google-api-ruby-client/lib/google/api_client.rb

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# Copyright 2010 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
require 'httpadapter'
require 'json'
require 'stringio'
require 'google/api_client/errors'
require 'google/api_client/environment'
require 'google/api_client/discovery'
require 'google/api_client/reference'
require 'google/api_client/result'
module Google
# TODO(bobaman): Document all this stuff.
##
# This class manages APIs communication.
class APIClient
##
# Creates a new Google API client.
#
# @param [Hash] options The configuration parameters for the client.
# @option options [Symbol, #generate_authenticated_request] :authorization
# (:oauth_1)
# The authorization mechanism used by the client. The following
# mechanisms are supported out-of-the-box:
# <ul>
# <li><code>:two_legged_oauth_1</code></li>
# <li><code>:oauth_1</code></li>
# <li><code>:oauth_2</code></li>
# </ul>
# @option options [String] :host ("www.googleapis.com")
# The API hostname used by the client. This rarely needs to be changed.
# @option options [String] :application_name
# The name and version of the application using the client. This should
# be given in the form `"{name}/{version}"`.
# @option options [String] :user_agent
# ("{app_name} google-api-ruby-client/{version} {os_name}/{os_version}")
# The user agent used by the client. Most developers will want to
# leave this value alone and use the `:application_name` option instead.
def initialize(options={})
# Normalize key to String to allow indifferent access.
options = options.inject({}) do |accu, (key, value)|
accu[key.to_s] = value
accu
end
# Almost all API usage will have a host of 'www.googleapis.com'.
self.host = options["host"] || 'www.googleapis.com'
# Most developers will want to leave this value alone and use the
# application_name option.
self.user_agent = options["user_agent"] || (
(options["application_name"] || '')
'google-api-ruby-client/' + VERSION::STRING +
' ' + ENV::OS_VERSION
).strip
# The writer method understands a few Symbols and will generate useful
# default authentication mechanisms.
self.authorization = options["authorization"] || :oauth_2
# The HTTP adapter controls all of the HTTP traffic the client generates.
# By default, Net::HTTP is used, but adding support for other clients
# is trivial.
if options["http_adapter"]
self.http_adapter = options["http_adapter"]
else
require 'httpadapter/adapters/net_http'
# NOTE: Do not rely on this default value, as it may change
self.http_adapter = HTTPAdapter::NetHTTPAdapter.new
end
@discovery_uris = {}
@discovery_documents = {}
@discovered_apis = {}
return self
end
##
# Returns the authorization mechanism used by the client.
#
# @return [#generate_authenticated_request] The authorization mechanism.
attr_reader :authorization
##
# Sets the authorization mechanism used by the client.
#
# @param [#generate_authenticated_request] new_authorization
# The new authorization mechanism.
def authorization=(new_authorization)
case new_authorization
when :oauth_1, :oauth
require 'signet/oauth_1/client'
# NOTE: Do not rely on this default value, as it may change
new_authorization = Signet::OAuth1::Client.new(
:temporary_credential_uri =>
'https://www.google.com/accounts/OAuthGetRequestToken',
:authorization_uri =>
'https://www.google.com/accounts/OAuthAuthorizeToken',
:token_credential_uri =>
'https://www.google.com/accounts/OAuthGetAccessToken',
:client_credential_key => 'anonymous',
:client_credential_secret => 'anonymous'
)
when :two_legged_oauth_1, :two_legged_oauth
require 'signet/oauth_1/client'
# NOTE: Do not rely on this default value, as it may change
new_authorization = Signet::OAuth1::Client.new(
:client_credential_key => nil,
:client_credential_secret => nil,
:two_legged => true
)
when :oauth_2
require 'signet/oauth_2/client'
# NOTE: Do not rely on this default value, as it may change
new_authorization = Signet::OAuth2::Client.new(
:authorization_uri =>
'https://accounts.google.com/o/oauth2/auth',
:token_credential_uri =>
'https://accounts.google.com/o/oauth2/token'
)
when nil
# No authorization mechanism
else
if !new_authorization.respond_to?(:generate_authenticated_request)
raise TypeError,
'Expected authorization mechanism to respond to ' +
'#generate_authenticated_request.'
end
end
@authorization = new_authorization
return @authorization
end
##
# Returns the HTTP adapter used by the client.
#
# @return [HTTPAdapter]
# The HTTP adapter object. The object must include the
# HTTPAdapter module and conform to its interface.
attr_reader :http_adapter
##
# Returns the HTTP adapter used by the client.
#
# @return [HTTPAdapter]
# The HTTP adapter object. The object must include the
# HTTPAdapter module and conform to its interface.
def http_adapter=(new_http_adapter)
if new_http_adapter.kind_of?(HTTPAdapter)
@http_adapter = new_http_adapter
else
raise TypeError, "Expected HTTPAdapter, got #{new_http_adapter.class}."
end
end
##
# The API hostname used by the client.
#
# @return [String]
# The API hostname. Should almost always be 'www.googleapis.com'.
attr_accessor :host
##
# The user agent used by the client.
#
# @return [String]
# The user agent string used in the User-Agent header.
attr_accessor :user_agent
##
# Returns the URI for the directory document.
#
# @return [Addressable::URI] The URI of the directory document.
def directory_uri
template = Addressable::Template.new(
"https://{host}/discovery/v1/apis"
)
return template.expand({"host" => self.host})
end
##
# Manually registers a URI as a discovery document for a specific version
# of an API.
#
# @param [String, Symbol] api The service name.
# @param [String] version The desired version of the service.
# @param [Addressable::URI] uri The URI of the discovery document.
def register_discovery_uri(api, version, uri)
api = api.to_s
version = version || 'v1'
@discovery_uris["#{api}:#{version}"] = uri
end
##
# Returns the URI for the discovery document.
#
# @param [String, Symbol] api The service name.
# @param [String] version The desired version of the service.
# @return [Addressable::URI] The URI of the discovery document.
def discovery_uri(api, version=nil)
api = api.to_s
version = version || 'v1'
return @discovery_uris["#{api}:#{version}"] ||= (begin
template = Addressable::Template.new(
"https://{host}/discovery/v1/apis/" +
"{api}/{version}/rest"
)
template.expand({
"host" => self.host,
"api" => api,
"version" => version
})
end)
end
##
# Manually registers a pre-loaded discovery document for a specific version
# of an API.
#
# @param [String, Symbol] api The service name.
# @param [String] version The desired version of the service.
# @param [String, StringIO] discovery_document
# The contents of the discovery document.
def register_discovery_document(api, version, discovery_document)
api = api.to_s
version = version || 'v1'
if discovery_document.kind_of?(StringIO)
discovery_document.rewind
discovery_document = discovery_document.string
elsif discovery_document.respond_to?(:to_str)
discovery_document = discovery_document.to_str
else
raise TypeError,
"Expected String or StringIO, got #{discovery_document.class}."
end
@discovery_documents["#{api}:#{version}"] =
::JSON.parse(discovery_document)
end
##
# Returns the parsed directory document.
#
# @return [Hash] The parsed JSON from the directory document.
def directory_document
return @directory_document ||= (begin
request_uri = self.directory_uri
request = ['GET', request_uri, [], []]
response = self.transmit(request)
status, headers, body = response
if status == 200 # TODO(bobaman) Better status code handling?
merged_body = body.inject(StringIO.new) do |accu, chunk|
accu.write(chunk)
accu
end
::JSON.parse(merged_body.string)
elsif status >= 400 && status < 500
raise ClientError,
"Could not retrieve discovery document at: #{request_uri}"
elsif status >= 500 && status < 600
raise ServerError,
"Could not retrieve discovery document at: #{request_uri}"
elsif status > 600
raise TransmissionError,
"Could not retrieve discovery document at: #{request_uri}"
end
end)
end
##
# Returns the parsed discovery document.
#
# @param [String, Symbol] api The service name.
# @param [String] version The desired version of the service.
# @return [Hash] The parsed JSON from the discovery document.
def discovery_document(api, version=nil)
api = api.to_s
version = version || 'v1'
return @discovery_documents["#{api}:#{version}"] ||= (begin
request_uri = self.discovery_uri(api, version)
request = ['GET', request_uri, [], []]
response = self.transmit(request)
status, headers, body = response
if status == 200 # TODO(bobaman) Better status code handling?
merged_body = body.inject(StringIO.new) do |accu, chunk|
accu.write(chunk)
accu
end
::JSON.parse(merged_body.string)
elsif status >= 400 && status < 500
raise ClientError,
"Could not retrieve discovery document at: #{request_uri}"
elsif status >= 500 && status < 600
raise ServerError,
"Could not retrieve discovery document at: #{request_uri}"
elsif status > 600
raise TransmissionError,
"Could not retrieve discovery document at: #{request_uri}"
end
end)
end
##
# Returns all APIs published in the directory document.
#
# @return [Array] The list of available APIs.
def discovered_apis
@directory_apis ||= (begin
document_base = self.directory_uri
if self.directory_document && self.directory_document['items']
self.directory_document['items'].map do |discovery_document|
Google::APIClient::API.new(
document_base,
discovery_document
)
end
else
[]
end
end)
end
##
# Returns the service object for a given service name and service version.
#
# @param [String, Symbol] api The service name.
# @param [String] version The desired version of the service.
#
# @return [Google::APIClient::API] The service object.
def discovered_api(api, version=nil)
if !api.kind_of?(String) && !api.kind_of?(Symbol)
raise TypeError,
"Expected String or Symbol, got #{api.class}."
end
api = api.to_s
version = version || 'v1'
return @discovered_apis["#{api}:#{version}"] ||= begin
document_base = self.discovery_uri(api, version)
discovery_document = self.discovery_document(api, version)
if document_base && discovery_document
Google::APIClient::API.new(
document_base,
discovery_document
)
else
nil
end
end
end
##
# Returns the method object for a given RPC name and service version.
#
# @param [String, Symbol] rpc_name The RPC name of the desired method.
# @param [String] version The desired version of the service.
#
# @return [Google::APIClient::Method] The method object.
def discovered_method(rpc_name, api, version=nil)
if !rpc_name.kind_of?(String) && !rpc_name.kind_of?(Symbol)
raise TypeError,
"Expected String or Symbol, got #{rpc_name.class}."
end
rpc_name = rpc_name.to_s
api = api.to_s
version = version || 'v1'
service = self.discovered_api(api, version)
if service.to_h[rpc_name]
return service.to_h[rpc_name]
else
return nil
end
end
##
# Returns the service object with the highest version number.
#
# @note <em>Warning</em>: This method should be used with great care.
# As APIs are updated, minor differences between versions may cause
# incompatibilities. Requesting a specific version will avoid this issue.
#
# @param [String, Symbol] api The name of the service.
#
# @return [Google::APIClient::API] The service object.
def preferred_version(api)
if !api.kind_of?(String) && !api.kind_of?(Symbol)
raise TypeError,
"Expected String or Symbol, got #{api.class}."
end
api = api.to_s
# TODO(bobaman): Update to use directory API.
return self.discovered_apis.detect do |a|
a.name == api && a.preferred == true
end
end
##
# Generates a request.
#
# @param [Google::APIClient::Method, String] api_method
# The method object or the RPC name of the method being executed.
# @param [Hash, Array] parameters
# The parameters to send to the method.
# @param [String] body The body of the request.
# @param [Hash, Array] headers The HTTP headers for the request.
# @param [Hash] options
# The configuration parameters for the request.
# - <code>:version</code> —
# The service version. Only used if <code>api_method</code> is a
# <code>String</code>. Defaults to <code>'v1'</code>.
# - <code>:authorization</code> —
# The authorization mechanism for the response. Used only if
# <code>:authenticated</code> is <code>true</code>.
# - <code>:authenticated</code> —
# <code>true</code> if the request must be signed or otherwise
# authenticated, <code>false</code>
# otherwise. Defaults to <code>true</code> if an authorization
# mechanism has been set, <code>false</code> otherwise.
#
# @return [Array] The generated request.
#
# @example
# request = client.generate_request(
# :api_method => 'chili.activities.list',
# :parameters =>
# {'scope' => '@self', 'userId' => '@me', 'alt' => 'json'}
# )
# method, uri, headers, body = request
def generate_request(options={})
# Note: The merge method on a Hash object will coerce an API Reference
# object into a Hash and merge with the default options.
options={
:version => 'v1',
:authorization => self.authorization
}.merge(options)
# The Reference object is going to need this to do method ID lookups.
options[:client] = self
# The default value for the :authenticated option depends on whether an
# authorization mechanism has been set.
if options[:authorization]
options = {:authenticated => true}.merge(options)
else
options = {:authenticated => false}.merge(options)
end
reference = Google::APIClient::Reference.new(options)
request = reference.to_request
if options[:authenticated]
request = self.generate_authenticated_request(:request => request)
end
return request
end
##
# Signs a request using the current authorization mechanism.
#
# @param [Hash] options The options to pass through.
#
# @return [Array] The signed or otherwise authenticated request.
def generate_authenticated_request(options={})
return authorization.generate_authenticated_request(options)
end
##
# Transmits the request using the current HTTP adapter.
#
# @param [Array] request The request to transmit.
# @param [#transmit] adapter The HTTP adapter.
#
# @return [Array] The response from the server.
def transmit(request, adapter=self.http_adapter)
if self.user_agent != nil
# If there's no User-Agent header, set one.
method, uri, headers, body = request
unless headers.kind_of?(Enumerable)
# We need to use some Enumerable methods, relying on the presence of
# the #each method.
class <<headers
include Enumerable
end
end
if self.user_agent.kind_of?(String)
unless headers.any? { |k, v| k.downcase == 'User-Agent'.downcase }
headers = headers.to_a.insert(0, ['User-Agent', self.user_agent])
end
elsif self.user_agent != nil
raise TypeError,
"Expected User-Agent to be String, got #{self.user_agent.class}"
end
end
adapter.transmit([method, uri, headers, body])
end
##
# Executes a request, wrapping it in a Result object.
#
# @param [Google::APIClient::Method, String] api_method
# The method object or the RPC name of the method being executed.
# @param [Hash, Array] parameters
# The parameters to send to the method.
# @param [String] body The body of the request.
# @param [Hash, Array] headers The HTTP headers for the request.
# @param [Hash] options
# The configuration parameters for the request.
# - <code>:version</code> —
# The service version. Only used if <code>api_method</code> is a
# <code>String</code>. Defaults to <code>'v1'</code>.
# - <code>:adapter</code> —
# The HTTP adapter.
# - <code>:authorization</code> —
# The authorization mechanism for the response. Used only if
# <code>:authenticated</code> is <code>true</code>.
# - <code>:authenticated</code> —
# <code>true</code> if the request must be signed or otherwise
# authenticated, <code>false</code>
# otherwise. Defaults to <code>true</code>.
#
# @return [Array] The response from the API.
#
# @example
# request = client.generate_request(
# :api_method => 'chili.activities.list',
# :parameters =>
# {'scope' => '@self', 'userId' => '@me', 'alt' => 'json'}
# )
def execute(*params)
# This block of code allows us to accept multiple parameter passing
# styles, and maintaining some backwards compatibility.
#
# Note: I'm extremely tempted to deprecate this style of execute call.
if params.last.respond_to?(:to_hash) && params.size == 1
options = params.pop
else
options = {}
end
options[:api_method] = params.shift if params.size > 0
options[:parameters] = params.shift if params.size > 0
options[:merged_body] = params.shift if params.size > 0
options[:headers] = params.shift if params.size > 0
options[:client] = self
reference = Google::APIClient::Reference.new(options)
request = self.generate_request(reference)
response = self.transmit(
request,
options[:adapter] || self.http_adapter
)
return Google::APIClient::Result.new(reference, request, response)
end
##
# Same as Google::APIClient#execute, but raises an exception if there was
# an error.
#
# @see Google::APIClient#execute
def execute!(*params)
result = self.execute(*params)
status, _, _ = result.response
if result.data.respond_to?(:error)
# You're going to get a terrible error message if the response isn't
# parsed successfully as an error.
error_message = result.data.error
end
if status >= 400 && status < 500
raise ClientError,
error_message || "A client error has occurred."
elsif status >= 500 && status < 600
raise ServerError,
error_message || "A server error has occurred."
elsif status > 600
raise TransmissionError,
error_message || "A transmission error has occurred."
end
return result
end
end
end
require 'google/api_client/version'