用Cocopod建一个framework

framework 和 library的区别
要了解什么是library。首先library分为static和dynamic。Static library是指有连接到一个文件，这个文件是有binary code，是在comile time feature，需要连接application里的binary，一般只会某个指定的application使用。而dynamaic一般会在多个application里使用，同时它是run time feature。一般来说static都是较大的文件，而dynamic会是比较小的文件。

回到framework和library。一般的framework是dynamic，是较小的file，和同时间多个application都可以使用。file的末尾会加
.framework
而static library就是一些比较大的file，它会在comlite time的是时候和application的resource code做linking。library有dynamic也有static
Static libraries — .a
Dynamic libraries — .dylib
小结：可以想象 static library都是一些source code，里面只有代码，而framework大多都是dynamic，所以它可以在里面加入图片，字体之类的asset。

接下来开始建造一个framework。我会用我之前写的networkFramework通过cocopod做出third party framework。

public protocol Session {
    func getData(with url: URL, completionHandler: @escaping (Data?, Error?) -> Void)
    func getData(with request: URLRequest, completionHandler: @escaping(Data?, Error?) -> Void)
}

extension URLSession: Session {
    public func getData(with request: URLRequest, completionHandler: @escaping (Data?, Error?) -> Void) {
        self.dataTask(with: request) { (data, _, error) in
            completionHandler(data, error)
        }.resume()
    }
    
    public func getData(with url: URL, completionHandler: @escaping (Data?, Error?) -> Void) {
        self.dataTask(with: url) { (data, _, error) in
            completionHandler(data, error)
        }.resume()
    }
}

这里做了一个dependency inversion，这把两个dependency调转了过来。在使用的时候更加方便，同时我们还可以使用其他的session进行代替，如alamofire。

public class APIRequestLoader {
    let apiRequest: APIRequestConfigure
    let urlSession: Session
    
    public init(apiRequest: APIRequestConfigure, urlSession: Session = URLSession.shared) {
        self.apiRequest = apiRequest
        self.urlSession = urlSession
    }
    
    public func loadRequest<T: Codable>(completionHandler: @escaping ((T?, Error?) -> Void)) {
        guard let request = try? apiRequest.makeRequest() else {
            completionHandler(nil, NetworkError.invalidRequest)
            return
        }
        urlSession.getData(with: request) { (data, error) in
            guard error == nil else {
                completionHandler(nil, error)
                return
            }
            guard let data = data else {
                completionHandler(nil, NetworkError.noData)
                return
            }
            do {
                let decodedData = try JSONDecoder().decode(T.self, from: data)
                completionHandler(decodedData, nil)
            } catch {
                completionHandler(nil, NetworkError.invalidJSONData)
            }
        }
    }
}

其他的和networkframe都一样，需要注意的是把class， function， protocol都需要加public，这样在其他file中就可以共享使用。
最后是在terminal里输入pod init。文件里会生成一个podspec的文件。在这个文件里需要输入官方的信息。

Pod::Spec.new do |spec|
  spec.name         = "NetworkFramework"
  spec.version      = "1.2.0"
  spec.summary      = "Let's use my networkFramework"


  spec.description  = "NetworkController can be use in swift"

  spec.homepage     = "https://github.com/grm121616/NetworkFramework"

  spec.license      = "MIT"
  # spec.license      = { :type => "MIT", :file => "FILE_LICENSE" }

  spec.author             = { "Jerry" => "niuBchen@hotmail.com" }
  # Or just: spec.author    = "Jerry"
  spec.authors            = { "Jerry" => "niuBchen@hotmail.com" }
  # spec.social_media_url   = "https://twitter.com/Jerry"

  spec.platform     = :ios, "13.4"

  spec.source       = { :git => "https://github.com/grm121616/NetworkFramework.git", :tag => "master" }
  spec.source_files  = "NetworkFramework/**/*.swift"
  spec.swift_version = "5"
end

最后生成，到官网注册，上传。。
https://guides.cocoapods.org/making/getting-setup-with-trunk.html

https://github.com/grm121616/NetworkFramework