feat: permissions, middleware authentication, migrations

projects/greenlight/cmd/api/errors.go

@@ -88,3 +88,18 @@ func (app *application) invalidAuthenticationTokenResponse(w http.ResponseWriter
 	message := "invalid or missing authentication token"
 	app.errorResponse(w, r, http.StatusUnauthorized, message)
 }
+
+func (app *application) authenticationRequiredResponse(w http.ResponseWriter, r *http.Request) {
+	message := "you must be authenticated to access this resource"
+	app.errorResponse(w, r, http.StatusUnauthorized, message)
+}
+
+func (app *application) inactiveAccountResponse(w http.ResponseWriter, r *http.Request) {
+	message := "your user account must be activated to access this resource"
+	app.errorResponse(w, r, http.StatusForbidden, message)
+}
+
+func (app *application) notPermittedResponse(w http.ResponseWriter, r *http.Request) {
+	message := "your user account doesn't have the necessary permissions to access this resource"
+	app.errorResponse(w, r, http.StatusForbidden, message)
+}

projects/greenlight/cmd/api/middleware.go

@@ -181,3 +181,66 @@ func (app *application) authenticate(next http.Handler) http.Handler {
 		next.ServeHTTP(w, r)
 	})
 }
+
+// anonymous.
+func (app *application) requireAuthenticatedUser(next http.HandlerFunc) http.HandlerFunc {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		user := app.contextGetUser(r)
+
+		if user.IsAnonymous() {
+			app.authenticationRequiredResponse(w, r)
+			return
+		}
+
+		next.ServeHTTP(w, r)
+	})
+}
+
+// Checks that a user is both authenticated and activated.
+func (app *application) requireActivatedUser(next http.HandlerFunc) http.HandlerFunc {
+	// Rather than returning this http.HandlerFunc we assign it to the variable fn.
+	fn := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		user := app.contextGetUser(r)
+
+		// Check that a user is activated.
+		if !user.Activated {
+			app.inactiveAccountResponse(w, r)
+			return
+		}
+
+		next.ServeHTTP(w, r)
+	})
+
+	// Wrap fn with the requireAuthenticatedUser() middleware before returning it.
+	return app.requireAuthenticatedUser(fn)
+}
+
+// Note that the first parameter for the middleware function is the permission code that
+// we require the user to have.
+func (app *application) requirePermission(code string, next http.HandlerFunc) http.HandlerFunc {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		// Retrieve the user from the request context.
+		user := app.contextGetUser(r)
+
+		// Get the slice of permissions for the user.
+		permissions, err := app.models.Permissions.GetAllForUser(user.ID)
+		if err != nil {
+			app.serverErrorResponse(w, r, err)
+			return
+		}
+
+		// Check if the slice includes the required permission. If it doesn't, then
+		// return a 403 Forbidden response.
+		if !permissions.Include(code) {
+			app.notPermittedResponse(w, r)
+			return
+		}
+
+		// Otherwise they have the required permission so we call the next handler in
+		// the chain.
+		next.ServeHTTP(w, r)
+	}
+
+	// Wrap this with the requireActivatedUser() middleware before returning it.
+	return app.requireActivatedUser(fn)
+}

projects/greenlight/cmd/api/routes.go

@@ -9,24 +9,24 @@ import (
 func (app *application) routes() http.Handler {
 	router := httprouter.New()
 
-	// Convert the notFoundResponse() helper to a http.Handler using the
-	// http.HandlerFunc() adapter, and then set it as the custom error handler for 404
-	// Not Found responses.
 	router.NotFound = http.HandlerFunc(app.notFoundResponse)
-
-	// Likewise, convert the methodNotAllowedResponse() helper to a http.Handler and set
-	// it as the custom error handler for 405 Method Not Allowed responses.
 	router.MethodNotAllowed = http.HandlerFunc(app.methodNotAllowedResponse)
-	router.HandlerFunc(http.MethodGet, "/v1/movies", app.listMoviesHandler)
+
 	router.HandlerFunc(http.MethodGet, "/v1/healthcheck", app.healthcheckHandler)
-	router.HandlerFunc(http.MethodPost, "/v1/movies", app.createMovieHandler)
-	router.HandlerFunc(http.MethodGet, "/v1/movies/:id", app.showMovieHandler)
-	router.HandlerFunc(http.MethodPatch, "/v1/movies/:id", app.updateMovieHandler)
-	router.HandlerFunc(http.MethodDelete, "/v1/movies/:id", app.deleteMovieHandler)
+
+	// Use the requirePermission() middleware on each of the /v1/movies** endpoints,
+	// passing in the required permission code as the first parameter.
+	router.HandlerFunc(http.MethodGet, "/v1/movies", app.requirePermission("movies:read", app.listMoviesHandler))
+	router.HandlerFunc(http.MethodPost, "/v1/movies", app.requirePermission("movies:write", app.createMovieHandler))
+	router.HandlerFunc(http.MethodGet, "/v1/movies/:id", app.requirePermission("movies:read", app.showMovieHandler))
+	router.HandlerFunc(http.MethodPatch, "/v1/movies/:id", app.requirePermission("movies:write", app.updateMovieHandler))
+	router.HandlerFunc(http.MethodDelete, "/v1/movies/:id", app.requirePermission("movies:write", app.deleteMovieHandler))
+
 	router.HandlerFunc(http.MethodPost, "/v1/users", app.registerUserHandler)
 	router.HandlerFunc(http.MethodPut, "/v1/users/activated", app.activateUserHandler)
-	router.HandlerFunc(http.MethodPost, "/v1/tokens/authentication", app.createAuthenticationTokenHandler)
-	// Wrap the router with the rateLimit() middleware.
-	// Use the authenticate() middleware on all requests.
+
+	router.HandlerFunc(http.MethodPost, "/v1/tokens/authentication",
+		app.createAuthenticationTokenHandler)
+
 	return app.recoverPanic(app.rateLimit(app.authenticate(router)))
 }

projects/greenlight/docs/api/greenlight-bruno/Authentication/Authenticate.yml

@@ -10,7 +10,7 @@ http:
     type: json
     data: |-
       {
-        "email": "bob@example.com",
+        "email": "alice@example.com",
         "password": "pa55word"
       }
   auth: inherit

projects/greenlight/docs/api/greenlight-bruno/Movies/Get Movies.yml

@@ -24,7 +24,9 @@ http:
       value: action
       type: query
       disabled: true
-  auth: inherit
+  auth:
+    type: bearer
+    token: VSLRNLGSTN2BXGE7PCEPB4LNKQ
 
 settings:
   encodeUrl: true

projects/greenlight/internal/data/models.go

@@ -12,21 +12,18 @@ var (
 	ErrEditConflict   = errors.New("edit conflict")
 )
 
-// Models struct which wraps the MovieModel. We'll add other models to this,
-// like a UserModel and PermissionModel, as our build progresses.
 type Models struct {
-	Movies MovieModel
-	Tokens TokenModel // Add a new Tokens field.
-	Users  UserModel
+	Movies      MovieModel
+	Permissions PermissionModel // Add a new Permissions field.
+	Tokens      TokenModel
+	Users       UserModel
 }
 
-// NewModels For ease of use, we also add a New()
-// method which returns a Models struct containing
-// the initialized MovieModel.
 func NewModels(db *sql.DB) Models {
 	return Models{
-		Movies: MovieModel{DB: db},
-		Tokens: TokenModel{DB: db}, // Initialize a new TokenModel instance.
-		Users:  UserModel{DB: db},
+		Movies:      MovieModel{DB: db},
+		Permissions: PermissionModel{DB: db}, // Initialize a new PermissionModel instance.
+		Tokens:      TokenModel{DB: db},
+		Users:       UserModel{DB: db},
 	}
 }

projects/greenlight/internal/data/permissions.go

@@ -0,0 +1,66 @@
+package data
+
+import (
+	"context"
+	"database/sql"
+	"time"
+)
+
+// Define a Permissions slice, which we will use to will hold the permission codes (like
+// "movies:read" and "movies:write") for a single user.
+type Permissions []string
+
+// Add a helper method to check whether the Permissions slice contains a specific
+// permission code.
+func (p Permissions) Include(code string) bool {
+	for i := range p {
+		if code == p[i] {
+			return true
+		}
+	}
+	return false
+}
+
+// PermissionModel type.
+type PermissionModel struct {
+	DB *sql.DB
+}
+
+// GetAllForUser method returns all permission codes for a specific user in a
+// Permissions slice. The code in this method should feel very familiar --- it uses the
+// standard pattern that we've already seen before for retrieving multiple data rows in
+// an SQL query.
+func (m PermissionModel) GetAllForUser(userID int64) (Permissions, error) {
+	query := `
+        SELECT permissions.code
+        FROM permissions
+        INNER JOIN users_permissions ON users_permissions.permission_id = permissions.id
+        INNER JOIN users ON users_permissions.user_id = users.id
+        WHERE users.id = $1`
+
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+
+	rows, err := m.DB.QueryContext(ctx, query, userID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var permissions Permissions
+
+	for rows.Next() {
+		var permission string
+
+		err := rows.Scan(&permission)
+		if err != nil {
+			return nil, err
+		}
+
+		permissions = append(permissions, permission)
+	}
+	if err = rows.Err(); err != nil {
+		return nil, err
+	}
+
+	return permissions, nil
+}

projects/greenlight/migrations/000006_add_permissions.down.sql

@@ -0,0 +1,3 @@
+DROP TABLE IF EXISTS users_permissions;
+DROP TABLE IF EXISTS permissions;
+

projects/greenlight/migrations/000006_add_permissions.up.sql

@@ -0,0 +1,17 @@
+CREATE TABLE IF NOT EXISTS permissions (
+    id bigserial PRIMARY KEY,
+    code text NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS users_permissions (
+    user_id bigint NOT NULL REFERENCES users ON DELETE CASCADE,
+    permission_id bigint NOT NULL REFERENCES permissions ON DELETE CASCADE,
+    PRIMARY KEY (user_id, permission_id)
+);
+
+-- Add the two permissions to the table.
+INSERT INTO permissions (code)
+VALUES 
+    ('movies:read'),
+    ('movies:write');
+