handlers.go

package main

import (
	"encoding/json"
	"io"
	"net/http"

	"github.com/davecgh/go-spew/spew"
)

// write blockchain when we receive an http request
func handleGetBlockchain(w http.ResponseWriter, r *http.Request) {
	bytes, err := json.MarshalIndent(Blockchain, "", "  ")
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	io.WriteString(w, string(bytes))
}

// takes JSON payload as an input (Data)
func handleWriteBlock(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	var m Message

	decoder := json.NewDecoder(r.Body)
	if err := decoder.Decode(&m); err != nil {
		respondWithJSON(w, r, http.StatusBadRequest, r.Body)
		return
	}
	defer r.Body.Close()

	//ensure atomicity when creating new block
	mutex.Lock()
	newBlock := generateBlock(Blockchain[len(Blockchain)-1], m.Data)
	mutex.Unlock()

	if isBlockValid(newBlock, Blockchain[len(Blockchain)-1]) {
		Blockchain = append(Blockchain, newBlock)
		spew.Dump(Blockchain)
	}

	respondWithJSON(w, r, http.StatusCreated, newBlock)

}