router.go

package main

import (
	"fmt"
	"mime"
	"net/http"
	"os"
	"path/filepath"
	"strings"
)

type RouteHandler func(w http.ResponseWriter, r *http.Request)
type Route struct {
    Method string
    Uri string
    Handler RouteHandler
}

type Router struct {
    routes []Route
}

func (r *Router) ServeHTTP (writer http.ResponseWriter, request *http.Request) {
    routeUriMatch := false

    for _, route := range r.routes {
	matches := routeMatches(request.RequestURI, route.Uri)

	if !matches {
	    fmt.Printf("no match\n")
	    continue
	}
	fmt.Printf("Found a match %s\n", route.Uri)
	routeUriMatch = true

	if route.Method != request.Method {
	    continue
	}

	route.Handler(writer, request)
	return
    }

    if routeUriMatch {
	writer.WriteHeader(405)
	writer.Write([]byte("<p>Method not allowed</p>"))
	return
    }

    path := "./public" + request.RequestURI
    fileBytes, err := os.ReadFile(path)

    if err == nil {
	ext := filepath.Ext(path)
	contentType := mime.TypeByExtension(ext)

	writer.Header().Set("Content-Type", contentType)
	writer.WriteHeader(200)
	writer.Write(fileBytes)
	return
    }
    // check if valid file
    
    writer.Header().Set("Content-Type", "text/html")
    writer.WriteHeader(404)
    writer.Write([]byte("<p>Not Found</p>"))
}

func (r *Router) Get(uri string, handler RouteHandler) {
    r.routes = append(r.routes, Route{"GET", uri, handler})
}

func (r *Router) Post(uri string, handler RouteHandler) {
    r.routes = append(r.routes, Route{"POST", uri, handler})
}

func (r *Router) Delete(uri string, handler RouteHandler) {
    r.routes = append(r.routes, Route{"DELETE", uri, handler})
}

func routeMatches(requestUri, route string) bool {
	fmt.Printf("Check request uri: %s matches %s\n", requestUri, route)
	requestUriParts := strings.Split(requestUri, "/")
	routeUriParts := strings.Split(route, "/")

	fmt.Printf("requestUriParts: %#v\n\n", requestUriParts)
	fmt.Printf("routeUriParts: %#v\n\n", routeUriParts)

	if len(requestUriParts) != len(routeUriParts) {
	    fmt.Printf("lenght mismatch\n")
	    return false
	}

	length := len(requestUriParts)
     
	for i := range length {
	    fmt.Printf("%d\n", i)
	    if strings.HasPrefix(routeUriParts[i], ":") {
		fmt.Printf("has prefix\n")
		// wildcard
		continue
	    }

	    if requestUriParts[i] != routeUriParts[i] {
		fmt.Printf("mismatch route part %s && %s\n", routeUriParts[i], requestUriParts[i])
		return false
	    }
	}

    return true
}

func startServer(host string, port int, router *Router) {
    serverHost := fmt.Sprintf("%s:%d", host, port)
    fmt.Printf("%s\n\n", serverHost)
    err := http.ListenAndServe(serverHost, router)
    check(err)
}

func home(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(200)
    w.Write([]byte("OK"))
}