Encrypt file extension

.env

@@ -1 +1,2 @@
 SECRET_KEY_BASE=123
+BB_SECRET='this is a test secret'

app/models/message.rb

@@ -6,12 +6,4 @@ def has_text_or_file?
       errors[:base] << "Either file or text are required"
     end
   end
-
-  def file_mime_type
-    Mime::Type.lookup_by_extension(file_extension).to_s
-  end
-
-  def file_name
-    "#{id}.#{file_extension}"
-  end
 end

lib/crypt.rb

@@ -31,12 +31,18 @@ def file_contents
     raise CryptError
   end
 
-  def file_mime_type
-    @message.file_mime_type
+  def file_extension
+    @crypto.decrypt64 @message.file_extension
+  rescue OpenSSL::Cipher::CipherError
+    raise CryptError
   end
 
   def file_name
-    @message.file_name
+    "#{@message.id}.#{file_extension}"
+  end
+
+  def file_mime_type
+    Mime::Type.lookup_by_extension(file_extension).to_s
   end
 
   # Active Record API
@@ -51,7 +57,8 @@ def destroy
 
   def save
     if has_file?
-      @message.file_contents = @crypto.encrypt64 @message.file_contents
+      @message.file_contents  = @crypto.encrypt64 @message.file_contents
+      @message.file_extension = @crypto.encrypt64 @message.file_extension
     end
     if has_text?
       @message.text = @crypto.encrypt64 @message.text

spec/controllers/messages_controller_spec.rb

@@ -77,6 +77,7 @@
     before do
       allow(Crypt).to receive(:find).with(guid, key) { crypt }
       allow(crypt).to receive(:file_contents) { "secret message" }
+      allow(crypt).to receive(:file_extension) { "txt" }
     end
 
     it "sends a file" do

spec/models/message_spec.rb

@@ -1,3 +1,4 @@
+require "crypt"
 require "rails_helper"
 
 describe Message do
@@ -8,12 +9,14 @@
   end
 
   it "determines its mime type" do
-    expect(Message.new(file_extension: "txt").file_mime_type).to eq "text/plain"
+    message = Crypt.new Message.new(file_contents: "foo bar", file_extension: "txt")
+    message.save
+    expect(message.file_mime_type).to eq "text/plain"
   end
 
   it "generates a filename from the id and extension" do
-    message = Message.new(id: "1b0dad15-732e-45cc-8da4-749b4b21585d", file_extension: "txt")
-
+    message = Crypt.new Message.new(id: "1b0dad15-732e-45cc-8da4-749b4b21585d", file_contents: "foo bar", file_extension: "txt")
+    message.save
     expect(message.file_name).to eq "1b0dad15-732e-45cc-8da4-749b4b21585d.txt"
   end
 end