Add method for deleting a contact from own mailbox

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxApi.java

@@ -1,5 +1,7 @@
 package org.briarproject.bramble.mailbox;
 
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.mailbox.MailboxProperties;
 
@@ -35,10 +37,17 @@ interface MailboxApi {
 	 * (contact was already added).
 	 */
 	void addContact(MailboxProperties properties, MailboxContact contact)
-			throws IOException, ApiException,
-			TolerableFailureException;
+			throws IOException, ApiException, TolerableFailureException;
+
+	/**
+	 * Deletes a contact from the mailbox.
+	 * This should get called after a contact was removed from Briar.
+	 */
+	void deleteContact(MailboxProperties properties, ContactId contactId)
+			throws IOException, ApiException;
 
 	@Immutable
+	@JsonSerialize
 	class MailboxContact {
 		public final int contactId;
 		public final String token, inboxId, outboxId;

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxApiImpl.java

@@ -5,6 +5,7 @@ import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.json.JsonMapper;
 
 import org.briarproject.bramble.api.WeakSingletonProvider;
+import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.mailbox.MailboxProperties;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
@@ -111,6 +112,21 @@ class MailboxApiImpl implements MailboxApi {
 		if (!response.isSuccessful()) throw new ApiException();
 	}
 
+	@Override
+	public void deleteContact(MailboxProperties properties, ContactId contactId)
+			throws IOException, ApiException {
+		if (!properties.isOwner()) throw new IllegalArgumentException();
+		String url = properties.getOnionAddress() + "/contacts/" +
+				contactId.getInt();
+		Request request = getRequestBuilder(properties.getAuthToken())
+				.delete()
+				.url(url)
+				.build();
+		OkHttpClient client = httpClientProvider.get();
+		Response response = client.newCall(request).execute();
+		if (response.code() != 200) throw new ApiException();
+	}
+
 	private Request.Builder getRequestBuilder(String token) {
 		return new Request.Builder()
 				.addHeader("Authorization", "Bearer " + token);