在 Swift Vapor 中返回一组响应可表示对象的最佳方法是什么？

debugcn 发表于 Dev

查尔斯·肯尼

语境：

最近，我决定从事 Swift 服务器端开发，因为我认为 Vapor 框架非常酷。我在试验过程中遇到了一些困难，想要一些关于叶和蒸汽模板的建议。

在渲染视图时，我已经多次查看文档。使用变量渲染模板化视图需要叶模板的名称和包含变量的响应可表示节点对象。

尝试使用模板和框架本身制定一个场景（因为这是我最好的学习方式），我尝试模拟博客格式。这是我的课程/获取请求：

// MARK: Blog Post Object

final class BlogPost: NodeRepresentable {

    var postId: Int
    var postTitle: String
    var postContent: String
    var postPreview: String

    func makeNode(context: Context) throws -> Node {
        return try Node(node: [
            "postId":self.postId,
            "postTitle":self.postTitle,
            "postContent":self.postContent,
            "postPreview":self.postPreview
        ])
    }

    init(_ postId: Int, _ postTitle: String, _ postContent: String) {

        self.postId = postId
        self.postTitle = postTitle
        self.postContent = postContent
        self.postPreview = postContent.trunc(100)
    }
}


// MARK: Blog view request; iterate over blog objects

drop.get("blog") { request in
    let result = try drop.database?.driver.raw("SELECT * FROM Posts;")

    guard let posts = result?.nodeArray else {
        throw Abort.serverError
    }

    var postCollection = [BlogPost]()


    for post in posts {
        guard let postId = post["postId"]?.int,
            let postTitle = post["postTitle"]?.string,
            let postContent = post["postPreview"]?.string else {
                throw Abort.serverError
        }

        let post = BlogPost(postId, postTitle, postContent)
        postCollection.append(post)
    }

    // Pass posts to be tokenized

    /* THIS CODE DOESN'T WORK BECAUSE "CANNOT CONVERT VALUE OF TYPE 
     * '[BLOGPOST]' TO EXPECTED DICTIONARY VALUE OF TYPE "NODE"
     * LOOKING FOR THE BEST METHOD TO PASS THIS LIST OF OBJECTS
     */

    drop.view.make("blog", [
        "posts":postCollection 
    ])

}

这是我的blog.leaf文件：

#extend("base")

#export("head") {
    <title>Blog</title>
}

#export("body") {

    <h1 class="page-header">Blog Posts</h1>

    <div class="page-content-container">

    #loop(posts, "posts") {
        <div class="post-container">
            <h3 style="post-title">#(posts["postTitle"])</h3>
            <p style="post-preview">#(posts["postPreview"])</h3>
        </div>
    }

    </div>

}

问题：

如您所见，我在寻找迭代对象并将它们的属性模板化到叶文件中的最佳方法上有些困难。有人有什么建议吗？顺便说一句，抱歉糟糕的编程约定。我是面向对象/协议编程的新手。

查尔斯·肯尼

我最终做的是使 Post 模型符合 Model 协议。

import Foundation
import HTTP
import Vapor


// MARK: Post Class

final class Post: Model {
    
    var id: Node?
    var title: String
    var content: String
    var date: Date
    var isVisible: Bool
    
    // TODO: Implement truncate extension for String and set preview
    // to content truncated to 100 characters
    
    var preview = "placeholder"
    
    var exists: Bool = false
    
    init(title: String, content: String, isVisible: Bool = true) {
        
        self.title = title
        self.content = content
        self.date = Date()
        self.isVisible = isVisible
    }
    
    init(node: Node, in context: Context) throws {
        
        let dateInt: Int = try node.extract("date")
        let isVisibleInt: Int = try node.extract("isVisible")
        
        id = try node.extract("id")
        title = try node.extract("title")
        content = try node.extract("content")
        date = Date(timeIntervalSinceNow: TimeInterval(dateInt))
        isVisible = Bool(isVisibleInt as NSNumber)
        exists = false
    }
    
    func makeNode(context: Context) throws -> Node {
        
        return try Node(node: [
            
            "id": id,
            "title": title,
            "content": content,
            "date": Int(date.timeIntervalSince1970),
            "isVisible": Int(isVisible as NSNumber)
            ])
    }
    
    static func prepare(_ database: Database) throws {
        
        try database.create("Posts") { posts in
            
            posts.id()
            posts.string("title", optional: false)
            posts.string("content", optional: false)
            posts.int("date", optional: false)
            posts.int("isVisible", optional: false)
        }
    }
    
    static func revert(_ database: Database) throws {
        
        try database.delete("posts")
    }
}

然后返回/创建 Post 对象的实例：

import Vapor
import Foundation
import HTTP

final class BlogController {
    
    func addRoutes(_ drop: Droplet) {
        
        let blogRouter = drop.grouped("blog")
        let blogAPIRouter = drop.grouped("api","blog")
        
        blogRouter.get("posts", handler: getPostsView)
        
        blogAPIRouter.get("posts", handler: getPosts)
        blogAPIRouter.post("newPost", handler: newPost)
    }
    
    // MARK: Get Posts
    func getPosts(_ request: Request) throws -> ResponseRepresentable {
        
        let posts = try Post.all().makeNode()
        return try JSON(node: [
            "Posts":posts
            ])
    }
    
    // Mark: New Post
    func newPost(_ request: Request) throws -> ResponseRepresentable {
        guard let title = request.data["title"]?.string,
            let content = request.data["content"]?.string else {
                
                throw Abort.badRequest
        }
        
        var post = Post(title: title, content: content)
        try post.save()
        
        return "success"
    }
    
    // Mark: Get Posts Rendered
    func getPostsView(_ request: Request) throws -> ResponseRepresentable {
        return try getPosts(request)
    }
    
    
}

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