library/cmd/serve/main.go

package main

import (
	"context"
	"encoding/json"
	"io/fs"
	"log"
	"net/http"
	"strings"
	"time"

	"git.yetaga.in/alazyreader/library/config"
	"git.yetaga.in/alazyreader/library/database"
	"git.yetaga.in/alazyreader/library/frontend"
	"git.yetaga.in/alazyreader/library/media"
	"github.com/kelseyhightower/envconfig"
)

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func obscureStr(in string, l int) string {
	return in[0:max(l, len(in))] + strings.Repeat("*", max(0, len(in)-l))
}

type Library interface {
	GetAllBooks(context.Context) ([]media.Book, error)
}

type RecordCollection interface {
	GetAllRecords(context.Context) ([]media.Record, error)
}

type Router struct {
	static fs.FS
	lib    Library
	rcol   RecordCollection
}

func writeJSON(w http.ResponseWriter, b []byte, status int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(status)
	w.Write(b)
	w.Write([]byte("\n"))
}

func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	if req.URL.Path == "/api/records" {
		RecordsAPIHandler(r.rcol).ServeHTTP(w, req)
		return
	}
	if req.URL.Path == "/api/books" {
		BooksAPIHandler(r.lib).ServeHTTP(w, req)
		return
	}
	StaticHandler(r.static).ServeHTTP(w, req)
}

func BooksAPIHandler(l Library) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		books, err := l.GetAllBooks(r.Context())
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		b, err := json.Marshal(books)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return

		}
		writeJSON(w, b, http.StatusOK)
	})
}

func RecordsAPIHandler(l RecordCollection) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		books, err := l.GetAllRecords(r.Context())
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		b, err := json.Marshal(books)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		writeJSON(w, b, http.StatusOK)
	})
}

func StaticHandler(f fs.FS) http.Handler {
	return http.FileServer(http.FS(f))
}

func main() {
	var c config.Config
	err := envconfig.Process("library", &c)
	if err != nil {
		log.Fatalln(err)
	}
	f, err := frontend.Root()
	if err != nil {
		log.Fatalln(err)
	}
	if c.DBUser == "" || c.DBPass == "" || c.DBHost == "" || c.DBPort == "" || c.DBName == "" {
		if c.DBPass != "" {
			c.DBPass = obscureStr(c.DBPass, 3)
		}
		if c.DiscogsToken != "" {
			c.DiscogsToken = obscureStr(c.DiscogsToken, 3)
		}
		log.Fatalf("vars: %+v", c)
	}
	lib, err := database.NewMySQLConnection(c.DBUser, c.DBPass, c.DBHost, c.DBPort, c.DBName)
	if err != nil {
		log.Fatalln(err)
	}
	err = lib.PrepareDatabase(context.Background())
	if err != nil {
		log.Fatalln(err)
	}
	latest, run, err := lib.RunMigrations(context.Background())
	if err != nil {
		log.Fatalln(err)
	}
	log.Printf("latest migration: %d; migrations run: %d", latest, run)
	discogsCache, err := database.NewDiscogsCache(c.DiscogsToken, time.Hour*24, "delta.mu.alpha")
	if err != nil {
		log.Fatalln(err)
	}
	go discogsCache.FlushCache(context.Background())
	r := &Router{
		static: f,
		lib:    lib,
		rcol:   discogsCache,
	}
	log.Println("Listening on http://0.0.0.0:8080/")
	log.Fatalln(http.ListenAndServe(":8080", r))
}