'Content-Type': 'application/json'
needs to be 'Content-Type': 'application/hal+json'
in order for it to work.
I recommend you watch these video tutorials
Learn Drupal 8 - REST API Part1
Learn Drupal 8 - REST API Part2
The login is covered in part 2, but part 1 is very informative and part 2 will make more sense if you watch part 1.
Although, the video tutorial uses the Google Chrome Postman add-on, your code needs to do the same.
Have a header with Content Type and Authorization
GET http://{my-host}/user/testing
Your URL to POST, GET, or PATCH shouldn't be your user page, unless you want to work with the user fields. The URL needs to have the entity you are working with.
For example: See the url's used in the video tuts.
You can even use Postman to generate your code
HTTP Generation
PATCH /node/1 HTTP/1.1
Host: forexample.com
Content-Type: application/hal+json
Authorization: Basic Q2FtaWxvOmNvY29saXNa
Cache-Control: no-cache // delete
Postman-Token: 3803eeac-0dc2-5c09-05e1-40d15d5b9820 // delete
{
"title": [
{
"value": "The title changed, WOOOHOOO!!!"
}
],
"type": [
{
"target_id": "article"
}
],
"_links": {
"type": {
"href": "http://forexample.com/rest/type/node/article"
}
}
}
PHPV1 generation
<?php
HttpRequest::methodRegister('PATCH');
$request = new HttpRequest();
$request->setUrl('http://forexample.com/node/1');
$request->setMethod(HttpRequest::HTTP_METH_PATCH);
$request->setHeaders(array(
'postman-token' => '9656f5e8-13a5-0e2b-23cb-5ac03af59b5b', // remove this line
'cache-control' => 'no-cache', // remove this line
'authorization' => 'Basic Q2FtaWxvOmNvY29saXNa',
'content-type' => 'application/hal+json'
));
$request->setBody('{
"title": [
{
"value": "The title changed, WOOOHOOO!!!"
}
],
"type": [
{
"target_id": "article"
}
],
"_links": {
"type": {
"href": "http://forexample.com/rest/type/node/article"
}
}
}');
try {
$response = $request->send();
echo $response->getBody();
} catch (HttpException $ex) {
echo $ex;
}
You can also generate for other languages like Python, jQuery, PHP Curl to name a few.