Made Url Unshortening more robust

This commit is contained in:
XorogVEVO 2022-02-27 08:26:20 +01:00
parent 7902913880
commit 376253996e
2 changed files with 49 additions and 6 deletions

View file

@ -26,3 +26,6 @@ dotnet_diagnostic.IDE0047.severity = none
# DV2001: No Dependency Diagram linked # DV2001: No Dependency Diagram linked
dotnet_diagnostic.DV2001.severity = none dotnet_diagnostic.DV2001.severity = none
# CS8602: Dereference of a possibly null reference.
dotnet_diagnostic.CS8602.severity = silent

View file

@ -104,20 +104,60 @@ public static class UniversalExtensions
/// </summary> /// </summary>
/// <param name="url">The shortened URL</param> /// <param name="url">The shortened URL</param>
/// <returns>The URL the redirect leads to</returns> /// <returns>The URL the redirect leads to</returns>
public static async Task<string> UnshortenUrl(string url) public static async Task<string> UnshortenUrl(string url, bool UseHeadMethod = true)
{ {
HttpClient client = new(new HttpClientHandler() { AllowAutoRedirect = false }); HttpClient client = new(new HttpClientHandler()
var request = await client.GetAsync(url); {
AllowAutoRedirect = false,
AutomaticDecompression = DecompressionMethods.GZip,
});
client.Timeout = TimeSpan.FromSeconds(10);
client.DefaultRequestHeaders.UserAgent.ParseAdd("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.82 Safari/537.36");
client.DefaultRequestHeaders.Add("upgrade-insecure-requests", "1");
client.DefaultRequestHeaders.Add("accept-encoding", "gzip, deflate, br");
client.DefaultRequestHeaders.Add("accept-language", "en-US,en;q=0.9");
client.MaxResponseContentBufferSize = 4096;
if (request.StatusCode is HttpStatusCode.Found HttpRequestMessage requestMessage = new HttpRequestMessage((UseHeadMethod ? HttpMethod.Head : HttpMethod.Get), url);
CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
var request_task = client.SendAsync(requestMessage, cancellationTokenSource.Token);
try
{
await request_task.WaitAsync(TimeSpan.FromSeconds(3));
}
catch (Exception)
{
if (UseHeadMethod)
return await UnshortenUrl(url, false);
throw;
}
if (!request_task.IsCompleted)
cancellationTokenSource.Cancel();
if (UseHeadMethod && request_task.IsFaulted && request_task.Exception.InnerException.GetType().FullName == "System.Net.Http.HttpRequestException")
return await UnshortenUrl(url, false);
var statuscode = request_task.Result.StatusCode;
var header = request_task.Result.Headers;
if (UseHeadMethod && statuscode is HttpStatusCode.NotFound or HttpStatusCode.InternalServerError)
return await UnshortenUrl(url, false);
if (statuscode is HttpStatusCode.Found
or HttpStatusCode.Redirect or HttpStatusCode.Redirect
or HttpStatusCode.SeeOther
or HttpStatusCode.RedirectKeepVerb or HttpStatusCode.RedirectKeepVerb
or HttpStatusCode.RedirectMethod or HttpStatusCode.RedirectMethod
or HttpStatusCode.PermanentRedirect or HttpStatusCode.PermanentRedirect
or HttpStatusCode.TemporaryRedirect) or HttpStatusCode.TemporaryRedirect)
{ {
if (request.Headers is not null && request.Headers.Location is not null) if (header is not null && header.Location is not null)
return await UnshortenUrl(request.Headers.Location.AbsoluteUri); return await UnshortenUrl(header.Location.AbsoluteUri);
else else
return url; return url;
} }