Don't require a url.

app.rb

@@ -17,6 +17,8 @@ def httparty_error(r)
 end
 
 get "/youtube" do
+  return "Insufficient parameters" if params[:q].empty?
+
   if /youtube\.com\/channel\/(?<channel_id>UC[^\/\?#]+)/ =~ params[:q]
     # https://www.youtube.com/channel/UC4a-Gbdw7vOaccHmFo40b9g/videos
   elsif /youtube\.com\/user\/(?<user>[^\/\?#]+)/ =~ params[:q]
@@ -29,8 +31,11 @@ def httparty_error(r)
     # https://www.youtube.com/khanacademy
   elsif /youtu\.be\/(?<video_id>[^\?#]+)/ =~ params[:q]
     # https://youtu.be/vVXbgbMp0oY?t=1s
+  elsif /(?<channel_id>UC[^\/\?#]+)/ =~ params[:q]
+    # it's a channel id
   else
-    return "That doesn't look like a youtube url. Sorry."
+    # it's probably a channel name
+    user = params[:q]
   end
 
   if user
@@ -56,21 +61,21 @@ def httparty_error(r)
   if channel_id
     redirect "https://www.youtube.com/feeds/videos.xml?channel_id=#{channel_id}"
   else
-    "Could not figure out channel id from url. Sorry."
+    "Could not find the channel. Sorry."
   end
 end
 
 get "/facebook" do
+  return "Insufficient parameters" if params[:q].empty?
+
   if /facebook\.com\/(?<name>[^\/\?#]+)/ =~ params[:q]
     # https://www.facebook.com/celldweller/info?tab=overview
   else
-    return "That doesn't look like a facebook url. Sorry."
+    name = params[:q]
   end
 
   response = HTTParty.get("https://graph.facebook.com/v2.3/#{name}?access_token=#{ENV["FACEBOOK_APP_ID"]}|#{ENV["FACEBOOK_APP_SECRET"]}")
-  if response.code == 404
-    return "Can't find a page with that name. Sorry."
-  end
+  return "Can't find a page with that name. Sorry." if response.code == 404
   raise FacebookException, response if !response.success?
 
   data = response.parsed_response
@@ -92,6 +97,7 @@ def httparty_error(r)
 
 get "/instagram/auth" do
   return "Already authed" if ENV["INSTAGRAM_ACCESS_TOKEN"]
+
   if params[:code]
     response = HTTParty.post("https://api.instagram.com/oauth/access_token", body: {
       client_id: ENV["INSTAGRAM_CLIENT_ID"],
@@ -109,18 +115,23 @@ def httparty_error(r)
 end
 
 get "/instagram" do
+  return "Insufficient parameters" if params[:q].empty?
+
   if /instagram\.com\/p\/(?<post_id>[^\/\?#]+)/ =~ params[:q]
     # https://instagram.com/p/4KaPsKSjni/
     response = HTTParty.get("https://api.instagram.com/v1/media/shortcode/#{post_id}?access_token=#{ENV["INSTAGRAM_ACCESS_TOKEN"]}")
     return response.parsed_response["meta"]["error_message"] if !response.success?
     user = response.parsed_response["data"]["user"]
   elsif /instagram\.com\/(?<name>[^\/\?#]+)/ =~ params[:q]
     # https://instagram.com/infectedmushroom/
+  else
+    name = params[:q]
+  end
+
+  if name
     response = HTTParty.get("https://api.instagram.com/v1/users/search?q=#{name}&access_token=#{ENV["INSTAGRAM_ACCESS_TOKEN"]}")
     raise InstagramException, response if !response.success?
     user = response.parsed_response["data"].find { |user| user["username"] == name }
-  else
-    return "That doesn't look like an instagram url. Sorry."
   end
 
   if user

config/initializers/05-nil.rb

@@ -0,0 +1,5 @@
+class NilClass
+  def empty?
+    true
+  end
+end

views/index.erb

@@ -33,19 +33,21 @@
     </hgroup>
   </header>
 
+<% if ENV["GOOGLE_API_KEY"] %>
   <div class="container">
     <form class="input-group" method="get" action="/youtube" target="_self">
       <div class="input-group-addon"><label for="youtube_q">YouTube</label></div>
-      <input class="form-control" type="search" name="q" id="youtube_q" placeholder="Enter url to a YouTube video or channel.">
+      <input class="form-control" type="search" name="q" id="youtube_q" placeholder="Enter a YouTube channel name, channel id, or a url to a channel or video.">
       <span class="input-group-btn">
         <input class="btn btn-primary" type="submit" value="Get RSS Feed">
       </span>
     </form>
+<% end %>
 
 <% if ENV["FACEBOOK_APP_ID"] and ENV["FACEBOOK_APP_SECRET"] %>
     <form class="input-group" method="get" action="/facebook" target="_self">
       <div class="input-group-addon"><label for="facebook_q">Facebook</label></div>
-      <input class="form-control" type="search" name="q" id="facebook_q" placeholder="Enter url to a Facebook page.">
+      <input class="form-control" type="search" name="q" id="facebook_q" placeholder="Enter a Facebook page name or its url.">
       <span class="input-group-btn">
         <input class="btn btn-primary" type="submit" value="Get RSS Feed">
       </span>
@@ -55,7 +57,7 @@
 <% if ENV["INSTAGRAM_ACCESS_TOKEN"] %>
     <form class="input-group" method="get" action="/instagram" target="_self">
       <div class="input-group-addon"><label for="instagram_q">Instagram</label></div>
-      <input class="form-control" type="search" name="q" id="instagram_q" placeholder="Enter url to an Instagram post or user.">
+      <input class="form-control" type="search" name="q" id="instagram_q" placeholder="Enter an Instagram username or a url to a user or post.">
       <span class="input-group-btn">
         <input class="btn btn-primary" type="submit" value="Get RSS Feed">
       </span>