github.com/go-kivik/kivik/v4@v4.3.2/x/kivikd/auth.go (about)

     1  // Licensed under the Apache License, Version 2.0 (the "License"); you may not
     2  // use this file except in compliance with the License. You may obtain a copy of
     3  // the License at
     4  //
     5  //  http://www.apache.org/licenses/LICENSE-2.0
     6  //
     7  // Unless required by applicable law or agreed to in writing, software
     8  // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
     9  // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
    10  // License for the specific language governing permissions and limitations under
    11  // the License.
    12  
    13  //go:build !js
    14  
    15  package kivikd
    16  
    17  import (
    18  	"net/http"
    19  
    20  	"github.com/go-kivik/kivik/v4/x/kivikd/auth"
    21  	"github.com/go-kivik/kivik/v4/x/kivikd/authdb"
    22  )
    23  
    24  type doneWriter struct {
    25  	http.ResponseWriter
    26  	done bool
    27  }
    28  
    29  func (w *doneWriter) WriteHeader(status int) {
    30  	w.done = true
    31  	w.ResponseWriter.WriteHeader(status)
    32  }
    33  
    34  func (w *doneWriter) Write(b []byte) (int, error) {
    35  	w.done = true
    36  	return w.ResponseWriter.Write(b)
    37  }
    38  
    39  func authHandler(next http.Handler) http.Handler {
    40  	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    41  		dw := &doneWriter{ResponseWriter: w}
    42  		s := GetService(r)
    43  		session, err := s.validate(dw, r)
    44  		if err != nil {
    45  			reportError(w, err)
    46  			return
    47  		}
    48  		sessionPtr := mustGetSessionPtr(r.Context())
    49  		*sessionPtr = session
    50  		if dw.done {
    51  			// The auth handler already responded to the request
    52  			return
    53  		}
    54  		next.ServeHTTP(w, r)
    55  	})
    56  }
    57  
    58  // validate must return a 401 error if there is an authentication failure.
    59  // No error means the user is permitted.
    60  func (s *Service) validate(w http.ResponseWriter, r *http.Request) (*auth.Session, error) {
    61  	if s.authHandlers == nil {
    62  		// Perpetual admin party
    63  		return s.createSession("", &authdb.UserContext{Roles: []string{"_admin"}}), nil
    64  	}
    65  	for methodName, handler := range s.authHandlers {
    66  		uCtx, err := handler.Authenticate(w, r)
    67  		if err != nil {
    68  			return nil, err
    69  		}
    70  		if uCtx != nil {
    71  			return s.createSession(methodName, uCtx), nil
    72  		}
    73  	}
    74  	// None of the auth methods succeeded, so return unauthorized
    75  	return s.createSession("", nil), nil
    76  }
    77  
    78  func (s *Service) createSession(method string, user *authdb.UserContext) *auth.Session {
    79  	return &auth.Session{
    80  		AuthMethod: method,
    81  		AuthDB:     s.Conf().GetString("couch_httpd_auth.authentication_db"),
    82  		Handlers:   s.authHandlerNames,
    83  		User:       user,
    84  	}
    85  }