Add Authenticate()

This function validates a username and password against the database.

1 files changed, 18 insertions, 0 deletions

diff --git a/password.go b/password.go
index 024ffd7..edbeb7a 100644
--- a/password.go
+++ b/password.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"database/sql"
+	"fmt"
 
 	_ "github.com/mattn/go-sqlite3"
 	"golang.org/x/crypto/bcrypt"
@@ -28,3 +29,20 @@ func Register(db *sql.DB, username, password string) error {
 
 	return err
 }
+
+func Authenticate(db *sql.DB, username, password string) error {
+	var hash []byte
+	err := Transaction(db, func(tx *sql.Tx) error {
+		row := tx.QueryRow(
+			`SELECT password_bcrypt from users WHERE username=?;`,
+			username,
+		)
+
+		return row.Scan(&hash)
+	})
+	if err != nil {
+		return fmt.Errorf("Failed to get password hash from database: %w", err)
+	}
+
+	return bcrypt.CompareHashAndPassword(hash, []byte(password))
+}