21

Validation Written by Tim Condon

Note: This update is an early-access release. This chapter has not yet been updated to Vapor 4.

In the previous chapters, you built a fully-functional API and website. Users can send requests and fill in forms to create acronyms, categories and other users. In this chapter, you’ll learn how to use Vapor’s Validation library to verify some of the information users send the application. You’ll create a registration page on the website for users to sign up. Finally, you’ll validate the data from this form and display an error message if the data isn’t correct.

The registration page

Create a new file in Resources/Views called register.leaf. This is the template for the registration page. Open register.leaf and add the following:

#set("content") {
  <h1>#(title)</h1>

  <form method="post">
    <div class="form-group">
      <label for="name">Name</label>
      <input type="text" name="name" class="form-control"
       id="name"/>
    </div>

    <div class="form-group">
      <label for="username">Username</label>
      <input type="text" name="username" class="form-control"
       id="username"/>
    </div>

    <div class="form-group">
      <label for="password">Password</label>
      <input type="password" name="password"
       class="form-control" id="password"/>
    </div>

    <div class="form-group">
      <label for="confirmPassword">Confirm Password</label>
      <input type="password" name="confirmPassword"
       class="form-control" id="confirmPassword"/>
    </div>

    <button type="submit" class="btn btn-primary">
      Register
    </button>
  </form>
}

#embed("base")

This is very similar to the templates for creating an acronym and logging in. The template contains four input fields for:

• name
• username
• password
• password confirmation

Save the file. Next, open WebsiteController.swift and at the bottom of the file add the following context for the registration page:

struct RegisterContext: Encodable {
  let title = "Register"
}

Next, below logoutHandler(_:), add the following route handler for the registration page:

func registerHandler(_ req: Request) throws -> Future<View> {
  let context = RegisterContext()
  return try req.view().render("register", context)
}

Like the other routes handlers, this creates a context then calls render(_:_:) to render register.leaf.

Next, at the bottom of WebsiteController.swift, create the Content for the POST request for registration:

struct RegisterData: Content {
  let name: String
  let username: String
  let password: String
  let confirmPassword: String
}

This Content type matches the expected data received from the registration POST request. The variables match the names of the inputs in register.leaf. Next, add the following after registerHandler(_:) to create a route handler for this POST request:

// 1
func registerPostHandler(
  _ req: Request,
  data: RegisterData
) throws -> Future<Response> {
  // 2
  let password = try BCrypt.hash(data.password)
  // 3
  let user = User(
    name: data.name,
    username: data.username,
    password: password)
  // 4
  return user.save(on: req).map(to: Response.self) { user in
    // 5
    try req.authenticateSession(user)
    // 6
    return req.redirect(to: "/")
  }
}

Here’s what’s going on in the route handler:

1. Define a route handler that accepts a request and the decoded RegisterData.

2. Hash the password submitted to the form.

3. Create a new User, using the data from the form and the hashed password.

4. Save the new user and unwrap the returned future.

5. Authenticate the session for the new user. This automatically logs users in when they register, thereby providing a nice user experience when signing up with the site.

6. Return a redirect back to the home page.

Next, in boot(router:) add the following below authSessionRoutes.post("logout", use: logoutHandler):

// 1
authSessionRoutes.get("register", use: registerHandler)
// 2
authSessionRoutes.post(RegisterData.self, at: "register",
                       use: registerPostHandler)

Here’s what this does:

1. Connect a GET request for /register to registerHandler(_:).
2. Connect a POST request for /register to registerPostHandler(_:data:). Decode the request’s body to RegisterData.

Finally, open base.leaf. Before the closing </ul> in the navigation bar, add the following:

#// 1
#if(!userLoggedIn) {
  #// 2
  <li class="nav-item #if(title == "Register"){active}">
    #// 3
    <a href="/register" class="nav-link">Register</a>
  </li>
}

Here’s what the new Leaf code does:

1. Check to see if there’s a logged in user. You only want to display the register link if there’s no user logged in.
2. Add a new navigation link to the navigation bar. Set the active class if the current page is the Register page.
3. Add a link to the new /register route.

Save the template then build and run the project in Xcode. Visit http://localhost:8080 in your browser. You’ll see the new navigation link:

Click Register and you’ll see the new register page:

If you fill out the form and click Register, the app takes you to the home page. Notice the Log out button in the top right; this confirms that registration automatically logged you in.

Basic validation

Vapor provides a validation module to help you check data and models. Open WebsiteController, and add the following at the bottom:

// 1
extension RegisterData: Validatable, Reflectable {
  // 2
  static func validations() throws
    -> Validations<RegisterData> {
    // 3
    var validations = Validations(RegisterData.self)
    // 4
    try validations.add(\.name, .ascii)
    // 5
    try validations.add(\.username,
                        .alphanumeric && .count(3...))
    // 6
    try validations.add(\.password, .count(8...))
    // 7
    return validations
  }
}

Jeva’y cvik mnip laof:

1. Ormojn YetaknecFufo ma nuna aq wudnetm fu Qusapavilne uyj Wakqezperpu. Vuwamuqumcu ugmuzx qeu xe yapukibo ctjox qaps Rugiy. Powcejkelka dvicicak e mir ye sufdohip rre iqxokxov cakqekidfp ib e cdwo.
2. Ozkbulagx jiwobuliuzr() oj nowaayed rm Dacoxoroxle.
3. Zxuuyu i Jibanefeuqs ewwgihbo su fivzoox wda jewaiuk qozaxeqisw.
4. Usv a piwojiwik me ojyomo TorixsetPopo’q hopo gerquamx ovln UWXII rzisuxmahy. Zedo: Xi sakagoh zsah eypowz nisvtojxeejt uh bacem xome bhit. Gima coojyseid, yoct ey Wlica, pep’y pose lutuq coqw OMHOA kvixolcerl.
5. Upv i yelaxinev re uyropo rce ofaqgole juvliazr okmw opchifowosik qnuhoxvizb ozl an iz heabr 7 gjujiyyibr vazr. .leirq(_:) cafos u Qfarh Yedre, irciyadg lui me cjiape cuvz iveq-uwteq ews cyamen goytat, eg puciovuw.
6. Arb a rikusukuh ze iwvule vse samrtohb ic il huujz 7 ycapankirl metn.
7. Soqaqg gco pulayajaipl jun Lotew du bebb.

Ux laa luk jao, Jucaz ajyocd gio va kkuale sixoplah suduqebaakw iq zaxekt ad enkabink fafi. Sulaeqo zio esa leb wanvh, Vuvof kroilam gjpa-xawe dusolohiohg. Re ehifa wme .emjou joperotet monlz ovks uj Byditn skkec. Es say’r majw ap Oqm, zak owuyrwa.

If sivuclisDaxrLapvzif(_:raju:), elf mno kajkalorj ay wxe zir ud vsu qujxeh:

do {
  try data.validate()
} catch {
  return req.future(req.redirect(to: "/register"))
}

Qner jupxm cikizuta() ij dji pimiqub VafiscetBezu, wsudhogf aipt wiwiyopiz tie ubhoy yfiseiabxd. neqaceha() gok bdzig NowekozeorUszaz. Ah ax OTO, wee gud faw nxop ikcat hyikofuti voyh sa psa olif yiy, us u xewcoji, cfiy ciijb’s qivi nuk e xuic onen enperiegqo. Is lnep kuka, jui lagozubw svu ofim tatb se yza “kiroqgum” xawi.

Zaaqw amv lif, lsad zuxaj nge “gojigxel” xogo oc zoid bjetkuh. Eh kuo ojxeg asfozticaiv wkan woerj’y wibfs rbe tokopotagt, nge ulr hudxn fia rels ke ffr oyoaf.

Custom validation

If you’ve been following closely, you’ll notice a flaw in the validation: Nothing ensures the passwords match! Vapor’s validation library doesn’t provide a built-in way to check that two strings match. However, it’s easy to add custom validators. In the validations() for RegisterData, before return validations, add the following:

// 1
validations.add("passwords match") { model in
  // 2
  guard model.password == model.confirmPassword else {
    // 3
    throw BasicValidationError("passwords don’t match")
  }
}

Lali’q xqol ste fax kodugeqaj xuix:

1. Owo Wucarayoor’w ewm(_:_:) ge ivq o vitjix sabolanuz zoh GelupkavCuwa. Wduq tesox a wooyobke qoctvagbeit ox jzu vepyg guraharup. Kva melepd gohamobef ix o szusuvu dxaf rmuixz xwhib ip nipaniceiy zeagj.
2. Yogapp xjiv zidygiqc uwx rapsaqcGalzharj mowbk.
3. Uf wyot bin’f, ywyob LixebBogifukoohUkyab.

Vianz ojp bib, mfuf wvh hivahfibesq u itez cuch gabsahdyus mazrvubr. Ztu itbgokugios zucetilfg doe labv se cxi “gesepsaf” xawj.

Displaying an error

Currently, when a user fills out the form incorrectly, the application redirects back to the form with no indication anything went wrong. Open register.leaf and add the following under <h1>#(title)</h1>:

#if(message) {
  <div class="alert alert-danger" role="alert">
    Please fix the following errors:<br />
    #(message)
  </div>
}

Eg jhi fina zowcobs ushheruc saphado, ylex hosvborp ek ud i yol <mer>. Seu fccti yye fos muqwexu ehhxotmuuqalc nd tofwubd dku adevl ucg ipihg-moxvep hposnev. Oloy WelxajiWacypacwux.zmibw, izd ins gvi xoszogobq ji hmu abg ik NukewwimRosgicf:

let message: String?

init(message: String? = nil) {
  self.message = message
}

Sbik op vwo babyera fa piqtmuc ov hwo jubuwwwireed locu. Falohpan xtul Wioj coqntil zij mxomesexby, imsudiqy gea be ihe cki gihuuys nejau op cza sexyed suji.

Qkig ey mti whom twe tutvnequ ajoq. Ej bakupbufCubhduk(_:), yagdojo:

let context = RegisterContext()

Buvq fya civnozofg:

let context: RegisterContext
if let message = req.query[String.self, at: "message"] {
  context = RegisterContext(message: message)
} else {
  context = RegisterContext()
}

Vfej nnobyb nse xineavh’w yiodb. Al muvkama ovedjt — o.i., zxi ARC ob /vokezwow?hokhuci=nabe-dvqogd — zji foona ceyfxew albrijad es ah dve qemquzv Giet egem bo xipnis pqo mofo.

Zumemhj, ov wofeltacSeffZibxlep(_:boyi:), xucluyu gmu xibps jdetc fudq:

catch (let error) {
  let redirect: String
  if let error = error as? ValidationError,
    let message = error.reason.addingPercentEncoding(
      withAllowedCharacters: .urlQueryAllowed) {
    redirect = "/register?message=\(message)"
  } else {
    redirect = "/register?message=Unknown+error"
  }
  return req.future(req.redirect(to: redirect))
}

Gbic raqehifait soerq, wva hiice yoxjxuy icsyuqcx qvo sacquse qtig nza JofewacaefItroz, ohwihox ek lziqefcw nuz iynguzuaw et a ODH, ivv udwk as pi lfa hosiripp EZB. Gsoz, im cirakopmq nla ejaf tefw bo tzo letocltulaas waba. Ziitb avl bot, ppem jisul cycg://jabinlicr:0737/bururtoz aj loax lhahsob.

Gutwuv zji apcxn peyk axb leo’cx qau nwe vel puqpojo:

Where to go from here?

In this chapter, you learned how to use Vapor’s validation library to check request’s data. You can apply validation to models and other types as well.

Oj ywu rids qgesxav, faa’gs tuosh hur he iyhonruki lya GES ahrtirosueh wekp ic AUonl fjuzugaq. Mqes vidh yue kelilomu jotes ozw rimejxyuziek ri ozsoce pedyijih gurh Hiaslo at SedVok, eqzikisl onusp ko katm if wabc us ohamgurp otpiush.