HTTP CRUD

Use case: in-memory item store

Single-item CRUD demo — GET /item returns JSON; POST /item replaces the stored name from the raw body.

Example source: vow-examples/vow-web-server/json_crud.vow

import lib.app
import lib.request
import lib.response
import lib.serve

var store_name: String = "widget";

fn get_item(_req: request.Request) -> response.Response {
    let body = "{\"name\":\"" + store_name + "\"}";
    return response.json(body);
}

fn create_item(req: request.Request) -> response.Response {
    let body = request.body(req, 65536);
    if len(body) == 0 {
        return response.bad_request("{\"error\":\"empty body\"}");
    }
    store_name = body;
    return response.json(201, "{\"ok\":true}");
}

fn main(caps: Caps) -> int {
    let a = app.post(
        app.get(app.app(), "/item", get_item),
        "/item",
        create_item
    );
    return match caps.net {
        Some(cap) => serve.listen(a, cap, 8787),
        None => 0 - 1,
    };
}

Run

./vow run vow-examples/vow-web-server/json_crud.vow -- --grant net:

curl -sf http://127.0.0.1:8787/item

curl -X POST http://127.0.0.1:8787/item \
  -H 'Content-Type: application/json' \
  -d '{"name":"gadget"}'

curl -sf http://127.0.0.1:8787/item

Key concepts

Topic	This example
Reading POST body	`request.body(req, max_len)`
JSON responses	`response.json` / `response.json(201, …)`
Error helper	`response.bad_request` for empty body
Mutable state	Module-level `var store_name`

Next