Builds an `httr2` request targeting the OpenAlex PRO endpoint, executes it, and extracts the pagination metadata. Only summary metadata is requested and the first page is fetched to minimise API usage.
Usage
pro_count(query_url, api_key = pro_api_key(), error_log = NULL)Arguments
- query_url
Character string containing the fully constructed OpenAlex PRO endpoint URL.
- api_key
Character string API key or `NULL`. Defaults to `pro_api_key()`. If `NULL` or `""`, the request is sent without an API key (subject to OpenAlex's unauthenticated limits).
- error_log
location of error log of API calls. (default: `NULL` (none)).