objects.getType

lib/messages.js

@@ -19,7 +19,7 @@ var message = structs.message;
 var ServicesBitfield = structs.ServicesBitfield;
 
 /**
- * Try to get command for the given encoded message.
+ * Try to get command of the given encoded message.
  * Note that this function doesn't do any validation because it is
  * already provided by `message.decode` routine. Normally you call this
  * for each incoming message and then call decode function of the

lib/objects.js

@@ -1,7 +1,7 @@
 /**
  * Working with objects.
- * NOTE: All operations with objects in this module are asynchronous and
+ * NOTE: Most operations with objects in this module are asynchronous
- * return promises.
+ * and return promises.
  * @see {@link https://bitmessage.org/wiki/Protocol_specification#Object_types}
  * @module bitmessage/objects
  */
@@ -25,6 +25,41 @@ var PubkeyBitfield = structs.PubkeyBitfield;
 var message = structs.message;
 var object = structs.object;
 
+/**
+ * Try to get type of the given encoded object message.
+ * Note that this function doesn't do any validation because it is
+ * already provided by `object.decode` routine. Normally you call this
+ * for each incoming object message and then call decode function of the
+ * appropriate object handler.
+ * @param {Buffer} buf - Buffer that starts with encoded object message
+ * @return {?integer} Object's type if any
+ */
+exports.getType = function(buf) {
+  // Message header: 4 + 12 + 4 + 4
+  // Object header: 8 + 8 + 4
+  if (buf.length < 44) {
+    return;
+  }
+  return buf.readUInt32BE(40, true);
+};
+
+/**
+ * Try to get type of the given object message payoad.
+ * Note that this function doesn't do any validation because it is
+ * already provided by `object.decodePayload` routine. Normally you call
+ * this for each incoming object message and then call decode function
+ * of the appropriate object handler.
+ * @param {Buffer} buf - Buffer that starts with object message payload
+ * @return {?integer} Object's type if any
+ */
+exports.getPayloadType = function(buf) {
+  // Object header: 8 + 8 + 4
+  if (buf.length < 20) {
+    return;
+  }
+  return buf.readUInt32BE(16, true);
+};
+
 /**
  * `getpubkey` object. When a node has the hash of a public key (from an
  * address) but not the public key itself, it must send out a request

package.json

@@ -50,7 +50,7 @@
     "bn.js": "^1.0.0",
     "bs58": "^2.0.0",
     "buffer-equal": "~0.0.1",
-    "eccrypto": "^0.9.4",
+    "eccrypto": "^0.9.5",
     "es6-promise": "^2.0.1",
     "hash.js": "^1.0.2",
     "nan": "^1.4.1",

test.js

@@ -495,6 +495,30 @@ describe("Message types", function() {
 
 // TODO(Kagami): Add tests for encodePayloadAsync/decodePayloadAsync as well.
 describe("Object types", function() {
+  it("should get type of the encoded object message", function() {
+    var encoded = object.encode({
+      nonce: Buffer(8),
+      ttl: 100,
+      type: object.BROADCAST,
+      version: 1,
+      objectPayload: Buffer("test"),
+    });
+    expect(objects.getType(encoded)).to.equal(object.BROADCAST);
+    expect(objects.getType(Buffer(4))).to.be.undefined;
+  });
+
+  it("should get type of the object message payload", function() {
+    var encoded = object.encodePayload({
+      nonce: Buffer(8),
+      ttl: 333,
+      type: object.MSG,
+      version: 1,
+      objectPayload: Buffer("test"),
+    });
+    expect(objects.getPayloadType(encoded)).to.equal(object.MSG);
+    expect(objects.getPayloadType(Buffer(7))).to.be.undefined;
+  });
+
   describe("getpubkey", function() {
     it("should encode and decode getpubkey v3", function() {
       return getpubkey.encodeAsync({