This Gem has the worst name in the history of SEO. But perhaps we can fix that if we all refer to it as "The HTTP Gem". Entering that phrase into Google actually pulls it up as #1 for me!
The HTTP Gem is an easy-to-use client library for making requests from Ruby. It uses a simple method chaining system for building requests, similar to libraries like JQuery or Python's Requests.
Add this line to your application's Gemfile:
gem 'http'
And then execute:
$ bundle
Or install it yourself as:
$ gem install http
Inside of your Ruby program do:
require 'http'
...to pull it in as a dependency.
Let's start with getting the response body as a string:
>> HTTP.get("https://www.google.com").to_s
=> "<html><head><meta http-equiv=\"content-type\" content=..."That's all it takes! To obtain an HTTP::Response object instead of the response
body, all we have to do is omit the #to_s on the end:
>> HTTP.get("https://www.google.com")
=> #<HTTP/1.0 200 OK @headers={"Content-Type"=>"text/html; charset=UTF-8", "Date"=>"Fri, ...>
=> #<HTTP::Response/1.1 200 OK @headers={"Content-Type"=>"text/html; ...>We can also obtain an HTTP::ResponseBody object for this response:
>> HTTP.get("https://www.google.com").body
=> #<HTTP::ResponseBody:814d7aac @streaming=false>The response body can be streamed with HTTP::ResponseBody#readpartial:
>> HTTP.get("https://www.google.com").body.readpartial
=> "<!doctype html><html "In practice you'll want to bind the HTTP::ResponseBody to a local variable (e.g. "body") and call readpartial on it repeatedly until it returns nil.
Making POST requests is simple too. Want to POST a form?
HTTP.post "https://example.com/resource", :form => {:foo => "42"}Making GET requests with query string parameters is as simple.
HTTP.get "https://example.com/resource", :params => {:foo => "bar"}Want to POST with a specific body, JSON for instance?
HTTP.post "https://example.com/resource", :body => JSON.dump(:foo => '42')It's easy!
The HTTP gem uses the concept of chaining to simplify requests. Let's say you want to get the latest commit of this library from Github in JSON format. One way we could do this is by tacking a filename on the end of the URL:
HTTP.get "https://github.com/tarcieri/http/commit/HEAD.json"The Github API happens to support this approach, but really this is a bit of a hack that makes it easy for people typing URLs into the address bars of browsers to perform the act of content negotiation. Since we have access to the full, raw power of HTTP, we can perform content negotiation the way HTTP intends us to, by using the Accept header:
HTTP.with_headers(:accept => 'application/json').
get("https://github.com/tarcieri/http/commit/HEAD")This requests JSON from Github. Github is smart enough to understand our request and returns a response with Content-Type: application/json. If you happen to have a library loaded which defines the JSON constant and implements JSON.parse, the HTTP gem will attempt to parse the JSON response.
Shorter aliases exists for HTTP.with_headers:
HTTP.with(:accept => 'application/json').
get("https://github.com/tarcieri/http/commit/HEAD")
HTTP[:accept => 'application/json'].
get("https://github.com/tarcieri/http/commit/HEAD")As important a concept as content negotiation is to HTTP, it sure should be easy, right? But usually it's not, and so we end up adding ".json" onto the ends of our URLs because the existing mechanisms make it too hard. It should be easy:
HTTP.accept('application/json').
get("https://github.com/tarcieri/http/commit/HEAD")This adds the appropriate Accept header for retrieving a JSON response for the given resource.
The HTTP Gem makes it simple to make multiple concurrent HTTP requests from a Celluloid::IO actor. Here's a parallel HTTP fetcher with the HTTP Gem and Celluloid::IO:
require 'celluloid/io'
require 'http'
class HttpFetcher
include Celluloid::IO
def fetch(url)
HTTP.get(url, socket_class: Celluloid::IO::TCPSocket).response
end
endThere's a little more to it, but that's the core idea!
- Fork the HTTP gem on github
- Make your changes and send me a pull request
- If I like them I'll merge them
- If I've accepted a patch, feel free to ask for a commit bit!
Copyright (c) 2014 Tony Arcieri. See LICENSE.txt for further details.