0

我正在尝试使用带有 Alamofire 的 Promisekit 的 while 循环来链接四个 GET 请求，返回一个值，然后使用新参数重新运行四个请求。这是我正在使用的当前代码：

        var index = 0
        var count = classDictionary["class"]!.count-1

        while index <= count {

        firstly {
            parseBooksXML(index)
            }.then { abrevCode in
                self.parseBooksXML2(index, key: abrevCode)
            }.then { courseNumber in
                self.parseBooksXML3(index, key: courseNumber)
            }.then { instructorCode in
                self.parseBooksXML4(instructorCode)
            }
            index += 1
        }

前三个函数中的每一个都返回一个承诺的字符串值，然后将其传递给下一个函数，直到第四个也是最后一个函数调用另一个函数来使用 Kanna 解析下载的 HTML。

理想情况下，我希望调用并完成所有四个函数，之后索引将递增并使用新的索引号再次运行循环。需要注意的是，传递给函数的索引是一种识别数组中的哪个索引值应该与哪个索引进行比较的方法。

为清楚起见，我在下面包含了 parseBooksXML 函数的代码：

func parseBooksXML(index: Int) -> Promise<String> {
    return Promise {fulfill, reject in

    let headers = [
        "Referer": "URL"
    ]


    Alamofire.request(.GET, "URL", headers: headers)
        .responseData { response in

            switch response.result {
            case .Success:
                let xml = SWXMLHash.parse(response.data!)

                do {

                    let range = self.classDictionary["class"]![index].rangeOfString("[a-zA-Z]{2,4}", options: .RegularExpressionSearch)
                    let result = self.classDictionary["class"]![index].substringWithRange(range!)

                    try self.abrevCode = (xml["departments"]["department"].withAttr("abrev", result).element!.attribute(by: "id")!.text)

                }
                catch {
                    print("Error: \(error)")

                }
                fulfill(self.abrevCode)

            case .Failure(let error):
                print(error)
            }
        }
    }
}

func parseBooksXML2(index: Int, key: String) -> Promise<String> {
    return Promise {fulfill, reject in

        let headers = [
        "Referer": "URL"
    ]


    Alamofire.request(.GET, "URL", headers: headers)
        .responseData { response in

            switch response.result {
            case .Success:
                let xml = SWXMLHash.parse(response.data!)
                 do {

                    let range = self.classDictionary["class"]![index].rangeOfString("\\d\\d\\d", options: .RegularExpressionSearch)
                    let result = self.classDictionary["class"]![index].substringWithRange(range!)

                    try self.courseNumber = (xml["courses"]["course"].withAttr("name", result).element?.attribute(by: "id")?.text)!

                 }
                 catch {
                    print("Error: \(error)")

                }
                fulfill(self.courseNumber)

            case .Failure(let error):
                print(error)
            }

        }
    }
}

func parseBooksXML3(index: Int, key: String) -> Promise<String> {
    return Promise {fulfill, reject in

        let headers = [
        "Referer": "URL"
    ]

    Alamofire.request(.GET, "URL", headers: headers)
        .responseData { response in

            switch response.result {
            case .Success:
                let xml = SWXMLHash.parse(response.data!)
                do {

                    let range = self.classDictionary["class"]![index].rangeOfString("[a-zA-Z]{1,3}?\\d?\\d?\\d?$", options: .RegularExpressionSearch)
                    let result = self.classDictionary["class"]![index].substringWithRange(range!)

                    try self.instructorCode = (xml["sections"]["section"].withAttr("instructor", self.classTeacher[index]).element?.attribute(by: "id")?.text)!
                }
                catch {
                    print("Error: \(error)")


                }
                fulfill(self.instructorCode)

            case .Failure(let error):
                print(error)
            }

        }
    }
}

func parseBooksXML4(key: String) -> Void {

        let headers = [
        "Referer": "URL"
    ]

    Alamofire.request(.GET, "URL", headers: headers)
        .responseData { response in

            switch response.result {
            case .Success:
                self.parseISBN(String(data: response.data!, encoding: NSUTF8StringEncoding)!)

            case .Failure(let error):
                print(error)
            }

        }
    }

任何帮助，将不胜感激！

4

2 回答 2

2

您需要使用when：

let count = classDictionary["class"]!.count-1

let promises = (0..<count).map { index -> Promise<ReplaceMe> in
    return firstly {
        parseBooksXML(index)
    }.then { abrevCode in
        self.parseBooksXML2(index, key: abrevCode)
    }.then { courseNumber in
        self.parseBooksXML3(index, key: courseNumber)
    }.then { instructorCode in
        self.parseBooksXML4(instructorCode)
    }
}

when(fulfilled: promises).then {
    //…
}
于 2016-09-12T06:43:20.240 回答
0

由于 parseBooksXML4 调用是异步的，因此您应该包装 parseBooksXML4() 调用以返回 promise 并等待其完成，然后再增加索引。

    firstly {
        parseBooksXML(index)
        }.then { abrevCode in
            self.parseBooksXML2(index, key: abrevCode)
        }.then { courseNumber in
            self.parseBooksXML3(index, key: courseNumber)
        }.then { instructorCode in
            self.parseBooksXML4(instructorCode)
        }.then { _ in
            index += 1
        }
    }
于 2016-09-11T19:37:53.740 回答