Fix sending File objects in nested objects in sendMediaGroup

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Unreleased
 
 - Rails 7.0 support.
+- Fix sending File objects in nested objects in sendMediaGroup.
 
 # 0.15.4
 

lib/telegram/bot/client.rb

@@ -1,5 +1,4 @@
 require 'active_support/core_ext/hash/keys'
-require 'json'
 require 'httpclient'
 
 module Telegram
@@ -8,7 +7,9 @@ module Telegram
       SERVER = 'https://api.telegram.org'.freeze
       URL_TEMPLATE = '%<server>s/bot%<token>s/'.freeze
 
+      autoload :RequestBodyFormatter, 'telegram/bot/client/request_body_formatter'
       autoload :TypedResponse, 'telegram/bot/client/typed_response'
+
       prepend Async
       include DebugClient
 
@@ -35,16 +36,8 @@ module Telegram
           prepend TypedResponse
         end
 
-        # Encodes nested hashes as json.
-        def prepare_body(body)
-          body = body.dup
-          body.each do |k, val|
-            body[k] = val.to_json if val.is_a?(Hash) || val.is_a?(Array)
-          end
-        end
-
         def prepare_async_args(action, body = {})
-          [action.to_s, Async.prepare_hash(prepare_body(body))]
+          [action.to_s, Async.prepare_hash(RequestBodyFormatter.format(body))]
         end
 
         def error_for_response(response)
@@ -70,7 +63,7 @@ module Telegram
       end
 
       def request(action, body = {})
-        response = http_request("#{base_uri}#{action}", self.class.prepare_body(body))
+        response = http_request("#{base_uri}#{action}", RequestBodyFormatter.format(body))
         raise self.class.error_for_response(response) if response.status >= 300
         JSON.parse(response.body)
       end

lib/telegram/bot/client/request_body_formatter.rb

@@ -0,0 +1,48 @@
+require 'json'
+
+module Telegram
+  module Bot
+    class Client
+      # Encodes nested hashes and arrays as json and extract File objects from them
+      # to the top level. Top-level File objects are handled by httpclient.
+      # More details: https://core.telegram.org/bots/api#sending-files
+      module RequestBodyFormatter
+        extend self
+
+        def format(body, action)
+          body = body.dup
+          if action.to_s == 'sendMediaGroup'
+            body = extract_files_from_array!(body, :media)
+          end
+          body.each do |key, val|
+            body[key] = val.to_json if val.is_a?(Hash) || val.is_a?(Array)
+          end
+        end
+
+        private
+
+        def extract_files_from_array!(body, field_name)
+          field_name = [field_name.to_sym, field_name.to_s].find { |x| body.key?(x) }
+          return body unless field_name && body[field_name].is_a?(Array)
+          files = {}
+          body[field_name] = body[field_name].map { |x| extract_files_from_hash(x, files) }
+          body.merge!(files)
+        end
+
+        # Replace File objects with `attach` URIs. File objects are added into `files` hash.
+        def extract_files_from_hash(hash, files)
+          return hash unless hash.is_a?(Hash)
+          hash.transform_values do |value|
+            if value.is_a?(File)
+              arg_name = "_file#{files.size}"
+              files[arg_name] = value
+              "attach://#{arg_name}"
+            else
+              value
+            end
+          end
+        end
+      end
+    end
+  end
+end

spec/telegram/bot/client/request_body_formatter_spec.rb

@@ -0,0 +1,62 @@
+RSpec.describe Telegram::Bot::Client::RequestBodyFormatter do
+  describe '.format' do
+    subject { described_class.format(input, action) }
+    let(:action) { :sendMessage }
+
+    context 'when plain hash is given' do
+      let(:input) { {a: 1, b: '2', c: nil} }
+      it { should eq input }
+    end
+
+    context 'when nested hash is given' do
+      let(:input) { {a: 1, b: '2', c: [1, 2], d: {a: 1}, e: {b: []}} }
+
+      it 'encodes nested hashes to json' do
+        expected = input.dup
+        %i[c d e].each { |x| expected[x] = expected[x].to_json }
+        should eq expected
+      end
+    end
+
+    context 'with sendMediaGroup action' do
+      let(:action) { :sendMediaGroup }
+      let(:input) { {media: [{a: file_1}, {'b' => file_2, c: 123}, {d: 456}], x: 789} }
+      let(:file_1) { File.new(__FILE__) }
+      let(:file_2) { File.new(__FILE__) }
+
+      it 'extracts files to the top-level' do
+        should eq(
+          media: [
+            {a: 'attach://_file0'},
+            {b: 'attach://_file1', c: 123},
+            {d: 456},
+          ].to_json,
+          x: 789,
+          '_file0' => file_1,
+          '_file1' => file_2,
+        )
+      end
+
+      context 'and input has string keys' do
+        let(:input) { super().stringify_keys }
+        it 'extracts files to the top-level' do
+          should eq(
+            'media' => [
+              {a: 'attach://_file0'},
+              {b: 'attach://_file1', c: 123},
+              {d: 456},
+            ].to_json,
+            'x' => 789,
+            '_file0' => file_1,
+            '_file1' => file_2,
+          )
+        end
+      end
+
+      context 'without media' do
+        let(:input) { {a: 1, b: '2', c: nil} }
+        it { should eq input }
+      end
+    end
+  end
+end

spec/telegram/bot/client_spec.rb

@@ -71,25 +71,6 @@ RSpec.describe Telegram::Bot::Client do
     end
   end
 
-  describe '.prepare_body' do
-    subject { described_class.prepare_body(input) }
-
-    context 'when plain hash is given' do
-      let(:input) { {a: 1, b: '2', c: nil} }
-      it { should eq input }
-    end
-
-    context 'when nested hash is given' do
-      let(:input) { {a: 1, b: '2', c: [1, 2], d: {a: 1}, e: {b: []}} }
-
-      it 'encodes nested hashes to json' do
-        expected = input.dup
-        %i[c d e].each { |x| expected[x] = expected[x].to_json }
-        should eq expected
-      end
-    end
-  end
-
   describe '.prepare_async_args' do
     subject { described_class.prepare_async_args(*input) }
     let(:input) { [:action, a: 1, b: :sym, c: [:other], 'd' => 'str'] }