Add htmx content cache feature

htmx-api/src/main/java/io/avaje/htmx/api/ContentCache.java

@@ -0,0 +1,16 @@
+package io.avaje.htmx.api;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+/**
+ * Mark a controller method as using a content cache.
+ */
+@Target(METHOD)
+@Retention(RUNTIME)
+public @interface ContentCache {
+
+}

htmx-nima-jstache/src/main/java/io/avaje/htmx/nima/jstache/DefaultTemplateProvider.java

@@ -1,5 +1,6 @@
 package io.avaje.htmx.nima.jstache;
 
+import io.avaje.htmx.nima.TemplateContentCache;
 import io.avaje.htmx.nima.TemplateRender;
 import io.avaje.inject.BeanScopeBuilder;
 import io.avaje.inject.spi.Plugin;
@@ -11,11 +12,12 @@ public final class DefaultTemplateProvider implements Plugin {
 
   @Override
   public Class<?>[] provides() {
-    return new Class<?>[]{TemplateRender.class};
+    return new Class<?>[]{TemplateRender.class, TemplateContentCache.class};
   }
 
   @Override
   public void apply(BeanScopeBuilder builder) {
     builder.provideDefault(null, TemplateRender.class, JStacheTemplateRender::new);
+    builder.provideDefault(null, TemplateContentCache.class, SimpleContentCache::new);
   }
 }

htmx-nima-jstache/src/main/java/io/avaje/htmx/nima/jstache/JStacheTemplateRender.java

@@ -1,15 +1,12 @@
 package io.avaje.htmx.nima.jstache;
 
 import io.avaje.htmx.nima.TemplateRender;
-import io.helidon.webserver.http.ServerRequest;
-import io.helidon.webserver.http.ServerResponse;
 import io.jstach.jstachio.JStachio;
 
 public final class JStacheTemplateRender implements TemplateRender {
 
   @Override
-  public void render(Object viewModel, ServerRequest req, ServerResponse res) {
-    var content = JStachio.render(viewModel);
-    res.send(content);
+  public String render(Object viewModel) {
+    return JStachio.render(viewModel);
   }
 }

htmx-nima-jstache/src/main/java/io/avaje/htmx/nima/jstache/SimpleContentCache.java

@@ -0,0 +1,31 @@
+package io.avaje.htmx.nima.jstache;
+
+import io.avaje.htmx.nima.TemplateContentCache;
+import io.helidon.webserver.http.ServerRequest;
+
+import java.util.concurrent.ConcurrentHashMap;
+
+public class SimpleContentCache implements TemplateContentCache {
+
+  private final ConcurrentHashMap<String,String> localCache = new ConcurrentHashMap<>();
+
+  @Override
+  public String key(ServerRequest req) {
+    return req.requestedUri().path().rawPath();
+  }
+
+  @Override
+  public String key(ServerRequest req, Object formParams) {
+    return req.requestedUri().path().rawPath() + formParams;
+  }
+
+  @Override
+  public String content(String key) {
+    return localCache.get(key);
+  }
+
+  @Override
+  public void contentPut(String key, String content) {
+    localCache.put(key, content);
+  }
+}

htmx-nima/src/main/java/io/avaje/htmx/nima/TemplateContentCache.java

@@ -0,0 +1,30 @@
+package io.avaje.htmx.nima;
+
+import io.helidon.webserver.http.ServerRequest;
+
+/**
+ * Defines caching of template content.
+ */
+public interface TemplateContentCache {
+
+  /**
+   * Return the key given the request.
+   */
+  String key(ServerRequest req);
+
+  /**
+   * Return the key given the request with form parameters.
+   */
+  String key(ServerRequest req, Object formParams);
+
+  /**
+   * Return the content given the key.
+   */
+  String content(String key);
+
+  /**
+   * Put the content into the cache.
+   */
+  void contentPut(String key, String content);
+
+}

htmx-nima/src/main/java/io/avaje/htmx/nima/TemplateRender.java

@@ -1,9 +1,5 @@
 package io.avaje.htmx.nima;
 
-
-import io.helidon.webserver.http.ServerRequest;
-import io.helidon.webserver.http.ServerResponse;
-
 /**
  * Template render API for Helidon.
  */
@@ -12,5 +8,5 @@ public interface TemplateRender {
   /**
    * Render the given template view model to the server response.
    */
-  void render(Object viewModel, ServerRequest req, ServerResponse res);
+  String render(Object viewModel);
 }

http-generator-core/src/main/java/io/avaje/http/generator/core/ControllerReader.java

@@ -49,6 +49,8 @@ public final class ControllerReader {
   private final boolean hasValid;
   /** Set true via {@code @Html} to indicate use of Templating */
   private final boolean html;
+  /** Set true via {@code @ContentCache} to indicate use of Templating content cache */
+  private boolean hasContentCache;
   private boolean methodHasValid;
 
   /**
@@ -200,6 +202,10 @@ public boolean html() {
     return html;
   }
 
+  public boolean hasContentCache() {
+    return hasContentCache;
+  }
+
   public TypeElement beanType() {
     return beanType;
   }
@@ -247,10 +253,11 @@ public void read(boolean withSingleton) {
   }
 
   private void deriveIncludeValidation() {
-    methodHasValid = methodHasValid();
+    methodHasValid = anyMethodHasValid();
+    hasContentCache = anyMethodHasContentCache();
   }
 
-  private boolean methodHasValid() {
+  private boolean anyMethodHasValid() {
     for (final MethodReader method : methods) {
       if (method.hasValid()) {
         return true;
@@ -259,6 +266,15 @@ private boolean methodHasValid() {
     return false;
   }
 
+  private boolean anyMethodHasContentCache() {
+    for (final MethodReader method : methods) {
+      if (method.hasContentCache()) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   private void readField(Element element) {
     if (!requestScope) {
       final String rawType = element.asType().toString();

http-generator-core/src/main/java/io/avaje/http/generator/core/MethodReader.java

@@ -41,6 +41,7 @@ public class MethodReader {
   private final List<? extends TypeMirror> actualParams;
   private final PathSegments pathSegments;
   private final boolean hasValid;
+  private final Optional<ContentCachePrism> contentCache;
   private final List<ExecutableElement> superMethods;
   private final Optional<RequestTimeoutPrism> timeout;
   private final HxRequestPrism hxRequest;
@@ -87,10 +88,12 @@ public class MethodReader {
         });
     if (isWebMethod()) {
       this.hasValid = initValid();
+      this.contentCache = initContentCache();
       this.instrumentContext = initResolver();
       this.pathSegments = PathSegments.parse(Util.combinePath(bean.path(), webMethodPath));
     } else {
       this.hasValid = false;
+      this.contentCache = Optional.empty();
       this.pathSegments = null;
       this.instrumentContext = false;
     }
@@ -124,7 +127,11 @@ private boolean initValid() {
 
   private boolean superMethodHasValid() {
     return superMethods.stream()
-        .anyMatch(e -> findAnnotation(ValidPrism::getOptionalOn).isPresent());
+      .anyMatch(e -> findAnnotation(ValidPrism::getOptionalOn).isPresent());
+  }
+
+  private Optional<ContentCachePrism> initContentCache() {
+    return findAnnotation(ContentCachePrism::getOptionalOn);
   }
 
   @Override
@@ -413,6 +420,10 @@ boolean hasValid() {
     return hasValid;
   }
 
+  public boolean hasContentCache() {
+    return contentCache.isPresent();
+  }
+
   public String simpleName() {
     return element.getSimpleName().toString();
   }

http-generator-core/src/main/java/io/avaje/http/generator/core/openapi/MediaType.java

@@ -4,6 +4,7 @@ public enum MediaType {
   APPLICATION_JSON("application/json"),
   TEXT_PLAIN("text/plain"),
   TEXT_HTML("text/html"),
+  HTML_UTF8("text/html;charset=UTF8"),
   UNKNOWN("");
 
   private final String value;

http-generator-core/src/main/java/io/avaje/http/generator/core/package-info.java

@@ -36,6 +36,7 @@
 @GeneratePrism(value = io.avaje.http.api.RequestTimeout.class, publicAccess = true)
 @GeneratePrism(value = io.avaje.htmx.api.HxRequest.class, publicAccess = true)
 @GeneratePrism(value = io.avaje.htmx.api.Html.class, publicAccess = true)
+@GeneratePrism(value = io.avaje.htmx.api.ContentCache.class, publicAccess = true)
 package io.avaje.http.generator.core;
 
 import io.avaje.prism.GeneratePrism;

http-generator-helidon/src/main/java/io/avaje/http/generator/helidon/nima/ControllerMethodWriter.java

@@ -131,7 +131,7 @@ void writeHandler(boolean requestScoped) {
         writer.append("    res.status(%s);", lookupStatusCode(statusCode)).eol();
       }
     }
-
+    boolean withFormParams = false;
     final var bodyType = method.bodyType();
     if (bodyType != null && !method.isErrorMethod() && !isFilter) {
       if ("InputStream".equals(bodyType)) {
@@ -144,26 +144,41 @@ void writeHandler(boolean requestScoped) {
       } else {
         defaultHelidonBodyContent();
       }
-    } else if (usesFormParams()) {
-      writer.append("    var formParams = req.content().as(Parameters.class);").eol();
+    } else {
+      withFormParams = usesFormParams();
+      if (withFormParams) {
+        writer.append("    var formParams = req.content().as(Parameters.class);").eol();
+      }
+    }
+    final ResponseMode responseMode = responseMode();
+    final boolean withContentCache = responseMode == ResponseMode.Templating && useContentCache();
+    if (withContentCache) {
+      writer.append("    var key = contentCache.key(req");
+      if (withFormParams) {
+        writer.append(", formParams");
+      }
+      writer.append(");").eol();
+      writer.append("    var cacheContent = contentCache.content(key);").eol();
+      writer.append("    if (cacheContent != null) {").eol();
+      writeContextReturn("      ");
+      writer.append("      res.send(cacheContent);").eol();
+      writer.append("      return;").eol();
+      writer.append("    }").eol();
     }
 
     final var segments = method.pathSegments();
     if (segments.fullPath().contains("{")) {
       writer.append("    var pathParams = req.path().pathParameters();").eol();
     }
-
     for (final PathSegments.Segment matrixSegment : segments.matrixSegments()) {
       matrixSegment.writeCreateSegment(writer, platform());
     }
-
     final var params = method.params();
     for (final MethodParam param : params) {
       if (!isExceptionOrFilterChain(param)) {
         param.writeCtxGet(writer, segments);
       }
     }
-
     if (method.includeValidate()) {
       for (final MethodParam param : params) {
         param.writeValidate(writer);
@@ -205,7 +220,7 @@ void writeHandler(boolean requestScoped) {
     }
     writer.append(");").eol();
 
-    if (!method.isVoid() && !isFilter) {
+    if (responseMode != ResponseMode.Void) {
       TypeMirror typeMirror = method.returnType();
       boolean includeNoContent = !typeMirror.getKind().isPrimitive();
       if (includeNoContent) {
@@ -214,21 +229,29 @@ void writeHandler(boolean requestScoped) {
         writer.append("    } else {").eol();
       }
       String indent = includeNoContent ? "      " : "    ";
-      writeContextReturn(indent);
-      if (isInputStream(method.returnType())) {
-        final var uType = UType.parse(method.returnType());
-        writer.append(indent).append("result.transferTo(res.outputStream());", uType.shortName()).eol();
-      } else if (producesJson()) {
-        if (returnTypeString()) {
-          writer.append(indent).append("res.send(result); // send raw JSON").eol();
-        } else {
-          final var uType = UType.parse(method.returnType());
-          writer.append(indent).append("%sJsonType.toJson(result, JsonOutput.of(res));", uType.shortName()).eol();
+      if (responseMode == ResponseMode.Templating) {
+        writer.append(indent).append("var content = renderer.render(result);").eol();
+        if (withContentCache) {
+          writer.append(indent).append("contentCache.contentPut(key, content);").eol();
         }
-      } else if (useTemplating()) {
-        writer.append(indent).append("renderer.render(result, req, res);").eol();
+        writeContextReturn(indent);
+        writer.append(indent).append("res.send(content);").eol();
+
       } else {
-        writer.append(indent).append("res.send(result);").eol();
+        writeContextReturn(indent);
+        if (responseMode == ResponseMode.InputStream) {
+          final var uType = UType.parse(method.returnType());
+          writer.append(indent).append("result.transferTo(res.outputStream());", uType.shortName()).eol();
+        } else if (responseMode == ResponseMode.Json) {
+          if (returnTypeString()) {
+            writer.append(indent).append("res.send(result); // send raw JSON").eol();
+          } else {
+            final var uType = UType.parse(method.returnType());
+            writer.append(indent).append("%sJsonType.toJson(result, JsonOutput.of(res));", uType.shortName()).eol();
+          }
+        } else {
+          writer.append(indent).append("res.send(result);").eol();
+        }
       }
       if (includeNoContent) {
         writer.append("    }").eol();
@@ -237,6 +260,34 @@ void writeHandler(boolean requestScoped) {
     writer.append("  }").eol().eol();
   }
 
+  enum ResponseMode {
+    Void,
+    Json,
+    Templating,
+    InputStream,
+    Other
+  }
+
+  ResponseMode responseMode() {
+    if (method.isVoid() || isFilter) {
+      return ResponseMode.Void;
+    }
+    if (isInputStream(method.returnType())) {
+      return ResponseMode.InputStream;
+    }
+    if (producesJson()) {
+      return ResponseMode.Json;
+    }
+    if (useTemplating()) {
+      return ResponseMode.Templating;
+    }
+    return ResponseMode.Other;
+  }
+
+  private boolean useContentCache() {
+    return method.hasContentCache();
+  }
+
   private boolean useTemplating() {
     return reader.html()
       && !"byte[]".equals(method.returnType().toString())
@@ -308,6 +359,7 @@ private void writeContextReturn(String indent) {
     final var contentTypeString = "res.headers().contentType(MediaTypes.";
     writer.append(indent);
     switch (produces) {
+      case HTML_UTF8 -> writer.append("res.headers().contentType(HTML_UTF8);").eol();
       case APPLICATION_JSON -> writer.append(contentTypeString).append("APPLICATION_JSON);").eol();
       case TEXT_HTML -> writer.append(contentTypeString).append("TEXT_HTML);").eol();
       case TEXT_PLAIN -> writer.append(contentTypeString).append("TEXT_PLAIN);").eol();