add GDrive provider support (#118)

* GDrive provider support
* More reliable basedir ownership
* Fix mimetype

vendor/golang.org/x/oauth2/hipchat/hipchat.go

@@ -0,0 +1,60 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package hipchat provides constants for using OAuth2 to access HipChat.
+package hipchat // import "golang.org/x/oauth2/hipchat"
+
+import (
+	"encoding/json"
+	"errors"
+
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/clientcredentials"
+)
+
+// Endpoint is HipChat's OAuth 2.0 endpoint.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://www.hipchat.com/users/authorize",
+	TokenURL: "https://api.hipchat.com/v2/oauth/token",
+}
+
+// ServerEndpoint returns a new oauth2.Endpoint for a HipChat Server instance
+// running on the given domain or host.
+func ServerEndpoint(host string) oauth2.Endpoint {
+	return oauth2.Endpoint{
+		AuthURL:  "https://" + host + "/users/authorize",
+		TokenURL: "https://" + host + "/v2/oauth/token",
+	}
+}
+
+// ClientCredentialsConfigFromCaps generates a Config from a HipChat API
+// capabilities descriptor. It does not verify the scopes against the
+// capabilities document at this time.
+//
+// For more information see: https://www.hipchat.com/docs/apiv2/method/get_capabilities
+func ClientCredentialsConfigFromCaps(capsJSON []byte, clientID, clientSecret string, scopes ...string) (*clientcredentials.Config, error) {
+	var caps struct {
+		Caps struct {
+			Endpoint struct {
+				TokenURL string `json:"tokenUrl"`
+			} `json:"oauth2Provider"`
+		} `json:"capabilities"`
+	}
+
+	if err := json.Unmarshal(capsJSON, &caps); err != nil {
+		return nil, err
+	}
+
+	// Verify required fields.
+	if caps.Caps.Endpoint.TokenURL == "" {
+		return nil, errors.New("oauth2/hipchat: missing OAuth2 token URL in the capabilities descriptor JSON")
+	}
+
+	return &clientcredentials.Config{
+		ClientID:     clientID,
+		ClientSecret: clientSecret,
+		Scopes:       scopes,
+		TokenURL:     caps.Caps.Endpoint.TokenURL,
+	}, nil
+}