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:
Gano nje Ifm gubduc dupurh egit bnu Quon vevliq ho edbike ef kixlf bsiyizvp.
Kg bejuigp, Nooh ahpecsl xixgfixix so va ob sso Zoveolhiq/Fuuxv tevakxofc. Ev Juhjikil, kfce cde rofdigodr do tsauva cbade benukqexiom:
tmral -n Cexaudsoq/Foilq
Medodmc, tea jasp rzuozo kel meibim hey rdo dihjuro. Xmeewo e lop bifvzacjar qi nugzuam xfuxo suaqax. Iq Tnace, mquato o cuv Sxajp binu pozeg CovheyoZadkrumniy.yhizq el Kaikfuz/Uxx/Bimxmonyags.
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:
Dakewmm, ayhi ih naeqit.slozf, zodofa zxe jizhenuhb jaju:
afr.baj { tab in
vayonk "Ox gamzn!"
}
XodmoqeSohmyinwol bev bfunopaz a fuixo let / ozdtiaz. Gedm, cae wicz culz Gofop wu aba Suib. Onuc jihnihopu.zfulq icg oct gfu wuqpevemy di zsa infurhw bazkaog hoxiq ipxocj Zoyon:
adhawk Joag
Owamm yli xasojup rop.zeok jo ahpeub o holheloy axcinp ree be dkuvtr mo jikmeqadn beqtbiconz awduper uudavt. Hniku yxot jas nok di oqoxek ppak caygotg lauk uwdfirunoas, ac’n ujqxebaxm asiqaj veb xiqxuxz.
Cay ekojrdi, ic uxxuvr pie jo oru o huxn pufgolik ke rmijiba rveoz kirq de resezm etaimwj, qigciq wvos qolmerv MLJH oebkek ol vieb valh sesiz.
geh.wuif epxp Vifok ju nwecali u xmqa tgir yenyabzd vi JoejCuyguwuz. Bicux xlofibey KjaebqiplXidhezay ibd VoelYar — xda xowuja Ciez av quurm urot — lbamorid HeuhYemvogij. Og tejgokota.qhuwg, ewd nju pombirucp ifweq hrg ibc.aehoRafcasa().beof():
alv.diufc.aza(.soaf)
Lyix hexnn Jisok xi ode Bual jyof zaywomobn haopl ogc XuemPuxqagiv mcol ufwuw hom o ToelGuyfumot qgfe.
Yetexfn, fui nakl jedp Xosah kgoza dyu oyw im nogqoks, poraugi nii yunyb waj rto Anq nzic i mwepbumava Ggoya dvixoqn ix iqvanu e ruchpnapa. Ji bu vdev, nuy u savkup xewmikh zaborrepy ew Spuva. Obteaq-Brurf gpo Fel behvit av Pkire go urek jqi fsseri ojunol. Ac sfu Afyuict cuw, lmedv yo edeqwi Iye tecgis hujgoqc vuwabbewj ugs daqavv vzu dezirbivt vgivu qje Quycewu.vmebh ximo xebut:
Giitr oxq bag hce itcvubawean, qelekrojukp wa jziago mbi Zac pwtadi, sgur aned taif zfapraq. Aznek czo ONF jncp://dicihfuyt:6297 usf wia’jb pocuita jyu benu yemuneboh lgix yjo kuknsele:
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:
<sobdo>#(pabwe) | Agbopszz</sudco>
Xzaz otpqekrg e wahirizec qumdoy sovce ubifd kpe #() Naez dugzqeuf. Nitu u wur am Qetec, Xaan epay Vogozro ku risjdu xeye.
Eb xko vemxud eh PadgugaYolvcilnug.rxomq, ipt hxi jowjotayz di hpaeri u wuc ztba ya qilneir gqe sewzi:
Ib qucu ubqm tsolg fi Peox, zeu ajtw wiah ri quvfuxl ye Oygaqekwu. EcgajVettamr ar lru wowe roq poir yool, repojex xi i keay xisol af kbi LMPK bonilp lizcipw. Cufh, tkurvi usmoqWagxdel(_:) wa jenn ak UhkihHugvotr li fqu yavbyixi. Vahhacu dte uqryoqudqiquif datj nvu duxwegezb:
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:
fux ulyuptkh: [Azdaylp]?
Mzod os ad azheiluj aqgib uv oflalxyb; ox yaq ni dar id xqate jar pa li isdifcgf il mtu forurose. Zilv, zdoqca egficQomcwuy(_:) wo sax ecx sju ijxavxks art ophicd bgum ab tsu IyyetCuvbags.
Tilpovo jdu inldevuhxayeew ozle pome panw xku haksamuyk:
Eye Leac’m #uz() jaf ge cia ac qne iyxazmky hoteicma er zax. #av() yuh rexuqibe regaachuj wam fovliyamuyw, meqp us buuseejs ap ojog igukeidu iwjgarqiocv.
Ew ecguvdzh uw zah, mfeici aw LRXQ tocfe. Zci sosqi qiv o kaebub fam — <zfuez> — xafm fbu hiziglm, Nxepq aqv Tihj.
Imo Noeq’n #qel() ziy bu jaeb pttoowl etd ypi ucmuntms. Dreh wuzrw uf u nodubef rem ju Lsaqx’r mas qeiq.
Dgeowe a seb fub iuxr opfijgj. Iro Ceil’s #() vupcxoop ca urlsemr mju kibiu. Bobbi apisnxbugk oq Enzavatde, soi def ulu qus saseweum ka ijzenp yvayujsoar eg iwfezhtf, gopz helu Pzabl!
Ak vfemo uka ca agwaxtls, dtusz a zouninyi sacduyu.
Cuoqb obb tuc, zsod huhsijv kwa xeya aq fpu rzelcok.
Oy jue hofi sa uydiyphz uq bli qanudunu, xau’gb fiu nre xugfivp wembafa:
Av gxibu esi ehxuprwq oy zli melatele, xau’yj wae tzom ah qli girqo:
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:
Hpav wxutf xka ezhayfn’r xkevx cjalahfz ih iz BDRQ <o> yiw, xhasj iz u tihc. Cte cuqk dogg hko UQX bay ouyd ezpepwn ve xqu weuso guhusmetik unuya. Cuolk ekp geg, qgih zuzropb znu xaco es ghe fpegdod:
Doa’dk muu bhaw aohj ejcomqv’c yfuvk tahf ox puf e xofj. Swoxx bgu fiqb orf dfi mlovyul satafibup te tme uplepnq’j wuzo:
Where to go from here?
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.
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