Wordpress REST API won't allow me to filter by author ID when called internally, works externally in Postman

Question

I'm currently making a custom API endpoint for a site that I'm building, which works absolutely fine aside from this issue with author ID's.

If I do a GET request to website.local/wp-json/wp/v2/podcasts it returns valid JSON of all of the podcasts Custom Post Type. If I do a GET request to website.local/wp-json/wp/v2/podcasts?author=1 it also returns valid JSON of all of the podcasts Custom Post Type - no problems here.

The problem however comes from some other code that I'm writing, I'm trying to do this in a custom function:

$server = rest_get_server();
$podcastsRequest = new WP_REST_Request( 'GET', '/wp/v2/podcasts?author=1');
$podcastsResponse = rest_do_request( $podcastsRequest );
$podcastsData = $server->response_to_data( $podcastsResponse, false );

When I run it in Postman I get the following response:

{
    "code": "rest_no_route",
    "message": "No route was found matching the URL and request method.",
    "data": {
        "status": 404
    }
}

If I do this call internally inside the function, it works fine:

$server = rest_get_server();
$podcastsRequest = new WP_REST_Request( 'GET', '/wp/v2/podcasts');
$podcastsResponse = rest_do_request( $podcastsRequest );
$podcastsData = $server->response_to_data( $podcastsResponse, false );

I cannot work out why it's producing that error when a direct call to it works fine?

EDIT: To give more context, this is the function I'm using:

function get_all_posts(WP_REST_Request $request){
    $server = rest_get_server();

    if($request->get_param('id')){
        // $author = $request->get_param('author');
        $podcastsRequest = new WP_REST_Request( 'GET', '/wp/v2/podcasts?author=1');
        // $articlesRequest = new WP_REST_Request( 'GET', '/wp/v2/articles?author=1');
        // $webinarsRequest = new WP_REST_Request( 'GET', '/wp/v2/webinars?author=1');
        // $expertInterviewsRequest = new WP_REST_Request( 'GET', '/wp/v2/expert-interviews?author=1');
        // $guidesRequest = new WP_REST_Request( 'GET', '/wp/v2/guides?author=1');
    } else {
        $podcastsRequest = new WP_REST_Request( 'GET', '/wp/v2/podcasts' );
        $articlesRequest = new WP_REST_Request( 'GET', '/wp/v2/articles' );
        $webinarsRequest = new WP_REST_Request( 'GET', '/wp/v2/webinars' );
        $expertInterviewsRequest = new WP_REST_Request( 'GET', '/wp/v2/expert-interviews' );
        $guidesRequest = new WP_REST_Request( 'GET', '/wp/v2/guides' );
    }

    $podcastsResponse = rest_do_request( $podcastsRequest );
    $podcastsData = $server->response_to_data( $podcastsResponse, false );


    $articlesResponse = rest_do_request( $articlesRequest );
    $articlesData = $server->response_to_data( $articlesResponse, false );

    $webinarsResponse = rest_do_request( $webinarsRequest );
    $webinarsData = $server->response_to_data( $webinarsResponse, false );

    $expertInterviewsResponse = rest_do_request( $expertInterviewsRequest );
    $expertInterviewsData = $server->response_to_data( $expertInterviewsResponse, false );

    $guidesResponse = rest_do_request( $guidesRequest );
    $guidesData = $server->response_to_data( $guidesResponse, false );

    $merged = array_merge(
        $podcastsData,
        $articlesData,
        $webinarsData,
        $expertInterviewsData,
        $guidesData,
    );

    return $merged;
}

add_action('rest_api_init', function () {
    register_rest_route( 'wp/v2', '/all-posts', [
        'methods'  => 'GET',
        'callback' => 'get_all_posts',
    ]);
});

As I've said above, if I just use the new WP_REST_Request( 'GET', '/wp/v2/podcasts' ); endpoints, it works fine, but if I try and use new WP_REST_Request( 'GET', '/wp/v2/podcasts?author=1' ); it returns that error, despite a direct call to website.local/wp-json/wp/v2/podcasts?author=1 returning all the posts for the author.

Answer 1

My approach to this was wrong, and I didn't understand the error properly. After taking another look at this, I was able to fix it by replacing this code:

if($request->get_param('id')){
    // $author = $request->get_param('author');
    $podcastsRequest = new WP_REST_Request( 'GET', '/wp/v2/podcasts?author=1');
    $articlesRequest = new WP_REST_Request( 'GET', '/wp/v2/articles?author=1');
    $webinarsRequest = new WP_REST_Request( 'GET', '/wp/v2/webinars?author=1');
    $expertInterviewsRequest = new WP_REST_Request( 'GET', '/wp/v2/expert-interviews?author=1');
    $guidesRequest = new WP_REST_Request( 'GET', '/wp/v2/guides?author=1');
} else {
    $podcastsRequest = new WP_REST_Request( 'GET', '/wp/v2/podcasts?author=1' );
    $articlesRequest = new WP_REST_Request( 'GET', '/wp/v2/articles?author=1' );
    $webinarsRequest = new WP_REST_Request( 'GET', '/wp/v2/webinars?author=1' );
    $expertInterviewsRequest = new WP_REST_Request( 'GET', '/wp/v2/expert-interviews?author=1' );
    $guidesRequest = new WP_REST_Request( 'GET', '/wp/v2/guides?author=1' );
}

with this code:

if($request->get_param('author')){
    $author = $request->get_param('author');

    $podcastsRequest = new WP_REST_Request( 'GET', '/wp/v2/podcasts');
    $podcastsRequest->set_query_params( array( 'author' => $author ));

    $articlesRequest = new WP_REST_Request( 'GET', '/wp/v2/articles');
    $articlesRequest->set_query_params( array( 'author' => $author ));

    $webinarsRequest = new WP_REST_Request( 'GET', '/wp/v2/webinars');
    $webinarsRequest->set_query_params( array( 'author' => $author ));

    $expertInterviewsRequest = new WP_REST_Request( 'GET', '/wp/v2/expert-interviews');
    $expertInterviewsRequest->set_query_params( array( 'author' => $author ));

    $guidesRequest = new WP_REST_Request( 'GET', '/wp/v2/guides');
    $guidesRequest->set_query_params( array( 'author' => $author ));
} else {
    $podcastsRequest = new WP_REST_Request( 'GET', '/wp/v2/podcasts');
    $articlesRequest = new WP_REST_Request( 'GET', '/wp/v2/articles');
    $webinarsRequest = new WP_REST_Request( 'GET', '/wp/v2/webinars');
    $expertInterviewsRequest = new WP_REST_Request( 'GET', '/wp/v2/expert-interviews');
    $guidesRequest = new WP_REST_Request( 'GET', '/wp/v2/guides');
}

This now works as the API endpoint isn't directly set up to match additional parameters on itself, however passing them through with set_query_params() did the job!