[Ionic 4] HTTP requests errors

I’m a couple of days trying to debug some app with HTTP requests in a localhost server. I think this is the one of the most frustrating errors that I stumbled across. The first error was with CORS, followed by some others, something like this:

XMLHttpRequest cannot load http://localhost:8888.
No 'Access-Control-Allow-Origin' header is present on the requested resource.
Origin 'http://localhost:8100' is therefore not allowed access.

I tried to allow all domains in the server configuration and in the app options, nothing changed. Later I changed the server configuration, changed the name ‘localhost’ to 127.0.0.1 (php -t 'myServerFolder' -S 127.0.0.1:1337), this made stop that CORS error, but I don’t effectively fixed it, the other errors keeping haunting me:

I also tried to deactive the chrome CORS with an extension and later with the options: "C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --disable-web-security --disable-gpu --user-data-dir=~/chromeTemp. Nothing changed.

Ionic v4
Dev Server: PHP built in server
Running with: ionic serve
Using angular HttpClient

home.page.ts

...

async Save(data) {
	let myLink = "http://localhost:1337/upload.php"
	let myDataArray = [{"point_id" : this.point_id, "name" : this.name, "obs" : this.obs, "coord" : this.coord}];
	let myData = JSON.stringify(myDataArray);

	const httpOptions = {
		headers: new HttpHeaders({
		  'Content-Type':  'application/json',
		  'Access-Control-Allow-Origin': '*',
		  'Access-Control-Allow-Methods': 'POST, GET, OPTIONS',
		  'Access-Control-Allow-Headers': 'Content-Type',
		  'Accept': 'application/json'
		})
	};

	const loading = await this.loadingController.create({
	    message: 'Uploading data...',
	});
	await loading.present();
	
	this.http.post(myLink, myData, httpOptions)
	.pipe(
	    finalize(() => {
	        loading.dismiss();
	    })
	)
	.subscribe(res => {
	    if (res['success']) {
	        this.presentToast('Data upload complete.')
	    } else {
	        this.presentToast('Data upload failed.')
	    }
	});
}

upload.php (headers only)

<?php
  header('Access-Control-Allow-Origin: *');
  header('Access-Control-Allow-Methods: GET, POST, OPTIONS');
  header('Access-Control-Allow-Headers: Origin, Content-Type, X-Auth-Token');
  header('Content-Type: application/json');

...

I can access the server through the browser without problems. If any other information is needed, just ask :smile:. Code based on this example.

Check in your PHP file, remove space from PHP tags before & after

Thanks for the suggestions, but there is no empty spaces before or after the php tag. Like I said in the end of the post, I can access the php file through the browser without problems.