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Web Applications in Racket

Web Applications in Racket🔗

Jay McCarthy

This manual describes the Racket libraries for building Web applications.

Running Web Servlets describes how to run the servlets you’ve written.

Stateful Servlets and Stateless Servlets describe two ways to write Web applications. Stateful Servlets use the entire Racket language, but their continuations are stored in the Web server’s memory. Stateless Servlets use a slightly restricted Racket language, but their continuations can be stored by the Web client or on a Web server’s disk. If you can, you want to use Stateless Servlets for the improved scalability.

The HTTP: Hypertext Transfer Protocol section describes the common library functions for manipulating HTTP requests and creating HTTP responses. In particular, this section covers cookies, authentication, and request bindings.

The final five sections (URL-Based Dispatch, Formlets: Functional Form Abstraction, Templates: Separation of View, Page: Short-hand for Common Patterns, and Testing Servlets) cover utility libraries that ease the creation of typical Web applications.

This manual closes with a frequently asked questions section: Troubleshooting and Tips.

    1 Running Web Servlets

      1.1 Instant Servlets

      1.2 Simple Single Servlet Servers

        1.2.1 Examples

 Stateless Servlets

        1.2.2 Full API

      1.3 Command-line Tools

    2 Stateful Servlets

      2.1 Example

      2.2 Responses

      2.3 Web Interaction

      2.4 Web Cells

      2.5 Continuation Managers

        2.5.1 General

        2.5.2 No Continuations

        2.5.3 Timeouts

        2.5.4 LRU

    3 Stateless Servlets

      3.1 Example

      3.2 Usage Considerations

      3.3 Serializable Continuations

      3.4 Native Interfaces

      3.5 Stateless Web Interaction

      3.6 Stateless Web Cells

      3.7 File Boxes

      3.8 Stateless Web Parameters

      3.9 Soft State

      3.10 Stuffers

        3.10.1 Basic Combinators

        3.10.2 Serialization

        3.10.3 Base64 Encoding

        3.10.4 GZip Compression

        3.10.5 Key/Value Storage

        3.10.6 Hash-addressed Storage

        3.10.7 HMAC-SHA1 Signing

        3.10.8 Helpers

    4 HTTP: Hypertext Transfer Protocol

      4.1 Requests

      4.2 Bindings

      4.3 Responses

      4.4 Placing Cookies

      4.5 Authenticated Cookies

      4.6 Extracting Cookies

      4.7 Redirect

      4.8 Basic Authentication

      4.9 Digest Authentication

      4.10 X-expression Support

      4.11 Empty Responses

      4.12 JSON Support

    5 URL-Based Dispatch

      5.1 Using web-server/dispatch

      5.2 API Reference

      5.3 Imperative Dispatch Containers

      5.4 Built-in URL patterns

      5.5 Extending web-server/dispatch

    6 Formlets: Functional Form Abstraction

      6.1 Basic Formlet Usage

      6.2 Static Syntactic Shorthand

      6.3 Dynamic Syntactic Shorthand

      6.4 Functional Usage

      6.5 Predefined Formlets

      6.6 Utilities

      6.7 Formlets and Stateless Servlets

    7 Templates: Separation of View

      7.1 Static

      7.2 Dynamic

      7.3 Gotchas

        7.3.1 @ Syntax: @ character, identifiers, and spaces

        7.3.2 Iteration

        7.3.3 Escaping

      7.4 HTTP Responses

      7.5 API Details

      7.6 Conversion Example

    8 Page: Short-hand for Common Patterns

    9 Testing Servlets

    10 Troubleshooting and Tips

      10.1 Why is my servlet failing with a can-be-response? contract violation after updating Racket?

      10.2 Why are my templates not updating on the server when I change the file on disk?

      10.3 Why are templates compiled into programs?

      10.4 Why are my stateful servlets not updating on the server when I change the file on disk?

      10.5 After refreshing my stateful servlet, old captured continuations don’t change or old global effects are gone. Why?

      10.6 How are stateless servlets different from stateful servlets vis a vis refreshing?

      10.7 What special considerations are there for security with the Web Server?

      10.8 My browser displays my page strangely: my CSS is ignored, sections are missing, etc.

      10.9 How do I use templates “dynamically"?