refactor(central): move ASN frontend logic to a separate web API service

8 files changed, 274 insertions, 143 deletions

diff --git a/.idea/compiler.xml b/.idea/compiler.xml
index 6620e8f..02f9838 100644
--- a/.idea/compiler.xml
+++ b/.idea/compiler.xml
@@ -29,8 +29,14 @@
         <processorPath useClasspath="false">
           <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-sql-client-templates/4.0.3/bbb167fc181ab7e793485da00b370610a6230fdf/vertx-sql-client-templates-4.0.3.jar" />
           <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-codegen/4.0.3/416429ea05c4c43afcf4104ab488bda10f43ba87/vertx-codegen-4.0.3-processor.jar" />
+          <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-web-api-service/4.0.3/15b6af169e6e1987822448f3a330b4a023d701b1/vertx-web-api-service-4.0.3.jar" />
           <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-service-proxy/4.0.3/df93b096a38ee0120e06943a8f7e3d0627c97418/vertx-service-proxy-4.0.3.jar" />
           <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-sql-client/4.0.3/2bb64597f96e27a4a431967bea77592286d35462/vertx-sql-client-4.0.3.jar" />
+          <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-web-validation/4.0.3/2f819dd0b8082664c339410cff6e40da3ae31536/vertx-web-validation-4.0.3.jar" />
+          <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-web/4.0.3/5d0cec868aadac3e098b1ab6409dc2cebae83930/vertx-web-4.0.3.jar" />
+          <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-json-schema/4.0.3/fb31dae192398722a07b23892e9f261a7b6c4a85/vertx-json-schema-4.0.3.jar" />
+          <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-web-common/4.0.3/274167d895a6170335a5fd7e71d4519b9608d275/vertx-web-common-4.0.3.jar" />
+          <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-auth-common/4.0.3/177afb713c00713eff76a6cd83a8090c601af474/vertx-auth-common-4.0.3.jar" />
           <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-core/4.0.3/40c496ede9a948ec673df8cf5ab227ff853dd061/vertx-core-4.0.3.jar" />
           <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/com.fasterxml.jackson.core/jackson-core/2.11.3/c2351800432bdbdd8284c3f5a7f0782a352aa84a/jackson-core-2.11.3.jar" />
           <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.netty/netty-handler-proxy/4.1.60.Final/2352f12826400e5db64b36fd951508ce9a61c196/netty-handler-proxy-4.1.60.Final.jar" />
@@ -45,6 +51,7 @@
           <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.netty/netty-buffer/4.1.60.Final/9d213d090deeca2541ad6827eb3345bcd6e1e701/netty-buffer-4.1.60.Final.jar" />
           <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.netty/netty-resolver/4.1.60.Final/caba5004618d27386ee9d5ee8b23b09b6548fb0b/netty-resolver-4.1.60.Final.jar" />
           <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.netty/netty-common/4.1.60.Final/44540113f7148f1014be879663501db8da1c37b0/netty-common-4.1.60.Final.jar" />
+          <entry name="$USER_HOME$/.local/share/gradle/caches/modules-2/files-2.1/io.vertx/vertx-bridge-common/4.0.3/423970a10bdc4fa14ce4ad18ef3f45d703e53420/vertx-bridge-common-4.0.3.jar" />
         </processorPath>
         <module name="dn42peering.central.main" />
       </profile>
diff --git a/central/build.gradle b/central/build.gradle
index c0ed922..d95951d 100644
--- a/central/build.gradle
+++ b/central/build.gradle
@@ -37,6 +37,8 @@ dependencies {
     annotationProcessor "io.vertx:vertx-service-proxy:${project.vertxVersion}"
     compileOnly "io.vertx:vertx-codegen:${project.vertxVersion}"
     implementation "io.vertx:vertx-grpc:${project.vertxVersion}"
+    implementation "io.vertx:vertx-web-api-service:${project.vertxVersion}"
+    annotationProcessor "io.vertx:vertx-web-api-service:${project.vertxVersion}"
 
     implementation project(':rpc-common')
 }
diff --git a/central/src/main/java/moe/yuuta/dn42peering/Main.java b/central/src/main/java/moe/yuuta/dn42peering/Main.java
index 5fa6690..8def1df 100644
--- a/central/src/main/java/moe/yuuta/dn42peering/Main.java
+++ b/central/src/main/java/moe/yuuta/dn42peering/Main.java
@@ -4,6 +4,7 @@ import io.vertx.core.*;
 import io.vertx.core.impl.logging.Logger;
 import io.vertx.core.impl.logging.LoggerFactory;
 import io.vertx.core.json.JsonObject;
+import moe.yuuta.dn42peering.asn.ASNHttpVerticle;
 import moe.yuuta.dn42peering.asn.ASNVerticle;
 import moe.yuuta.dn42peering.node.NodeVerticle;
 import moe.yuuta.dn42peering.peer.PeerVerticle;
@@ -14,6 +15,7 @@ import moe.yuuta.dn42peering.whois.WhoisVerticle;
 import javax.annotation.Nonnull;
 import java.io.FileInputStream;
 import java.io.InputStream;
+import java.util.Arrays;
 
 public class Main {
     public static void main(@Nonnull String... args) throws Throwable {
@@ -36,14 +38,15 @@ public class Main {
                 .setConfig(config)
                 .setInstances(Runtime.getRuntime().availableProcessors() * 2);
         Logger logger = LoggerFactory.getLogger("Main");
-        CompositeFuture.all(
+        CompositeFuture.all(Arrays.asList(
                 Future.<String>future(f -> vertx.deployVerticle(PeerVerticle.class.getName(), options, f)),
                 Future.<String>future(f -> vertx.deployVerticle(WhoisVerticle.class.getName(), options, f)),
                 Future.<String>future(f -> vertx.deployVerticle(ASNVerticle.class.getName(), options, f)),
+                Future.<String>future(f -> vertx.deployVerticle(ASNHttpVerticle.class.getName(), options, f)),
                 Future.<String>future(f -> vertx.deployVerticle(NodeVerticle.class.getName(), options, f)),
                 Future.<String>future(f -> vertx.deployVerticle(ProvisionVerticle.class.getName(), options, f)),
                 Future.<String>future(f -> vertx.deployVerticle(HTTPPortalVerticle.class.getName(), options, f))
-        ).onComplete(res -> {
+        )).onComplete(res -> {
             if (res.succeeded()) {
                 logger.info("The server started.");
             } else {
diff --git a/central/src/main/java/moe/yuuta/dn42peering/asn/ASNHandler.java b/central/src/main/java/moe/yuuta/dn42peering/asn/ASNHandler.java
index 7abc27e..0b88540 100644
--- a/central/src/main/java/moe/yuuta/dn42peering/asn/ASNHandler.java
+++ b/central/src/main/java/moe/yuuta/dn42peering/asn/ASNHandler.java
@@ -11,6 +11,7 @@ import io.vertx.ext.mail.MailConfig;
 import io.vertx.ext.mail.MailMessage;
 import io.vertx.ext.mail.MailResult;
 import io.vertx.ext.web.Router;
+import io.vertx.ext.web.api.service.RouteToEBServiceHandler;
 import io.vertx.ext.web.common.template.TemplateEngine;
 import io.vertx.ext.web.handler.BodyHandler;
 import io.vertx.ext.web.templ.freemarker.FreeMarkerTemplateEngine;
@@ -45,28 +46,10 @@ public class ASNHandler implements ISubRouter {
     @Nonnull
     @Override
     public Router mount(@Nonnull Vertx vertx) {
-        final IASNService asnService = IASNService.createProxy(vertx, IASNService.ADDRESS);
-        final IWhoisService whoisService = IWhoisService.createProxy(vertx, IWhoisService.ADDRESS);
-        // Preserve. We need to get email address out of it later.
-        final JsonObject mailConfig = vertx.getOrCreateContext().config().getJsonObject("mail");
-        final MailClient mailClient = MailClient.create(vertx, new MailConfig(mailConfig));
-
-        final TemplateEngine engine = FreeMarkerTemplateEngine.create(vertx, "ftlh");
         final Router router = Router.router(vertx);
         router.get("/")
                 .produces("text/html")
-                .handler(ctx -> {
-                    renderIndex(engine, null, null, res -> {
-                        if(res.succeeded()) {
-                            ctx.response()
-                                    .putHeader(HttpHeaders.CONTENT_TYPE, "text/html")
-                                    .end(res.result());
-                        } else {
-                            ctx.fail(res.cause());
-                            logger.error("Cannot render /asn.", res.cause());
-                        }
-                    });
-                });
+                .handler(RouteToEBServiceHandler.build(vertx.eventBus(), IASNHttpService.ADDRESS, "index"));
 
         final ObjectSchemaBuilder registerSchema = objectSchema()
                 .allowAdditionalProperties(false)
@@ -81,129 +64,8 @@ public class ASNHandler implements ISubRouter {
                         .body(Bodies.formUrlEncoded(registerSchema))
                         .predicate(RequestPredicate.BODY_REQUIRED)
                         .build())
-                .handler(ctx -> {
-                    final JsonObject parameters = ctx.<RequestParameters>get(ValidationHandler.REQUEST_CONTEXT_KEY)
-                            .body().getJsonObject();
-                    final String upperASN = parameters.getString("asn").toUpperCase();
-                    // Start: Check if the ASN exists.
-                    Future.<Void>future(f -> asnService.exists(upperASN, true, true, ar -> {
-                        if(ar.succeeded()) {
-                            if(ar.result()) {
-                                f.fail(new FormException("This ASN exists in our records. Please login instead of registering."));
-                            } else {
-                                f.complete();
-                            }
-                        } else {
-                            f.fail(ar.cause());
-                        }
-                    }))
-                    // Lookup ASN
-                    .<WhoisObject>compose(exists ->
-                            Future.future(f -> whoisService.query(upperASN, f)))
-                    // Lookup emails
-                    .<List<String>>compose(asnLookup -> {
-                        if(asnLookup == null) {
-                            return Future.failedFuture(new FormException("The ASN is not found in the DN42 registry."));
-                        } else {
-                            return Future.future(f -> asnService.lookupEmails(asnLookup, ar -> {
-                                if(ar.succeeded()) {
-                                    if(ar.result().isEmpty()) {
-                                        f.fail(new FormException("The tech-c contact for this ASN does not have emails."));
-                                    } else {
-                                        f.complete(ar.result());
-                                    }
-                                } else {
-                                    f.fail(ar.cause());
-                                }
-                            }));
-                        }
-                    })
-                    // Generate random password and register.
-                    .<Pair<String /* Random password */, List<String> /* Emails */>>compose(emails -> Future.future(f -> {
-                        final String randomPassword = new RandomStringGenerator.Builder()
-                                .withinRange('a', 'z')
-                                .build()
-                                .generate(15);
-                        asnService.registerOrChangePassword(upperASN, randomPassword, ar -> {
-                            if(ar.succeeded()) {
-                                f.complete(new Pair<>(randomPassword, emails));
-                            } else {
-                                f.fail(ar.cause());
-                            }
-                        });
-                    }))
-                    // Send mails.
-                    .compose(pair -> CompositeFuture.any(Stream.of(pair.b)
-                            .map(mail -> new MailMessage()
-                                    .setFrom(mailConfig.getString("from"))
-                                    .setTo(mail)
-                                    .setText(String.format("Hi %s! Welcome to dn42 peering! Your peering initial password is %s. Make sure to change it.",
-                                            upperASN,
-                                            pair.a))
-                                    .setSubject("Peering initial password"))
-                            .map(message -> Future.<MailResult>future(f -> mailClient.sendMail(message, f)))
-                            .collect(Collectors.toList())))
-                    // Render HTML or report errors
-                    .onComplete(ar -> {
-                        if(ar.succeeded()) {
-                            // Get MailResult's out of the future.
-                            final List<MailResult> sendRes = ar.result().list();
-                            renderSuccess(engine, sendRes, res -> {
-                                if(res.succeeded()) {
-                                    ctx.response()
-                                            .putHeader(HttpHeaders.CONTENT_TYPE, "text/html")
-                                            .end(res.result());
-                                } else {
-                                    ctx.fail(res.cause());
-                                    logger.error("Cannot render /asn (success).", res.cause());
-                                }
-                            });
-                        } else {
-                            if(ar.cause() instanceof HTTPException) {
-                                ctx.response().setStatusCode(((HTTPException) ar.cause()).code).end();
-                            } else if(ar.cause() instanceof FormException) {
-                                renderIndex(engine,
-                                        Arrays.asList(((FormException) ar.cause()).errors.clone()),
-                                        upperASN,
-                                        res -> {
-                                    if(res.succeeded()) {
-                                        ctx.response()
-                                                .putHeader(HttpHeaders.CONTENT_TYPE, "text/html")
-                                                .end(res.result());
-                                    } else {
-                                        ctx.fail(res.cause());
-                                        logger.error("Cannot render /asn (with errors).", res.cause());
-                                    }
-                                });
-                            } else {
-                                logger.error(String.format("Cannot register ASN %s.", upperASN), ar.cause());
-                                ctx.fail(ar.cause());
-                            }
-                        }
-                    });
-                });
+                .handler(RouteToEBServiceHandler.build(vertx.eventBus(), IASNHttpService.ADDRESS, "register"));
 
         return router;
     }
-
-    private void renderIndex(@Nonnull TemplateEngine engine,
-                             @Nullable List<String> errors,
-                             @Nullable String asn,
-                             @Nonnull Handler<AsyncResult<Buffer>> handler) {
-        final Map<String, Object> root = new HashMap<>();
-        root.put("input_asn", asn == null ? "" : asn);
-        root.put("errors", errors);
-        engine.render(root, "asn/index.ftlh", handler);
-    }
-
-    private void renderSuccess(@Nonnull TemplateEngine engine,
-                                 @Nonnull List<MailResult> sendRes,
-                                 @Nonnull Handler<AsyncResult<Buffer>> handler) {
-        final Map<String, Object> root = new HashMap<>();
-        root.put("emails", sendRes.stream()
-                .filter(Objects::nonNull) // Nulls mean failures.
-                .flatMap(res -> res.getRecipients().stream())
-                .collect(Collectors.toList()));
-        engine.render(root, "asn/success.ftlh", handler);
-    }
 }
diff --git a/central/src/main/java/moe/yuuta/dn42peering/asn/ASNHttpVerticle.java b/central/src/main/java/moe/yuuta/dn42peering/asn/ASNHttpVerticle.java
new file mode 100644
index 0000000..32f1a24
--- /dev/null
+++ b/central/src/main/java/moe/yuuta/dn42peering/asn/ASNHttpVerticle.java
@@ -0,0 +1,41 @@
+package moe.yuuta.dn42peering.asn;
+
+import io.vertx.core.AbstractVerticle;
+import io.vertx.core.Future;
+import io.vertx.core.Promise;
+import io.vertx.core.eventbus.MessageConsumer;
+import io.vertx.core.impl.logging.Logger;
+import io.vertx.core.impl.logging.LoggerFactory;
+import io.vertx.core.json.JsonObject;
+import io.vertx.serviceproxy.ServiceBinder;
+
+public class ASNHttpVerticle extends AbstractVerticle {
+    private final Logger logger = LoggerFactory.getLogger(getClass().getSimpleName());
+
+    private MessageConsumer<JsonObject> consumer;
+
+    @Override
+    public void start(Promise<Void> startPromise) throws Exception {
+        consumer = new ServiceBinder(vertx)
+                .setAddress(IASNHttpService.ADDRESS)
+                .register(IASNHttpService.class, new IASNHttpServiceImpl(vertx));
+        consumer.completionHandler(ar -> {
+            if (ar.succeeded()) {
+                startPromise.complete();
+            } else {
+                startPromise.fail(ar.cause());
+            }
+        });
+    }
+
+    @Override
+    public void stop(Promise<Void> stopPromise) throws Exception {
+        Future.future(f -> consumer.unregister(ar -> {
+            if (ar.succeeded()) f.complete();
+            else f.fail(ar.cause());
+        })).onComplete(ar -> {
+            if (ar.succeeded()) stopPromise.complete();
+            else stopPromise.fail(ar.cause());
+        });
+    }
+}
diff --git a/central/src/main/java/moe/yuuta/dn42peering/asn/IASNHttpService.java b/central/src/main/java/moe/yuuta/dn42peering/asn/IASNHttpService.java
new file mode 100644
index 0000000..aaa6913
--- /dev/null
+++ b/central/src/main/java/moe/yuuta/dn42peering/asn/IASNHttpService.java
@@ -0,0 +1,22 @@
+package moe.yuuta.dn42peering.asn;
+
+import io.vertx.core.AsyncResult;
+import io.vertx.core.Handler;
+import io.vertx.core.json.JsonObject;
+import io.vertx.ext.web.api.service.ServiceRequest;
+import io.vertx.ext.web.api.service.ServiceResponse;
+import io.vertx.ext.web.api.service.WebApiServiceGen;
+
+import javax.annotation.Nonnull;
+
+@WebApiServiceGen
+public interface IASNHttpService {
+    String ADDRESS = IASNHttpService.class.getName();
+
+    void index(@Nonnull ServiceRequest context,
+               @Nonnull Handler<AsyncResult<ServiceResponse>> handler);
+
+    void register(@Nonnull JsonObject body,
+                  @Nonnull ServiceRequest context,
+                  @Nonnull Handler<AsyncResult<ServiceResponse>> handler);
+}
diff --git a/central/src/main/java/moe/yuuta/dn42peering/asn/IASNHttpServiceImpl.java b/central/src/main/java/moe/yuuta/dn42peering/asn/IASNHttpServiceImpl.java
new file mode 100644
index 0000000..b2105a4
--- /dev/null
+++ b/central/src/main/java/moe/yuuta/dn42peering/asn/IASNHttpServiceImpl.java
@@ -0,0 +1,168 @@
+package moe.yuuta.dn42peering.asn;
+
+import io.vertx.core.*;
+import io.vertx.core.buffer.Buffer;
+import io.vertx.core.http.HttpHeaders;
+import io.vertx.core.impl.logging.Logger;
+import io.vertx.core.impl.logging.LoggerFactory;
+import io.vertx.core.json.JsonObject;
+import io.vertx.ext.mail.MailClient;
+import io.vertx.ext.mail.MailConfig;
+import io.vertx.ext.mail.MailMessage;
+import io.vertx.ext.mail.MailResult;
+import io.vertx.ext.web.RoutingContext;
+import io.vertx.ext.web.api.service.ServiceRequest;
+import io.vertx.ext.web.api.service.ServiceResponse;
+import io.vertx.ext.web.common.template.TemplateEngine;
+import io.vertx.ext.web.templ.freemarker.FreeMarkerTemplateEngine;
+import moe.yuuta.dn42peering.jaba.Pair;
+import moe.yuuta.dn42peering.portal.FormException;
+import moe.yuuta.dn42peering.portal.HTTPException;
+import moe.yuuta.dn42peering.portal.RenderingUtils;
+import moe.yuuta.dn42peering.whois.IWhoisService;
+import moe.yuuta.dn42peering.whois.WhoisObject;
+import org.apache.commons.text.RandomStringGenerator;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import java.util.*;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+class IASNHttpServiceImpl implements IASNHttpService {
+    private final Logger logger = LoggerFactory.getLogger(getClass().getSimpleName());
+
+    private final IASNService asnService;
+    private final IWhoisService whoisService;
+    private final MailClient mailClient;
+    private final JsonObject mailConfig;
+    private final TemplateEngine templateEngine;
+
+    // Testing API
+    public IASNHttpServiceImpl(@Nonnull IASNService asnService,
+                               @Nonnull IWhoisService whoisService,
+                               @Nonnull MailClient mailClient,
+                               @Nonnull JsonObject mailConfig,
+                               @Nonnull TemplateEngine templateEngine) {
+        this.asnService = asnService;
+        this.whoisService = whoisService;
+        this.mailClient = mailClient;
+        this.mailConfig = mailConfig;
+        this.templateEngine = templateEngine;
+    }
+
+    public IASNHttpServiceImpl(@Nonnull Vertx vertx) {
+        this.asnService = IASNService.createProxy(vertx, IASNService.ADDRESS);
+        this.whoisService = IWhoisService.createProxy(vertx, IWhoisService.ADDRESS);
+        mailConfig = vertx.getOrCreateContext().config().getJsonObject("mail");
+        mailClient = MailClient.create(vertx, new MailConfig(mailConfig));
+        templateEngine = FreeMarkerTemplateEngine.create(vertx, "ftlh");
+    }
+
+    @Override
+    public void index(@Nonnull ServiceRequest context, @Nonnull Handler<AsyncResult<ServiceResponse>> handler) {
+        renderIndex(null, null, handler);
+    }
+
+    @Override
+    public void register(@Nonnull JsonObject parameters,
+                         @Nonnull ServiceRequest context,
+                         @Nonnull Handler<AsyncResult<ServiceResponse>> handler) {
+        final String upperASN = parameters.getString("asn").toUpperCase();
+        // Start: Check if the ASN exists.
+        Future.<Void>future(f -> asnService.exists(upperASN, true, true, ar -> {
+            if (ar.succeeded()) {
+                if (ar.result()) {
+                    f.fail(new FormException("This ASN exists in our records. Please login instead of registering."));
+                } else {
+                    f.complete();
+                }
+            } else {
+                f.fail(ar.cause());
+            }
+        }))
+                // Lookup ASN
+                .<WhoisObject>compose(exists ->
+                        Future.future(f -> whoisService.query(upperASN, f)))
+                // Lookup emails
+                .<List<String>>compose(asnLookup -> {
+                    if (asnLookup == null) {
+                        return Future.failedFuture(new FormException("The ASN is not found in the DN42 registry."));
+                    } else {
+                        return Future.future(f -> asnService.lookupEmails(asnLookup, ar -> {
+                            if (ar.succeeded()) {
+                                if (ar.result().isEmpty()) {
+                                    f.fail(new FormException("The tech-c contact for this ASN does not have emails."));
+                                } else {
+                                    f.complete(ar.result());
+                                }
+                            } else {
+                                f.fail(ar.cause());
+                            }
+                        }));
+                    }
+                })
+                // Generate random password and register.
+                .<Pair<String /* Random password */, List<String> /* Emails */>>compose(emails -> Future.future(f -> {
+                    final String randomPassword = new RandomStringGenerator.Builder()
+                            .withinRange('a', 'z')
+                            .build()
+                            .generate(15);
+                    asnService.registerOrChangePassword(upperASN, randomPassword, ar -> {
+                        if (ar.succeeded()) {
+                            f.complete(new Pair<>(randomPassword, emails));
+                        } else {
+                            f.fail(ar.cause());
+                        }
+                    });
+                }))
+                // Send mails.
+                .compose(pair -> CompositeFuture.any(Stream.of(pair.b)
+                        .map(mail -> new MailMessage()
+                                .setFrom(mailConfig.getString("from"))
+                                .setTo(mail)
+                                .setText(String.format("Hi %s! Welcome to dn42 peering! Your peering initial password is %s. Make sure to change it.",
+                                        upperASN,
+                                        pair.a))
+                                .setSubject("Peering initial password"))
+                        .map(message -> Future.<MailResult>future(f -> mailClient.sendMail(message, f)))
+                        .collect(Collectors.toList())))
+                // Render HTML or report errors
+                .onSuccess(res -> {
+                    // Get MailResult's out of the future.
+                    final List<MailResult> sendRes = res.list();
+                    renderSuccess(sendRes, handler);
+                })
+                .onFailure(err -> {
+                    if (err instanceof HTTPException) {
+                        handler.handle(Future.succeededFuture(new ServiceResponse(((HTTPException) err).code, null, null, null)));
+                    } else if (err instanceof FormException) {
+                        renderIndex(Arrays.asList(((FormException) err).errors.clone()),
+                                upperASN,
+                                handler);
+                    } else {
+                        logger.error(String.format("Cannot register ASN %s.", upperASN), err);
+                        handler.handle(Future.failedFuture(err));
+                    }
+                });
+    }
+
+    private void renderIndex(@Nullable List<String> errors,
+                             @Nullable String asn,
+                             @Nonnull Handler<AsyncResult<ServiceResponse>> handler) {
+        final Map<String, Object> root = new HashMap<>();
+        root.put("input_asn", asn == null ? "" : asn);
+        root.put("errors", errors);
+        templateEngine.render(root, "asn/index.ftlh", RenderingUtils.getGeneralRenderingHandler(handler));
+    }
+
+    private void renderSuccess(@Nonnull List<MailResult> sendRes,
+                               @Nonnull Handler<AsyncResult<ServiceResponse>> handler) {
+        final Map<String, Object> root = new HashMap<>();
+        root.put("emails", sendRes.stream()
+                .filter(Objects::nonNull) // Nulls mean failures.
+                .flatMap(res -> res.getRecipients().stream())
+                .collect(Collectors.toList()));
+        templateEngine.render(root, "asn/success.ftlh", RenderingUtils.getGeneralRenderingHandler(handler));
+    }
+}
diff --git a/central/src/main/java/moe/yuuta/dn42peering/portal/RenderingUtils.java b/central/src/main/java/moe/yuuta/dn42peering/portal/RenderingUtils.java
new file mode 100644
index 0000000..a8514f3
--- /dev/null
+++ b/central/src/main/java/moe/yuuta/dn42peering/portal/RenderingUtils.java
@@ -0,0 +1,26 @@
+package moe.yuuta.dn42peering.portal;
+
+import io.vertx.core.AsyncResult;
+import io.vertx.core.Future;
+import io.vertx.core.Handler;
+import io.vertx.core.MultiMap;
+import io.vertx.core.buffer.Buffer;
+import io.vertx.core.http.HttpHeaders;
+import io.vertx.ext.web.api.service.ServiceResponse;
+
+import javax.annotation.Nonnull;
+
+public class RenderingUtils {
+    public static Handler<AsyncResult<Buffer>> getGeneralRenderingHandler(@Nonnull Handler<AsyncResult<ServiceResponse>> handler) {
+        return res -> {
+            if (res.succeeded()) {
+                handler.handle(Future.succeededFuture(new ServiceResponse(200,
+                        null,
+                        res.result(),
+                        MultiMap.caseInsensitiveMultiMap().add(HttpHeaders.CONTENT_TYPE, "text/html"))));
+            } else {
+                handler.handle(Future.failedFuture(res.cause()));
+            }
+        };
+    }
+}