implemented PoW backend

3 files changed, 82 insertions, 2 deletions

diff --git a/srv/cmd/mediocre-blog/api.go b/srv/cmd/mediocre-blog/api.go
new file mode 100644
index 0000000..b4f90d6
--- /dev/null
+++ b/srv/cmd/mediocre-blog/api.go
@@ -0,0 +1,24 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+)
+
+func internalServerError(rw http.ResponseWriter, r *http.Request, err error) {
+	http.Error(rw, "internal server error", 500)
+	log.Printf("%s %s: internal server error: %v", r.Method, r.URL, err)
+}
+
+func jsonResult(rw http.ResponseWriter, r *http.Request, v interface{}) {
+	b, err := json.Marshal(v)
+	if err != nil {
+		internalServerError(rw, r, err)
+		return
+	}
+	b = append(b, '\n')
+
+	rw.Header().Set("Content-Type", "application/json")
+	rw.Write(b)
+}
diff --git a/srv/cmd/mediocre-blog/main.go b/srv/cmd/mediocre-blog/main.go
index a1b20be..2952999 100644
--- a/srv/cmd/mediocre-blog/main.go
+++ b/srv/cmd/mediocre-blog/main.go
@@ -4,20 +4,54 @@ import (
 	"flag"
 	"log"
 	"net/http"
+	"strconv"
+
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/pow"
+	"github.com/tilinna/clock"
 )
 
 func main() {
 	staticDir := flag.String("static-dir", "", "Directory from which static files are served")
-	//redisAddr := flag.String("redis-addr", "127.0.0.1:6379", "Address which redis is listening on")
 	listenAddr := flag.String("listen-addr", ":4000", "Address to listen for HTTP requests on")
+	powTargetStr := flag.String("pow-target", "0x000FFFF", "Proof-of-work target, lower is more difficult")
+	powSecret := flag.String("pow-secret", "", "Secret used to sign proof-of-work challenge seeds")
+
+	// parse config
+
 	flag.Parse()
 
-	if *staticDir == "" {
+	switch {
+	case *staticDir == "":
 		log.Fatal("-static-dir is required")
+	case *powSecret == "":
+		log.Fatal("-pow-secret is required")
+	}
+
+	powTargetUint, err := strconv.ParseUint(*powTargetStr, 0, 32)
+	if err != nil {
+		log.Fatalf("parsing -pow-target: %v", err)
 	}
+	powTarget := uint32(powTargetUint)
+
+	// initialization
+
+	clock := clock.Realtime()
+
+	powStore := pow.NewMemoryStore(clock)
+	defer powStore.Close()
+
+	mgr := pow.NewManager(pow.ManagerParams{
+		Clock:  clock,
+		Store:  powStore,
+		Secret: []byte(*powSecret),
+		Target: powTarget,
+	})
 
 	mux := http.NewServeMux()
 	mux.Handle("/", http.FileServer(http.Dir(*staticDir)))
+	mux.Handle("/api/pow/challenge", newPowChallengeHandler(mgr))
+
+	// run
 
 	log.Printf("listening on %q", *listenAddr)
 	log.Fatal(http.ListenAndServe(*listenAddr, mux))
diff --git a/srv/cmd/mediocre-blog/pow.go b/srv/cmd/mediocre-blog/pow.go
new file mode 100644
index 0000000..22b82f3
--- /dev/null
+++ b/srv/cmd/mediocre-blog/pow.go
@@ -0,0 +1,22 @@
+package main
+
+import (
+	"encoding/hex"
+	"net/http"
+
+	"github.com/mediocregopher/blog.mediocregopher.com/srv/pow"
+)
+
+func newPowChallengeHandler(mgr pow.Manager) http.Handler {
+	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		challenge := mgr.NewChallenge()
+
+		jsonResult(rw, r, struct {
+			Seed   string `json:"seed"`
+			Target uint32 `json:"target"`
+		}{
+			Seed:   hex.EncodeToString(challenge.Seed),
+			Target: challenge.Target,
+		})
+	})
+}