Subject: Client Credentials Grant with Consumer Key and Consumer Secret

Issue: #82 Comment:

src/Service.gs

@@ -241,6 +241,38 @@ Service_.prototype.setExpirationMinutes = function(expirationMinutes) {
  return this;
 };
 
+/**
+ * Sets the consumer secret to use for grant flow authorization.
+ * @param {string} consummerSecret The consumer secret.
+ * @return {Service_} This service, for chaining.
+ */
+Service_.prototype.setConsumerSecret = function(consummerSecret) {
+ this.consumerSecret_ = consummerSecret;
+ return this;
+};
+
+/**
+ * Sets the consumer key to use for grant flow authorization.
+ * If not set the client ID will be used instead.
+ * @param {string} consumerKey This consumer key
+ * @return {Service_} This service, for chaining.
+ */
+Service_.prototype.setConsumerKey = function(consumerKey) {
+ this.consumerKey_ = consumerKey;
+ return this;
+};
+
+/**
+ * Sets the grant_type for an extension of grant flow authorization
+ * @param {string} grantType The extension grant type.
+ * @return {Service_} This service, for chaining.
+ */
+
+Service_.prototype.setGrantType = function(grantType) {
+ this.grantType_ = grantType;
+ return this;
+};
+
 /**
  * Gets the authorization URL. The first step in getting an OAuth2 token is to
  * have the user visit this URL and approve the authorization request. The
@@ -345,6 +377,13 @@ Service_.prototype.hasAccess = function() {
  this.lastError_ = e;
  return false;
  }
+ } else if (this.consumerSecret_){
+ try {
+ this.requestCCG_();
+ } catch (e) {
+ this.lastError_ = e;
+ return false;
+ }
  } else {
  return false;
  }
@@ -629,3 +668,37 @@ Service_.prototype.createJwt_ = function() {
  var signature = Utilities.base64EncodeWebSafe(signatureBytes);
  return toSign + '.' + signature;
 };
+
+/**
+ * Uses Client Credentials Grant flow for getting an access token.
+ * https://tools.ietf.org/html/rfc6749#section-4.4
+ */
+Service_.prototype.requestCCG_ = function() {
+ validate_({
+ 'Token URL': this.tokenUrl_
+ });
+ var consumerKey = this.consumerKey_ || this.clientId_;
+ var headers = {
+ 'Accept': this.tokenFormat_,
+ 'Authorization': 'Basic ' + Utilities.base64Encode(consumerKey + ':' + this.consumerSecret_)
+ };
+ if (this.tokenHeaders_) {
+ headers = _.extend(headers, this.tokenHeaders_);
+ }
+ var tokenPayload = {
+ scope: this.params_.scope,
+ grant_type: 'client_credentials' || this.grantType_
+ };
+ if (this.tokenPayloadHandler_) {
+ tokenPayload = this.tokenPayloadHandler_(tokenPayload);
+ Logger.log('Token payload from tokenPayloadHandler: %s', JSON.stringify(tokenPayload));
+ }
+ var response = UrlFetchApp.fetch(this.tokenUrl_, {
+ method: 'post',
+ headers: headers,
+ payload: tokenPayload,
+ muteHttpExceptions: true
+ });
+ var token = this.getTokenFromResponse_(response);
+ this.saveToken_(token);
+};