Hello Web

A webserver that serves one web page showing Hello, web! using the basic-webserver platform.

There are much more basic-webserver examples.

Code

app [Model, init!, respond!] { web: platform "https://github.com/roc-lang/basic-webserver/releases/download/0.12.0/Q4h_In-sz1BqAvlpmCsBHhEJnn_YvfRRMiNACB_fBbk.tar.br" }

import web.Stdout
import web.Http exposing [Request, Response]
import web.Utc

# Model is produced by `init`.
Model : {}

# With `init` you can set up a database connection once at server startup,
# generate css by running `tailwindcss`,...
# In this case we don't have anything to initialize, so it is just `Ok({})`.

init! : {} => Result Model []
init! = |_| Ok({})

respond! : Request, Model => Result Response [ServerErr Str]_
respond! = |req, _|
    # Log request datetime, method and url
    datetime = Utc.to_iso_8601(Utc.now!({}))

    Stdout.line!("${datetime} ${Inspect.to_str(req.method)} ${req.uri}")?

    Ok(
        {
            status: 200,
            headers: [],
            body: Str.to_utf8("<b>Hello, web!</b></br>"),
        },
    )

Output

Run this from the directory that has main.roc in it and go to http://localhost:8000/ in your browser:

$ roc main.roc --linker=legacy
Listening on http://127.0.0.1:8000

• Change the port (8000); e.g export ROC_BASIC_WEBSERVER_PORT=8888
• Change the host (localhost); e.g. export ROC_BASIC_WEBSERVER_HOST=0.0.0.0
• Change the number of threads; e.g. export TOKIO_WORKER_THREADS=4

Optimized build:

$ roc build --optimize main.roc --linker=legacy