C# Console App HTTP API request in a foreach loop - how to pause loop at 100 loops then continue?

Question

My code works, however, because I am using a public API, I'm limited to 100 requests at a time.

Currently I am using a foreach loop to execute a request. The code looks like this.

public static List<string> keyList = new List<string>();
public static string Uri1 = "api url address";
public static string URLreq;
public static List<string> reqs = new List<string>();

static void apiReq()
{
    string filePath = "Path To File\\a.txt";
    var fileLines = System.IO.File.ReadAllLines(filePath);                    
    foreach(string s in fileLines)
    {
         keyList.Add(s);
    }

    for (int ab = 0; ab < keyList.Count; ab++)
    {
        URLreq = Uri1 + keyList[ab];
        reqs.Add(URLreq);

    }

    foreach (string ra in reqs)
    {
        Uri uri = new Uri(ra);
        // Create the web request  
        HttpWebRequest request = WebRequest.Create(uri) as HttpWebRequest;

        // Get response  
        using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
        {

            // Get the response stream  
            StreamReader reader = new StreamReader(response.GetResponseStream());

            // Console application output  
            Console.WriteLine(ra + " : " + reader.ReadToEnd());

        }

    }

    Console.ReadLine();
 }

Could you suggest how can I execute 100 requests using this loop, then pause for 2 seconds, then continue from loop 101 to 200, then pause, 201 to 300 etc.

Answer 1

Add an Counter into your method, something like this:

static void apiReq()
{
    string filePath = "Path To File\\a.txt";
    var fileLines = System.IO.File.ReadAllLines(filePath);          
    int requestCounter = 0; // Adding a counter
    foreach(string s in fileLines)
    {
         keyList.Add(s);
    }

    for (int ab = 0; ab < keyList.Count; ab++)
    {
        URLreq = Uri1 + keyList[ab];
        reqs.Add(URLreq);

    }

    foreach (string ra in reqs)
    {
        if (requestCounter % 100 == 0) // Every 100th step
        {
            Thread.Sleep(2000); // Wait for 2 seconds
        }

        Uri uri = new Uri(ra);
        // Create the web request  
        HttpWebRequest request = WebRequest.Create(uri) as HttpWebRequest;

        // Get response  
        using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
        {
            // ..
        }

        requestCounter++; // Count upwards
    }
    // ..
}

Answer 2

Thank you @Smartis !

I managed to do it with:

foreach (string ra in reqs)
{
    for (int o = 0; o < reqs.Count; o++)
    {
        requestCounter = reqs.IndexOf(ra);
    }

    Uri uri = new Uri(ra);
    // Create the web request  
    HttpWebRequest request = WebRequest.Create(uri) as HttpWebRequest;

    // Get response  
    using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
    {

        // Get the response stream  
        StreamReader reader = new StreamReader(response.GetResponseStream());

        // Console application output  
        Console.WriteLine(ra + " : " + reader.ReadToEnd());

    }

    if (requestCounter % 100 == 0) // Every 100th step
    {
        System.Threading.Thread.Sleep(2000); // Wait for 2 seconds
    }
}