Drupal 8, http request to server and append to the site - drupal

Question

I have a Drupal 8 site and I need to make a http request to another server (for content) and append it into the page like footer. I can't do this after DOM is loaded because of SEO issues.
I'm familiar with WordPress and so easy to do it with WP. However, I'm confused about how to do this with .twig, Drupal 8. Any suggestions would be great. Thanks.

Answer 1

If you want the content to be part of the DOM when it is sent to the browser this is not something you want to do in Twig, you should have the content loaded earlier in the process.
You can create a module that defines custom block and place that block in the correct region of your theme.
The block plugin class requires you to write a build() method that returns a render array for your block. Within build() you can do whatever you need to acquire the content, including making an HTTP Request using Symfony's Guzzle client:
public function build() {
$url = 'https://www.example.com/remote/service';
$client = \Drupal::httpClient();
$request = $client->createRequest('GET', $url);
// Do whatever's needed to extract the data you need from the request...
$build = ['my_remote_block' => [
'#theme' => 'my_custom_theme_function',
'#attributes' => [
//An array of variables to pass to the theme
],
'#cache' => [
//Some appropriate cache settings
],
],
];
If you are getting HTML back from your request you could skip the custom theme function and return an array with '#type' => 'markup' and then a field for the markup. The rest of this example assumes you get data back and want to render it yourself.
In your module's .module file you can define the custom theme function (so you can use a twig file of your own design).
function my_module_theme($existing, $type, $theme, $path) {
return [
'my_custom_theme_function' => [
'variables'=> [
// defaults for variables used in this block.
],
],
];
}
Then finally you can create a twig file named my-custom-theme-function.html.twig to render the output.
Often these kinds of setups are quite slow (since the browser's request then triggers another HTTP request + processing time) so you should consider either caching the block as much as possible or using a technique like BigPipe (which is probably not an option for you based on your question but seemed worth pointing out).