Category: News from ways4.eu-Blog

Sketch of Biker Woman

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image of sketch biker woman

sketch/study of Biker woman in Action.

Created digitally with ArtRage software

The post Sketch of Biker Woman appeared first on Strictly Confidential.

source https://www.ways4.eu/blog/2020/07/13/sketch-of-biker-woman/?utm_source=rss&utm_medium=rss&utm_campaign=sketch-of-biker-woman

(Deutsch) HowTo: Erstellen von kollaborativen Echtzeit-Aufgabenlisten in React

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Sorry, this entry is only available in German.

The post (Deutsch) HowTo: Erstellen von kollaborativen Echtzeit-Aufgabenlisten in React appeared first on Strictly Confidential.

source https://www.ways4.eu/blog/2020/06/04/how-to-kollaborative-aufgabenliste-in-react/?utm_source=rss&utm_medium=rss&utm_campaign=how-to-kollaborative-aufgabenliste-in-react

Container Komponenten in React

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Ein React-Pattern, das im Coding von React Frontends Berücksichtigung finden sollte, ist das Container-Komponenten-Pattern.

Die Idee ist einfach:

Ein Container ruft Daten ab und rendert dann die entsprechende Unterkomponente. So simpel.

“Entsprechend” bedeutet eine Komponente mit demselben Namensbestandteil:

GuineaPigsContainer => GuineaPigs
AnimalsContainer => Animals
EventListContainer => EventList

Konzept verstanden ?

Warum Container?

Angenommen, du hast eine Komponente, die Kommentare anzeigt. Da du noch nichts vom Container-Komponenten-Pattern gehört hast, platzierst du deinen Code so, dass  alles an einem Ort ist:

class CommentList extends React.Component {
  this.state = { comments: [] };

  componentDidMount() {
    fetchSomeComments(comments =>
      this.setState({ comments: comments }));
  }  render() {
    return (
      <ul>
        {this.state.comments.map(c => (
          <li>{c.body}—{c.author}</li>
        ))}
      </ul>
    );
  }
}

Deine Komponente ist sowohl für das Abrufen als auch für das Präsentieren von Daten verantwortlich. Daran ist nichts „Falsches“, aber einige Vorteile von React werden damit nicht nutzbar, zB:

Wiederverwendbarkeit

CommentList kann nur unter genau den gleichen Umständen wiederverwendet werden.

Datenstruktur

Die Markup-Komponenten sollten die Erwartungen an die benötigten Daten angeben. PropTypes sind dafür optimal.
Unsere Komponente hat eine Erwartung an die Datenstruktur, kann diese jedoch nicht ausdrücken. Wenn sich der json-Endpunkt ändert, wird der Datenfluß zur Komponente unterbrochen (silent).

Noch einmal. Diesmal mit einem Container

Lass uns zunächst den Datenabruf in eine Containerkomponente verlagern:

class CommentListContainer extends React.Component {
  state = { comments: [] };  componentDidMount() {
    fetchSomeComments(comments =>
      this.setState({ comments: comments }));
  }  render() {
    return <CommentList comments={this.state.comments} />;
  } 
}

Lass uns nun CommentList überarbeiten, um comments als prop zu verwenden:

const CommentList = props =>
  <ul>
    {props.comments.map(c => (
      <li>{c.body}—{c.author}</li>
    ))}
  </ul>

Also, was haben wir damit erreicht ?

Tatsächlich eine ganze Menge….

  • Wir haben das Abrufen und Rendern von Daten getrennt.
  • Wir haben unsere CommentList-Komponente wiederverwendbar gemacht.
  • Wir haben CommentList die Möglichkeit gegeben, PropTypes festzulegen und damit ggf. auch im Fehlerfall “laut” zu scheitern.

Containerkomponenten können die Struktur und Lesbarkeit von React-Code erheblich verbessern und sie erleichtern das Lesen des Komponenten-Codes.

Probiere es aus !

The post Container Komponenten in React appeared first on Strictly Confidential.

source https://www.ways4.eu/blog/2020/05/18/container-komponenten-in-react/?utm_source=rss&utm_medium=rss&utm_campaign=container-komponenten-in-react

MQTT server mosquitto on Raspberry Smarthome server does not start

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Problem

After a few days of absence, I was unfortunately faced with some problems on my Raspberry smart home server.

Among other things, the Mosquitto MQTT server, which is supposed to receive and process messages from the various iot devices, was not available.

Analysis

After analyzing the process overview with

ps -A | grep mosq

unfortunately no output was shown, i.e. the process had obviously not started.

The manual start with

sudo mosquitto

then led to success. The MQTT server was running and also receiving or processing all messages. Only the service to the Mosquitto caused problems.
After completing the manually started process, another attempt was made with

sudo systemctl start mosquitto.service

then start the service. The subsequent query with

sudo systemctl status mosquitto.service

initially provided a promising answer that the service had started successfully.

Unfortunately not quite successful, there is still no entry for mosquitto in the process overview, and the MQTT message processing did not work either.

Reason

After some troubleshooting, the problem was solved. The cause was an apparently corrupt mosquitto.db that is used by the mosquitto service to cache messages.

Solution

This problem can be easily solved by deleting the corresponding file in the directory / var / lib / mosquitto using:

sudo rm mosquitto.db

If then restarted with

sudo systemctl restart mosquitto.service

 mosquitto works fine. The service is automatically restarted even after a reboot.

The post MQTT server mosquitto on Raspberry Smarthome server does not start appeared first on Strictly Confidential.

source https://www.ways4.eu/blog/2019/12/16/mqtt-server-mosquitto-on-raspberry-smarthome-server-does-not-start/

How rating platforms can be tricked :-)

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London’s best restaurant

On Tripadvisor, the garden arbor of a reporter for the Vice magazine became London’s best restaurant. Oobah Butler, the name of the reporter, had planned it for a long time ago. The ingredients: a website, a logo, and exclusivity (no address, tables by appointment only). Butler uploaded softly drawn photos of his dishes, which he called “contemplation,” “desire,” and “love.” In fact, these consisted of shaving cream, colored toilet blocks and rinsing sponges. Ordered 5-star reviews from his friends made “The Shed at Dulwich” go up in the TripAdvisor rankings. After a few weeks, Butler’s gazebo was among the best 10,000 restaurants in the city, after three months at number 156. After six months, the arbor of the last (18 149) had climbed to first place – although a restaurant had never existed before and never had served a dish. “If I can turn my garden into London’s best restaurant, then almost anything is possible,” said Butler.

Worst restaurant on Yelp

Davide Cerretini, the owner of the Italian restaurant “Botto Bistro” in Richmond, California, took the opposite route. He wanted to be the restaurant with the worst rating on Yelp. Cerretini spent about $ 250 a month advertising on the portal until he realized it did not do much. When he booked no more ads, 5-star ratings had disappeared, 1-star ratings would have increased, he recalled later. He felt bullied and wondered: What happens if I just reverse the power of the portal? He gave every guest who valued his restaurant a single star up to 50% off a pizza. More than 3000 1-star ratings came together like this. The idea arose: The Bistro became the worst restaurant on Yelp – and a viral hit. Cerretini said, “It takes great chefs, great talent, and a great experience to get a Michelin star, but getting a 1-star rating on Yelp requires a lot more.“

 

The post How rating platforms can be tricked 🙂 appeared first on Strictly Confidential.

source https://www.ways4.eu/blog/2019/10/31/howto-trick-rating-platforms/