v/vlib/veb/auth/README.md
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## Description
`veb.auth` is a module that helps with common logic required for authentication.
It allows to easily generate hashed and salted passwords and to compare password hashes.
It also handles authentication tokens, including DB table creation and insertion.
All DBs are supported.
## Usage
```v
import veb
import db.pg
import veb.auth
pub struct App {
veb.StaticHandler
pub mut:
db pg.DB
auth auth.Auth[pg.DB] // or auth.Auth[sqlite.DB] etc
}
const port = 8081
pub struct Context {
veb.Context
current_user User
}
struct User {
id int @[primary; sql: serial]
name string
password_hash string
salt string
}
fn main() {
mut app := &App{
db: pg.connect(host: 'localhost', user: 'postgres', password: '', dbname: 'postgres')!
}
app.auth = auth.new(app.db)
veb.run[App, Context](mut app, port)
}
@[post]
pub fn (mut app App) register_user(mut ctx Context, name string, password string) veb.Result {
salt := auth.generate_salt()
new_user := User{
name: name
password_hash: auth.hash_password_with_salt(password, salt)
salt: salt
}
user_id := sql app.db {
insert new_user into User
} or { 0 }
// Generate and insert the token using user ID
token := app.auth.add_token(user_id) or { '' }
// Authenticate the user by adding the token to the cookies
ctx.set_cookie(name: 'token', value: token)
return ctx.redirect('/')
}
@[post]
pub fn (mut app App) login_post(mut ctx Context, name string, password string) veb.Result {
user := app.find_user_by_name(name) or {
ctx.error('Bad credentials')
return ctx.redirect('/login')
}
// Verify user password using veb.auth
if !auth.compare_password_with_hash(password, user.salt, user.password_hash) {
ctx.error('Bad credentials')
return ctx.redirect('/login')
}
// Find the user token in the Token table
token := app.auth.add_token(user.id) or { '' }
// Authenticate the user by adding the token to the cookies
ctx.set_cookie(name: 'token', value: token)
return ctx.redirect('/')
}
pub fn (mut app App) find_user_by_name(name string) ?User {
// ... db query
return User{}
}
```
## Security considerations
`hash_password_with_salt` and its related functions use `sha256` for hashing with a single
iteration. This is not secure for production use, and you should use a more secure hashing
algorithm and multiple iterations.
See also:
- [OWASP Password Storage Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/Password_Storage_Cheat_Sheet.html)