Merge pull request #171 from octokit/milestones-kill-your-rate-limit

ApplyParameters should respect existing querystring parameters

Octokit.Tests/Helpers/UriExtensionsTests.cs

@@ -36,7 +36,7 @@ namespace Octokit.Tests.Helpers
                 Assert.Equal(new Uri("issues?foo=fooval&bar=barval", UriKind.Relative), uriWithParameters);
             }
 
-            [Fact]
+            [Fact(Skip="I don't believe this test is valid")]
             public void OverwritesExistingParameters()
             {
                 var uri = new Uri("https://example.com?crap=crapola");
@@ -62,6 +62,21 @@ namespace Octokit.Tests.Helpers
                 Assert.Equal(uri, uriWithNullParameters);
             }
 
+            [Fact]
+            public void CombinesExistingParametersWithNewParameters()
+            {
+                var uri = new Uri("https://api.github.com/repositories/1/milestones?state=closed&sort=due_date&direction=asc&page=2");
+
+                var parameters = new Dictionary<string, string> { { "state", "open" }, { "sort", "other"} };
+
+                var actual = uri.ApplyParameters(parameters);
+
+                Assert.True(actual.Query.Contains("state=open"));
+                Assert.True(actual.Query.Contains("sort=other"));
+                Assert.True(actual.Query.Contains("direction=asc"));
+                Assert.True(actual.Query.Contains("page=2"));
+            }
+
             [Fact]
             public void EnsuresArgumentNotNull()
             {

Octokit/Helpers/UriExtensions.cs

@@ -12,6 +12,34 @@ namespace Octokit
 
             if (parameters == null || !parameters.Any()) return uri;
 
+            string queryString;
+            if (uri.IsAbsoluteUri)
+            {
+                queryString = uri.Query;
+            }
+            else
+            {
+                var hasQueryString = uri.OriginalString.IndexOf("?", StringComparison.Ordinal);
+                queryString = hasQueryString == -1
+                    ? ""
+                    : uri.OriginalString.Substring(hasQueryString);
+            }
+
+            var values = queryString.Replace("?", "")
+                                    .Split(new[] { '&' }, StringSplitOptions.RemoveEmptyEntries);
+
+            var existingParameters = values.ToDictionary(
+                        key => key.Substring(0, key.IndexOf('=')),
+                        value => value.Substring(value.IndexOf('=') + 1));
+
+            foreach (var existing in existingParameters)
+            {
+                if (!parameters.ContainsKey(existing.Key))
+                {
+                    parameters.Add(existing);
+                }
+            }
+
             string query = String.Join("&", parameters.Select(kvp => kvp.Key + "=" + kvp.Value));
             if (uri.IsAbsoluteUri)
             {