Merge pull request 'Add encoder(s)' (#1) from encoder into main

Reviewed-on: #1

.gitignore

@@ -24,3 +24,6 @@ ssb_bfe-*.tar
 
 # Temporary files, for example, from tests.
 /tmp/
+
+# Ignore the lockfile
+mix.lock

README.md

@@ -2,6 +2,41 @@
 
 Binary Field Encodings (BFE) for Secure Scuttlebutt (SSB).
 
+See the [SSB Binary Field Encodings Specification](https://github.com/ssbc/ssb-bfe-spec) for details.
+
+## Encoding
+
+```elixir
+SsbBfe.encode(value)
+```
+
+### Elixir Types
+
+Encoding of the following Elixir types is supported:
+
+ - List
+ - Map
+ - Tuple
+ - String
+ - Boolean
+ - Nil
+ - Integer
+ - Float
+
+Note: encoding of structs is not supported. You may wish to convert your struct to amap and encode it that way.
+
+### Scuttlebutt Types
+
+Encoding of the following Scuttlebutt types is supported:
+
+ - Feed (classic)
+ - Message (classic)
+ - Blob
+ - Signature
+ - Private message (box, box2)
+
+Note: encoding of URIs is not currently supported, nor are other formats such as Gabby Grove and Bendy Butt.
+
 ## Installation
 
 If [available in Hex](https://hex.pm/docs/publish), the package can be installed
@@ -15,7 +50,12 @@ def deps do
 end
 ```
 
+## Documentation
+
 Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
 and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
 be found at <https://hexdocs.pm/ssb_bfe>.
 
+## License
+
+LGPL-3.0.

lib/ssb_bfe.ex

@@ -15,4 +15,50 @@ defmodule SsbBfe do
   def hello do
     :world
   end
+
+  def encode(value) when is_list(value) do
+    Enum.map(value, fn x -> encode(x) end)
+  end
+
+  def encode(value) when is_map(value) do
+    Enum.reduce(
+      value,
+      %{},
+      fn {k, v}, acc ->
+        Map.put(acc, k, SsbBfe.encode(v))
+      end
+    )
+  end
+
+  def encode(value) when is_tuple(value) do
+    Enum.map(Tuple.to_list(value), fn x -> encode(x) end)
+  end
+
+  def encode(value) when is_bitstring(value) do
+    cond do
+      String.starts_with?(value, "@") ->
+        SsbBfe.Encoder.encode_feed(value)
+
+      String.starts_with?(value, "%") ->
+        SsbBfe.Encoder.encode_msg(value)
+
+      String.starts_with?(value, "&") ->
+        SsbBfe.Encoder.encode_blob(value)
+
+      String.ends_with?(value, ".sig.ed25519") ->
+        SsbBfe.Encoder.encode_sig(value)
+
+      String.ends_with?(value, [".box", ".box2"]) ->
+        SsbBfe.Encoder.encode_box(value)
+
+      true ->
+        SsbBfe.Encoder.encode_str(value)
+    end
+  end
+
+  def encode(value) when is_boolean(value), do: SsbBfe.Encoder.encode_bool(value)
+
+  def encode(value) when is_number(value), do: value
+
+  def encode(value) when is_nil(value), do: SsbBfe.Encoder.encode_nil()
 end

lib/ssb_bfe/encoder.ex

@@ -1,5 +1,55 @@
+# might be good to use a multiclause function for the `encode` function
+# - use the `when` conditional guard with e.g. `is_number` 
+
 defmodule SsbBfe.Encoder do
-  def encode_bool(blob_id) do
-    # Enum.sum(list) / Kernel.length(list)
+  # Extract the base64 substring from a sigil-link and decode it.
+  defp extract_base64_data(str) do
+    base64_data = String.slice(str, 1..44)
+    Base.decode64(base64_data)
   end
-end
+
+  # Provide a pattern with which to split a string and base64 decode the first part.
+  defp extract_base64_data(str, pattern) do
+    [base64_data | _] = String.split(str, pattern)
+    Base.decode64(base64_data)
+  end
+
+  def encode_blob(blob_id) do
+    blob_tf_tag = SsbBfe.Types.get_blob_type(blob_id)
+    {:ok, decoded_base64_data} = extract_base64_data(blob_id)
+    blob_tf_tag <> decoded_base64_data
+  end
+
+  def encode_bool(true), do: <<6, 1, 1>>
+
+  def encode_bool(false), do: <<6, 1, 0>>
+
+  def encode_box(box_str) do
+    box_tf_tag = SsbBfe.Types.get_box_type(box_str)
+    {:ok, decoded_base64_data} = extract_base64_data(box_str, ".")
+    box_tf_tag <> decoded_base64_data
+  end
+
+  def encode_feed(feed_id) do
+    feed_tf_tag = SsbBfe.Types.get_feed_type(feed_id)
+    {:ok, decoded_base64_data} = extract_base64_data(feed_id)
+    feed_tf_tag <> decoded_base64_data
+  end
+
+  def encode_msg(msg_id) do
+    msg_tf_tag = SsbBfe.Types.get_msg_type(msg_id)
+    {:ok, decoded_base64_data} = extract_base64_data(msg_id)
+    msg_tf_tag <> decoded_base64_data
+  end
+
+  def encode_nil(), do: <<6, 2>>
+
+  def encode_sig(sig) do
+    {:ok, decoded_base64_data} = extract_base64_data(sig, ".sig.ed25519")
+    <<4, 0>> <> decoded_base64_data
+  end
+
+  def encode_str(str), do: <<6, 0>> <> str
+
+  # def encode_uri(uri)
+end 

lib/ssb_bfe/types.ex

@@ -8,7 +8,7 @@ defmodule SsbBfe.Types do
       <<2, 0>>
     end
   end
-  
+
   @doc ~S"""
   Take a box as a string and return the encoded bytes representing the box
   type-format. Return `nil` if the ID does not end with `.box` or `.box2`.
@@ -17,8 +17,10 @@ defmodule SsbBfe.Types do
     cond do
       String.ends_with?(boxed_str, ".box") ->
         <<5, 0>>
+
       String.ends_with?(boxed_str, ".box2") ->
         <<5, 1>>
+
       true ->
         nil
     end
@@ -43,8 +45,10 @@ defmodule SsbBfe.Types do
     cond do
       String.ends_with?(msg_id, ".sha256") ->
         <<1, 0>>
+
       String.ends_with?(msg_id, ".cloaked") ->
         <<1, 2>>
+
       true ->
         nil
     end

mix.exs

@@ -23,6 +23,7 @@ defmodule SsbBfe.MixProject do
     [
       # {:dep_from_hexpm, "~> 0.3.0"},
       # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+      {:poison, "~> 5.0"}
     ]
   end
 end

test/ssb_bfe_test.exs

@@ -2,7 +2,91 @@ defmodule SsbBfeTest do
   use ExUnit.Case
   doctest SsbBfe
 
-  test "greets the world" do
-    assert SsbBfe.hello() == :world
+  setup do
+    [
+      blob: "&S7+CwHM6dZ9si5Vn4ftpk/l/ldbRMqzzJos+spZbWf4=.sha256",
+      box1: "bG92ZSBjb2xsYXBzZXMgc3BhY2V0aW1l.box",
+      box2: "bG92ZSBjb2xsYXBzZXMgc3BhY2V0aW1l.box2",
+      feed_classic: "@d/zDvFswFbQaYJc03i47C9CgDev+/A8QQSfG5l/SEfw=.ed25519",
+      msg_classic: "%R8heq/tQoxEIPkWf0Kxn1nCm/CsxG2CDpUYnAvdbXY8=.sha256",
+      sig: "nkY4Wsn9feosxvX7bpLK7OxjdSrw6gSL8sun1n2TMLXKySYK9L5itVQnV2nQUctFsrUOa2istD2vDk1B0uAMBQ==.sig.ed25519",
+      str: "golden ripples in the meshwork",
+    ]
+  end
+
+  # HAPPY PATH ENCODING TESTS
+
+  test "classic feed is encoded correctly", context do
+    encoded_feed = SsbBfe.encode(context.feed_classic)
+    
+    assert encoded_feed == <<0, 0, 119, 252, 195, 188, 91, 48, 21, 180, 26, 96, 151, 52, 222, 46, 59, 11, 208, 160, 13, 235, 254, 252, 15, 16, 65, 39, 198, 230, 95, 210, 17, 252>>
+  end
+
+  test "classic msg is encoded correctly", context do
+    encoded_msg = SsbBfe.encode(context.msg_classic)
+
+    assert encoded_msg == <<1, 0, 71, 200, 94, 171, 251, 80, 163, 17, 8, 62, 69, 159, 208, 172, 103, 214, 112, 166, 252, 43, 49, 27, 96, 131, 165, 70, 39, 2, 247, 91, 93, 143>>
+  end
+
+  test "blob is encoded correctly", context do
+    encoded_blob = SsbBfe.encode(context.blob)
+
+    assert encoded_blob == <<2, 0, 75, 191, 130, 192, 115, 58, 117, 159, 108, 139, 149, 103, 225, 251, 105, 147, 249, 127, 149, 214, 209, 50, 172, 243, 38, 139, 62, 178, 150, 91, 89, 254>>
+  end
+
+  test "signature is encoded correctly", context do
+    encoded_sig = SsbBfe.encode(context.sig)
+
+    assert encoded_sig == <<4, 0, 158, 70, 56, 90, 201, 253, 125, 234, 44, 198, 245, 251, 110, 146, 202, 236, 236, 99, 117, 42, 240, 234, 4, 139, 242, 203, 167, 214, 125, 147, 48, 181, 202, 201, 38, 10, 244, 190, 98, 181, 84, 39, 87, 105, 208, 81, 203, 69, 178, 181, 14, 107, 104, 172, 180, 61, 175, 14, 77, 65, 210, 224, 12, 5>>
+  end
+
+  test "box is encoded correctly", context do
+    encoded_box = SsbBfe.encode(context.box1)
+
+    assert encoded_box == <<5, 0, 108, 111, 118, 101, 32, 99, 111, 108, 108, 97, 112, 115, 101, 115, 32, 115, 112, 97, 99, 101, 116, 105, 109, 101>>
+  end
+
+  test "box2 is encoded correctly", context do
+    encoded_box2 = SsbBfe.encode(context.box2)
+
+    assert encoded_box2 == <<5, 1, 108, 111, 118, 101, 32, 99, 111, 108, 108, 97, 112, 115, 101, 115, 32, 115, 112, 97, 99, 101, 116, 105, 109, 101>>
+  end
+
+  test "plain string is encoded correctly", context do
+    encoded_str = SsbBfe.encode(context.str)
+
+    assert encoded_str == <<6, 0, 103, 111, 108, 100, 101, 110, 32, 114, 105, 112, 112, 108, 101, 115, 32, 105, 110, 32, 116, 104, 101, 32, 109, 101, 115, 104, 119, 111, 114, 107>>
+  end
+
+  test "boolean is encoded correctly" do
+    encoded_bool_true = SsbBfe.encode(true)
+    encoded_bool_false = SsbBfe.encode(false)
+
+    assert encoded_bool_true == <<6, 1, 1>>
+    assert encoded_bool_false == <<6, 1, 0>>
+  end
+
+  test "nil is encoded correctly" do
+    encoded_nil = SsbBfe.encode(nil)
+
+    assert encoded_nil == <<6, 2>>
+  end
+
+  test "list is encoded correctly" do
+    encoded_list = SsbBfe.encode([true, nil, "ganoderma"])
+
+    assert encoded_list == [<<6, 1, 1>>, <<6, 2>>, <<6, 0, 103, 97, 110, 111, 100, 101, 114, 109, 97>>]
+  end
+
+  test "map is encoded correctly", context do
+    encoded_map = SsbBfe.encode(%{"bool" => false, "feed" => context.feed_classic})
+
+    assert encoded_map == %{"bool" => <<6, 1, 0>>, "feed" => <<0, 0, 119, 252, 195, 188, 91, 48, 21, 180, 26, 96, 151, 52, 222, 46, 59, 11, 208, 160, 13, 235, 254, 252, 15, 16, 65, 39, 198, 230, 95, 210, 17, 252>>}
+  end
+
+  test "tuple is encoded correctly", context do
+    encoded_tuple = SsbBfe.encode({7, context.msg_classic})
+
+    assert encoded_tuple == [7, <<1, 0, 71, 200, 94, 171, 251, 80, 163, 17, 8, 62, 69, 159, 208, 172, 103, 214, 112, 166, 252, 43, 49, 27, 96, 131, 165, 70, 39, 2, 247, 91, 93, 143>>]
   end
 end