The proper method for making multiple API requests from a list, with a maximum rate of two requests per second, is to use a queue system that allows you to schedule and execute requests at a controlled rate. Here's a high-level approach:
- Define a queue data structure to hold the list of API endpoints to call, and a counter to keep track of the number of requests made so far.
- Configure a timer that triggers every half-second (or slower if preferred, depending on the maximum rate), or use a sleep function to pause execution in between requests.
- In the loop or timer, check the queue to see if there are any requests to make. If there are, dequeue the next item.
- Before making the API request, check the request counter to see if the maximum rate of two requests per second has been reached. If not, increment the counter.
- Make the API request using a library or function that supports asynchronous or non-blocking I/O, so that the execution of the code doesn't block the timer loop. Save the result in a data cache or file.
- After the API request is complete, decrement the counter, and loop again to process the next item in the queue.
This approach ensures that calls are made at a controlled rate, preventing the API provider from blocking your requests or throttling your access. It also allows you to efficiently process the list without exceeding its limits.