Basic stuff:
| Field | Sample | Description |
| :--- | :--- | :--- |
| Scheme | http | The protocol used. |
| Domain name | https://martino.im | The location of the resource. |
| Port | :80 | The "gate" used to access the resource. |
| Path | //path/to/myfile.html | The path to the resource we are looking for. |
| Parameters | ?key1=value1&key2=value2 | Parameters used to manage the operations for the resource. |
| Anchor | #SomewherelnTheDocument | A bookmark to a location in the webpage. |
Possible answers:
| Code | Description | Actual Meaning (Server's perspective) |
| :--- | :--- | :--- |
| 2xx | The action was successfully received, understood and accepted. | Everything is okay! |
| 3xx | The client must perform additional actions to fulfil the request. | I know what you want, but it is not there, anymore. Let me tell you the new location... |
| 4xx | The request is syntactically incorrect or cannot be fulfilled | I have actually no idea of what you want.|
| 5xx | The server has failed to fulfil an apparently valid request. | I just decided to blow up and stop, working.|
The most commonly utilized web servers are:
- Apache
- NGINX
- Microsoft IIS
- LiteSpeed Web Server
## Static files and dynamic files
Static files are content that is already generated and complete and, when served, doesn’t require any additional information/data. HTML, JS, CSS, images are example of static files.
There are several reasons why **dynamic** files are crucial in web development:
* **Efficiency and Scalability:** Scale web applications as demand grows is easier since the server can generate pages and content as needed, rather than relying on static files that must be manually updated.
* **Customization and Interactivity:** generating pages on-the-fly, dynamic files make it possible to personalize web pages based on the individual user's preferences and behaviors. This is probably the most important feature of a dynamic website.
## JSON
- JSON stands for JavaScript Object Notation.
- It is used as a data transfer convention over the internet.
- JSON is written in the format of a JavaScript Object/Array.
## API and REST
APIs enable abstraction of the internal workings of a system, providing only the relevant parts to the programmer.
An API is categorized as REST API if it adheres to the following principles:
- Client-Server paradigm
- Stateless
- Uniform interface
- Cacheability
- Layered system
NGINX and Apache are good for static file serving and load balancing. In 2009, JavaScript was recognized as an actual programming language and not just a browser tool.
## NodeJS and modules
Node.js is an environment for running JavaScript code outside a web browser, using the V8 engine. Modules are officially used to package and import code inside other modules. All modules used are saved in the ``node_modules`` folder within the project.
**Endpoints** are the main part of the web server, and each one corresponds to a functionality offered by the server.
It's very important to not upload `node_modules` folder since using `npm install` inside the folder any module is automatically fetched with `npm`.
````javascript
import express from 'express';
const app = express();
//Each endpoint corresponds to a functionality that we offer
// Simple endpoint that send a message when called
app.get('/', (req, res) => {
res.send("Everything's OK!").status(200);
})
// Endpoint that saves a value in the database
app.post('/db', async (req, res) => {
// The data is stored in the body of the request
let data = req.body;
// try/catch is a construct that allows to try to do something.
// If it fails, the operation inside the catch are executed
try {
// Trying to save data in the DB
await model.DB.create(data);
res.status(200).send()
}
catch {
// Send back error in case something went wrong (for example, empty fields)
res.status(400).send()
}
})
// The server listen port 3000
app.listen(3000);
````
| Method | Function | Description |
|:------ |:-------------- |:-------------------------------------------- |
| GET | `app.get(...) ` | Requests that usually want to retrieve data. |
| POST | `app.post (...)` | Requests that want to create new data. |
| PUT | `app.put(...) ` | Requests that want to modify existing data. |
| DELETE | `app.delete (...)` | Requests that want to delete existing data |
[Postman](https://www.postman.com/) is a website that can be used for testing servers. It is basically used to simplify the creation of APIs.
## Random notes
### Nodejs Express
### NodeJS project
When you land into a project where there is `package.json` you can install everything ... using `npm install` .
Remember to not commit `node_modules`.
`npm run build`