got pow working on the subscribe endpoint

srv/cmd/mediocre-blog/mailinglist.go

@@ -16,6 +16,7 @@ func mailingListSubscribeHandler(ml mailinglist.MailingList) http.Handler {
 			parts[1] == "" ||
 			len(email) >= 512 {
 			badRequest(rw, r, errors.New("invalid email"))
+			return
 		}
 
 		if err := ml.BeginSubscription(email); errors.Is(err, mailinglist.ErrAlreadyVerified) {
@@ -23,7 +24,10 @@ func mailingListSubscribeHandler(ml mailinglist.MailingList) http.Handler {
 			// verification email was sent.
 		} else if err != nil {
 			internalServerError(rw, r, err)
+			return
 		}
+
+		jsonResult(rw, r, struct{}{})
 	})
 }
 
@@ -44,6 +48,8 @@ func mailingListFinalizeHandler(ml mailinglist.MailingList) http.Handler {
 			internalServerError(rw, r, err)
 			return
 		}
+
+		jsonResult(rw, r, struct{}{})
 	})
 }
 
@@ -63,5 +69,7 @@ func mailingListUnsubscribeHandler(ml mailinglist.MailingList) http.Handler {
 			internalServerError(rw, r, err)
 			return
 		}
+
+		jsonResult(rw, r, struct{}{})
 	})
 }

srv/cmd/mediocre-blog/main.go

@@ -5,6 +5,8 @@ import (
 	"flag"
 	"fmt"
 	"net/http"
+	"net/http/httputil"
+	"net/url"
 	"path"
 	"strconv"
 	"strings"
@@ -26,11 +28,13 @@ func main() {
 	logger := mlog.NewLogger(nil)
 
 	hostname := flag.String("hostname", "localhost:4000", "Hostname to advertise this server as")
-	staticDir := flag.String("static-dir", "", "Directory from which static files are served")
 	listenAddr := flag.String("listen-addr", ":4000", "Address to listen for HTTP requests on")
 	dataDir := flag.String("data-dir", ".", "Directory to use for long term storage")
 
-	powTargetStr := flag.String("pow-target", "0x000FFFF", "Proof-of-work target, lower is more difficult")
+	staticDir := flag.String("static-dir", "", "Directory from which static files are served (mutually exclusive with -static-proxy-url)")
+	staticProxyURLStr := flag.String("static-proxy-url", "", "HTTP address from which static files are served (mutually exclusive with -static-dir)")
+
+	powTargetStr := flag.String("pow-target", "0x0000FFFF", "Proof-of-work target, lower is more difficult")
 	powSecret := flag.String("pow-secret", "", "Secret used to sign proof-of-work challenge seeds")
 
 	smtpAddr := flag.String("ml-smtp-addr", "", "Address of SMTP server to use for sending emails for the mailing list")
@@ -41,8 +45,8 @@ func main() {
 	flag.Parse()
 
 	switch {
-	case *staticDir == "":
+	case *staticDir == "" && *staticProxyURLStr == "":
-		logger.Fatal(context.Background(), "-static-dir is required")
+		logger.Fatal(context.Background(), "-static-dir or -static-proxy-url is required")
 	case *powSecret == "":
 		logger.Fatal(context.Background(), "-pow-secret is required")
 	case *smtpAddr == "":
@@ -51,6 +55,14 @@ func main() {
 		logger.Fatal(context.Background(), "-ml-smtp-auth is required")
 	}
 
+	var staticProxyURL *url.URL
+	if *staticProxyURLStr != "" {
+		var err error
+		if staticProxyURL, err = url.Parse(*staticProxyURLStr); err != nil {
+			loggerFatalErr(context.Background(), logger, "parsing -static-proxy-url", err)
+		}
+	}
+
 	powTargetUint, err := strconv.ParseUint(*powTargetStr, 0, 32)
 	if err != nil {
 		loggerFatalErr(context.Background(), logger, "parsing -pow-target", err)
@@ -68,7 +80,6 @@ func main() {
 
 	ctx := mctx.Annotate(context.Background(),
 		"hostname", *hostname,
-		"staticDir", *staticDir,
 		"listenAddr", *listenAddr,
 		"dataDir", *dataDir,
 		"powTarget", fmt.Sprintf("%x", powTarget),
@@ -76,6 +87,12 @@ func main() {
 		"smtpSendAs", smtpSendAs,
 	)
 
+	if *staticDir != "" {
+		ctx = mctx.Annotate(ctx, "staticDir", *staticDir)
+	} else {
+		ctx = mctx.Annotate(ctx, "staticProxyURL", *staticProxyURLStr)
+	}
+
 	clock := clock.Realtime()
 
 	powStore := pow.NewMemoryStore(clock)
@@ -112,7 +129,15 @@ func main() {
 	})
 
 	mux := http.NewServeMux()
-	mux.Handle("/", http.FileServer(http.Dir(*staticDir)))
+
+	var staticHandler http.Handler
+	if *staticDir != "" {
+		staticHandler = http.FileServer(http.Dir(*staticDir))
+	} else {
+		staticHandler = httputil.NewSingleHostReverseProxy(staticProxyURL)
+	}
+
+	mux.Handle("/", staticHandler)
 
 	apiMux := http.NewServeMux()
 	apiMux.Handle("/pow/challenge", newPowChallengeHandler(powMgr))

srv/cmd/mediocre-blog/pow.go

@@ -11,6 +11,7 @@ import (
 
 func newPowChallengeHandler(mgr pow.Manager) http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+
 		challenge := mgr.NewChallenge()
 
 		jsonResult(rw, r, struct {
@@ -25,6 +26,7 @@ func newPowChallengeHandler(mgr pow.Manager) http.Handler {
 
 func requirePowMiddleware(mgr pow.Manager, h http.Handler) http.Handler {
 	return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+
 		seedHex := r.PostFormValue("powSeed")
 		seed, err := hex.DecodeString(seedHex)
 		if err != nil || len(seed) == 0 {

srv/pow/pow.go

@@ -141,7 +141,7 @@ type Challenge struct {
 // Errors which may be produced by a Manager.
 var (
 	ErrInvalidSolution = errors.New("invalid solution")
-	ErrExpiredSolution = errors.New("expired solution")
+	ErrExpiredSeed     = errors.New("expired seed")
 )
 
 // Manager is used to both produce proof-of-work challenges and check their
@@ -150,7 +150,7 @@ type Manager interface {
 	NewChallenge() Challenge
 
 	// Will produce ErrInvalidSolution if the solution is invalid, or
-	// ErrExpiredSolution if the solution has expired.
+	// ErrExpiredSeed if the seed has expired.
 	CheckSolution(seed, solution []byte) error
 }
 
@@ -193,6 +193,7 @@ type manager struct {
 // NewManager initializes and returns a Manager instance using the given
 // parameters.
 func NewManager(params ManagerParams) Manager {
+	params = params.withDefaults()
 	return &manager{
 		params: params,
 	}
@@ -252,8 +253,8 @@ func (m *manager) CheckSolution(seed, solution []byte) error {
 	if err != nil {
 		return fmt.Errorf("parsing challenge parameters from seed: %w", err)
 
-	} else if c.ExpiresAt <= m.params.Clock.Now().Unix() {
+	} else if now := m.params.Clock.Now().Unix(); c.ExpiresAt <= now {
-		return ErrExpiredSolution
+		return ErrExpiredSeed
 	}
 
 	ok := (SolutionChecker{}).Check(

static/default.nix

@@ -37,7 +37,7 @@ in
             name = "mediocre-blog-static-dev";
             buildInputs = all_inputs;
             shellHook = ''
-                exec ${jekyll_env}/bin/jekyll serve -s ./src -d ./_site -w -I -D -H 0.0.0.0
+                exec ${jekyll_env}/bin/jekyll serve -s ./src -d ./_site -w -I -D -H 0.0.0.0 -P 4001
             '';
         };
 

static/src/assets/solvePow.js

@@ -0,0 +1,28 @@
+const fromHexString = hexString =>
+  new Uint8Array(hexString.match(/.{1,2}/g).map(byte => parseInt(byte, 16)));
+
+const toHexString = bytes =>
+  bytes.reduce((str, byte) => str + byte.toString(16).padStart(2, '0'), '');
+
+onmessage = async (e) => {
+  const seed = fromHexString(e.data.seedHex);
+  const target = e.data.target;
+
+  const fullBuf = new ArrayBuffer(seed.byteLength*2);
+
+  const fullBufSeed = new Uint8Array(fullBuf, 0, seed.byteLength);
+  seed.forEach((v, i) => fullBufSeed[i] = v);
+
+  const randBuf = new Uint8Array(fullBuf, seed.byteLength);
+
+  while (true) {
+    crypto.getRandomValues(randBuf);
+    const digest = await crypto.subtle.digest('SHA-512', fullBuf);
+    const digestView = new DataView(digest);
+    if (digestView.getUint32(0) < target) {
+      postMessage(toHexString(randBuf));
+      return;
+    }
+  }
+
+};

static/src/follow.md

@@ -6,7 +6,121 @@ nofollow: true
 
 Here's your options for receiving updates about new blog posts:
 
-## Option 1: RSS
+## Option 1: Email
+
+Email is by far my preferred option for notifying followers of new posts.
+
+The entire email list system for this blog, from storing subscriber email
+addresses to the email server which sends the notifications out, has been
+designed from scratch and is completely self-hosted in my living room.
+
+I solemnly swear that:
+
+* You will never receive an email from this blog except to notify of a new post.
+
+* Your email will never be provided or sold to anyone else for any reason.
+
+With all that said, if you'd like to receive an email everytime a new blog post
+is published then input your email below and smash that subscribe button!
+
+<style>
+
+#emailStatus.success {
+    color: green;
+}
+
+#emailStatus.fail {
+    color: red;
+}
+
+</style>
+
+<input type="email" placeholder="name@host.com" id="emailAddress" />
+<input class="button-primary" type="submit" value="Subscribe" id="emailSubscribe" />
+<span id="emailStatus"></span>
+
+<script>
+const emailAddress = document.getElementById("emailAddress");
+const emailSubscribe = document.getElementById("emailSubscribe");
+const emailSubscribeOrigValue = emailSubscribe.value;
+const emailStatus = document.getElementById("emailStatus");
+
+const solvePow = async (seedHex, target) => {
+
+    const worker = new Worker('/assets/solvePow.js');
+
+    const p = new Promise((resolve, reject) => {
+        worker.postMessage({seedHex, target});
+        worker.onmessage = resolve;
+    });
+
+    const solutionHex = (await p).data;
+    worker.terminate();
+
+    return solutionHex;
+}
+
+emailSubscribe.onclick = async () => {
+
+    emailSubscribe.disabled = true;
+    emailSubscribe.className = "";
+    emailSubscribe.value = "Please hold...";
+
+    await (async () => {
+
+        setErr = (errStr, retry) => {
+            emailStatus.className = "fail";
+            emailStatus.innerHTML = errStr
+            if (retry) emailStatus.innerHTML += "  (please try again)";
+        };
+
+        if (!window.isSecureContext) {
+            setErr("The browser environment is not secure.", false);
+            return;
+        }
+
+        const getPowReq = new Request('/api/pow/challenge');
+        const res = await fetch(getPowReq)
+            .then(response => response.json())
+
+        if (res.error) {
+            setErr(res.error, true);
+            return;
+        }
+
+        const powSol = await solvePow(res.seed, res.target);
+
+        const subscribeForm = new FormData();
+        subscribeForm.append('powSeed', res.seed);
+        subscribeForm.append('powSolution', powSol);
+        subscribeForm.append('email', emailAddress.value);
+
+        const subscribeReq = new Request('/api/mailinglist/subscribe', {
+            method: 'POST',
+            body: subscribeForm,
+        });
+
+        const subRes = await fetch(subscribeReq)
+            .then(response => response.json());
+
+        if (subRes.error) {
+            setErr(subRes.error, true);
+            return;
+        }
+
+        emailStatus.className = "success";
+        emailStatus.innerHTML = "Verification email sent (check your spam folder)";
+
+    })();
+
+    emailSubscribe.disabled = false;
+    emailSubscribe.className = "button-primary";
+    emailSubscribe.value = emailSubscribeOrigValue;
+};
+
+</script>
+
+## Option 2: RSS
 
 RSS is the classic way to follow any blog. It comes from a time before
 aggregators like reddit and twitter stole the show, when people felt capable to
@@ -31,14 +145,9 @@ recommendations:
   iPhone/iPad/Mac devices, so I'm told. Their homepage description makes a much
   better sales pitch for RSS than I ever could.
 
-## Option 2: Twitter
+## Option 3: Twitter
 
 New posts are automatically published to [my Twitter](https://twitter.com/{{
 site.twitter_username }}). Simply follow me there and pray the algorithm smiles
 upon my tweets enough to show them to you! :pray: :pray: :pray:
 
-## Option 3: Email?
-
-I tried setting up an RSS-to-Email list thing on Mailchimp but it doesn't seem
-to like my RSS feed. If anyone knows a better alternative please [email
-me.](mailto:mediocregopher@gmail.com)