Merge pull request #13 from zcash/magic-wormhole

Magic wormhole

README.md

@@ -42,29 +42,39 @@ rpcuser=user
 rpcpassword=password
 ```
 
-## Walking through a new trade
+## Example trade
 
 You can try this on regtest on one computer, or on testnet across two computers.
 
 Since this is beta software that is still under active development, we recommend that you do not trade more than you can afford to lose on mainnet.
 
+We use the term "seller" for whoever initiates the trade, and "buyer" for whoever fulfills the other end.
+
 ### Seller:
 
-To initiate a new trade, seller creates a trade and names it.
+To initiate a new trade, the seller enters all the necessary trade data and saves it under a tradeid. We will use the tradeid "testtrade" for this example. The amounts being traded will have to be agreed upon in advance, and the seller will need the buyer's destination addresses on both chains.
 
 `xcat newtrade testtrade`
 
-After creating, they are prompted to export it as hex, to transfer info to the buyer.
+After creating, the seller exports the trade data encoded as a hex string to transfer the terms of the trade to the buyer. They can send this hex string to the buyer through email or any other channel, but there is also built-in support to transfer the data directly between two computers through [magic-wormhole](https://github.com/warner/magic-wormhole).
+
+A standard export. Returns a long hex string which the seller sends to the buyer.
 
 `xcat exporttrade testtrade`
 
-Copy the resulting hex string and send it to the buyer.
+An export using magic-wormhole, which uses a short passphrase the seller must communicate to the buyer.
+
+`xcat -w exporttrade testtrade`
 
 ### Buyer:
 
-To examine trade, buyer imports it.
+To examine trade, buyer imports it. A standard import requires the full hex string.
 
-`xcat importttrade <hexstring> testtrade`
+`xcat importttrade testtrade <hexstring>`
+
+An import using magic-wormhole, which prompts the user for the short passphrase generated by the seller.
+
+`xcat -w importtrade`
 
 If it looks ok, inform seller to proceed.
 

xcat/cli.py

@@ -7,6 +7,7 @@ import xcat.userInput as userInput
 from xcat.trades import *
 from xcat.protocol import *
 import ast
+import subprocess
 
 def save_state(trade, tradeid):
     save(trade)
@@ -107,20 +108,38 @@ def checkBuyStatus(tradeid):
             print("Secret not found in redeemtx")
 
 # Import a trade in hex, and save to db
-def importtrade(hexstr, tradeid):
+def importtrade(tradeid, hexstr=''):
     trade = x2s(hexstr)
     trade = db.instantiate(trade)
     import_addrs(trade)
     print(trade.toJSON())
     save_state(trade, tradeid)
 
+def wormhole_importtrade():
+    res = subprocess.call('wormhole receive', shell=True)
+    if res == 0:
+        tradeid = input("Enter filename of received trade data to import (printed on line above): ")
+        with open(tradeid) as infile:
+            hexstr = infile.readline().strip()
+        importtrade(tradeid, hexstr)
+        print("Successfully imported trade using magic-wormhole")
+        os.remove(tradeid)
+    else:
+        print("Importing trade using magic-wormhole failed.")
+
 # Export a trade by its tradeid
-def exporttrade(tradeid):
-    # trade = get_trade()
+def exporttrade(tradeid, wormhole=False):
     trade  = db.get(tradeid)
     hexstr = s2x(trade.toJSON())
-    print(hexstr)
-    return hexstr
+    if wormhole:
+        tradefile = os.path.join(root_dir, '.tmp/{0}'.format(tradeid))
+        with open(tradefile, '+w') as outfile:
+            outfile.write(hexstr)
+        print("Exporting trade to buyer using magic wormhole.")
+        subprocess.call('wormhole', 'send', tradefile)
+    else:
+        print(hexstr)
+        return hexstr
 
 def findtrade(tradeid):
     trade = db.get(tradeid)
@@ -153,6 +172,7 @@ def newtrade(tradeid):
     save_state(trade, tradeid)
 
 def main():
+    root_dir = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
     parser = argparse.ArgumentParser(formatter_class=argparse.RawTextHelpFormatter,
         description=textwrap.dedent('''\
                 == Trades ==
@@ -164,7 +184,8 @@ def main():
 
                 '''))
     parser.add_argument("command", action="store", help="list commands")
-    parser.add_argument("argument", action="store", nargs="*", help="add an argument")
+    parser.add_argument("arguments", action="store", nargs="*", help="add arguments")
+    parser.add_argument("-w", "--wormhole", action="store_true", help="Transfer trade data through magic-wormhole")
     # parser.add_argument("--daemon", "-d", action="store_true", help="Run as daemon process")
     # TODO: function to view available trades
     # TODO: function to tell if tradeid already exists for newtrade
@@ -173,12 +194,18 @@ def main():
     # how to hold state of role
     command = args.command
     if command == 'importtrade':
-        hexstr = args.argument[0]
-        tradeid = args.argument[1]
-        importtrade(hexstr, tradeid)
+        if args.wormhole:
+            wormhole_importtrade()
+        else:
+            if len(args.argument) != 2:
+                print("Usage: importtrade [tradeid] [hexstring]")
+                exit()
+            tradeid = args.argument[0]
+            hexstr = args.argument[1]
+            importtrade(tradeid, hexstr)
     elif command == 'exporttrade':
         tradeid = args.argument[0]
-        exporttrade(tradeid)
+        exporttrade(tradeid, args.wormhole)
     elif command == "findtrade":
         print("Finding trade")
         key = args.argument[0]
@@ -208,6 +235,7 @@ def main():
     elif command == "step3":
         tradeid = args.argument[0]
         checkSellStatus(tradeid)
+    # TODO: When trade finishes, delete wormhole file in tmp dir.
     elif command == "step4":
         tradeid = args.argument[0]
         checkBuyStatus(tradeid)