Add request compression information

Author: JordonPhillips

smithy-docgen-core/src/main/java/software/amazon/smithy/docgen/core/integrations/BuiltinsIntegration.java

@@ -23,6 +23,7 @@
 import software.amazon.smithy.docgen.core.interceptors.PatternInterceptor;
 import software.amazon.smithy.docgen.core.interceptors.RangeInterceptor;
 import software.amazon.smithy.docgen.core.interceptors.RecommendedInterceptor;
+import software.amazon.smithy.docgen.core.interceptors.RequestCompressionInterceptor;
 import software.amazon.smithy.docgen.core.interceptors.SensitiveInterceptor;
 import software.amazon.smithy.docgen.core.interceptors.SinceInterceptor;
 import software.amazon.smithy.docgen.core.interceptors.SparseInterceptor;
@@ -69,6 +70,7 @@ public List<? extends CodeInterceptor<? extends CodeSection, DocWriter>> interce
         // the ones at the end will be at the top of the rendered pages. Therefore, interceptors
         // that provide more critical information should appear at the bottom of this list.
         return List.of(
+                new RequestCompressionInterceptor(),
                 new NoReplaceBindingInterceptor(),
                 new NoReplaceOperationInterceptor(),
                 new SparseInterceptor(),

smithy-docgen-core/src/main/java/software/amazon/smithy/docgen/core/interceptors/RequestCompressionInterceptor.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package software.amazon.smithy.docgen.core.interceptors;
+
+import java.util.Optional;
+import software.amazon.smithy.docgen.core.sections.ShapeDetailsSection;
+import software.amazon.smithy.docgen.core.writers.DocWriter;
+import software.amazon.smithy.docgen.core.writers.DocWriter.AdmonitionType;
+import software.amazon.smithy.model.traits.RequestCompressionTrait;
+import software.amazon.smithy.utils.CodeInterceptor;
+import software.amazon.smithy.utils.SmithyInternalApi;
+
+/**
+ * Adds information about request compression to operations with the
+ * <a href="https://smithy.io/2.0/spec/behavior-traits.html#requestcompression-trait">
+ * requestCompression trait</a>.
+ */
+@SmithyInternalApi
+public final class RequestCompressionInterceptor implements CodeInterceptor<ShapeDetailsSection, DocWriter> {
+    @Override
+    public Class<ShapeDetailsSection> sectionType() {
+        return ShapeDetailsSection.class;
+    }
+
+    @Override
+    public boolean isIntercepted(ShapeDetailsSection section) {
+        return section.shape().hasTrait(RequestCompressionTrait.class);
+    }
+
+    @Override
+    public void write(DocWriter writer, String previousText, ShapeDetailsSection section) {
+        var trait = section.shape().expectTrait(RequestCompressionTrait.class);
+        writer.openAdmonition(AdmonitionType.IMPORTANT);
+
+        // Have particular support for single-element lists.
+        writer.putContext("encoding", trait.getEncodings().size() == 1
+                ? Optional.of(trait.getEncodings().get(0))
+                : Optional.empty());
+        writer.putContext("encodings", trait.getEncodings());
+
+        writer.write("""
+                This operation supports optional request compression using \
+                ${?encoding}${encoding:L} encoding.${/encoding}\
+                ${^encoding}one of the following priority-ordered encodings: \
+                ${#encodings}${value:L}${^key.last}, ${/key.last}${/encodings}.${/encoding}""");
+        writer.closeAdmonition();
+        writer.writeWithNoFormatting(previousText);
+    }
+}

smithy-docgen-test/model/main.smithy

@@ -45,6 +45,9 @@ service DocumentedService {
         }
     ]
 )
+@requestCompression(
+    encodings: ["gzip"]
+)
 operation DocumentedOperation {
     input := {
         /// This is an idempotency token, which will inherently mark this operation