From fa091ceda66166b95090132d42cad7a8ee5b545a Mon Sep 17 00:00:00 2001
From: garritfra <garritfranke@gmail.com>
Date: Sat, 22 Dec 2018 17:40:58 +0100
Subject: [PATCH] Add peers

---
 README.md           |  8 ++++----
 core/Blockchain.go  | 11 +++++++++--
 server/webserver.go | 20 ++++++++++++++++++++
 3 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index 6579b1e..43a7d89 100644
--- a/README.md
+++ b/README.md
@@ -48,7 +48,7 @@ The REST API currently exposes these Endpoints:
 
 Use the following endpoints to connect multiple nodes together
 
-| Method | Route     | Description                                       |
-| :----- | :-------- | :------------------------------------------------ |
-| POST   | /add_peer | Add a new peer address to the network             |
-| GET    | /update   | Compare chain with peers, and update if nessesary |
\ No newline at end of file
+| Method | Route      | Description                                       |
+| :----- | :--------- | :------------------------------------------------ |
+| POST   | /add_peers | Add new peer addresses to the network             |
+| GET    | /update    | Compare chain with peers, and update if nessesary |
\ No newline at end of file
diff --git a/core/Blockchain.go b/core/Blockchain.go
index 5b3dcc8..adc332e 100644
--- a/core/Blockchain.go
+++ b/core/Blockchain.go
@@ -10,6 +10,7 @@ import (
 type Blockchain struct {
 	Blocks              []Block
 	PendingTransactions []Transaction
+	Peers               []string
 }
 
 // MineBlock adds a block to the chain
@@ -38,7 +39,7 @@ func (bc *Blockchain) MineBlock() Block {
 func NewBlockchain() Blockchain {
 	log.Print("Creating Blockchain...")
 
-	blockchain := Blockchain{Blocks: make([]Block, 0), PendingTransactions: make([]Transaction, 0)}
+	blockchain := Blockchain{Blocks: make([]Block, 0), PendingTransactions: make([]Transaction, 0), Peers: make([]string, 0)}
 
 	// Mine Genesis Block
 	blockchain.MineBlock()
@@ -62,6 +63,11 @@ func (bc *Blockchain) GetLastHash() string {
 	return bc.Blocks[len(bc.Blocks)-1].Hash()
 }
 
+// AddPeer appends the IP address to the list of peers known to the chain
+func (bc *Blockchain) AddPeer(peer string) {
+	bc.Peers = append(bc.Peers, peer)
+}
+
 // IsValid checks, if the chain has any faulty blocks
 func (bc *Blockchain) IsValid() bool {
 	for i := 1; i < len(bc.Blocks); i++ {
@@ -78,11 +84,12 @@ type JSONBlockchain struct {
 	Blocks              []JSONBlock
 	Blockcount          int
 	PendingTransactions []Transaction
+	Peers               []string
 }
 
 // AsJSON returns the Blockchain as a JSON Blockchain
 func (bc *Blockchain) AsJSON() JSONBlockchain {
-	jsonChain := JSONBlockchain{PendingTransactions: bc.PendingTransactions}
+	jsonChain := JSONBlockchain{PendingTransactions: bc.PendingTransactions, Peers: bc.Peers}
 
 	for _, block := range bc.Blocks {
 		jsonChain.Blocks = append(jsonChain.Blocks, block.AsJSON())
diff --git a/server/webserver.go b/server/webserver.go
index dda7d78..a9de49a 100644
--- a/server/webserver.go
+++ b/server/webserver.go
@@ -33,6 +33,8 @@ func registerRouteHandlers() {
 	http.HandleFunc("/pending_transactions", handleListPendingTransactions)
 	http.HandleFunc("/add_transaction", handleAddTransaction)
 	http.HandleFunc("/is_valid", handleIsValid)
+
+	http.HandleFunc("/add_peers", handleAddPeers)
 }
 
 func handleError(err error, w http.ResponseWriter, r *http.Request) {
@@ -70,3 +72,21 @@ func handleIsValid(w http.ResponseWriter, r *http.Request) {
 	valid := blockchain.IsValid()
 	json.NewEncoder(w).Encode(valid)
 }
+
+// Takes an a string-slice, and adds it to the known peers
+func handleAddPeers(w http.ResponseWriter, r *http.Request) {
+	decoder := json.NewDecoder(r.Body)
+	var receivedPeers []string
+	err := decoder.Decode(&receivedPeers)
+
+	if err == nil {
+		for _, peer := range receivedPeers {
+			blockchain.AddPeer(peer)
+		}
+	} else {
+		handleError(err, w, r)
+	}
+
+	json.NewEncoder(w).Encode(blockchain.Peers)
+
+}