訪問Amazon Mechanical Turk最簡單的例子是什麼？

Question

我正在尋找一個訪問C＃中的Amazon Mechanical Turk web服務的簡單示例。我知道C＃有一個SDK，但我想在使用它之前瞭解基本的機制。

Answer 1

這是我想出來訪問Mechanical Turk的最簡單的代碼示例。它創建簽名並調用GetAccountBalance操作。

using System; 
using System.Globalization; 
using System.IO; 
using System.Net; 
using System.Security.Cryptography; 
using System.Text; 

namespace TurkTest { 
    class Program { 

     static void Main(string[] args) { 
      const string SERVICE_NAME = "AWSMechanicalTurkRequester"; // requester service for MTurk 
      const string TIMESTAMP_FORMAT = "yyyy-MM-ddTHH:mm:ss.fffZ"; 

      // Modify these with your values. 
      const string operation = "GetAccountBalance"; 
      const string accessKey = "<Your access key>"; 
      const string secretAccessKey = "<Your secret access key>"; 

      // Millisecond values in the timestamp string can result in intermittent BadClaimsSupplied errors. 
      // Get the current UTC time and use that to create a new time with milliseconds set to zero to avoid this case. 
      DateTime now = DateTime.UtcNow; 
      now = new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute, now.Second, 0, DateTimeKind.Utc); 
      string timeStamp = now.ToString(TIMESTAMP_FORMAT, CultureInfo.InvariantCulture); 

      // Create the hash-based messaged authentication algorithm (SHA1) using our secret access key as the key. 
      var hmac = new HMACSHA1(Encoding.UTF8.GetBytes(secretAccessKey)); 

      // Combine the service name, operation and timestamp and then hash them to produce the signature. 
      var dataBytes = Encoding.UTF8.GetBytes(SERVICE_NAME + operation + timeStamp); 
      string signature = Convert.ToBase64String(hmac.ComputeHash(dataBytes)); 

      // Build the URL to send to Amazon 
      string url = 
       @"https://mechanicalturk.amazonaws.com/?Service=AWSMechanicalTurkRequester&AWSAccessKeyId={0}&Version=2012-03-25&Operation={1}&Signature={2}&Timestamp={3}"; 
      url = string.Format(url, accessKey, operation, signature, timeStamp); 

      // Send a request and write the response to the console. 
      using (WebClient client = new WebClient()) { 
       using (StreamReader reader = new StreamReader(client.OpenRead(url))) { 
        Console.WriteLine(reader.ReadToEnd()); 
       } 
      } 

      Console.Read(); 
     } 
    } 
}