Question

我正在尝试使用BrightFutures在SwiftExpress中创建一个基本的异步示例，并且失败了。这就是我所拥有的：

class FileSystem {
    class func read(fileURL:NSURL, convert:(NSData?) -> Action<AnyContent>) -> Future<Action<AnyContent>, AnyError> {
        let promise = Promise<Action<AnyContent>, AnyError>()

        Queue.global.async {
            let fileData = NSData(contentsOfURL:fileURL)
            let action = convert(fileData)
            promise.success(action)
        }

        return promise.future
    }
}

这是服务器：

import Express
import TidyJSON
import BrightFutures
import Result

let app = express()

app.views.register(JsonView())

// Parameters: JSON object {"filePath" : "<filePath>"}
app.post("/readFile") { request -> Future<Action<AnyContent>, AnyError> in
    //check if JSON has arrived
    guard let json = request.body?.asJSON(),
        let jsonDict = json.object,
        let filePath = jsonDict["filePath"],
        let filePathString = filePath.string else {
        return future {
            var response = [
                "status": "error",
                "message" : "Invalid request"
            ]
            return Result(value: Action.render(JsonView.name, context: response))
        }
    }

    print("json: \(json)")
    print("json: \(json.object)")

    let url = NSURL(fileURLWithPath: filePathString)

    return FileSystem.read(url, convert: { data -> Action<AnyContent> in
        var response = [String:AnyObject]()
        var status:String

        if data == nil {
            status = "error"
            response["message"] = "Could not read file"
        }
        else {
            status = "ok"
            response["result"] = data!
        }

        response["status"] = status

        return Action.render(JsonView.name, context: response)
    }).onSuccess { action in
        print("action: \(action)")
    }
}

app.all("/*") { request in
    return Action.ok("Got a unknown request.")
}

app.listen(9999).onSuccess { server in
    print("Express was successfully launched on port", server.port)
}

app.run()

当我使用Postman连接到此时，我得到一个“{}”作为回应。我可以设置断点，我知道代码正在执行，我知道我有一个错误（它无法找到文件 - 我本人故意），只是看不出为什么响应没有错误状态和消息。想法？

Answer 1

问题解决了！单行错了：

var response = [String:AnyObject]()

需要：

var response = [String:String]()

在使用Bright Futures的Swift Express中，如何处理异步操作？

1 个答案: