FEATURE: add a way to map arbitrary urls to a topic, post, or category. Useful for sites that have migrated to Discourse and want to redirect from their old site to Discourse with 301 redirects.

spec/controllers/permalinks_controller_spec.rb

@@ -0,0 +1,19 @@
+require 'spec_helper'
+
+describe PermalinksController do
+  describe 'show' do
+    it "should redirect to a permalink's target_url with status 301" do
+      permalink = Fabricate(:permalink)
+      Permalink.any_instance.stubs(:target_url).returns('/t/the-topic-slug/42')
+      get :show, url: permalink.url
+      response.should redirect_to('/t/the-topic-slug/42')
+      response.status.should == 301
+    end
+
+    it 'return 404 if permalink record does not exist' do
+      get :show, url: '/not/a/valid/url'
+      response.status.should == 404
+    end
+  end
+
+end

spec/fabricators/permalink_fabricator.rb

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+Fabricator(:permalink) do
+  url { sequence(:url) {|i| "my/#{i}/url" } }
+end

spec/models/permalink_spec.rb

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+require "spec_helper"
+
+describe Permalink do
+
+  describe "new record" do
+    it "strips blanks" do
+      permalink = described_class.create(url: " my/old/url  ")
+      permalink.url.should == "my/old/url"
+    end
+
+    it "removes leading slash" do
+      permalink = described_class.create(url: "/my/old/url")
+      permalink.url.should == "my/old/url"
+    end
+  end
+
+  describe "target_url" do
+
+    let(:permalink)       { Fabricate.build(:permalink) }
+    let(:topic)           { Fabricate(:topic) }
+    let(:post)            { Fabricate(:post, topic: topic) }
+    let(:category)        { Fabricate(:category) }
+    subject(:target_url)  { permalink.target_url }
+
+    it "returns a topic url when topic_id is set" do
+      permalink.topic_id = topic.id
+      target_url.should == topic.relative_url
+    end
+
+    it "returns nil when topic_id is set but topic is not found" do
+      permalink.topic_id = 99999
+      target_url.should be_nil
+    end
+
+    it "returns a post url when post_id is set" do
+      permalink.post_id = post.id
+      target_url.should == post.url
+    end
+
+    it "returns nil when post_id is set but post is not found" do
+      permalink.post_id = 99999
+      target_url.should be_nil
+    end
+
+    it "returns a post url when post_id and topic_id are both set" do
+      permalink.post_id = post.id
+      permalink.topic_id = topic.id
+      target_url.should == post.url
+    end
+
+    it "returns a category url when category_id is set" do
+      permalink.category_id = category.id
+      target_url.should == category.url
+    end
+
+    it "returns nil when category_id is set but category is not found" do
+      permalink.category_id = 99999
+      target_url.should be_nil
+    end
+
+    it "returns a post url when topic_id, post_id, and category_id are all set for some reason" do
+      permalink.post_id = post.id
+      permalink.topic_id = topic.id
+      permalink.category_id = category.id
+      target_url.should == post.url
+    end
+
+    it "returns nil when nothing is set" do
+      target_url.should be_nil
+    end
+  end
+end