current user. • set_default_headers - may be used to set additional headers on the response (such as a custom Server header). Error Handling If a handler raises an exception, Tornado will call RequestHandler and a one-line description of the error (e.g. “500: Internal Server Error”) otherwise. To produce a custom error page, override RequestHandler.write_error (probably in a base class shared by all your handlers) the client closes the connection (but see that method’s docstring for caveats). 6.1.6 Templates and UI Tornado includes a simple, fast, and flexible templating language. This section describes that language

Coroutines Queue example - a concurrent web spider Structure of a Tornado web application Templates and UI Authentication and security Running and deploying Web framework tornado.web — RequestHandler and Error Handling Redirection Asynchronous handlers Templates and UI Configuring templates Template syntax Security Internationalization UI modules Authentication and security Cookies and signed cookies current user. set_default_headers - may be used to set additional headers on the response (such as a custom Server header). Error Handling If a handler raises an exception, Tornado will call RequestHandler

Operations on Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 11.15 Custom pretty-printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 11.16 "Value types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1513 98.8 Creating Custom AbstractTestSet Types . . . . . . . . . . . . . . . . . . . . . . . 1514 98.9 Test utilities . maintenance and care of multi-threading locks . . . . . . . . . . . . . . . . 1592 101.19 Arrays with custom indices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1596 101.20 Module loading

Operations on Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 11.15 Custom pretty-printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 11.16 "Value types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1513 98.8 Creating Custom AbstractTestSet Types . . . . . . . . . . . . . . . . . . . . . . . 1514 98.9 Test utilities . maintenance and care of multi-threading locks . . . . . . . . . . . . . . . . 1592 101.19 Arrays with custom indices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1596 101.20 Module loading

Operations on Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 12.15 Custom pretty-printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 12.16 "Value types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1788 102.8 Creating Custom AbstractTestSet Types . . . . . . . . . . . . . . . . . . . . . . . 1789 102.9 Test utilities . Package Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1862 105.15 Custom LLVM Passes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1863 105.16 Working

Operations on Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 12.15 Custom pretty-printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 12.16 "Value types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1788 102.8 Creating Custom AbstractTestSet Types . . . . . . . . . . . . . . . . . . . . . . . 1789 102.9 Test utilities . Package Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1862 105.15 Custom LLVM Passes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1863 105.16 Working

Operations on Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 12.15 Custom pretty-printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 12.16 "Value types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1788 102.8 Creating Custom AbstractTestSet Types . . . . . . . . . . . . . . . . . . . . . . . 1789 102.9 Test utilities . Package Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1862 105.15 Custom LLVM Passes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1863 105.16 Working

Operations on Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 12.15 Custom pretty-printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 12.16 "Value types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1839 103.8 Creating Custom AbstractTestSet Types . . . . . . . . . . . . . . . . . . . . . . . 1840 103.9 Test utilities . Package Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1916 106.15 Custom LLVM Passes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1918 106.16 Working

Operations on Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 12.15 Custom pretty-printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 12.16 "Value types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1837 103.8 Creating Custom AbstractTestSet Types . . . . . . . . . . . . . . . . . . . . . . . 1838 103.9 Test utilities . Package Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1914 106.15 Custom LLVM Passes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1915 106.16 Working

Operations on Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 12.15 Custom pretty-printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 12.16 "Value types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1836 103.8 Creating Custom AbstractTestSet Types . . . . . . . . . . . . . . . . . . . . . . . 1837 103.9 Test utilities . Package Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1913 106.15 Custom LLVM Passes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1915 106.16 Working