104 lines
4.1 KiB
Ruby
104 lines
4.1 KiB
Ruby
# Copyright 2015, Google Inc.
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions are
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# met:
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#
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# * Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# * Redistributions in binary form must reproduce the above
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# copyright notice, this list of conditions and the following disclaimer
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# in the documentation and/or other materials provided with the
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# distribution.
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# * Neither the name of Google Inc. nor the names of its
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# contributors may be used to endorse or promote products derived from
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# this software without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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require 'googleauth/signet'
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require 'googleauth/credentials_loader'
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require 'jwt'
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require 'multi_json'
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module Google
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# Module Auth provides classes that provide Google-specific authorization
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# used to access Google APIs.
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module Auth
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# Authenticates requests using Google's Service Account credentials.
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#
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# This class allows authorizing requests for service accounts directly
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# from credentials from a json key file downloaded from the developer
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# console (via 'Generate new Json Key').
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#
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# cf [Application Default Credentials](http://goo.gl/mkAHpZ)
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class ServiceAccountCredentials < Signet::OAuth2::Client
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JWT_AUD_URI_KEY = :jwt_aud_uri
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AUTH_METADATA_KEY = Signet::OAuth2::AUTH_METADATA_KEY
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TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v3/token'
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extend CredentialsLoader
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# Reads the private key and client email fields from the service account
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# JSON key.
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def self.read_json_key(json_key_io)
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json_key = MultiJson.load(json_key_io.read)
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fail 'missing client_email' unless json_key.key?('client_email')
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fail 'missing private_key' unless json_key.key?('private_key')
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[json_key['private_key'], json_key['client_email']]
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end
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# Initializes a ServiceAccountCredentials.
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#
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# @param json_key_io [IO] an IO from which the JSON key can be read
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# @param scope [string|array|nil] the scope(s) to access
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def initialize(json_key_io, scope = nil)
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private_key, client_email = self.class.read_json_key(json_key_io)
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super(token_credential_uri: TOKEN_CRED_URI,
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audience: TOKEN_CRED_URI,
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scope: scope,
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issuer: client_email,
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signing_key: OpenSSL::PKey::RSA.new(private_key))
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end
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# Extends the superclass behaviour to construct a jwt token if the
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# google jwt uri key is present in the input hash.
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#
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# The jwt is used as the authentication token.
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def apply!(a_hash, opts = {})
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jwt_aud_uri = a_hash.delete(JWT_AUD_URI_KEY)
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unless jwt_aud_uri.nil?
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jwt_token = new_jwt_token(jwt_aud_uri, opts)
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a_hash[AUTH_METADATA_KEY] = "Bearer #{jwt_token}"
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return a_hash
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end
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super
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end
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# Creates a jwt uri token.
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def new_jwt_token(jwt_aud_uri, options = {})
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now = Time.new
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skew = options[:skew] || 60
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assertion = {
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'iss' => issuer,
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'sub' => issuer,
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'aud' => jwt_aud_uri,
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'exp' => (now + expiry).to_i,
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'iat' => (now - skew).to_i
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}
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JWT.encode(assertion, signing_key, signing_algorithm)
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end
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end
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end
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end
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