counterfact/dist/repl/repl.js

a library for building a fake REST API for testing

import repl from "node:repl";
function printToStdout(line) {
    process.stdout.write(`${line}\n`);
}
export function startRepl(contextRegistry, config, print = printToStdout) {
    function printProxyStatus() {
        if (config.proxyUrl === "") {
            print("The proxy URL is not set.");
            print('To set it, type ".proxy url <url>');
            return;
        }
        print("Proxy Configuration:");
        print("");
        print(`The proxy URL is ${config.proxyUrl}`);
        print("");
        print("Paths prefixed with [+] will be proxied.");
        print("Paths prefixed with [-] will not be proxied.");
        print("");
        const entries = [...config.proxyPaths.entries()].sort(([path1], [path2]) => path1 < path2 ? -1 : 1);
        for (const [path, state] of entries) {
            print(`${state ? "[+]" : "[-]"} ${path}/`);
        }
    }
    function setProxyUrl(url) {
        if (url === undefined) {
            print("usage: .proxy url <url>");
            return;
        }
        config.proxyUrl = url;
        print(`proxy URL is set to ${url}`);
    }
    function turnProxyOnOrOff(text) {
        const [command, endpoint] = text.split(" ");
        const printEndpoint = endpoint === undefined || endpoint === "" ? "/" : endpoint;
        config.proxyPaths.set((endpoint ?? "").replace(/\/$/u, ""), command === "on");
        if (command === "on") {
            print(`Requests to ${printEndpoint} will be proxied to ${config.proxyUrl || "<proxy URL>"}${printEndpoint}`);
        }
        if (command === "off") {
            print(`Requests to ${printEndpoint} will be handled by local code`);
        }
    }
    const replServer = repl.start({ prompt: "⬣> " });
    replServer.defineCommand("counterfact", {
        action() {
            print("This is a read-eval-print loop (REPL), the same as the one you get when you run node with no arguments.");
            print("Except that it's connected to the running server, which you can access with the following globals:");
            print("");
            print("- loadContext('/some/path'): to access the context object for a given path");
            print("- context: the root context ( same as loadContext('/') )");
            print("");
            print("For more information, see https://counterfact.dev/docs/usage.html");
            print("");
            this.clearBufferedCommand();
            this.displayPrompt();
        },
        help: "Get help with Counterfact",
    });
    replServer.defineCommand("proxy", {
        action(text) {
            if (text === "help" || text === "") {
                print(".proxy [on|off] - turn the proxy on/off at the root level");
                print(".proxy [on|off] <path-prefix> - turn the proxy on for a path");
                print(".proxy status - show the proxy status");
                print(".proxy help - show this message");
            }
            else if (text.startsWith("url")) {
                setProxyUrl(text.split(" ")[1]);
            }
            else if (text === "status") {
                printProxyStatus();
            }
            else {
                turnProxyOnOrOff(text);
            }
            this.clearBufferedCommand();
            this.displayPrompt();
        },
        help: 'proxy configuration (".proxy help" for details)',
    });
    replServer.context.loadContext = (path) => contextRegistry.find(path);
    replServer.context.context = replServer.context.loadContext("/");
    return replServer;
}