hatecomputers.club/api/serve.go

package api

import (
	"crypto/rand"
	"database/sql"
	"fmt"
	"log"
	"net/http"
	"time"

	"git.hatecomputers.club/hatecomputers/hatecomputers.club/args"
)

type RequestContext struct {
	DBConn *sql.DB
	Args   *args.Arguments

	Id    string
	Start time.Time
}

type Continuation func(*RequestContext, *http.Request, http.ResponseWriter) ContinuationChain
type ContinuationChain func(Continuation, Continuation) ContinuationChain

func randomId() string {
	uuid := make([]byte, 16)
	_, err := rand.Read(uuid)
	if err != nil {
		panic(err)
	}

	uuid[8] = uuid[8]&^0xc0 | 0x80
	uuid[6] = uuid[6]&^0xf0 | 0x40

	return fmt.Sprintf("%x-%x-%x-%x-%x", uuid[0:4], uuid[4:6], uuid[6:8], uuid[8:10], uuid[10:])
}

func LogRequestContinuation(context *RequestContext, req *http.Request, resp http.ResponseWriter) ContinuationChain {
	return func(success Continuation, _failure Continuation) ContinuationChain {
		context.Start = time.Now()
		context.Id = randomId()

		log.Println(req.Method, req.URL.Path, req.RemoteAddr, context.Id)
		return success(context, req, resp)
	}
}

func LogExecutionTimeContinuation(context *RequestContext, req *http.Request, resp http.ResponseWriter) ContinuationChain {
	return func(success Continuation, _failure Continuation) ContinuationChain {
		end := time.Now()

		log.Println(context.Id, "took", end.Sub(context.Start))

		return success(context, req, resp)
	}
}

func HealthCheckContinuation(context *RequestContext, req *http.Request, resp http.ResponseWriter) ContinuationChain {
	return func(success Continuation, _failure Continuation) ContinuationChain {
		resp.WriteHeader(200)
		resp.Write([]byte("healthy"))
		return success(context, req, resp)
	}
}

func FailurePassingContinuation(context *RequestContext, req *http.Request, resp http.ResponseWriter) ContinuationChain {
	return func(_success Continuation, failure Continuation) ContinuationChain {
		return failure(context, req, resp)
	}
}

func IdContinuation(context *RequestContext, req *http.Request, resp http.ResponseWriter) ContinuationChain {
	return func(success Continuation, _failure Continuation) ContinuationChain {
		return success(context, req, resp)
	}
}

func MakeServer(argv *args.Arguments, dbConn *sql.DB) *http.Server {
	mux := http.NewServeMux()

	fileServer := http.FileServer(http.Dir(argv.StaticPath))
	mux.Handle("/static/", http.StripPrefix("/static/", fileServer))

	makeRequestContext := func() *RequestContext {
		return &RequestContext{
			DBConn: dbConn,
			Args:   argv,
		}
	}

	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		requestContext := makeRequestContext()
		LogRequestContinuation(requestContext, r, w)(TemplateContinuation("home.html", nil, true), FailurePassingContinuation)(LogExecutionTimeContinuation, LogExecutionTimeContinuation)(IdContinuation, IdContinuation)
	})

	mux.HandleFunc("GET /api/health", func(w http.ResponseWriter, r *http.Request) {
		requestContext := makeRequestContext()
		LogRequestContinuation(requestContext, r, w)(HealthCheckContinuation, FailurePassingContinuation)(LogExecutionTimeContinuation, LogExecutionTimeContinuation)(IdContinuation, IdContinuation)
	})

	mux.HandleFunc("GET /{name}", func(w http.ResponseWriter, r *http.Request) {
		requestContext := makeRequestContext()
		name := r.PathValue("name")
		LogRequestContinuation(requestContext, r, w)(TemplateContinuation(name+".html", nil, true), FailurePassingContinuation)(LogExecutionTimeContinuation, LogExecutionTimeContinuation)(IdContinuation, IdContinuation)
	})

	return &http.Server{
		Addr:    ":" + fmt.Sprint(argv.Port),
		Handler: mux,
	}
}