server.js

'use strict';

// require built-in dependencies
const path = require('path');
const util = require('util');
const fs = require('fs');

const readFile = util.promisify(fs.readFile);
const writeFile = util.promisify(fs.writeFile);
const readDir = util.promisify(fs.readdir);

// require express-related dependencies
const express = require('express');
const cors = require('cors');
const bodyParser = require('body-parser');

// require local dependencies
const logger = require('./middleware/logger');

// declare local constants and helper functions
const PORT = process.env.PORT || 4600;
const DATA_DIR = 'data';
const TAG_RE = /#\w+/g;
const slugToPath = (slug) => {
  const filename = `${slug}.md`;
  return path.join(DATA_DIR, filename);
};

const removeExtension = (item) => {
  const pos = item.lastIndexOf('.');
  return item.slice(0, pos);
}

// initialize express app
const app = express();

// use middlewares
app.use(cors());
app.use(logger);
app.use(bodyParser.json());
// this commented line of code will statically serve the frontend
// it will not work until you:
// $ cd client
// $ yarn install
// $ yarn build
app.use('/', express.static(path.join(__dirname, 'client', 'build')));



// GET: '/api/page/:slug'
// success response: {status: 'ok', body: '<file contents>'}
// failure response: {status: 'error', message: 'Page does not exist.'}
app.get('/api/page/:slug', async (req, res) => {
  const filename = slugToPath(req.params.slug);
  try {
    const body = await readFile(filename, 'utf-8');
    res.json({
      status: 'ok',
      body
    });
    // return jsonOK(res, { body });
  } catch (e) {
    res.json({
      status: 'error',
      message: 'Page does not exist.'
    });
  }
});



// POST: '/api/page/:slug'
//  body: {body: '<file text content>'}
// tries to write the body to the given file
//  success response: {status: 'ok'}
//  failure response: {status: 'error', message: 'Could not write page.'}
app.post('/api/page/:slug', async (req, res) => {
  const filename = slugToPath(req.params.slug);
  try {
    console.log('**post all pages**');
    const content = req.body;
    await writeFile(filename, content.body);

    res.json({status: 'ok'});

  } catch (e) {
    console.log('something went wrong');
    res.json({
      status: 'error',
      message: 'Could not write page.'
    });
  }
});


// GET: '/api/pages/all'
// sends an array of all file names in the DATA_DIR
// file names do not have .md, just the name!
//  success response: {status:'ok', pages: ['fileName', 'otherFileName']}
//  failure response: no failure response
app.get('/api/pages/all', async (req, res) => {
  try {
    console.log('**get all pages**');

    const pages = [];
    const files = fs.readdirSync(DATA_DIR);
    files.forEach(file => {
      const sliced = removeExtension(file);
      pages.push(sliced);
    });
    //send response
    res.json({
      status: 'ok',
      pages: pages
    });


  } catch (e) {
    console.log('something went wrong');
    res.json({
      status: 'error',
      message: e
    });
  }
});


// GET: '/api/tags/all'
// sends an array of all tag names in all files, without duplicates!
// tags are any word in all documents with a # in front of it
// hint: use the TAG_RE regular expression to search the contents of each file
//  success response: {status:'ok', tags: ['tagName', 'otherTagName']}
//  failure response: no failure response
app.get('/api/tags/all', async (req, res) => {
  try {
    console.log('**get all tags**');
    const tags = [];
    const files = fs.readdirSync(DATA_DIR);
    files.forEach(file => {

      //read files one by one
      const readFile = `${DATA_DIR}/${file}`;
      const  data = fs.readFileSync(readFile, 'utf8');

      const matchTag = data.match(TAG_RE);
      //if we found a match we add it to the tags array
      //matchTag is also an array
      if (matchTag){
        matchTag.forEach(tag => {
          //remove '#'
          const tmp = tag.substring(1, tag.length);
          tags.push(tmp);
        });
      }

    });
    
    //remove duplicates of our array
    const uniq = [...new Set(tags)];
    //send response
    res.json({
      status: 'ok',
      tags: uniq
    });
    
  } catch (e) {
    console.log('something went wrong');
    res.json({
      status: 'error',
      message: e
    });
  }

});


// GET: '/api/tags/:tag'
// searches through the contents of each file looking for the :tag
// it will send an array of all file names that contain this tag (without .md!)
//  success response: {status:'ok', tag: 'tagName', pages: ['tagName', 'otherTagName']}
//  failure response: no failure response
app.get('/api/tags/:tag', async (req, res) => {
  try{
    console.log('**get search for tag in each file**');
    const filesWithTags = [];
    const files = fs.readdirSync(DATA_DIR);

    files.forEach(file => {
      //read files one by one
      const readFile = `${DATA_DIR}/${file}`;
      const  data = fs.readFileSync(readFile, 'utf8');

      //get :tag param
      const matchTag = data.match(req.params.tag);
      //file contains the tag
      if (matchTag){
        const sliced = removeExtension(file);
        filesWithTags.push(sliced);
      }
    });
    //send response
    res.json({
      status: 'ok',
      pages: filesWithTags
    });

  }
  catch(e){
    console.log('something went wrong');
    res.json({
      status: 'error',
      message: e
    });
  }

});


// this needs to be here for the frontend to create new wiki pages
//  if the route is not one from above
//  it assumes the user is creating a new page
app.get('*', (req, res) => {
  res.sendFile(path.join(__dirname, 'client', 'build', 'index.html'));
});


app.listen(PORT, (err) => {
  if (err) {
    console.error(err);
    return;
  }
  console.log(`Wiki app is serving at http://localhost:${PORT}`)
});