public bool CanExecute(string userName, string fullCommandText)
{
// TODO: Check the cooldown on the image descriptor
// Match the regular expression pattern against a text string.
var imageCheck = _UrlCheck.Match(fullCommandText);
var instagramCheck = _InstagramCheck.Match(fullCommandText);
if (imageCheck.Captures.Count == 0 && !instagramCheck.Success)
{
return(false);
}
if (imageCheck.Captures.Count != 0)
{
this.ImageUrl = imageCheck.Captures[0].Value;
}
if (instagramCheck.Captures.Count != 0)
{
this.Provider = ImageProviders.Instagram;
this.ImageUrl = HandleInstagram(instagramCheck).GetAwaiter().GetResult();
return(!string.IsNullOrEmpty(this.ImageUrl));
}
return((!ImageUrl.Contains('#') && imageCheck.Captures.Count > 0) && ValidImageType(ImageUrl).GetAwaiter().GetResult());
async Task <bool> ValidImageType(string url)
{
HttpResponseMessage response;
using (var client = _ClientFactory.CreateClient("ImageDescriptor"))
{
try
{
var request = new HttpRequestMessage
{
Method = HttpMethod.Head,
RequestUri = new Uri(url)
};
response = await client.SendAsync(request, cancellationToken : CancellationToken.None);
response.EnsureSuccessStatusCode();
}
catch
{
return(false);
}
return(response.Content.Headers.ContentType.MediaType.ToLowerInvariant().StartsWith("image/"));
}
}
}
public static IImageProvider GetImageProvider(ImageProviders provider)
{
switch (provider)
{
case ImageProviders.FileSystem:
return(new FSImageProvider());
case ImageProviders.Azure:
return(new AzureImageProvider);
default:
throw new Exception("Invalid image provider");
}
}
public static void AddImageProvider <T>(string basePath) where T : ImageProviderBase
{
if (string.IsNullOrEmpty(basePath))
{
throw new ArgumentException("Base path may not be null or empty. Use SetDefaultImageProvider<T> instead.");
}
if (ImageProviders.ContainsKey(basePath))
{
throw new ArgumentException("Base path already exists in collection.");
}
var objectCreator = ObjectCreation.GetCreator <T, ImageProviderBase>();
ImageProviders.Add(basePath, objectCreator);
}
