nerdic_walker/app.js

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');

const axios = require('axios');
const playwright = require('playwright');
const cheerio = require('cheerio');
var timeout = require('connect-timeout')

var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

app.use(logger('dev'));
app.use(timeout('10s'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(haltOnTimedout);
app.use(cookieParser());
app.use(haltOnTimedout);
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', indexRouter);
app.use('/users', usersRouter);

function haltOnTimedout (req, res, next) {
  if (!req.timedout) next()
}

// get text from selector
app.get("/element/:selector/:url(*)", (req, res, next) => {

  axios.get(req.params.url)
  .then(function (response) {
    var $ = cheerio.load(response.data);

    var element = $(req.params.selector.replace("+", " ")).text();
    
    console.log(element);
    res.json(element);
  })
  .catch(function (error) {
    // handle error
    console.log(error);
    res.json({error: error, params: req.params});
  })
  .then(function () {
    // always executed
  });
  // res.json(req.params);
});

// get screenshot

app.get("/screenshot/:browser/:pos/:width/:url(*)", (req, res, next) => {

  (async () => {
    
      switch(req.params.browser) {
        case 'webkit': {
            var browser = await playwright.webkit.launch();
            break;
          }
          case 'firefox': {
            var browser = await playwright.firefox.launch();
            break;
        }
        default: {
            var browser = await playwright.chromium.launch();
            break;
        }
      }


      const context = await browser.newContext({
        viewport: {
          width: parseInt(req.params.width),
          height: 1080
        }
      });

      var full = false;
      var pos = 0;

      const page = await context.newPage();
      console.log(req.params.width);
      await page.goto(req.params.url);

      if (req.params.pos == "full" || isNaN(req.params.pos)) {
        full = true;
      } else {
        await page.evaluate(async (pos) => {
          for (let i = 0; i < pos; i += 10) {
            window.scrollTo(0, i);
          }
        }, req.params.pos);
      }
      
      const screenshot = await page.screenshot({
        fullPage: full
      });
      //await page.screenshot({ path: `example-${browserType.name()}.png` });
      await browser.close();
      res.contentType('image/png');
      res.end(screenshot, 'binary');
  })().catch(function (error) {
      console.log(error);
  });

  // res.json(req.params);
});

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;