README.md

![Wisp](https://github.com/lpil/wisp/blob/main/docs/images/cover.png?raw=true)

[![Package Version](https://img.shields.io/hexpm/v/wisp)](https://hex.pm/packages/wisp)
[![Hex Docs](https://img.shields.io/badge/hex-docs-ffaff3)](https://hexdocs.pm/wisp/)

Wisp is a practical Gleam web framework rapid development and easy maintenance.
We worry about the hassle of web development, and you focus on writing your
application.

It is based around two concepts: handlers and middleware.

# Handlers

A handler is a function that takes a HTTP request and returns a HTTP
response. A handler may also take other arguments, such as a "context" type
defined in your application which may hold other state such as a database
connection or user session.

```gleam
import wisp.{Request, Response}

pub type Context {
  Context(secret: String)
}

pub fn handle_request(request: Request, context: Context) -> Response {
  wisp.ok()
}
```

# Middleware

A middleware is a function that takes a response returning function as its
last argument, and itself returns a response. As with handlers both
middleware and the functions they take as an argument may take other
arguments.

Middleware can be applied in a handler with Gleam's `use` syntax. Here the
`log_request` middleware is used to log a message for each HTTP request
handled, and the `serve_static` middleware is used to serve static files
such as images and CSS.

```gleam
import wisp.{Request, Response}

pub fn handle_request(request: Request) -> Response {
  use <- wisp.log_request
  use <- wisp.serve_static(request, under: "/static", from: "/public")
  wisp.ok()
}
```

# Learning Wisp

The Wisp examples are a good place to start. They cover various scenarios and
include comments and tests.

- [Hello, World!](https://github.com/lpil/wisp/tree/main/examples/0-hello-world)
- [Routing](https://github.com/lpil/wisp/tree/main/examples/1-routing)
- [Working with form data](https://github.com/lpil/wisp/tree/main/examples/2-working-with-form-data)
- [Working with JSON](https://github.com/lpil/wisp/tree/main/examples/3-working-with-json)
- [Working with other formats](https://github.com/lpil/wisp/tree/main/examples/4-working-with-other-formats)
- [Using a database](https://github.com/lpil/wisp/tree/main/examples/5-using-a-database)
- [Serving static assets](https://github.com/lpil/wisp/tree/main/examples/6-serving-static-assets)
- [Logging](https://github.com/lpil/wisp/tree/main/examples/7-logging)
- [Working with cookies](https://github.com/lpil/wisp/tree/main/examples/8-working-with-cookies)
- [Configuring default responses](https://github.com/lpil/wisp/tree/main/examples/9-configuring-default-responses)

API documentation is available on [HexDocs](https://hexdocs.pm/wisp/).

# Wisp applications

These open source Wisp applications may be useful examples.

- [https://packages.gleam.run/](https://github.com/gleam-lang/packages): A HTML
  serving application that uses an SQLite + LiteFS database, deployed to Fly.io.