aitch

Aitch

A simple HTTP client.

Features:

• Supports Gzip|Deflate response
• Automatically parses JSON, HTML and XML responses
• Automatically follows redirect

Installation

Add this line to your application's Gemfile:

gem "aitch"

And then execute:

$ bundle

Or install it yourself as:

$ gem install aitch

Usage

Configuration

These are the default settings:

Aitch.configure do |config|
  # Set request timeout.
  config.timeout = 5

  # Set default headers.
  config.default_headers = {}

  # Set follow redirect.
  config.follow_redirect = true

  # Set redirection limit.
  config.redirect_limit = 5

  # Set the user agent.
  config.user_agent = "Aitch/0.0.1 (http://rubygems.org/gems/aitch)"

  # Set the logger.
  config.logger = nil

  # Set the base url.
  config.base_url = nil
end

Requests

Performing requests:

response = Aitch.get("http://example.org", params, headers, options)
           Aitch.post("http://example.org", params, headers, options)
           Aitch.put("http://example.org", params, headers, options)
           Aitch.patch("http://example.org", params, headers, options)
           Aitch.delete("http://example.org", params, headers, options)
           Aitch.options("http://example.org", params, headers, options)
           Aitch.trace("http://example.org", params, headers, options)
           Aitch.head("http://example.org", params, headers, options)

You can also use a DSL.

response = Aitch.get do
  url "http://simplesideias.com.br"
  headers Authorization: "Token token=abc"
  options follow_redirect: false
  params a: 1, b: 2
end

Finally, you can use keyword arguments:

Aitch.get(
  url: "http://example.org",
  params: {a: 1, b: 2},
  headers: {Authorization: "Token token=abc"},
  options: {follow_redirect: false}
)

Response

The response object:

response.html?
response.xml?
response.json?
response.content_type
response.headers
response.location
response.success?         # status >= 200 && status <= 399
response.redirect?        # status 3xx
response.error?           # status 4xx or 5xx
response.error            # response error
response.body             # returned body
response.data             # Parsed response body

Parsing JSON, XML and HTML with Nokogiri

If your response is a JSON, XML or a HTML content type, we'll automatically convert the response into the appropriate object.

response = Aitch.get("http://simplesideias.com.br")

response.data.class
#=> Nokogiri::HTML::Document

response.data.css("h1").size
#=> 69

response = Aitch.get("http://simplesideias.com.br/feed")

response.data.class
#=> Nokogiri::XML::Document

response.data.css("item").size
#=> 10

response = Aitch.get("https://api.github.com/users/fnando")
response.data.class
#=> Hash

response.data["login"]
#=> fnando

Following redirects

The configuration:

Aitch.configure do |config|
  config.follow_redirect = true
  config.redirect_limit = 10
end

The request:

Aitch.get("http://example.org")

If the redirect limit is exceeded, then the Aitch::TooManyRedirectsError exception is raised.

Basic auth

Setting basic auth credentials:

response = Aitch.get do
  url "http://restrict.example.org/"
  options user: "john", password: "test"
end

Setting custom headers

Aitch.get do
  url "http://example.org"
  headers "User-Agent" => "MyBot/1.0.0"
end

The header value can be a callable object.

Aitch.configure do |config|
  config.default_headers = {
    "Authorization" => -> { "Token token=#{ENV.fetch("API_TOKEN")}" }
  }
end

Creating namespaced requests

Sometimes you don't want to use the global settings (maybe you're building a lib). In this case, you can instantiate the namespace.

Request = Aitch::Namespace.new
Request.configure do |config|
  config.user_agent = "MyLib/1.0.0"
end

Request.get("http://example.org")

Validating responses

When you know the kind of response you're expecting, you can validate it by specifying the expect option.

Aitch.get do
  url "http://example.org"
  options expect: 200
end

If this request receives anything other than 200, it will raise a Aitch::StatusCodeError exception.

Expect(200 OK) <=> Actual(404 Not Found)

You can also provide a list of accepted statuses, like expect: [200, 201].

Response Parsers

You can register new response parsers by using Aitch::ResponseParser.register(name, parser), where parser must implement the methods match?(content_type) and load(response_body). This is how you could load CSV values.

require "csv"

module CSVParser
  def self.type
    :csv
  end

  def self.match?(content_type)
    content_type.to_s =~ /csv/
  end

  def self.load(source)
    CSV.parse(source.to_s)
  end
end

Aitch::ResponseParser.prepend(:csv, CSVParser)

The default behavior is returning the response body. You can replace it as the following:

module DefaultParser
  def self.type
    :default
  end

  def self.match?(content_type)
    true
  end

  def self.load(source)
    source.to_s
  end
end

# You should use append here, to ensure
# that is that last parser on the list.
Aitch::ResponseParser.append(:default, DefaultParser)

Aitch comes with response parsers for HTML, XML and JSON.

By default, the JSON parser will be JSON. To set it to something else, use Aitch::ResponseParser::JSONParser.engine.

require "oj"
Aitch::ResponseParser::JSONParser.engine = Oj

Setting the base url

When you're creating a wrapper for an API, usually the hostname is the same for the whole API. In this case, you can avoid having to pass it around all the time by setting Aitch::Configuration#base_url. This option is meant to be used when you instantiate a new namespace.

Client = Aitch::Namespace.new

Client.configure do |config|
  config.base_url = "https://api.example.com"
end

Client.get("/users")

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request