feign.jaxrs.JAXRSContract Maven / Gradle / Ivy

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/*
 * Copyright © 2012 The Feign Authors ([email protected])
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package feign.jaxrs;

import static feign.Util.checkState;
import static feign.Util.emptyToNull;
import static feign.Util.removeValues;

import feign.DeclarativeContract;
import feign.MethodMetadata;
import feign.Request;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.Collections;
import javax.ws.rs.*;

/**
 * Please refer to the Feign
 * JAX-RS README.
 */
public class JAXRSContract extends DeclarativeContract {

  static final String ACCEPT = "Accept";
  static final String CONTENT_TYPE = "Content-Type";

  // Protected so unittest can call us
  // XXX: Should parseAndValidateMetadata(Class, Method) be public instead? The old deprecated
  // parseAndValidateMetadata(Method) was public..
  @Override
  protected MethodMetadata parseAndValidateMetadata(Class targetType, Method method) {
    return super.parseAndValidateMetadata(targetType, method);
  }

  public JAXRSContract() {
    super.registerClassAnnotation(
        Path.class,
        (path, data) -> {
          if (path != null && !path.value().isEmpty()) {
            String pathValue = path.value();
            if (!pathValue.startsWith("/")) {
              pathValue = "/" + pathValue;
            }
            if (pathValue.endsWith("/")) {
              // Strip off any trailing slashes, since the template has already had slashes
              // appropriately
              // added
              pathValue = pathValue.substring(0, pathValue.length() - 1);
            }
            // jax-rs allows whitespace around the param name, as well as an optional regex. The
            // contract
            // should
            // strip these out appropriately.
            pathValue = pathValue.replaceAll("\\{\\s*(.+?)\\s*(:.+?)?\\}", "\\{$1\\}");
            data.template().uri(pathValue);
          }
        });
    super.registerClassAnnotation(Consumes.class, this::handleConsumesAnnotation);
    super.registerClassAnnotation(Produces.class, this::handleProducesAnnotation);

    registerMethodAnnotation(
        methodAnnotation -> {
          final Class annotationType = methodAnnotation.annotationType();
          final HttpMethod http = annotationType.getAnnotation(HttpMethod.class);
          return http != null;
        },
        (methodAnnotation, data) -> {
          final Class annotationType = methodAnnotation.annotationType();
          final HttpMethod http = annotationType.getAnnotation(HttpMethod.class);
          checkState(
              data.template().method() == null,
              "Method %s contains multiple HTTP methods. Found: %s and %s",
              data.configKey(),
              data.template().method(),
              http.value());
          data.template().method(Request.HttpMethod.valueOf(http.value()));
        });

    super.registerMethodAnnotation(
        Path.class,
        (path, data) -> {
          final String pathValue = emptyToNull(path.value());
          if (pathValue == null) {
            return;
          }
          String methodAnnotationValue = path.value();
          if (!methodAnnotationValue.startsWith("/") && !data.template().url().endsWith("/")) {
            methodAnnotationValue = "/" + methodAnnotationValue;
          }
          // jax-rs allows whitespace around the param name, as well as an optional regex. The
          // contract
          // should
          // strip these out appropriately.
          methodAnnotationValue =
              methodAnnotationValue.replaceAll("\\{\\s*(.+?)\\s*(:.+?)?\\}", "\\{$1\\}");
          data.template().uri(methodAnnotationValue, true);
        });
    super.registerMethodAnnotation(Consumes.class, this::handleConsumesAnnotation);
    super.registerMethodAnnotation(Produces.class, this::handleProducesAnnotation);

    // trying to minimize the diff
    registerParamAnnotations();
  }

  private void handleProducesAnnotation(Produces produces, MethodMetadata data) {
    final String[] serverProduces =
        removeValues(produces.value(), mediaType -> emptyToNull(mediaType) == null, String.class);
    checkState(serverProduces.length > 0, "Produces.value() was empty on %s", data.configKey());
    data.template().header(ACCEPT, Collections.emptyList()); // remove any previous produces
    data.template().header(ACCEPT, serverProduces);
  }

  private void handleConsumesAnnotation(Consumes consumes, MethodMetadata data) {
    final String[] serverConsumes =
        removeValues(consumes.value(), mediaType -> emptyToNull(mediaType) == null, String.class);
    checkState(serverConsumes.length > 0, "Consumes.value() was empty on %s", data.configKey());
    data.template().header(CONTENT_TYPE, serverConsumes);
  }

  protected void registerParamAnnotations() {
    {
      registerParameterAnnotation(
          PathParam.class,
          (param, data, paramIndex) -> {
            final String name = param.value();
            checkState(
                emptyToNull(name) != null,
                "PathParam.value() was empty on parameter %s",
                paramIndex);
            nameParam(data, name, paramIndex);
          });
      registerParameterAnnotation(
          QueryParam.class,
          (param, data, paramIndex) -> {
            final String name = param.value();
            checkState(
                emptyToNull(name) != null,
                "QueryParam.value() was empty on parameter %s",
                paramIndex);
            final String query = addTemplatedParam(name);
            data.template().query(name, query);
            nameParam(data, name, paramIndex);
          });
      registerParameterAnnotation(
          HeaderParam.class,
          (param, data, paramIndex) -> {
            final String name = param.value();
            checkState(
                emptyToNull(name) != null,
                "HeaderParam.value() was empty on parameter %s",
                paramIndex);
            final String header = addTemplatedParam(name);
            data.template().header(name, header);
            nameParam(data, name, paramIndex);
          });
      registerParameterAnnotation(
          FormParam.class,
          (param, data, paramIndex) -> {
            final String name = param.value();
            checkState(
                emptyToNull(name) != null,
                "FormParam.value() was empty on parameter %s",
                paramIndex);
            data.formParams().add(name);
            nameParam(data, name, paramIndex);
          });
    }
  }

  // Not using override as the super-type's method is deprecated and will be removed.
  // Protected so JAXRS2Contract can make use of this
  protected String addTemplatedParam(String name) {
    return String.format("{%s}", name);
  }
}