Golang如何实现简单的API网关

// ReverseProxy is an HTTP Handler that takes an incoming request and// sends it to another server, proxying the response back to the// client.type ReverseProxy struct {

    // Director must be a function which modifies

    // the request into a new request to be sent

    // using Transport. Its response is then copied

    // back to the original client unmodified.

    // Director must not access the provided Request

    // after returning.

    Director func(*http.Request)

    Transport http.RoundTripper

    FlushInterval time.Duration

    ErrorLog *log.Logger

    BufferPool BufferPool   // ModifyResponse is an optional function that modifies the

    // Response from the backend. It is called if the backend

    // returns a response at all, with any HTTP status code.

    // If the backend is unreachable, the optional ErrorHandler is

    // called without any call to ModifyResponse.

    //

    // If ModifyResponse returns an error, ErrorHandler is called

    // with its error value. If ErrorHandler is nil, its default

    // implementation is used.

    ModifyResponse func(*http.Response) error

    ErrorHandler func(http.ResponseWriter, *http.Request, error)}