TxBuilder: adds fromTransaction impl. and basic tests

src/transaction_builder.js

@@ -1,9 +1,10 @@
 var assert = require('assert')
 var scripts = require('./scripts')
 
-var ECKey = require('./eckey')
+var ECPubKey = require('./ecpubkey')
-var Transaction = require('./transaction')
+var ECSignature = require('./ecsignature')
 var Script = require('./script')
+var Transaction = require('./transaction')
 
 function TransactionBuilder() {
   this.prevOutMap = {}
@@ -14,7 +15,7 @@ function TransactionBuilder() {
   this.tx = new Transaction()
 }
 
-TransactionBuilder.prototype.addInput = function(prevTx, index, prevOutScript, sequence) {
+TransactionBuilder.prototype.addInput = function(prevTx, index, sequence, prevOutScript) {
   var prevOutHash
 
   if (typeof prevTx === 'string') {
@@ -103,7 +104,6 @@ TransactionBuilder.prototype.sign = function(index, privKey, redeemScript, hashT
   }
 
   var input = this.signatures[index]
-
   assert.equal(input.hashType, hashType, 'Inconsistent hashType')
   assert.deepEqual(input.redeemScript, redeemScript, 'Inconsistent redeemScript')
 
@@ -130,29 +130,34 @@ TransactionBuilder.prototype.__build = function(allowIncomplete) {
 
   var tx = this.tx.clone()
 
+  // Create script signatures from signature meta-data
   this.signatures.forEach(function(input, index) {
     var scriptSig
+    var scriptType = input.scriptType
 
     var signatures = input.signatures.map(function(signature) {
       return signature.toScriptSignature(input.hashType)
     })
 
-    if (input.scriptType === 'pubkeyhash') {
+    switch (scriptType) {
-      var signature = signatures[0]
+      case 'pubkeyhash':
-      var publicKey = input.pubKeys[0]
+        var signature = signatures[0]
-      scriptSig = scripts.pubKeyHashInput(signature, publicKey)
+        var pubKey = input.pubKeys[0]
+        scriptSig = scripts.pubKeyHashInput(signature, pubKey)
 
-    } else if (input.scriptType === 'multisig') {
+        break
-      var redeemScript = allowIncomplete ? undefined : input.redeemScript
+      case 'multisig':
-      scriptSig = scripts.multisigInput(signatures, redeemScript)
+        var redeemScript = allowIncomplete ? undefined : input.redeemScript
+        scriptSig = scripts.multisigInput(signatures, redeemScript)
 
-    } else if (input.scriptType === 'pubkey') {
+        break
-      var signature = signatures[0]
+      case 'pubkey':
-      scriptSig = scripts.pubKeyInput(signature)
+        var signature = signatures[0]
-
+        scriptSig = scripts.pubKeyInput(signature)
-    } else {
-      assert(false, input.scriptType + ' not supported')
 
+        break
+      default:
+        assert(false, scriptType + ' not supported')
     }
 
     if (input.redeemScript) {
@@ -165,4 +170,83 @@ TransactionBuilder.prototype.__build = function(allowIncomplete) {
   return tx
 }
 
+TransactionBuilder.fromTransaction = function(transaction) {
+  var txb = new TransactionBuilder()
+
+  // Extract/add inputs
+  transaction.ins.forEach(function(txin) {
+    txb.addInput(txin.hash, txin.index, txin.sequence)
+  })
+
+  // Extract/add outputs
+  transaction.outs.forEach(function(txout) {
+    txb.addOutput(txout.script, txout.value)
+  })
+
+  // Extract/add signatures
+  transaction.ins.forEach(function(txin) {
+    // Ignore empty scripts
+    if (txin.script.buffer.length === 0) return
+
+    var redeemScript
+    var scriptSig = txin.script
+    var scriptType = scripts.classifyInput(scriptSig)
+
+    // Re-classify if P2SH
+    if (scriptType === 'scripthash') {
+      redeemScript = Script.fromBuffer(scriptSig.chunks.slice(-1)[0])
+      scriptSig = Script.fromChunks(scriptSig.chunks.slice(0, -1))
+
+      scriptType = scripts.classifyInput(scriptSig)
+      assert.equal(scripts.classifyOutput(redeemScript), scriptType, 'Non-matching scriptSig and scriptPubKey in input')
+    }
+
+    // Extract hashType, pubKeys and signatures
+    var hashType, pubKeys, signatures
+
+    switch (scriptType) {
+      case 'pubkeyhash':
+        var parsed = ECSignature.parseScriptSignature(scriptSig.chunks[0])
+        var pubKey = ECPubKey.fromBuffer(scriptSig.chunks[1])
+
+        hashType = parsed.hashType
+        pubKeys = [pubKey]
+        signatures = [parsed.signature]
+
+        break
+      case 'multisig':
+        var scriptSigs = scriptSig.chunks.slice(1) // ignore OP_0
+        var parsed = scriptSigs.map(function(scriptSig) {
+          return ECSignature.parseScriptSignature(scriptSig)
+        })
+
+        hashType = parsed[0].hashType
+        pubKeys = []
+        signatures = parsed.map(function(p) { return p.signature })
+
+        break
+      case 'pubkey':
+        var parsed = ECSignature.parseScriptSignature(scriptSig.chunks[0])
+
+        hashType = parsed.hashType
+        pubKeys = []
+        signatures = [parsed.signature]
+
+        break
+      default:
+        assert(false, scriptType + ' not supported')
+    }
+
+    txb.signatures[txin.index] = {
+      hashType: hashType,
+      pubKeys: pubKeys,
+      redeemScript: redeemScript,
+      scriptType: scriptType,
+      signatures: signatures
+    }
+  })
+
+  return txb
+}
+
 module.exports = TransactionBuilder

test/fixtures/transaction_builder.json

@@ -4,11 +4,14 @@
       {
         "description": "pubKeyHash->pubKeyHash 1:1 transaction",
         "txid": "bd641f4b0aa8bd70189ab45e935c4762f0e1c49f294b4779d79887937b7cf42e",
+        "txhex": "0100000001ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff000000006b483045022100a3b254e1c10b5d039f36c05f323995d6e5a367d98dd78a13d5bbc3991b35720e022022fccea3897d594de0689601fbd486588d5bfa6915be2386db0397ee9a6e80b601210279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798ffffffff0110270000000000001976a914aa4d7985c57e011a8b3dd8e0e5a73aaef41629c588ac00000000",
         "inputs": [
           {
             "index": 0,
             "prevTx": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
-            "privKeys": ["KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn"]
+            "privKeys": [
+              "KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn"
+            ]
           }
         ],
         "outputs": [
@@ -21,12 +24,15 @@
       {
         "description": "pubKey->pubKeyHash 1:1 transaction",
         "txid": "a900dea133a3c51e9fe55d82bf4a4f50a4c3ac6e380c841f93651a076573320c",
+        "txhex": "0100000001ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff00000000494830450221009833abb3ab49d7004c06bcc79eafd6905ada3eee91f3376ad388548034acd9a702202e84dda6ef2678c82256afcfc459aaa68e179b2bb0e6b2dc3f1410e132c5e6c301ffffffff0100f90295000000001976a914aa4d7985c57e011a8b3dd8e0e5a73aaef41629c588ac00000000",
         "inputs": [
           {
             "index": 0,
             "prevTx": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
             "prevTxScript": "0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798 OP_CHECKSIG",
-            "privKeys": ["KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn"]
+            "privKeys": [
+              "KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn"
+            ]
           }
         ],
         "outputs": [
@@ -39,11 +45,15 @@
       {
         "description": "2-of-2 P2SH multisig -> pubKeyHash 1:1 Transaction",
         "txid": "8c500ce6eef6c78a10de923b68394cf31120151bdc4600e4b12de865defa9d24",
+        "txhex": "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",
         "inputs": [
           {
             "index": 0,
             "prevTx": "4971f016798a167331bcbc67248313fbc444c6e92e4416efd06964425588f5cf",
-            "privKeys": ["91avARGdfge8E4tZfYLoxeJ5sGBdNJQH4kvjJoQFacbgwmaKkrx", "91avARGdfge8E4tZfYLoxeJ5sGBdNJQH4kvjJoQFacbgww7vXtT"],
+            "privKeys": [
+              "91avARGdfge8E4tZfYLoxeJ5sGBdNJQH4kvjJoQFacbgwmaKkrx",
+              "91avARGdfge8E4tZfYLoxeJ5sGBdNJQH4kvjJoQFacbgww7vXtT"
+            ],
             "redeemScript": "OP_2 0479be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8 04c6047f9441ed7d6d3045406e95c07cd85c778e4b8cef3ca7abac09b95c709ee51ae168fea63dc339a3c58419466ceaeef7f632653266d0e1236431a950cfe52a OP_2 OP_CHECKMULTISIG"
           }
         ],
@@ -101,7 +111,9 @@
           {
             "index": 0,
             "prevTx": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
-            "privKeys": ["KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn"]
+            "privKeys": [
+              "KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn"
+            ]
           },
           {
             "index": 1,
@@ -123,7 +135,9 @@
             "index": 0,
             "prevTx": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
             "prevTxScript": "OP_RETURN 06deadbeef03f895a2ad89fb6d696497af486cb7c644a27aa568c7a18dd06113401115185474",
-            "privKeys": ["KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn"]
+            "privKeys": [
+              "KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn"
+            ]
           }
         ],
         "outputs": [

test/transaction_builder.js

@@ -33,33 +33,36 @@ describe('TransactionBuilder', function() {
   })
 
   describe('addInput', function() {
-    it('accepts a txHash and index', function() {
+    it('accepts a txHash, index [and sequence number]', function() {
-      var vin = txb.addInput(prevTxHash, 1)
+      var vin = txb.addInput(prevTxHash, 1, 54)
       assert.equal(vin, 0)
 
       var txin = txb.tx.ins[0]
       assert.equal(txin.hash, prevTxHash)
       assert.equal(txin.index, 1)
+      assert.equal(txin.sequence, 54)
       assert.equal(txb.prevOutScripts[0], undefined)
     })
 
-    it('accepts a txHash, index and scriptPubKey', function() {
+    it('accepts a txHash, index [, sequence number and scriptPubKey]', function() {
-      var vin = txb.addInput(prevTxHash, 1, prevTx.outs[1].script)
+      var vin = txb.addInput(prevTxHash, 1, 54, prevTx.outs[1].script)
       assert.equal(vin, 0)
 
       var txin = txb.tx.ins[0]
       assert.equal(txin.hash, prevTxHash)
       assert.equal(txin.index, 1)
+      assert.equal(txin.sequence, 54)
       assert.equal(txb.prevOutScripts[0], prevTx.outs[1].script)
     })
 
-    it('accepts a prevTx and index', function() {
+    it('accepts a prevTx, index [and sequence number]', function() {
-      var vin = txb.addInput(prevTx, 1)
+      var vin = txb.addInput(prevTx, 1, 54)
       assert.equal(vin, 0)
 
       var txin = txb.tx.ins[0]
       assert.deepEqual(txin.hash, prevTxHash)
       assert.equal(txin.index, 1)
+      assert.equal(txin.sequence, 54)
       assert.equal(txb.prevOutScripts[0], prevTx.outs[1].script)
     })
 
@@ -70,7 +73,7 @@ describe('TransactionBuilder', function() {
 
     it('throws if prevOutScript is not supported', function() {
       assert.throws(function() {
-        txb.addInput(prevTxHash, 0, Script.EMPTY)
+        txb.addInput(prevTxHash, 0, undefined, Script.EMPTY)
       }, /PrevOutScript not supported \(nonstandard\)/)
     })
 
@@ -153,7 +156,7 @@ describe('TransactionBuilder', function() {
             prevTxScript = Script.fromASM(input.prevTxScript)
           }
 
-          txb.addInput(input.prevTx, input.index, prevTxScript)
+          txb.addInput(input.prevTx, input.index, input.sequence, prevTxScript)
         })
 
         f.outputs.forEach(function(output) {
@@ -191,7 +194,7 @@ describe('TransactionBuilder', function() {
             prevTxScript = Script.fromASM(input.prevTxScript)
           }
 
-          txb.addInput(input.prevTx, input.index, prevTxScript)
+          txb.addInput(input.prevTx, input.index, input.sequence, prevTxScript)
         })
 
         f.outputs.forEach(function(output) {
@@ -220,4 +223,15 @@ describe('TransactionBuilder', function() {
       })
     })
   })
+
+  describe('fromTransaction', function() {
+    fixtures.valid.build.forEach(function(f) {
+      it('builds the correct TransactionBuilder for ' + f.description, function() {
+        var tx = Transaction.fromHex(f.txhex)
+        var txb = TransactionBuilder.fromTransaction(tx)
+
+        assert.equal(txb.build().toHex(), f.txhex)
+      })
+    })
+  })
 })