Add initial Microsoft Teams support

Documentation on https://github.com/42wim/matterbridge/wiki/MS-Teams-setup

vendor/github.com/yaegashi/msgraph.go/msauth/README.md

@@ -0,0 +1,70 @@
+# msauth
+
+## Introduction
+
+Very simple package to authorize applications against [Microsoft identity platform].
+
+It utilizes [v2.0 endpoint] so that it can authorize users using both personal (Microsoft) and organizational (Azure AD) account.
+
+## Usage
+
+### Device authorization grant
+
+- [OAuth 2.0 device authorization grant flow]
+
+```go
+const (
+	tenantID     = "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX"
+	clientID     = "YYYYYYYY-YYYY-YYYY-YYYY-YYYYYYYYYYYY"
+	tokenCachePath  = "token_cache.json"
+)
+
+var scopes = []string{"openid", "profile", "offline_access", "User.Read", "Files.Read"}
+
+	ctx := context.Background()
+	m := msauth.NewManager()
+	m.LoadFile(tokenCachePath)
+	ts, err := m.DeviceAuthorizationGrant(ctx, tenantID, clientID, scopes, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	m.SaveFile(tokenCachePath)
+
+	httpClient := oauth2.NewClient(ctx, ts)
+	...
+```
+
+### Client credentials grant
+
+- [OAuth 2.0 client credentials grant flow]
+
+```go
+const (
+	tenantID     = "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX"
+	clientID     = "YYYYYYYY-YYYY-YYYY-YYYY-YYYYYYYYYYYY"
+	clientSecret = "ZZZZZZZZZZZZZZZZZZZZZZZZ"
+)
+
+var scopes = []string{msauth.DefaultMSGraphScope}
+
+	ctx := context.Background()
+	m := msauth.NewManager()
+	ts, err := m.ClientCredentialsGrant(ctx, tenantID, clientID, clientSecret, scopes)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	httpClient := oauth2.NewClient(ctx, ts)
+    ...
+```
+
+### Authorization code grant
+
+- [OAuth 2.0 authorization code grant flow]
+- Not yet implemented.
+
+[Microsoft identity platform]: https://docs.microsoft.com/en-us/azure/active-directory/develop/
+[v2.0 endpoint]: https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-overview
+[OAuth 2.0 device authorization grant flow]: https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-device-code
+[OAuth 2.0 client credentials grant flow]: https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow
+[OAuth 2.0 authorization code grant flow]: https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-auth-code-flow

vendor/github.com/yaegashi/msgraph.go/msauth/client_credentials_grant.go

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+package msauth
+
+import (
+	"context"
+
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/clientcredentials"
+	"golang.org/x/oauth2/microsoft"
+)
+
+// ClientCredentialsGrant performs OAuth 2.0 client credentials grant and returns auto-refreshing TokenSource
+func (m *Manager) ClientCredentialsGrant(ctx context.Context, tenantID, clientID, clientSecret string, scopes []string) (oauth2.TokenSource, error) {
+	config := &clientcredentials.Config{
+		ClientID:     clientID,
+		ClientSecret: clientSecret,
+		TokenURL:     microsoft.AzureADEndpoint(tenantID).TokenURL,
+		Scopes:       scopes,
+		AuthStyle:    oauth2.AuthStyleInParams,
+	}
+	var err error
+	ts := config.TokenSource(ctx)
+	_, err = ts.Token()
+	if err != nil {
+		return nil, err
+	}
+	return ts, nil
+}

vendor/github.com/yaegashi/msgraph.go/msauth/device_authorization_grant.go

@@ -0,0 +1,96 @@
+package msauth
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+	"time"
+
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/microsoft"
+)
+
+const (
+	deviceCodeGrantType       = "urn:ietf:params:oauth:grant-type:device_code"
+	authorizationPendingError = "authorization_pending"
+)
+
+// DeviceCode is returned on device auth initiation
+type DeviceCode struct {
+	DeviceCode      string `json:"device_code"`
+	UserCode        string `json:"user_code"`
+	VerificationURL string `json:"verification_url"`
+	ExpiresIn       int    `json:"expires_in"`
+	Interval        int    `json:"interval"`
+	Message         string `json:"message"`
+}
+
+// DeviceAuthorizationGrant performs OAuth 2.0 device authorization grant and returns auto-refreshing TokenSource
+func (m *Manager) DeviceAuthorizationGrant(ctx context.Context, tenantID, clientID string, scopes []string, callback func(*DeviceCode) error) (oauth2.TokenSource, error) {
+	endpoint := microsoft.AzureADEndpoint(tenantID)
+	endpoint.AuthStyle = oauth2.AuthStyleInParams
+	config := &oauth2.Config{
+		ClientID: clientID,
+		Endpoint: endpoint,
+		Scopes:   scopes,
+	}
+	if t, ok := m.TokenCache[generateKey(tenantID, clientID)]; ok {
+		tt, err := config.TokenSource(ctx, t).Token()
+		if err == nil {
+			return config.TokenSource(ctx, tt), nil
+		}
+		if _, ok := err.(*oauth2.RetrieveError); !ok {
+			return nil, err
+		}
+	}
+	scope := strings.Join(scopes, " ")
+	res, err := http.PostForm(deviceCodeURL(tenantID), url.Values{"client_id": {clientID}, "scope": {scope}})
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	if res.StatusCode != http.StatusOK {
+		b, _ := ioutil.ReadAll(res.Body)
+		return nil, fmt.Errorf("%s: %s", res.Status, string(b))
+	}
+	dc := &DeviceCode{}
+	dec := json.NewDecoder(res.Body)
+	err = dec.Decode(&dc)
+	if err != nil {
+		return nil, err
+	}
+	if callback != nil {
+		err = callback(dc)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		fmt.Fprintln(os.Stderr, dc.Message)
+	}
+	values := url.Values{
+		"client_id":   {clientID},
+		"grant_type":  {deviceCodeGrantType},
+		"device_code": {dc.DeviceCode},
+	}
+	interval := dc.Interval
+	if interval == 0 {
+		interval = 5
+	}
+	for {
+		time.Sleep(time.Second * time.Duration(interval))
+		token, err := m.requestToken(ctx, tenantID, clientID, values)
+		if err == nil {
+			m.Cache(tenantID, clientID, token)
+			return config.TokenSource(ctx, token), nil
+		}
+		tokenError, ok := err.(*TokenError)
+		if !ok || tokenError.ErrorObject != authorizationPendingError {
+			return nil, err
+		}
+	}
+}

vendor/github.com/yaegashi/msgraph.go/msauth/msauth.go

@@ -0,0 +1,148 @@
+// Package msauth implements a library to authorize against Microsoft identity platform:
+// https://docs.microsoft.com/en-us/azure/active-directory/develop/
+//
+// It utilizes v2.0 endpoint
+// so it can authorize users with both personal (Microsoft) and organizational (Azure AD) account.
+package msauth
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"sync"
+	"time"
+
+	"golang.org/x/oauth2"
+)
+
+const (
+	// DefaultMSGraphScope is the default scope for MS Graph API
+	DefaultMSGraphScope = "https://graph.microsoft.com/.default"
+	endpointURLFormat   = "https://login.microsoftonline.com/%s/oauth2/v2.0/%s"
+)
+
+// TokenError is returned on failed authentication
+type TokenError struct {
+	ErrorObject      string `json:"error"`
+	ErrorDescription string `json:"error_description"`
+}
+
+// Error implements error interface
+func (t *TokenError) Error() string {
+	return fmt.Sprintf("%s: %s", t.ErrorObject, t.ErrorDescription)
+}
+
+func generateKey(tenantID, clientID string) string {
+	return fmt.Sprintf("%s:%s", tenantID, clientID)
+}
+
+func deviceCodeURL(tenantID string) string {
+	return fmt.Sprintf(endpointURLFormat, tenantID, "devicecode")
+}
+
+func tokenURL(tenantID string) string {
+	return fmt.Sprintf(endpointURLFormat, tenantID, "token")
+}
+
+type tokenJSON struct {
+	AccessToken  string `json:"access_token"`
+	TokenType    string `json:"token_type"`
+	RefreshToken string `json:"refresh_token"`
+	ExpiresIn    int    `json:"expires_in"`
+}
+
+func (e *tokenJSON) expiry() (t time.Time) {
+	if v := e.ExpiresIn; v != 0 {
+		return time.Now().Add(time.Duration(v) * time.Second)
+	}
+	return
+}
+
+// Manager is oauth2 token cache manager
+type Manager struct {
+	mu         sync.Mutex
+	TokenCache map[string]*oauth2.Token
+}
+
+// NewManager returns a new Manager instance
+func NewManager() *Manager {
+	return &Manager{TokenCache: map[string]*oauth2.Token{}}
+}
+
+// LoadBytes loads token cache from opaque bytes (it's actually JSON)
+func (m *Manager) LoadBytes(b []byte) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	return json.Unmarshal(b, &m.TokenCache)
+}
+
+// SaveBytes saves token cache to opaque bytes (it's actually JSON)
+func (m *Manager) SaveBytes() ([]byte, error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	return json.Marshal(m.TokenCache)
+}
+
+// LoadFile loads token cache from file
+func (m *Manager) LoadFile(path string) error {
+	b, err := ioutil.ReadFile(path)
+	if err != nil {
+		return err
+	}
+	return m.LoadBytes(b)
+}
+
+// SaveFile saves token cache to file
+func (m *Manager) SaveFile(path string) error {
+	b, err := m.SaveBytes()
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(path, b, 0644)
+}
+
+// Cache stores a token into token cache
+func (m *Manager) Cache(tenantID, clientID string, token *oauth2.Token) {
+	m.TokenCache[generateKey(tenantID, clientID)] = token
+}
+
+// requestToken requests a token from the token endpoint
+// TODO(ctx): use http client from ctx
+func (m *Manager) requestToken(ctx context.Context, tenantID, clientID string, values url.Values) (*oauth2.Token, error) {
+	res, err := http.PostForm(tokenURL(tenantID), values)
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	b, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return nil, err
+	}
+	if res.StatusCode != http.StatusOK {
+		var terr *TokenError
+		err = json.Unmarshal(b, &terr)
+		if err != nil {
+			return nil, err
+		}
+		return nil, terr
+	}
+	var tj *tokenJSON
+	err = json.Unmarshal(b, &tj)
+	if err != nil {
+		return nil, err
+	}
+	token := &oauth2.Token{
+		AccessToken:  tj.AccessToken,
+		TokenType:    tj.TokenType,
+		RefreshToken: tj.RefreshToken,
+		Expiry:       tj.expiry(),
+	}
+	if token.AccessToken == "" {
+		return nil, errors.New("msauth: server response missing access_token")
+	}
+	return token, nil
+}