Fix block file, error handling

lib/bridge.ex

@@ -95,7 +95,7 @@ defmodule BitcoinStream.Bridge do
     [_topic, payload, _size] = message;
 
     # keep last block on disk for preloading
-    :ok = File.write("block.dat", payload, [:append, :binary])
+    :ok = File.write("block.dat", payload, [:binary])
 
     case BitcoinBlock.decode(payload) do
       {:ok, block} ->

lib/protocol/block.ex

@@ -26,25 +26,32 @@ defstruct [
 ]
 
 def decode(block_binary) do
-  bytes = byte_size(block_binary)
+  with  bytes <- byte_size(block_binary),
-  hex = Base.encode16(block_binary, case: :lower);
+        hex <- Base.encode16(block_binary, case: :lower),
-  {:ok, raw_block} = Bitcoinex.Block.decode(hex)
+        {:ok, raw_block} <- Bitcoinex.Block.decode(hex),
-  id = Bitcoinex.Block.block_id(block_binary)
+        id <- Bitcoinex.Block.block_id(block_binary),
-
+        {summarised_txns, total_value} <- summarise_txns(raw_block.txns)
-  {summarised_txns, total_value} = summarise_txns(raw_block.txns)
+  do
-
+    {:ok, %__MODULE__{
-  {:ok, %__MODULE__{
+      version: raw_block.version,
-    version: raw_block.version,
+      prev_block: raw_block.prev_block,
-    prev_block: raw_block.prev_block,
+      merkle_root: raw_block.merkle_root,
-    merkle_root: raw_block.merkle_root,
+      timestamp: raw_block.timestamp,
-    timestamp: raw_block.timestamp,
+      bits: raw_block.bits,
-    bits: raw_block.bits,
+      bytes: bytes,
-    bytes: bytes,
+      txn_count: raw_block.txn_count,
-    txn_count: raw_block.txn_count,
+      txns: summarised_txns,
-    txns: summarised_txns,
+      value: total_value,
-    value: total_value,
+      id: id
-    id: id
+    }}
-  }}
+  else
+    {:error, reason} ->
+      IO.puts("Error decoding data for BitcoinBlock: #{reason}")
+      :error
+    _ ->
+      IO.puts("Error decoding data for BitcoinBlock: (unknown reason)")
+      :error
+  end
 end
 
 defp summarise_txns(txns) do

lib/socket_handler.ex

@@ -15,36 +15,17 @@ defmodule BitcoinStream.SocketHandler do
   end
 
   def load_block() do
-    case File.read("block.dat") do
+    with  {:ok, blockData} <- File.read("block.dat"),
-      {:ok, blockData } ->
+          {:ok, block} <- BitcoinBlock.decode(blockData),
-        case BitcoinBlock.decode(blockData) do
+          {:ok, payload} <- Jason.encode(%{type: "block", block: block})
-          {:ok, block} ->
+          do
-            IO.puts('file decoded ok')
+      {:ok, payload}
-            case Jason.encode(%{type: "block", block: block}) do
+    else
-              {:ok, payload} ->
-                IO.puts("block encoded ok");
-                { :ok, payload };
-              {:error, reason} ->
-                IO.puts("Error json encoding block: #{reason}");
-                :error
-              _ ->
-                IO.puts("json encoding failed: (unknown reason)")
-                :error
-            end
-          {:error, reason} ->
-            IO.puts("Block decoding failed: #{reason}");
-            :error
-          _ ->
-            IO.puts("Block decoding failed: (unknown reason)")
-            :error
-        end
-
       {:error, reason} ->
-        IO.puts("Reading block file failed: #{reason}");
+        IO.puts("Block decoding failed: #{reason}");
         :error
-
       _ ->
-        IO.puts("Reading block file failed (unknown reason)")
+        IO.puts("Block decoding failed: (unknown reason)");
         :error
     end
   end