Month: October 2017

If you have an empty json_encode() and don’t know what the hell just went wrong, then this piece of code is really helpful.

$json = json_encode(array('message' => 'OK', 'data' => $row["description"]));
if ($json) {
    echo $json;
} else {
    error_log(json_last_error_msg());
}

If you get an error saying invalid UTF-8 characters or something similar, then all you need to do is set the character set of your database to UTF-8 in the following way.

connect_errno) {
    echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
    die();
}

 var_dump($mysqli->get_charset());
// you should see something like 'latin1'

 if (!$mysqli->set_charset("utf8")) {
    error_log("Error loading character set utf8: %s\n", $mysqli->error);
    exit();
}

var_dump($mysqli->get_charset());
// you should see something like 'UTF-8'

// Do your stuff here.

$mysqli->close();

is_int()

The is_int() doesn’t tell you if the string is actually a number, instead it returns false.

If you convert your string numeric into an int and then do this, only then will it work. But there is a problem with this approach, while converting string to an int, we use intval(). This converts strings to 0's.
is_numeric()
So the best way to find out whether a variable is an actual numeric or not is to use this php function.

Deleting a cookie stored in a browser using JavaScript is very easy. For example if you have a cookie named token in your browser and want to delete it, all you have to do is provide the cookie name and set it to a past date. This deletes it immediately. You can take a look at cookies in chrome’s developer tools.

function setCookie(name, value, days) {
  var d = new Date();
  d.setTime(d.getTime() + (days * 24 * 60 * 60 * 1000));
  var expires = 'expires=' + d.toUTCString();
  document.cookie = name + '=' + value + ';' + expires + ';path=/';
}

function deleteCookie(name) {
  document.cookie = name + '=;expires=' + new Date(1970, 0, 1).toUTCString() + ';path=/'
}

setCookie('token', 'value here', 1);

deleteCookie('token');

Demo

Creating a HTTP Intercepter

Angular V4.4.4
We need to inherit the ‘HttpIntercepter’ class and override the ‘intercept’ method to be able to intercept all the HTTP requests you make using ‘HttpClient’.
auth-interceptor.ts

import {Injectable} from '@angular/core';
import {Observable} from 'rxjs/Observable';
// import 'rxjs/add/operator/do';
import {HttpEvent, HttpResponse, HttpInterceptor, HttpHandler, HttpRequest} from '@angular/common/http';
 
@Injectable()
export class AuthInterceptor implements HttpInterceptor {
  constructor(private auth: AuthService) {}
 
  intercept(req: HttpRequest, next: HttpHandler): Observable> {
    // Clone the request as it is immutable. You can also save the original request in the following way
    // const prevReq = req.clone();
    const authReq = req.clone({headers: req.headers.set('Authorization', 'Bearer ' + getToken())});
    // or you can use the shorter version of the same.
    //const authReq = req.clone({setHeaders: {Authorization: 'Bearer ' + getToken()}});
    // Pass on the cloned request instead of the original request.
    return next.handle(authReq);
    /* you can test the above function by doing a console.log() here. For this you will need to import 'HttpResponse' and the 'do' operator.
     .do(event => {
        if (event instanceof HttpResponse) {    
          console.log(getToken());
        }
      });
   */
  }
}

Updating app.module.ts

Now you need to include the ‘AuthInterceptor’ class as part of our main app module providers after you have imported ‘HTTP_INTERCEPTORS’.
app.module.ts

import {NgModule} from '@angular/core';
import {AuthInterceptor} from './auth-interceptor'
import {HTTP_INTERCEPTORS} from '@angular/common/http';

@NgModule({
  providers: [{
    provide: HTTP_INTERCEPTORS,
    useClass: AuthInterceptor,
    multi: true,
  }],
})
export class AppModule {}

Calculate the time difference for javascript date objects in years, months, days, hours, minutes and seconds. Whether they are in the future or in the past. The function accounts for all very easily. Since this is a lightweight function you can easily use this as part of any application, without incurring much overhead.
github

Code

var timeAgo = function(date) {
  var d = new Date();
  var UTCsecondsNow = (d.getTime() + d.getTimezoneOffset() * 60 * 1000);
  var UTCseconds = (date.getTime() + date.getTimezoneOffset() * 60 * 1000);
  var diff = UTCsecondsNow - UTCseconds;
  var tense = 'ago';
  if (diff < 0) {
    tense = 'later';
    diff = Math.abs(diff);
  }
  if (diff === 0) return 0;
  // 365.25 * 24 * 60 * 60 * 1000
  var years = singular(Math.round(diff / 31557600000), 'Year');
  if (years)
    return years + tense;
  var months = singular(Math.round(diff / 2592000000), 'Month');
  if (months)
    return months + tense;
  var days = singular(Math.round(diff / 86400000), 'Day');
  if (days)
    return days + tense;
  var hours = singular(Math.round(diff / 3600000), 'Hour');
  if (hours)
    return hours + tense;
  var mins = singular(Math.round(diff / 60000), 'Minute');
  if (mins)
    return mins + tense;
  var secs = singular(Math.round(diff / 1000), 'Second');
  if (secs)
    return secs + tense;
};

var singular = function(num, str) {
  if (num > 1) {
    if (num === 1)
      return '1 ' + str + ' ';
    else
      return num + ' ' + str + 's ';
  }
  return '';
};

Usage

timeAgo( new Date('2016-12-04T11:45:00.000Z') )

Output

10 Months ago

Demo