stream the body directly to an IO.
uri = URI('http://example.com/large_file') Net::HTTP.start(uri.host, uri.port) do |http| request = Net::HTTP::Get.new uri.request_uri http.request request do |response| open 'large_file', 'w' do |io| response.read_body do |chunk| io.write chunk end end end end
HTTPS is enabled for an HTTP connection by Net::HTTP#use_ssl=.
uri = URI('https://secure.example.com/some_path?query=string') Net::HTTP.start(uri.host, uri.port, :use_ssl => uri.scheme == 'https').start do |http| request = Net::HTTP::Get.new uri.request_uri response = http.request request # Net::HTTPResponse object end
In previous versions of ruby you would need to require ‘net/https’ to use HTTPS. This is no longer true.
Net::HTTP::Proxy has the same methods as Net::HTTP but its instances always connect via the proxy instead of directly to the given host.
proxy_addr = 'your.proxy.host' proxy_port = 8080 Net::HTTP::Proxy(proxy_addr, proxy_port).start('www.example.com') {|http| # always connect to your.proxy.addr:8080 }
Net::HTTP::Proxy returns a Net::HTTP instance when proxy_addr is nil so there is no need for conditional code.
See Net::HTTP::Proxy for further details and examples such as proxies that require a username and password.
Here is the HTTP request class hierarchy.
Here is HTTP response class hierarchy. All classes are defined in Net module and are subclasses of Net::HTTPResponse.
For unhandled HTTP extensions
1xx
100
101
2xx
200
201
202
203
204
205
206
3xx
300
301
302
303
304
305
307
4xx
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
5xx
500
501
502
503
504
505
There is also the Net::HTTPBadResponse exception which is raised when there is a protocol error.
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