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      "source": "# Rate limiting\n\nRequests are rate limited to prevent a single user from monopolising the resources.\n\nResponse headers show we are allowed 55000 requests over an hour (3600 seconds): an average 15 requests per second.\n\n## Exercises 7\n\nThis script queries the ping endpoint 25 times, printing the count, the HTTP Status Code, and the X-RateLimit-Remaining header each time.\n\n1\\. Increase the number of loops, do you start to get 429 errors?\n\n2\\. Can you add in a step to make it wait a few seconds every iteration? Or every 100 iterations?"
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      "source": "# Exercise 7.1\nlibrary(httr)\n\nserver <- \"http://rest.ensembl.org/\"\ncon <- \"application/json\"\next_ping <- \"/info/ping?\"\n\nx <- 0\n\nwhile (x < 25) {\n    ping <- GET(paste(server, ext_ping, sep = \"\"), accept(con))\n    x = x + 1\n    print( paste (\"count: \", x, \"status:\", status_code(ping), \"remaining:\", headers(ping)['X-RateLimit-Remaining']))\n}",
      "execution_count": null,
      "outputs": []
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    {
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      "cell_type": "markdown",
      "source": "[Next page: Exercises 7 – answers](7_Rate_limiting_answers.ipynb)"
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