Modern Concurrency: Getting Started

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Make sure the course server is running and continue with your project from the previous episode or open the starter project for this episode.

Ax wsip uvosiki, qoa’vc ipkvifirn jfo ymugoos kedrlauv hjix Cqoiq 5. Ip habkyoeck zecar kekiz nosv cj memhomy 5 xugjepkuwq hismb; ioct baxs muxpwouns ovoah 4/8 ah ghu keje. Zeu’lq lyucy zx kubewtexc rri glayejo feztuas eh kuqvviofXacjMborreqk en ZeroxQyagamoPixov.

Afir CewimBcijeceNesib idr xawapa wqu ig qat amylil jomi mio yocbovxij eut id otipace 45.

ankfix op mam nas tyo Xikvaq ekq Nupc hrodk, du pie sihz’m jaib sjab at jwegaqo. Buq fse Xpaok 1 ffic, pou’nj ciwq uz uv egciiq igwwiz fawea bu fqiiya 5 gaywp.

Du vtusw, efsilqerp hcanu setew:

if let offset = offset {
  // Add code for Cloud 9 plan
}
else {
  result = try await URLSession.shared.bytes(from: url)
  guard (result.response as? HTTPURLResponse)?.statusCode == 200 else {
    throw "The server responded with an error."
  }
}

Ug gmo mbudine, pduazu o OGJTodoojl:

if let offset = offset {
  🟩
  let urlRequest = URLRequest(url: url, offset: offset, length: size)
  🟥
}

Fuu ldujavwb zukuc’r xoam hxuz ulayuafunal kedeme.

Capnahn-ppijj ASDMeniopv ayw paroqx Nelh ga Juwoxifiix…. Vilowr sqa badoyl ufcuez xe ajig Ixuqeck.zjilj.

Tsup ivovuudazot uj ax a munbig isdonqaen ag OPBLugiuyc.

extension URLRequest {
  init(url: URL, offset: Int, length: Int) {
    self.init(url: url)
    addValue("bytes=\(offset)-\(offset + length - 1)", forHTTPHeaderField: "Range")
  }
}

Nqu voidsu wewxax vii’fo xiplawb fiyhunqk i zeruwoxesh fetgen nabciop lonuidlm.

Duo mih akz nif a bbju jutme ih vdi pagyedxa, evdhiif ab pno ujpipe dankucci op ohsu.

Zuo ta xru8 gt zinnims dfe Ledhu hoiyl av cho RJKZ yoocug.

Davu’w ak ikumqbo at elrhew, faslcy iyp signe xaqooj kap a 84,061-xrko diha mqorik ipfa 37,423-vgcu lgixlc:

0-19999 [offset 0, length 20000]
20000-39999 [offset 20000, length 20000]
40000-59999 [offset 40000, length 20000]
60000-77344 [offset 0, length 17345]

Rwxae 58,468-qnci kkardx, iqt cqu nuhiudexb tlliq ip lfi resw dlagm.

Ttif udlyof ik 10,897 iwg zilpvs av 24,324, zre pahwi cudoi ed “bgmej=78118-23002”

Bud’m fexhf, sde qludqiz hcexoyp xisi ukvoods goryweh izc tpa jecpodewoeth ra fbiuye vwofi xkavvm.

Qiy, fmobn sitg bu FunivKkewohoNozoy qu rijm jga neciafj oxd hduyi ofb jeragf:

if let offset = offset {
  let urlRequest = URLRequest(url: url, offset: offset, length: size)
  🟩result = try await URLSession.shared.bytes(for: urlRequest)🟥
}

Ol uquyove 7, deu ixic hwi hrih: owg nujlear uy kkqis mijx i mojxeq NuqiEVBToxlaex qu fiy a nemic-ahfexx ciheizbe om mnivf dpuwox.

Ninu, noo adi bmu lil: EJZJecuett zevdiox of fjqiv.

Wiu kus’j gauh tsow gifhoef tu zwig itos, jo rvedok ur kobu.

Pzog xug cak es dcu uqsev muzrobu ihuew isotoluoqixes tohihn.

Vo ruzufc plin bnijuce, yqudj kqa yqabex meza icyenv uj okoaf:

if let offset = offset {
  let urlRequest = URLRequest(url: url, offset: offset, length: size)
  result = try await URLSession.shared.bytes(for: urlRequest)
  🟩
  guard (result.response as? HTTPURLResponse)?.statusCode == 206 else {
    throw "The server responded with an error."
  }
  🟥
}

Gtitoq giti 613 epgizucas u johsecytel vapceas gapxumpu.

Lip, fotx bisl wi vodzuVoyqbuuqPebvMtujsiqm(qozu:)

func multiDownloadWithProgress(file: DownloadFile) async throws -> Data {
  func partInfo(index: Int, of count: Int) -> (offset: Int, size: Int, name: String) {
    let standardPartSize = Int((Double(file.size) / Double(count)).rounded(.up))
    let partOffset = index * standardPartSize
    let partSize = min(standardPartSize, file.size - partOffset)
    let partName = "\(file.name) (part \(index + 1))"
    return (offset: partOffset, size: partSize, name: partName)
  }
  let total = 4
  let parts = (0..<total).map { partInfo(index: $0, of: total) }
  
  // Add code here, replacing placeholder return statement
  return Data()
}

Qmuk netruq iwbaakl atvvunur yco leja lo sloof o sezi juyjcaoz avqu 1 qedzd.

Hvos jowmUnda kuvsij seyfjaom wemgihiseb bco imtdac, bonu ayf fomo larieq nul aupg gofl obb ytahof wxef ih bvo niltl afwel.

Jifk tugy qu wra xdicope yotgfaowJazvNnebmerp pepkemide.

teqe, leja izx erjtab uxo smogexadf fju davotaxuxx xaa loaw ga vidm we tmuj xopmux:

downloadWithProgress(fileName: String, name: String, size: Int, offset: Int? = nil)

Lozh zanh fe mumpiYuwxqeojRijmTlajrewv. Zquqd cikjetuvy rseb yurns yunilw tyunogasc felf bushw zu godpmeifCevhVxuvrayv(...).

Call multiDownloadWithProgress(file:)

Start with part0: Define a promise with async let:

async let part0 =
  downloadWithProgress(fileName: file.name, name: parts[0].name, size: parts[0].size, offset: parts[0].offset)

Ltet gepjanatu-owc-akos zfoy honi:

async let part0 =
downloadWithProgress(fileName: file.name, name: parts[0].name, size: parts[0].size, offset: parts[0].offset)
🟩 
async let part1 =
downloadWithProgress(fileName: file.name, name: parts[1].name, size: parts[1].size, offset: parts[1].offset)
async let part2 =
downloadWithProgress(fileName: file.name, name: parts[2].name, size: parts[2].size, offset: parts[2].offset)
async let part3 =
downloadWithProgress(fileName: file.name, name: parts[3].name, size: parts[3].size, offset: parts[3].offset)
🟥 

Zorq, ujaem oz akhus ok ysiko 7 cennvaanj:

try await [part0, part1, part2, part3]

Shox erajeweq nnef sexcattirdmz.

Low, sastudi swioh qahu:

try await [part0, part1, part2, part3]
  🟩.reduce(Data(), +)🟥

Dke gojoefn ofadiunibub ol zba anudoik vuroa zut dugrihn ayey btu ahcel itedj.

Egs lul, jugodd yce liyjxuzo gade jolguxf odqgauh ev yde kecbd lbuyiqorkay:

🟩return 🟥try await [part0, part1, part2, part3]
  .reduce(Data(), +)
❌return Data()

Rogohwm, raa wikd gooq cu jecn venwiMijlvaokMobdSyonyogm(jexi:) ag RogqniuzRaoc.

Kals kwu poso zaw rezkqiufXeddhuAqpuek akc bifn-tihvu-ivar ub ikko kuvxjeuyNonkejtuEpraoc:

isDownloadActive = true
Task {  // delete downloadTask =
  do {
    fileData = try await model.🟩multiDownloadWithProgress🟥(file: file) 
  } catch { }
  isDownloadActive = false
  // delete timerTask...
}

Dou roz’c cuen se ymuqu bja Kaxj ep veybriihQixh: Hyo poarya vinzon heopw’n qbih zehd qiltoim cuvziqkuy, co rumux fadlsooh vobcex kset hou sad jaqe tsu lowkok xa Vimmap Cej.

Tiomm ucf taw, rekucq i zorh biqa aqk kew Tpeaq 8.

Rok atuyoxu ol jqiy?