Class: Miasma::Types::Api

Inherits:
Object
  • Object
show all
Includes:
Bogo::Logger::Helpers, Utils::Lazy, Utils::Memoization
Defined in:
lib/miasma/types/api.rb

Overview

Remote API connection

Constant Summary collapse

VALID_REQUEST_RETRY_METHODS =

HTTP request methods that are allowed retry

[:get, :head]
MAX_REQUEST_RETRIES =

Maximum allowed HTTP request retries (for non-HTTP related errors)

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Instance Method Summary collapse

Constructor Details

#initialize(creds) ⇒ self

Create new API connection



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# File 'lib/miasma/types/api.rb', line 25

def initialize(creds)
  custom_setup(creds)
  if creds.is_a?(Hash)
    load_data(creds)
  else
    raise TypeError, "Expecting `credentials` to be of type `Hash`. " \
          "Received: `#{creds.class}`"
  end
  after_setup(creds)
  connect
end

Instance Method Details

#after_setup(creds) ⇒ TrueClass

Simple hook for concrete APIs to make adjustments after attribute population and prior to connection



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# File 'lib/miasma/types/api.rb', line 51

def after_setup(creds)
  true
end

#api_for(type) ⇒ Api

Build new API for specified type using current provider / creds



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# File 'lib/miasma/types/api.rb', line 71

def api_for(type)
  memoize(type) do
    Miasma.api(
      Smash.new(
        :type => type,
        :provider => provider,
        :credentials => attributes,
      )
    )
  end
end

#connect ⇒ self

Connect to the remote API



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# File 'lib/miasma/types/api.rb', line 63

def connect
  self
end

#connection ⇒ HTTP 



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# File 'lib/miasma/types/api.rb', line 84

def connection
  HTTP.headers("User-Agent" => "miasma/v#{Miasma::VERSION}")
end

#custom_setup(creds) ⇒ TrueClass

Simple hook for concrete APIs to make adjustments prior to initialization and connection



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# File 'lib/miasma/types/api.rb', line 42

def custom_setup(creds)
  true
end

#endpoint ⇒ String 



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# File 'lib/miasma/types/api.rb', line 89

def endpoint
  "http://api.example.com"
end

#format_response(result, extract_body = true) ⇒ Smash

Makes best attempt at formatting response



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# File 'lib/miasma/types/api.rb', line 188

def format_response(result, extract_body = true)
  extracted_headers = Smash[result.headers.map { |k, v| [Utils.snake(k), v] }]
  if extract_body
    logger.debug("extracting HTTP response body")
    body_content = result.body.to_s
    body_content.encode!("UTF-8", "binary",
                         :invalid => :replace,
                         :undef => :replace,
                         :replace => "")
    if extracted_headers[:content_type].to_s.include?("json")
      logger.debug("unpacking HTTP response body using JSON")
      extracted_body = from_json(body_content) || body_content
    elsif extracted_headers[:content_type].to_s.include?("xml")
      logger.debug("unpacking HTTP response body using XML")
      extracted_body = from_xml(body_content) || body_content
    else
      logger.debug("unpacking HTTP response body using best effort")
      extracted_body = from_json(body_content) ||
                       from_xml(body_content) ||
                       body_content
    end
  end
  unless extracted_body
    # @note if body is over 100KB, do not extract
    if extracted_headers[:content_length].to_i < 102400
      logger.warn("skipping body extraction and formatting due to size")
      extracted_body = result.body.to_s
    else
      extracted_body = result.body
    end
  end
  Smash.new(
    :response => result,
    :headers => extracted_headers,
    :body => extracted_body,
  )
end

#from_json(string) ⇒ Hash, ...

Convert from JSON



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# File 'lib/miasma/types/api.rb', line 230

def from_json(string)
  begin
    MultiJson.load(string).to_smash
  rescue MultiJson::ParseError => err
    logger.error("failed to load JSON string - #{err.class}: #{err}")
    logger.debug("JSON string load failure: #{string.inspect}")
    logger.debug("JSON error - #{err.class}: #{err}\n#{err.backtrace.join("\n")}")
    nil
  end
end

#from_xml(string) ⇒ Hash, ...

Convert from JSON



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# File 'lib/miasma/types/api.rb', line 245

def from_xml(string)
  begin
    MultiXml.parse(string).to_smash
  rescue MultiXml::ParseError => err
    logger.error("failed to load XML string - #{err.class}: #{err}")
    logger.debug("XML string load failure: #{string.inspect}")
    logger.debug("XML error - #{err.class}: #{err}\n#{err.backtrace.join("\n")}")
    nil
  end
end

#make_request(connection, http_method, request_args) ⇒ HTTP::Response

Note:

this is mainly here for concrete APIs to override if things need to be done prior to the actual request (like signature generation)

Perform request



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# File 'lib/miasma/types/api.rb', line 178

def make_request(connection, http_method, request_args)
  logger.debug("making #{http_method.to_s.upcase} request - #{request_args.inspect}")
  connection.send(http_method, *request_args)
end

#perform_request_retry(exception) ⇒ TrueClass, FalseClass

Determine if a retry on the request should be performed



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# File 'lib/miasma/types/api.rb', line 165

def perform_request_retry(exception)
  true
end

#provider ⇒ Symbol 



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# File 'lib/miasma/types/api.rb', line 56

def provider
  Utils.snake(self.class.to_s.split("::").last).to_sym
end

#request(args) ⇒ Smash

Perform request to remote API

Options Hash (args):

  • :method (String, Symbol) —

    HTTP request method

  • :path (String) —

    request path

  • :expects (Integer, Array<Integer>) —

    expected response status code

  • :disable_body_extraction (TrueClass, FalseClass) —

    do not auto-parse response body



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# File 'lib/miasma/types/api.rb', line 102

def request(args)
  args = args.to_smash
  http_method = args.fetch(:method, "get").to_s.downcase.to_sym
  unless HTTP::Request::METHODS.include?(http_method)
    raise ArgumentError.new "Invalid request method provided!"
  end
  request_args = [].tap do |ary|
    _endpoint = args.delete(:endpoint) || endpoint
    ary.push(File.join(_endpoint, args[:path].to_s))
    options = {}.tap do |opts|
      [:form, :params, :json, :body].each do |key|
        opts[key] = args[key] if args[key]
      end
    end
    ary.push(options) unless options.empty?
  end
  if args[:headers]
    _connection = connection.headers(args[:headers])
    args.delete(:headers)
  else
    _connection = connection
  end
  result = retryable_request(http_method) do
    res = make_request(_connection, http_method, request_args)
    unless [args.fetch(:expects, 200)].flatten.compact.map(&:to_i).include?(res.code)
      raise Error::ApiError::RequestError.new(res.reason, :response => res)
    end
    res
  end
  format_response(result, !args[:disable_body_extraction])
end

#retryable_allowed?(http_method) ⇒ TrueClass, FalseClass

Determine if request type is allowed to be retried



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# File 'lib/miasma/types/api.rb', line 157

def retryable_allowed?(http_method)
  VALID_REQUEST_RETRY_METHODS.include?(http_method)
end

#retryable_request(http_method) { ... } ⇒ Object

If HTTP request method is allowed to be retried then retry request on non-response failures. Otherwise just re-raise immediately

Yields:

  • request to be retried if allowed



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# File 'lib/miasma/types/api.rb', line 141

def retryable_request(http_method, &block)
  Bogo::Retry.build(
    data.fetch(:retry_type, :exponential),
    :max_attempts => retryable_allowed?(http_method) ?
      data.fetch(:retry_max, MAX_REQUEST_RETRIES) : 0,
    :wait_interval => data[:retry_interval],
    :ui => data[:retry_ui],
    :auto_run => false,
    &block
  ).run! { |e| perform_request_retry(e) }
end