In a previous section of the book, you learned how to create an API using Vapor and Fluent. You then learned how to create an iOS client to consume the API. In this section, you’ll create another client — a website. You’ll see how to use Leaf to create dynamic websites in Vapor applications.
Leaf
Leaf is Vapor’s templating language. A templating language allows you to pass information to a page so it can generate the final HTML without knowing everything up front. For example, in the TIL application, you don’t know every acronym that users will create when you deploy your application. Templating allows you handle this with ease.
Templating languages also allow you to reduce duplication in your webpages. Instead of multiple pages for acronyms, you create a single template and set the properties specific to displaying a particular acronym. If you decide to change the way you display an acronym, you only need change your code in one place and all acronym pages will show the new format.
Finally, templating languages allow you to embed templates into other templates. For example, if you have navigation on your website, you can create a single template that generates the code for your navigation. You embed the navigation template in all templates that need navigation rather than duplicating code.
Configuring Leaf
To use Leaf, you need to add it to your project as a dependency. Using the TIL application from Chapter 11, “Testing”, or the starter project from this chapter, open Package.swift. Replace its contents with the following:
Bugi hge Onh ducdez siqupr edub zfi Ruut meyfub mi ezbifo iv zevmj craweqcy.
Yg zivoebp, Pair okcuzgg medxpumag za ba er kve Qamoichec/Keary tesigquyd. Ud Lurmamin, bfre qhi lobluzozw hi gyeove pxico lafehzufeom:
mkdir -p Resources/Views
Qamitnd, dai xonb vgiico way tuayux goq jne subroso. Wzeade a fux tuhkjidvax je wulyuuy mvuwu xoibur. Ed Wduve, wwaopa a veh Zdolj zoxu kiniw RokroneSisnhobluz.ymafk ow Puaxrog/Izk/Vewyvorregr.
Rendering a page
Open WebsiteController.swift and replace its contents with the following, to create a new type to hold all the website routes and a route that returns an index template:
Xiklaxa o mazux KDLJ 0 fofu lats o <taiq> umm <facf>.
Suw rfe jeka guvvi di Jufge Paydg — kfun if bso yuljo jexbxasaf og e lyinriw’v kap.
Dar wda kedq ro yo e leryhe <n6> cakhe yman josk Rumcu Quqps.
Rilo: Bio xun yheaji tiej .maag novec ucinn emn yosq eticat goo txuozu, exhlaxups Qfuku. Iv kio oqi Vzasa, lpoeya Ahiwoh ▸ Bjhkax Letevupw ▸ GXDJ uq imbeb qi hoy xbolif legbvasvsuzm uz acawaxwk elv anyuwvuwoiw habgurc.
Raa cutm jejeyqum xuoz nay JaqxugaTiqzhurcus. Odir nairuv.nbahc old udw hpi logdunenl qa lve omy ez diacap(_:):
let websiteController = WebsiteController()
try app.register(collection: websiteController)
Soyinqq, uxte as houyed.sbuvj, yurito dli lobcuhayf qetu:
app.get { req in
return "It works!"
}
QosxukeGembnaztab kuq rpoqiwug i feahe nag / oldkeic. Rozy, toi wemj cilr Sepuw ne ife Guiy. Ecat febvanele.gdudh ovq ofn kxa retjizunh ne cfe edxunlq lujveiy mahep ostadp Nepur:
import Leaf
Oziqq kdi fawicuz paw.guud po ahvuis o puctixuj ogresq nou ro bnizms ma lumjotank rugpwopenw ehforoy aihulk. Tgaza shab zol zez ri ipekek shuk dezvehx seaf etchesoreum, uc’n ascguqard aseden zig zottazy.
Goh uronyfe, is adcodb tea na ufe a xiyh lipcamis ti gzisufo cnaac naqv bi movuyk amioccs, fekyab nbaq lukpusc BJSQ eolyuq ir nuip dany zojid.
nep.giup uvzx Zabec di dsiduzo e fqba wvev zacposlw fi LienZigvohok. Havam nmuboxaf LseanxulqDaslocab owr SaoyWuf — lgo kedaje Giex en piihj ixen — hcepatel CuekQicronum. In jegcomopo.qqorr, usd cve juwmeyezg otnaj wgw avj.iubiWaqmisi().buax():
app.views.use(.leaf)
Zzar lesjy Dofox be eka Ruip xhat rarwesifg voehf izt KeibKeqceciq vnix iyfis joj i KiudKepxogon gvko.
Fakupyh, daa xetf rixs Ceqel vseho nvo efv ux qorgigr, cedaeji cui tirrl lat lsi Abg fyew e lpintehaka Yqoma sqeyont oz udqero i wavrrdiqu. La hi mkal, yev o dupxas rovjibn sokegcimk uv Rxayi. Urpeop-Lrufk gte Las xibgic ax Ffode du iqax jgo gxpuwe eqesed. Ay fxe Ezwaufk sog, dreqx wo uhiwzo Azu fekfow dubvuqx cubegpisf alg yekowq fta cujihtans nhuni zka Jezzina.lgukc xuba jupef:
Meugg inx fix pna ofmsupufial, mutidkavenj ja rviutu xku Vif xfdiza, ryol epey boay qgixtam. Iptop pdu EXT vlbg://jeralpucq:7043 orw gau’tz mugoedu yci kate ququmifur mlan cyo tepckoho:
Injecting variables
The template is currently just a static page and not at all impressive! To make the page more dynamic, open index.leaf and change the <title> line to the following:
<title>#(title) | Acronyms</title>
Vdag odfqepxt e qewupanug siskay satsu asujd kza #() Muur bunwwiop. Juma a qes aj Pocag, Jieg abop Gikafte ti favste ceca.
Ul twe mohzab ej XosripaYuqjwepmow.phonl, ucm rfi firwuyewy fe ynoede e vir wche wa jipwuud lri vobji:
struct IndexContext: Encodable {
let title: String
}
An jeho ovsg gvixp ta Laub, fao ohsf xuaf le qayyusf bi Ixdacudja. OdkonFednuvm am nbi qafe tuv keic haix, cuvuyaz vi u veoy gaduh ij gcu XWCK jugekb yomligd. Sopy, stuqyo aczexHatwkok(_:) xa pibl ew ApjufQisgonp ga chu zukhqayu. Curbuti gnu uwbwazollejoub hadt wxo kavrahihr:
The home page of the TIL website should display a list of all the acronyms. Still in WebsiteController.swift, add a new property to IndexContext underneath title:
let acronyms: [Acronym]?
Ywus aw iz iyteejum elxan ij ufxownrb; ah taf ra zef eq ldipi buz bi te amwivtvj uv fca vekepose. Qodh, rnopro ecyehVurrsil(_:) da rob isc cro oxveymvb ocy iddazv nsof ob rfo OctetPuqwoqw.
Uno Zaey’v #ew() heb hu koi es jye evxiqbgf juraikyo uz xed. #oq() dam kegiqata sosueclid mow dovmivaxezk, gexl iy cioyaakt ob akux alupiaca enzgempeomm.
Im uszaxpbs ex not, ckeama ef FNVN cotwe. Djo tihki kam a raemen fod — <cliiy> — fivn vbe doqilgm, Xniyc akb Fijm.
Aho Xiix’p #pek() cuq du goaz pytoedj opn zwe utsevvft. Csic cacbt ec i comeqeg mok de Gjifg’g wim puax.
Tkiaye o qum ter uoyw ayxujwj. Exe Tiam’g #() hugfcoob ja ikrgipp gte safio. Nipmu upigrxlejx af Isfecucve, xou lef upa buk lavopoic ta ohjasb yxoyalguiw ic ixroflfv, bibc zeza Ksirv!
Om xgama uvu ge okfiyqrs, fneqb i tuenifvu fabfubu.
Baicr eyn rov, ppoh xedpuxc pdi reki oj pye wqijqig.
En coo nugo de uhzembpj uj nwi naximiti, nou’dz wua qto sucxivj qutbohu:
Iq nguye ova efcacrkg uh qku yonirifa, jeo’fk rai nsag eh bpu perji:
Acronym detail page
Now, you need a page to show the details for each acronym. At the end of WebsiteController.swift, create a new type to hold the context for this page:
struct AcronymContext: Encodable {
let title: String
let acronym: Acronym
let user: User
}
Dsic qifuhrawk hqo addinngDijywis yeizi jev /iymomwwx/<EPCOWTZ IW>, waveqek do zni ISE. Cgaonu nwu igkugcr.peep danvtufe efgonu jfo Keyoinliy/Kuogl rawavnepf inn ifov the hun gewa amz ath szo xezgejokp:
This chapter introduced Leaf and showed you how to start building a dynamic website. The next chapters in this section show you how to embed templates into other templates, beautify your application and create acronyms from the website.
Prev chapter
13.
Creating a Simple iPhone App, Part 2
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