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Fixes communicating retry-after in RateLimitingPlugin #497

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Merged
merged 1 commit into from
Jan 17, 2024
Merged

Fixes communicating retry-after in RateLimitingPlugin #497

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25 changes: 16 additions & 9 deletions dev-proxy-plugins/Behavior/RateLimitingPlugin.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@

using Microsoft.Extensions.Configuration;
using Microsoft.DevProxy.Abstractions;
using Microsoft.DevProxy.Plugins.MockResponses;
using System.Net;
using System.Text.Json;
using System.Text.RegularExpressions;
Expand Down Expand Up @@ -35,7 +34,6 @@ public class RateLimitConfiguration
public int ResetTimeWindowSeconds { get; set; } = 60;
public int WarningThresholdPercent { get; set; } = 80;
public int RateLimit { get; set; } = 120;
public int RetryAfterSeconds { get; set; } = 5;
public RateLimitResponseWhenLimitExceeded WhenLimitExceeded { get; set; } = RateLimitResponseWhenLimitExceeded.Throttle;
public string CustomResponseFile { get; set; } = "rate-limit-response.json";
public MockResponseResponse? CustomResponse { get; set; }
Expand All @@ -54,7 +52,7 @@ public class RateLimitingPlugin : BaseProxyPlugin
private ThrottlingInfo ShouldThrottle(Request request, string throttlingKey)
{
var throttleKeyForRequest = BuildThrottleKey(request);
return new ThrottlingInfo(throttleKeyForRequest == throttlingKey ? _configuration.RetryAfterSeconds : 0, _configuration.HeaderRetryAfter);
return new ThrottlingInfo(throttleKeyForRequest == throttlingKey ? (int)(_resetTime - DateTime.Now).TotalSeconds : 0, _configuration.HeaderRetryAfter);
}

private void ThrottleResponse(ProxyRequestArgs e) => UpdateProxyResponse(e, HttpStatusCode.TooManyRequests);
Expand Down Expand Up @@ -89,7 +87,7 @@ private void UpdateProxyResponse(ProxyHttpEventArgsBase e, HttpStatusCode errorS
);
}

headers.Add(new(_configuration.HeaderRetryAfter, _configuration.RetryAfterSeconds.ToString()));
headers.Add(new(_configuration.HeaderRetryAfter, ((int)(_resetTime - DateTime.Now).TotalSeconds).ToString()));

e.Session.GenericResponse(body ?? string.Empty, errorStatus, headers.Select(h => new HttpHeader(h.Name, h.Value)).ToArray());
return;
Expand Down Expand Up @@ -193,7 +191,7 @@ _urlsToWatch is null ||
e.ThrottledRequests.Add(new ThrottlerInfo(
BuildThrottleKey(request),
ShouldThrottle,
DateTime.Now.AddSeconds(_configuration.RetryAfterSeconds)
_resetTime
));
ThrottleResponse(e);
state.HasBeenSet = true;
Expand All @@ -202,9 +200,18 @@ _urlsToWatch is null ||
{
if (_configuration.CustomResponse is not null)
{
var headers = _configuration.CustomResponse.Headers is not null ?
_configuration.CustomResponse.Headers.Select(h => new HttpHeader(h.Name, h.Value)).ToArray() :
Array.Empty<HttpHeader>();
var headersList = _configuration.CustomResponse.Headers is not null ?
_configuration.CustomResponse.Headers.Select(h => new HttpHeader(h.Name, h.Value)).ToList() :
new List<HttpHeader>();

var retryAfterHeader = headersList.FirstOrDefault(h => h.Name.Equals(_configuration.HeaderRetryAfter, StringComparison.OrdinalIgnoreCase));
if (retryAfterHeader is not null && retryAfterHeader.Value == "@dynamic")
{
headersList.Add(new HttpHeader(_configuration.HeaderRetryAfter, ((int)(_resetTime - DateTime.Now).TotalSeconds).ToString()));
headersList.Remove(retryAfterHeader);
}

var headers = headersList.ToArray();

// allow custom throttling response
var responseCode = (HttpStatusCode)(_configuration.CustomResponse.StatusCode ?? 200);
Expand All @@ -213,7 +220,7 @@ _urlsToWatch is null ||
e.ThrottledRequests.Add(new ThrottlerInfo(
BuildThrottleKey(request),
ShouldThrottle,
DateTime.Now.AddSeconds(_configuration.RetryAfterSeconds)
_resetTime
));
}

Expand Down