Accept more symbol download URL patterns (#666)

Support symbol requests with the following URL patterns:
 
1. {key}ffffffff
2. {key}1
3. {key}

Addresses #224

Co-authored-by: ahehl <78979516+ahehl@users.noreply.github.com>

src/BaGet.Core/Storage/SymbolStorageService.cs

@@ -63,6 +63,12 @@ private string GetPathForKey(string filename, string key)
                 throw new ArgumentException(nameof(key));
             }
 
+            // The key's first 32 characters are the GUID, the remaining characters are the age.
+            // See: https://github.com/dotnet/symstore/blob/98717c63ec8342acf8a07aa5c909b88bd0c664cc/docs/specs/SSQP_Key_Conventions.md#portable-pdb-signature
+            // Debuggers should always use the age "ffffffff", however Visual Studio 2019
+            // users have reported other age values. We will ignore the age.
+            key = key.Substring(0, 32) + "ffffffff";
+
             return Path.Combine(
                 SymbolsPathPrefix,
                 filename.ToLowerInvariant(),

tests/BaGet.Tests/ApiIntegrationTests.cs

@@ -374,14 +374,16 @@ public async Task SymbolDownloadReturnsOk()
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
         }
 
-        [Fact]
-        public async Task PrefixedSymbolDownloadReturnsOk()
+        [Theory]
+        [InlineData("api/download/symbols/testdata.pdb/16F71ED8DD574AA2AD4A22D29E9C981B1/testdata.pdb")]
+        [InlineData("api/download/symbols/testdata.pdb/16F71ED8DD574AA2AD4A22D29E9C981B/testdata.pdb")]
+        [InlineData("api/download/symbols/testprefix/testdata.pdb/16F71ED8DD574AA2AD4A22D29E9C981Bffffffff/testdata.pdb")]
+        public async Task MalformedSymbolDownloadReturnsOk(string uri)
         {
             await _factory.AddPackageAsync(_packageStream);
             await _factory.AddSymbolPackageAsync(_symbolPackageStream);
 
-            using var response = await _client.GetAsync(
-                "api/download/symbols/testprefix/testdata.pdb/16F71ED8DD574AA2AD4A22D29E9C981Bffffffff/testdata.pdb");
+            using var response = await _client.GetAsync(uri);
 
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
         }