rescue BadURIError for invalid URL format

app.rb

@@ -2,6 +2,7 @@ require 'roda'
 require 'securerandom'
 require 'json'
 require 'sequel'
+require 'open-uri'
 
 class App < Roda
   plugin :sessions, secret: ENV.delete('APP_SESSION_SECRET')
@@ -60,6 +61,14 @@ class App < Roda
           return {message: "invalid url parameter"}.to_json
         end
 
+        begin
+          OpenURI.open_uri(url)
+        rescue URI::BadURIError
+          response.status = 400
+          return {message: "invalid url parameter"}.to_json
+        end
+
+
         if links.filter(:url => url).first.nil?
           code = SecureRandom.urlsafe_base64 4
           links.insert(url: url, code: code) 

spec/create_spec.rb

@@ -45,8 +45,8 @@ describe "Submit API request to create new link" do
     expect(last_response.status).to eq(400)
     response_json = JSON.parse(last_response.body)
     expect(response_json['message']).to eq('invalid url parameter')
-
   end
+
   it "should return with a 400 status and 'missing url parameter' message when an empty url is submitted" do
     data = {
     }
@@ -54,7 +54,15 @@ describe "Submit API request to create new link" do
     expect(last_response.status).to eq(400)
     response_json = JSON.parse(last_response.body)
     expect(response_json['message']).to eq('missing url parameter')
-
-  end
   end
 
+  it "should return with a 400 status and 'invalid url parameter' message when an invalid url is submitted" do
+    data = {
+      url: 'not-an-url'
+    }
+    post('/links', data.to_json, "CONTENT_TYPE" => "application/json")
+    expect(last_response.status).to eq(400)
+    response_json = JSON.parse(last_response.body)
+    expect(response_json['message']).to eq('invalid url parameter')
+  end
+end