/// <summary>
/// Assigns request context to given easy handle.
/// </summary>
public void AssignContext(SafeEasyHandle easy, T context)
{
if (!_busy.TryAdd(easy, context))
{
throw new Exception("Trying to assign request context to handle that already has its context.");
}
}
public HandleCompletedAction OnComplete(SafeEasyHandle easy, MyRequestContext context, CURLcode errorCode)
{
Console.WriteLine($"Request label: {context.Label}.");
if (errorCode != CURLcode.OK)
{
Console.BackgroundColor = ConsoleColor.DarkRed;
Console.ForegroundColor = ConsoleColor.White;
Console.WriteLine($"cURL error code: {errorCode}");
var pErrorMsg = CurlNative.Easy.StrError(errorCode);
var errorMsg = Marshal.PtrToStringAnsi(pErrorMsg);
Console.WriteLine($"cURL error message: {errorMsg}");
Console.ResetColor();
Console.WriteLine("--------");
Console.WriteLine();
context.Dispose();
return(HandleCompletedAction.ResetHandleAndNext);
}
// Get HTTP response code.
CurlNative.Easy.GetInfo(easy, CURLINFO.RESPONSE_CODE, out int httpCode);
if (httpCode != 200)
{
Console.BackgroundColor = ConsoleColor.DarkRed;
Console.ForegroundColor = ConsoleColor.White;
Console.WriteLine($"Invalid HTTP response code: {httpCode}");
Console.ResetColor();
Console.WriteLine("--------");
Console.WriteLine();
context.Dispose();
return(HandleCompletedAction.ResetHandleAndNext);
}
Console.WriteLine($"Response code: {httpCode}");
// Get effective URL.
IntPtr pDoneUrl;
CurlNative.Easy.GetInfo(easy, CURLINFO.EFFECTIVE_URL, out pDoneUrl);
var doneUrl = Marshal.PtrToStringAnsi(pDoneUrl);
Console.WriteLine($"Effective URL: {doneUrl}");
// Get response body as string.
var html = context.ContentData.ReadAsString();
// Scrape question from HTML source.
var match = Regex.Match(html, "<title>(.+?)<\\/");
Console.WriteLine($"Question: {match.Groups[1].Value.Trim()}");
Console.WriteLine("--------");
Console.WriteLine();
context.Dispose();
return(HandleCompletedAction.ResetHandleAndNext);
}
/// <summary>
/// Unassigns request context for given easy handle.
/// </summary>
public void UnassignContext(SafeEasyHandle easy)
{
if (!_busy.TryRemove(easy, out T _))
{
throw new Exception("Given handle doesn't have stored any request context.");
}
}
/// <summary>
/// Retrieves request context for given easy handle.
/// </summary>
public void GetAssignedContext(SafeEasyHandle easy, out T context)
{
if (!_busy.TryGetValue(easy, out context))
{
throw new Exception("Cannot find request context for given easy handle.");
}
}
public bool TryNext(SafeEasyHandle easy, out MyRequestContext context)
{
// If question ID is higher than maximum, return false.
if (_currentQuestion > _maxQuestion)
{
context = null;
return(false);
}
// Create request context. Assign it a label to easily recognize it later.
var contextLocal = new MyRequestContext
{
Label = $"StackOverflow Question #{_currentQuestion}"
};
// Copy response header (it contains HTTP code and response headers, for example
// "Content-Type") to MemoryStream in our RequestContext.
context = contextLocal;
context.HeaderFunction = (data, size, nmemb, userdata) =>
{
var length = (int)size * (int)nmemb;
var buffer = new byte[length];
Marshal.Copy(data, buffer, 0, length);
contextLocal.HeaderStream.Write(buffer, 0, length);
return((UIntPtr)length);
};
// Copy response body (it for example contains HTML source) to MemoryStream
// in our RequestContext.
context.ContentFunction = (data, size, nmemb, userdata) =>
{
var length = (int)size * (int)nmemb;
var buffer = new byte[length];
Marshal.Copy(data, buffer, 0, length);
contextLocal.ContentStream.Write(buffer, 0, length);
return((UIntPtr)length);
};
// Set request URL.
CurlNative.Easy.SetOpt(easy, CURLoption.URL, $"http://stackoverflow.com/questions/{_currentQuestion}/");
// Follow redirects.
CurlNative.Easy.SetOpt(easy, CURLoption.FOLLOWLOCATION, 1);
CurlNative.Easy.SetOpt(easy, CURLoption.HEADERFUNCTION, context.HeaderFunction);
CurlNative.Easy.SetOpt(easy, CURLoption.WRITEFUNCTION, context.ContentFunction);
_currentQuestion++;
return(true);
}
public ValueTask <bool> MoveNextAsync(SafeEasyHandle easy)
{
// If question ID is higher than maximum, return false.
if (_currentQuestion > _maxQuestion)
{
Current = null;
return(new ValueTask <bool>(false));
}
// Create request context. Assign it a label to easily recognize it later.
var context = new MyRequestContext($"StackOverflow Question #{_currentQuestion}");
// Set request URL.
CurlNative.Easy.SetOpt(easy, CURLoption.URL, $"https://stackoverflow.com/questions/{_currentQuestion}/");
// Follow redirects.
CurlNative.Easy.SetOpt(easy, CURLoption.FOLLOWLOCATION, 1);
// Set request timeout.
CurlNative.Easy.SetOpt(easy, CURLoption.TIMEOUT_MS, 3000);
// Copy response header (it contains HTTP code and response headers, for example
// "Content-Type") to MemoryStream in our RequestContext.
CurlNative.Easy.SetOpt(easy, CURLoption.HEADERFUNCTION, context.HeaderData.DataHandler);
// Copy response body (it for example contains HTML source) to MemoryStream
// in our RequestContext.
CurlNative.Easy.SetOpt(easy, CURLoption.WRITEFUNCTION, context.ContentData.DataHandler);
// Point the certificate bundle file path to verify HTTPS certificates.
//CurlNative.Easy.SetOpt(easy, CURLoption.CAINFO, CurlResources.CaBundlePath);
_currentQuestion++;
Current = context;
return(new ValueTask <bool>(true));
}
public static extern CURLcode GetInfo(SafeEasyHandle handle, CURLINFO option, out double value);
public static extern CURLcode SetOpt(SafeEasyHandle handle, CURLoption option, DataHandler value);
public static extern CURLcode SetOpt(SafeEasyHandle handle, CURLoption option, string value);
public static extern void Reset(SafeEasyHandle handle);
public static extern CURLcode Perform(SafeEasyHandle handle);
public static CURLcode SetOpt(SafeEasyHandle handle, CURLoption option, CURLAUTH auth)
{
return(SetOpt(handle, option, (int)auth));
}
/// <summary>
/// Change status of cURL easy handle from busy to free.
/// </summary>
public void Free(SafeEasyHandle easy)
{
_free.Add(easy);
}
/// <summary>
/// Try get unused cURL easy handle.
/// </summary>
/// <returns>TRUE if successful, FALSE if all handles are busy.</returns>
public bool TryTakeFree(out SafeEasyHandle easy)
{
return(_free.TryTake(out easy));
}
public static extern CURLcode GetInfo(SafeEasyHandle handle, CURLINFO option, IntPtr value);
public static extern CURLMcode RemoveHandle(SafeMultiHandle multiHandle, SafeEasyHandle easyHandle);
public EasyHandleContext(SafeEasyHandle easy)
{
Easy = easy;
}