http URL not calling in Angular

Http uses rxjs and is a cold/lazy observable, meaning that you should subscribe to it to make it work.

  this.http.get(`http://swapi.co/api/people/1`).map((response:Response) => {
                console.log(response.json());
                response.json();
            }).subscribe();

Or if you want to subscribe from somewhere else , you should return the http.get method like this : :

 getAllPersons():Observable<any>{
    console.log("Here");
       return this.http.get(`http://swapi.co/api/people/1`).map((response:Response) => {
        console.log(response.json());
        response.json();
    });
    } 

and then :

   getAllPersons().subscribe();

building and Deploying Google Firebase cloud functions

https://firebase.google.com/docs/functions/get-started

$ firebase deploy --only functions

$ firebase deploy --only functions:addMessage

Cannot set variable of undefined

https://stackoverflow.com/questions/38807643/error-uncaught-in-promise-typeerror-cannot-set-property-isadmin-of-null

when variable not set in function "then" block, this doesnt work, need to a copy of "this" reference with in the calling function.

down voteaccepted

Either you can use arrow function firebase.database().ref('/userProfile/' + user.uid).once('value') .then((snapshot) => { or use var self = this; firebase.database().ref('/userProfile/' + user.uid).once('value') .then(function(snapshot) { self.isAdmin = true; otherwise this doesn't point to the current function when it's called. See also https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Functions/Arrow_functions

promise-polyfill error while using Firebase in Angular

ERROR in ./~/firebase/app/shared_promise.js

Module not found: Error: Can't resolve 'promise-polyfill'

Solution: 
npm install promise-polyfill --save-exact

continuous integration | angular cli + firebase + travis ci

https://houssein.me/continuous-integration-angular-firebase-travisci

Angular project with gitHub

http://developer.telerik.com/featured/quick-angular-2-hosting-angular-cli-github-pages/

Udemy course videos download

Courtesy: Pankaj Barnwal, Quora ( https://www.quora.com/How-do-I-download-videos-from-Udemy)

How to Download your subscribed course videos from Udemy:

If you don't mind getting your hand dirty in coding, may i suggest you a python script 'python-dl' which is best to download videos from the mentioned course site.

Step-by-step Guide -

if you dont have pip installer, have it installed via following command-

sudo apt install python-pip

Now download python script "python-dl" through pip install-

sudo pip install udemy-dl

Below is the command to download entire udemy course using this script

udemy-dl course-link

Next type your username & password and you will be good to go, or you can type them in the same sentence like this

udemy-dl -u username -p password course link

Advance Usage - This is where it gets fun. if you want to download specific video from the list, use following command -

udemy-dl -u username -p password --lecture-start lecture No where you want download to start --lecture-end end point

For Example -

udemy-dl -u abcd@xyz.com -p HND$#$5 --lecture-start 52 --lecture-end 58 https://www.udemy.com/COURSE_NAME

Note - This script does not pull written docs but it works great for videos.