67 lines
2.4 KiB
Nim
67 lines
2.4 KiB
Nim
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import db_mysql, nimcrypto, md5, strutils
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proc connectDb(user, password: string): DbConn =
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## Connect to the database "user_db" and create
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## the table "users" if it doesn’t exist yet.
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result = open("localhost", user, password, "user_db")
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result.exec(sql"""CREATE TABLE IF NOT EXISTS users (
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userid INT PRIMARY KEY AUTO_INCREMENT,
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username VARCHAR(32) UNIQUE KEY NOT NULL,
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pass_salt tinyblob NOT NULL,
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pass_md5 tinyblob NOT NULL)""")
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proc createUser(db: DbConn; username, password: string) =
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## Create a new user in the table "users".
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## The password salt and the password MD5 are managed as strings
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## but stored in tinyblobs as required.
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var passSalt = newString(16)
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if randomBytes(passSalt) != 16:
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raise newException(ValueError, "unable to build a salt.")
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var passMd5 = newString(16)
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for i, b in toMD5(passSalt & password): passMd5[i] = chr(b)
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if db.tryExec(sql"INSERT INTO users (username, pass_salt, pass_md5) VALUES (?, ?, ?)",
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username, passSalt, passMd5):
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echo "User $1 created." % username
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else:
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echo "Could not create user $1." % username
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proc authenticateUser(db: DbConn; user, password: string): bool =
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## Try to authenticate the user.
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## The authentication fails if the user doesn’t exist in "users" table or if the
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## password doesn’t match with the salt and password MD5 retrieved from the table.
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let row = db.getRow(sql"SELECT pass_salt, pass_md5 FROM users WHERE username = ?", user)
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if row[0].len != 0:
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let digest = toMd5(row[0] & password)
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for i in 0..15:
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if digest[i] != byte(row[1][i]): return
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result = true
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proc clean(db: DbConn) =
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## Remove all users from "users" table.
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db.exec(sql"DELETE FROM user_db.users")
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when isMainModule:
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proc authResult(status: bool): string =
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if status: "Succeeded" else: "Failed"
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# Connect to database and create user "Alice".
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let db = connectDb("admin", "admin_password")
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db.createUser("Alice", "Alice_password")
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# Try to authenticate Alice...
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# ... with a wrong password...
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var result = db.authenticateUser("Alice", "another_password").authResult()
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echo result, " to authenticate Alice with a wrong password."
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# ... then with the right password.
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result = db.authenticateUser("Alice", "Alice_password").authResult()
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echo result, " to authenticate Alice with the right password."
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# Clean-up and close.
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db.clean()
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db.close()
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