Build an Amazon clone: Nodejs + MongoDB + Stripe Payment (Udemy course)

Ref:

https://www.udemy.com/build-an-amazon-clone-nodejs-stripe-elasticsearch/
Check git log, branches, pm/history.txt for development progress

DONE:

• setup project by run npm init
• add pm/history.txt for project management purpose
• setup git and add first commit
• add eslint and config
• connected to mlab database
  • note about mongodb://:@ds261138.mlab.com:61138/amazonclone
  • here dbuser need to be created on user tab on selected db, this is not account used to login to mlab itself.

• mongoose Schema.pre must has a function style callback not arrow function because of fat arrow lexically binds the function to current scope so this will not be Schema instance

• both cookie and session are place to store data
• cookie store data on client side, thus can be accessed by user
  • cookie is sent by browser to server each request
  • cookie-parser is used to parser that cookie
• session store data on server side, thus cannot be accessed by user
  • server identify user using a session id (session.sid)
  • session.sid is stored in cookie (signed or unsinged)
  • because cookie is sent by browser to server each request, server will get session.sid from cookie to identify user from session
  • express-session is used to handle above steps
• express-flash using exppres-session to pass message from route to route

• route use passport.authenticate('local-login')
• if user authen successfully, user object shall be passed to passport return done(null, user); passport will then call passport.serializeUser to get which information should be saved into session (here user._id)
• then on another route passport get that saved info and give to passport.deserializeUser and the req.user shall be assiged to user got from done(err, user); in deserializeUser function

• For example when user login succesfully we redirect he/she to his/her profile page. On that route we check for req.user which should be set by passport. But there is some cases when user login succesfully we call redirect, and redirecting happened before session, which has user info from passport.serializeUser, be saved. Thus, on profile route passport cannot get user info back from session, cannot call passport.deserializeUser and cannot set req.user
• Because req.user is not set, request shall be redirect to login page again.
• FIX: (this is temporary, should check more)

node_modules/express-session/index.js ( comment line: return writetop(); add line: return; )

if (shouldSave(req)) {
  req.session.save(function onsave(err) {
    if (err) {
      defer(next, err);
    }
    writeend();
  });
  // return writetop();
  return;
  ...
}

https://memto.github.io/linux/tooltips/2018/04/04/elasticsearch-ubuntu-16-04/

https://memto.github.io/linux/program/tooltips/2018/04/04/mongoosastic-4-4-1-and-elasticsearch-6-2-3/

• Another temporary fix for: '[mapper_parsing_exception] No handler for type [string] declared on field [category]'

node_modules/mongoosastic/lib/mapping-generator.js

function getTypeFromPaths (paths, field) {
    let type = false

    if (paths[field] && paths[field].options.type === Date) {
      return 'date'
    }

    if (paths[field] && paths[field].options.type === Boolean) {
      return 'boolean'
    }

    if (paths[field] && paths[field].options.type === String) {
      return 'text'
    }
    ...
}


function getMapping (cleanTree, inPrefix) {
  ...
  // If it is a objectid make it a string.
  if (value.type === 'objectid') {
    if (value.ref && value.es_schema) {
      mapping[field].type = 'object'
      mapping[field].properties = getMapping(value, prefix + field)
      continue
    }
    // do not continue here so we can handle other es_ options
    mapping[field].type = 'text'
  }
  ...
}

• Error: [illegal_argument_exception] mapper [category] of different type, current type [string], merged_type [ObjectMapper]
• Cause: this is because there is already index in elasticsearch with category mapping as type string
• Fix: delete existed index: curl -XDELETE http://localhost:9200/products

TODO: