From 32dbac49469e50dae928b399bcddef5030339771 Mon Sep 17 00:00:00 2001
From: Ramakrishnan Muthukrishnan <ram@rkrishnan.org>
Date: Sun, 13 Sep 2015 20:18:07 +0530
Subject: [PATCH] Main: generate random peerid

---
 functorrent.cabal |  2 +-
 src/main/Main.hs  | 18 +++++++++++++-----
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/functorrent.cabal b/functorrent.cabal
index f69e7d3..dd0a306 100644
--- a/functorrent.cabal
+++ b/functorrent.cabal
@@ -64,8 +64,8 @@ executable functorrent
                        mtl,
                        network,
                        network-uri,
-                       parsec,
                        QuickCheck,
+                       random,
                        safe
 
 test-suite functorrent-test
diff --git a/src/main/Main.hs b/src/main/Main.hs
index b82d27a..dff915f 100644
--- a/src/main/Main.hs
+++ b/src/main/Main.hs
@@ -3,11 +3,11 @@ module Main where
 
 import Prelude hiding (log, length, readFile, getContents)
 
-import Control.Monad.Reader(runReaderT)
 import Data.ByteString.Char8 (ByteString, getContents, readFile, unpack)
 import System.Environment (getArgs)
 import System.Exit (exitSuccess)
 import System.Directory (doesFileExist)
+import System.Random (getStdGen, randomRs)
 
 import FuncTorrent.Logger (initLogger, logMessage, logStop)
 import FuncTorrent.Metainfo (Info(..), Metainfo(..), torrentToMetainfo)
@@ -17,9 +17,6 @@ import FuncTorrent.Tracker (peers, getTrackerResponse)
 logError :: String -> (String -> IO ()) -> IO ()
 logError e logMsg = logMsg $ "parse error: \n" ++ e
 
-peerId :: String
-peerId = "-HS0001-*-*-20150215"
-
 exit :: IO ByteString
 exit = exitSuccess
 
@@ -35,10 +32,21 @@ parse [a] = do
     else error "file does not exist"
 parse _ = exit
 
+-- peer id is exactly 20 bytes long.
+-- peer id starts with '-', followed by 2 char client id'
+-- followed by 4 ascii digits for version number, followed by
+-- a '-'. Rest are random digits to fill the 20 bytes.
+mkPeerID :: IO String
+mkPeerID = do
+  stdgen <- getStdGen
+  let digits = randomRs (0, 9) stdgen :: [Integer]
+  return $ "-HS9001-" ++ (concatMap show $ take (20 - 8) digits)
+
 main :: IO ()
 main = do
     args <- getArgs
     logR <- initLogger
+    peerId <- mkPeerID    
     let log = logMessage logR
     log "Starting up functorrent"
     log $ "Parsing arguments " ++ concat args
@@ -51,7 +59,7 @@ main = do
        log "Trying to fetch peers"
 
        log $ "Trackers: " ++ head (announceList m)
-       trackerResp <- runReaderT (getTrackerResponse peerId) m
+       trackerResp <- getTrackerResponse peerId m
        case  trackerResp of
         Left e -> log $ "Error" ++ unpack e
         Right peerList -> do
-- 
2.37.2