add welcome message to was message handler

src/main/java/com/meta/cp4m/message/WAMessageHandler.java

@@ -47,19 +47,20 @@ public class WAMessageHandler implements MessageHandler<WAMessage> {
 
   private static final TextChunker CHUNKER = TextChunker.standard(MAX_CHARS_PER_MESSAGE);
 
-  private final ExecutorService readExecutor = Executors.newVirtualThreadPerTaskExecutor();
+  private final ExecutorService asyncExecutor = Executors.newVirtualThreadPerTaskExecutor();
   private final Deduplicator<Identifier> messageDeduplicator = new Deduplicator<>(10_000);
   private final String appSecret;
   private final String verifyToken;
   private final String accessToken;
   private final String appSecretProof;
-
+  private final @Nullable String welcomeMessage;
   private URI baseURL = DEFAULT_BASE_URI;
 
   public WAMessageHandler(WAMessengerConfig config) {
     this.verifyToken = config.verifyToken();
     this.accessToken = config.accessToken();
     this.appSecret = config.appSecret();
+    this.welcomeMessage = config.welcomeMessage().orElse(null);
     this.appSecretProof = MetaHandlerUtils.hmac(accessToken, appSecret);
   }
 
@@ -77,6 +78,27 @@ private List<WAMessage> post(Context ctx, WebhookPayload payload) {
                 Payload<?> payloadValue;
                 switch (message) {
                   case TextWebhookMessage m -> payloadValue = new Payload.Text(m.text().body());
+                  case WelcomeWebhookMessage ignored -> {
+                    if (welcomeMessage != null) {
+                      WAMessage welcome =
+                          new WAMessage(
+                              message.timestamp(),
+                              message.id(),
+                              message.from(),
+                              phoneNumberId,
+                              welcomeMessage,
+                              Message.Role.USER);
+                      asyncExecutor.submit(
+                          () -> {
+                            try {
+                              respond(welcome);
+                            } catch (IOException e) {
+                              LOGGER.error("unable to send welcome message");
+                            }
+                          });
+                    }
+                    continue;
+                  }
                   default -> {
                     LOGGER.warn(
                         "received message of type '"
@@ -93,7 +115,7 @@ private List<WAMessage> post(Context ctx, WebhookPayload payload) {
                         phoneNumberId,
                         payloadValue,
                         Message.Role.USER));
-                readExecutor.execute(() -> markRead(phoneNumberId, message.id().toString()));
+                asyncExecutor.execute(() -> markRead(phoneNumberId, message.id().toString()));
               }
             });
     return waMessages;
@@ -144,7 +166,8 @@ private void send(Identifier recipient, Identifier sender, String text) throws I
         .setHeader("Authorization", "Bearer " + accessToken)
         .setHeader("appsecret_proof", appSecretProof)
         .bodyString(bodyString, ContentType.APPLICATION_JSON)
-        .execute();
+        .execute()
+        .discardContent();
   }
 
   @Override
@@ -192,7 +215,8 @@ private void markRead(Identifier phoneNumberId, String messageId) {
           .setHeader("Authorization", "Bearer " + accessToken)
           .setHeader("appsecret_proof", appSecretProof)
           .bodyString(bodyString, ContentType.APPLICATION_JSON)
-          .execute();
+          .execute()
+          .discardContent();
     } catch (IOException e) {
       // nothing we can do here, marking later messages as read will mark all previous messages read
       // so this is not a fatal issue

src/main/java/com/meta/cp4m/message/WAMessengerConfig.java

@@ -10,20 +10,25 @@
 
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.google.common.base.Preconditions;
+import java.util.Optional;
 import java.util.UUID;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 public class WAMessengerConfig implements HandlerConfig {
 
   private final String name;
   private final String verifyToken;
   private final String appSecret;
   private final String accessToken;
+  private final @Nullable String welcomeMessage;
 
   private WAMessengerConfig(
       @JsonProperty("name") String name,
       @JsonProperty("verify_token") String verifyToken,
       @JsonProperty("app_secret") String appSecret,
-      @JsonProperty("access_token") String accessToken) {
+      @JsonProperty("access_token") String accessToken,
+      @Nullable @JsonProperty("welcome_message") String welcomeMessage) {
+    this.welcomeMessage = welcomeMessage;
 
     Preconditions.checkArgument(name != null && !name.isBlank(), "name cannot be blank");
     Preconditions.checkArgument(
@@ -41,7 +46,15 @@ private WAMessengerConfig(
 
   public static WAMessengerConfig of(String verifyToken, String appSecret, String accessToken) {
     // human readability of the name only matters when it's coming from a config
-    return new WAMessengerConfig(UUID.randomUUID().toString(), verifyToken, appSecret, accessToken);
+    return new WAMessengerConfig(
+        UUID.randomUUID().toString(), verifyToken, appSecret, accessToken, null);
+  }
+
+  public static WAMessengerConfig of(
+      String verifyToken, String appSecret, String accessToken, @Nullable String welcomeMessage) {
+    // human readability of the name only matters when it's coming from a config
+    return new WAMessengerConfig(
+        UUID.randomUUID().toString(), verifyToken, appSecret, accessToken, welcomeMessage);
   }
 
   @Override
@@ -65,4 +78,8 @@ public WAMessageHandler toMessageHandler() {
   public String accessToken() {
     return accessToken;
   }
+
+  public Optional<String> welcomeMessage() {
+    return Optional.ofNullable(welcomeMessage);
+  }
 }

src/main/java/com/meta/cp4m/message/webhook/whatsapp/WebhookMessage.java

@@ -33,6 +33,7 @@
   @JsonSubTypes.Type(value = StickerWebhookMessage.class, name = "sticker"),
   @JsonSubTypes.Type(value = UnknownWebhookMessage.class, name = "unknown"),
   @JsonSubTypes.Type(value = VideoWebhookMessage.class, name = "video"),
+  @JsonSubTypes.Type(value = WelcomeWebhookMessage.class, name = "request_welcome"),
 })
 public interface WebhookMessage {
 
@@ -100,6 +101,7 @@ enum WebhookMessageType {
     STICKER,
     SYSTEM,
     VIDEO,
+    REQUEST_WELCOME,
     UNKNOWN;
 
     @Override

src/main/java/com/meta/cp4m/message/webhook/whatsapp/WelcomeWebhookMessage.java

@@ -0,0 +1,79 @@
+/*
+ *
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.meta.cp4m.message.webhook.whatsapp;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.meta.cp4m.Identifier;
+import java.time.Instant;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Objects;
+import java.util.Optional;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public class WelcomeWebhookMessage implements ReferableWebhookMessage {
+  private final @Nullable Referral referral;
+  private final @Nullable WebhookMessageContext context;
+  private final Collection<Error> errors;
+  private final Identifier from;
+  private final Identifier id;
+  private final Instant timestamp;
+
+  @JsonCreator
+  public WelcomeWebhookMessage(
+      @JsonProperty("context") @Nullable WebhookMessageContext context,
+      @JsonProperty("error") Collection<Error> errors,
+      @JsonProperty("from") String from,
+      @JsonProperty("id") String id,
+      @JsonProperty("timestamp") long timestamp,
+      @JsonProperty("referral") @Nullable Referral referral) {
+    this.referral = referral;
+    this.context = context;
+    this.errors = errors == null ? Collections.emptyList() : errors;
+    this.from = Identifier.from(Objects.requireNonNull(from));
+    this.id = Identifier.from(Objects.requireNonNull(id));
+    this.timestamp = Instant.ofEpochSecond(timestamp);
+  }
+
+  @Override
+  public Optional<Referral> referral() {
+    return Optional.ofNullable(referral);
+  }
+
+  @Override
+  public Optional<WebhookMessageContext> context() {
+    return Optional.ofNullable(context);
+  }
+
+  @Override
+  public Collection<Error> errors() {
+    return errors;
+  }
+
+  @Override
+  public Identifier from() {
+    return from;
+  }
+
+  @Override
+  public Identifier id() {
+    return id;
+  }
+
+  @Override
+  public Instant timestamp() {
+    return timestamp;
+  }
+
+  @Override
+  public WebhookMessageType type() {
+    return WebhookMessageType.REQUEST_WELCOME;
+  }
+}

src/test/java/com/meta/cp4m/message/ServiceTestHarness.java

@@ -21,6 +21,7 @@
 import org.apache.hc.core5.http.ContentType;
 import org.apache.hc.core5.net.URIBuilder;
 import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.common.reflection.qual.NewInstance;
 import org.checkerframework.common.returnsreceiver.qual.This;
 
 public class ServiceTestHarness<T extends Message> {
@@ -48,13 +49,25 @@ private ServiceTestHarness(
   public static ServiceTestHarness<WAMessage> newWAServiceTestHarness() {
     ChatStore<WAMessage> chatStore = MemoryStoreConfig.of(1, 1).toStore();
     DummyLLMPlugin<WAMessage> llmPlugin = new DummyLLMPlugin<>("dummy plugin response text");
-    WAMessageHandler handler =
-        WAMessengerConfig.of(VERIFY_TOKEN, APP_SECRET, ACCESS_TOKEN).toMessageHandler();
+    WAMessengerConfig config = WAMessengerConfig.of(VERIFY_TOKEN, APP_SECRET, ACCESS_TOKEN);
+    WAMessageHandler handler = config.toMessageHandler();
     ServiceTestHarness<WAMessage> harness = new ServiceTestHarness<>(chatStore, handler, llmPlugin);
     handler.baseUrl(harness.webserverURI());
     return harness;
   }
 
+  public @NewInstance ServiceTestHarness<T> withHandler(MessageHandler<T> handler) {
+    this.stop();
+    ServiceTestHarness<T> harness =
+        new ServiceTestHarness<>(this.chatStore, handler, this.llmPlugin);
+    switch (handler) {
+      case WAMessageHandler w -> w.baseUrl(harness.webserverURI());
+      case FBMessageHandler fb -> fb.baseURLFactory(ignored -> harness.webserverURI());
+      default -> {}
+    }
+    return harness;
+  }
+
   public Request post() {
     return Request.post(serviceURI());
   }

src/test/java/com/meta/cp4m/message/WAMessageHandlerTest.java

@@ -11,6 +11,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 import com.fasterxml.jackson.databind.json.JsonMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.meta.cp4m.DummyWebServer.ReceivedRequest;
 import com.meta.cp4m.Identifier;
 import com.meta.cp4m.message.webhook.whatsapp.Utils;
@@ -22,8 +23,10 @@
 import java.util.stream.Stream;
 import org.apache.hc.client5.http.fluent.Response;
 import org.checkerframework.checker.nullness.qual.Nullable;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.NullSource;
+import org.junit.jupiter.params.provider.ValueSource;
 
 class WAMessageHandlerTest {
 
@@ -104,13 +107,51 @@ class WAMessageHandlerTest {
   private final ServiceTestHarness<WAMessage> harness =
       ServiceTestHarness.newWAServiceTestHarness();
 
-  @BeforeEach
-  void setUp() {
+  @ParameterizedTest
+  @NullSource
+  @ValueSource(strings = {"Hello Worldy!!", ""})
+  void welcomeMessage(final @Nullable String welcomeMessage)
+      throws IOException, InterruptedException {
+    ServiceTestHarness<WAMessage> harness =
+        this.harness.withHandler(
+            WAMessengerConfig.of(
+                    this.harness.verifyToken(),
+                    this.harness.appSecret(),
+                    this.harness.accessToken(),
+                    welcomeMessage)
+                .toMessageHandler());
     harness.start();
+    ObjectNode webhookPayload = (ObjectNode) MAPPER.readTree(VALID);
+    ObjectNode msg =
+        (ObjectNode)
+            webhookPayload
+                .get("entry")
+                .get(0)
+                .get("changes")
+                .get(0)
+                .get("value")
+                .get("messages")
+                .get(0);
+    msg.remove("text");
+    msg.put("type", "request_welcome");
+    harness.post(MAPPER.writeValueAsString(webhookPayload)).execute();
+    @Nullable ReceivedRequest res = harness.pollWebserver(200);
+    if (welcomeMessage == null) {
+      assertThat(res).isNull();
+    } else {
+      assertThat(res).isNotNull();
+      assertThat(MAPPER.readTree(res.body()))
+          .isEqualTo(
+              MAPPER.readTree(
+                  "{\"recipient_type\":\"individual\",\"messaging_product\":\"whatsapp\",\"type\":\"text\",\"to\":\"123456123\",\"text\":{\"body\":\""
+                      + welcomeMessage
+                      + "\"}}"));
+    }
   }
 
   @Test
   void valid() throws IOException, InterruptedException {
+    harness.start();
     Response request = harness.post(VALID).execute();
     assertThat(request.returnResponse().getCode()).isEqualTo(200);
 
@@ -156,6 +197,7 @@ void valid() throws IOException, InterruptedException {
 
   @Test
   void doesNotSendNonTextMessages() throws IOException, InterruptedException {
+    harness.start();
     harness.llmPlugin().addResponseToSend(new Payload.Image(new byte[0], "image/jpeg"));
     Response request = harness.post(VALID).execute();
     assertThat(request.returnResponse().getCode()).isEqualTo(200);
@@ -173,6 +215,7 @@ void doesNotSendNonTextMessages() throws IOException, InterruptedException {
 
   @Test
   void noMessages() throws IOException, InterruptedException {
+    harness.start();
     Response request = harness.post(NO_MESSAGES).execute();
     assertThat(request.returnResponse().getCode()).isEqualTo(200);
     assertThat(harness.pollWebserver(250)).isNull();