Make Rack::ShowExceptions handle invalid POST data

Otherwise you get an exception trying to render the exception page.

Fixes #991

2 files changed, 23 insertions, 2 deletions

diff --git a/lib/rack/show_exceptions.rb b/lib/rack/show_exceptions.rb
index 843af607..8ca96ef0 100644
--- a/lib/rack/show_exceptions.rb
+++ b/lib/rack/show_exceptions.rb
@@ -313,7 +313,7 @@ module Rack
         <% end %>
 
         <h3 id="post-info">POST</h3>
-        <% if req.POST and not req.POST.empty? %>
+        <% if ((req.POST and not req.POST.empty?) rescue (no_post_data = "Invalid POST data"; nil)) %>
           <table class="req">
             <thead>
               <tr>
@@ -331,7 +331,7 @@ module Rack
             </tbody>
           </table>
         <% else %>
-          <p>No POST data.</p>
+          <p><%= no_post_data || "No POST data" %>.</p>
         <% end %>
 
 
diff --git a/test/spec_show_exceptions.rb b/test/spec_show_exceptions.rb
index a4ade121..73a0536f 100644
--- a/test/spec_show_exceptions.rb
+++ b/test/spec_show_exceptions.rb
@@ -25,6 +25,27 @@ describe Rack::ShowExceptions do
 
     assert_match(res, /RuntimeError/)
     assert_match(res, /ShowExceptions/)
+    assert_match(res, /No GET data/)
+    assert_match(res, /No POST data/)
+  end
+
+  it "handles invalid POST data exceptions" do
+    res = nil
+
+    req = Rack::MockRequest.new(
+      show_exceptions(
+        lambda{|env| raise RuntimeError }
+    ))
+
+    res = req.post("/", "HTTP_ACCEPT" => "text/html", "rack.input" => StringIO.new(String.new << '(%bad-params%)'))
+
+    res.must_be :server_error?
+    res.status.must_equal 500
+
+    assert_match(res, /RuntimeError/)
+    assert_match(res, /ShowExceptions/)
+    assert_match(res, /No GET data/)
+    assert_match(res, /Invalid POST data/)
   end
 
   it "works with binary data in the Rack environment" do