122 lines
4.0 KiB
JavaScript
122 lines
4.0 KiB
JavaScript
/**
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* Headless-Firefox screenshot helper (W3C WebDriver via geckodriver):
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*
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* node dev/shot-firefox.mjs <url> <pollExpr> <outPng> [timeoutMs=25000]
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*
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* <pollExpr> is evaluated with execute/sync and polled until it returns
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* a non-null value (the page should set the state first), then the
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* session's screenshot is saved to <outPng>.
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*/
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import { spawn, execFileSync } from 'node:child_process';
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import { existsSync, readdirSync, writeFileSync } from 'node:fs';
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const [url, expr, outPng, timeoutMs = '30000'] = process.argv.slice(2);
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if (!url || !expr || !outPng) {
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console.error('usage: node dev/shot-firefox.mjs <url> <pollExpr> <outPng> [timeoutMs]');
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process.exit(2);
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}
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const sleep = (ms) => new Promise((r) => setTimeout(r, ms));
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let geckodriver;
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try {
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geckodriver = execFileSync('sh', ['-c', 'command -v geckodriver'], { encoding: 'utf8' }).trim();
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} catch {
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console.error('need firefox + geckodriver on PATH');
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process.exit(2);
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}
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const firefoxCandidates = [];
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try {
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const ff = execFileSync('sh', ['-c', 'command -v firefox'], { encoding: 'utf8' }).trim();
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if (ff) firefoxCandidates.push(ff);
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} catch { /* not on PATH */ }
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try {
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const snapRev = readdirSync('/snap/firefox', { withFileTypes: true }).map((d) => d.name);
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for (const rev of [null, ...snapRev]) {
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const base = rev ? `/snap/firefox/${rev}` : '/snap/firefox/current';
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const p = `${base}/usr/lib/firefox/firefox`;
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if (existsSync(p)) firefoxCandidates.push(p);
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}
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} catch { /* no /snap/firefox */ }
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if (firefoxCandidates.length === 0) {
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console.error('no firefox binary found');
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process.exit(2);
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}
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const PORT = 4444 + (process.pid % 100);
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const driver = spawn(geckodriver, ['--port', String(PORT), '--log', 'fatal'], { stdio: 'ignore' });
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const base = `http://127.0.0.1:${PORT}`;
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const fail = (msg) => {
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try { driver.kill('SIGKILL'); } catch { /* dead */ }
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console.error(msg);
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process.exit(1);
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};
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const wd = async (method, path, body) => {
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const res = await fetch(base + path, {
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method,
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headers: { 'Content-Type': 'application/json' },
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body: body === undefined ? undefined : JSON.stringify(body),
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});
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const text = await res.text();
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let data = null;
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try { data = JSON.parse(text); } catch { /* empty */ }
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if (!res.ok) throw new Error(`WebDriver ${method} ${path} → ${res.status}: ${text.slice(0, 300)}`);
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return data;
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};
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try {
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let up = false;
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for (let i = 0; i < 60; i++) {
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try {
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const v = await (await fetch(`${base}/status`)).json();
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if (v?.value?.ready || v?.status === 'ok' || v?.value) { up = true; break; }
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} catch { /* not up */ }
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await sleep(250);
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}
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if (!up) fail('geckodriver never came up');
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let sess;
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let lastErr = null;
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for (const ff of firefoxCandidates) {
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try {
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sess = await wd('POST', '/session', {
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capabilities: {
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alwaysMatch: {
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browserName: 'firefox',
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'moz:firefoxOptions': {
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args: ['-headless'],
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binary: ff,
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},
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},
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},
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});
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break;
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} catch (err) {
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lastErr = String(err?.message ?? err);
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}
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}
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if (!sess) fail(`no firefox candidate accepted: ${lastErr}`);
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const sid = sess.value?.sessionId;
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await wd('POST', `/session/${sid}/window/size`, { width: 1280, height: 720 }).catch(() => {});
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await wd('POST', `/session/${sid}/url`, { url });
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const deadline = Date.now() + Number(timeoutMs);
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let pollErr = null;
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while (Date.now() < deadline) {
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await sleep(300);
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try {
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const r = await wd('POST', `/session/${sid}/execute/sync`, { script: expr, args: [] });
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if (r.value !== undefined && r.value !== null) break;
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} catch (err) {
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pollErr = String(err?.message ?? err);
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}
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}
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await sleep(400); // let the last frame paint
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const shot = await wd('GET', `/session/${sid}/screenshot`);
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writeFileSync(outPng, Buffer.from(shot.value, 'base64'));
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console.log(`saved ${outPng}${pollErr ? ` (last poll error: ${pollErr})` : ''}`);
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await wd('DELETE', `/session/${sid}`).catch(() => {});
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} finally {
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try { driver.kill('SIGKILL'); } catch { /* dead */ }
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}
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