brooklyn-server/utils/rest-swagger/src/main/java/org/apache/brooklyn/rest/apidoc/ApiListingResource.java

/*
 * Copyright 2015 The Apache Software Foundation.
 *
 * 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 org.apache.brooklyn.rest.apidoc;

import com.sun.jersey.spi.container.servlet.WebConfig;
import io.swagger.annotations.ApiOperation;
import io.swagger.config.FilterFactory;
import io.swagger.config.Scanner;
import io.swagger.config.ScannerFactory;
import io.swagger.config.SwaggerConfig;
import io.swagger.core.filter.SpecFilter;
import io.swagger.core.filter.SwaggerSpecFilter;
import io.swagger.jaxrs.Reader;
import io.swagger.jaxrs.config.JaxrsScanner;
import io.swagger.jaxrs.config.ReaderConfigUtils;
import io.swagger.jaxrs.listing.SwaggerSerializers;
import io.swagger.models.Swagger;
import io.swagger.util.Yaml;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Application;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.Cookie;
import javax.ws.rs.core.HttpHeaders;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.UriInfo;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * ApiListingResource usable within a jersey servlet filter.
 *
 * Taken from io.swagger:swagger-jaxrs, class
 * io.swagger.jaxrs.listing.ApiListingResource, which can only be used within a
 * servlet context. We are here using a filter, but jersey has a WebConfig class
 * that can substitute ServletConfig and FilterConfig.
 *
 * @todo Remove when the rest-server is no longer running within a filter (e.g.
 * as a standalone OSGi http service)
 *
 * @author Ciprian Ciubotariu <cheepeero@gmx.net>
 */
public class ApiListingResource {

    static Logger LOGGER = LoggerFactory.getLogger(ApiListingResource.class);

    @Context
    ServletContext context;

    boolean initialized = false;

    private static class ServletConfigAdapter implements ServletConfig {

        private final WebConfig webConfig;

        private ServletConfigAdapter(WebConfig webConfig) {
            this.webConfig = webConfig;
        }

        @Override
        public String getServletName() {
            return webConfig.getName();
        }

        @Override
        public ServletContext getServletContext() {
            return webConfig.getServletContext();
        }

        @Override
        public String getInitParameter(String name) {
            return webConfig.getInitParameter(name);
        }

        @Override
        public Enumeration<String> getInitParameterNames() {
            return webConfig.getInitParameterNames();
        }

    }

    protected synchronized Swagger scan(Application app, WebConfig sc) {
        Swagger swagger = null;
        Scanner scanner = ScannerFactory.getScanner();
        LOGGER.debug("using scanner " + scanner);

        if (scanner != null) {
            SwaggerSerializers.setPrettyPrint(scanner.getPrettyPrint());
            swagger = (Swagger) context.getAttribute("swagger");

            Set<Class<?>> classes;
            if (scanner instanceof JaxrsScanner) {
                JaxrsScanner jaxrsScanner = (JaxrsScanner) scanner;
                classes = jaxrsScanner.classesFromContext(app, new ServletConfigAdapter(sc));
            } else {
                classes = scanner.classes();
            }
            if (classes != null) {
                Reader reader = new Reader(swagger, ReaderConfigUtils.getReaderConfig(context));
                swagger = reader.read(classes);
                if (scanner instanceof SwaggerConfig) {
                    swagger = ((SwaggerConfig) scanner).configure(swagger);
                } else {
                    SwaggerConfig configurator = (SwaggerConfig) context.getAttribute("reader");
                    if (configurator != null) {
                        LOGGER.debug("configuring swagger with " + configurator);
                        configurator.configure(swagger);
                    } else {
                        LOGGER.debug("no configurator");
                    }
                }
                context.setAttribute("swagger", swagger);
            }
        }
        initialized = true;
        return swagger;
    }

    private Swagger process(
            Application app,
            WebConfig sc,
            HttpHeaders headers,
            UriInfo uriInfo) {
        Swagger swagger = (Swagger) context.getAttribute("swagger");
        if (!initialized) {
            swagger = scan(app, sc);
        }
        if (swagger != null) {
            SwaggerSpecFilter filterImpl = FilterFactory.getFilter();
            if (filterImpl != null) {
                SpecFilter f = new SpecFilter();
                swagger = f.filter(swagger, filterImpl, getQueryParams(uriInfo.getQueryParameters()), getCookies(headers),
                        getHeaders(headers));
            }
        }
        return swagger;
    }

    @GET
    @Produces({MediaType.APPLICATION_JSON, "application/yaml"})
    @ApiOperation(value = "The swagger definition in either JSON or YAML", hidden = true)
    @Path("/swagger.{type:json|yaml}")
    public Response getListing(
            @Context Application app,
            @Context WebConfig sc,
            @Context HttpHeaders headers,
            @Context UriInfo uriInfo,
            @PathParam("type") String type) {
        if (StringUtils.isNotBlank(type) && type.trim().equalsIgnoreCase("yaml")) {
            return getListingYaml(app, sc, headers, uriInfo);
        } else {
            return getListingJson(app, sc, headers, uriInfo);
        }
    }

    @GET
    @Produces({MediaType.APPLICATION_JSON})
    @Path("/swagger")
    @ApiOperation(value = "The swagger definition in JSON", hidden = true)
    public Response getListingJson(
            @Context Application app,
            @Context WebConfig sc,
            @Context HttpHeaders headers,
            @Context UriInfo uriInfo) {
        Swagger swagger = process(app, sc, headers, uriInfo);

        if (swagger != null) {
            return Response.ok().entity(swagger).build();
        } else {
            return Response.status(404).build();
        }
    }

    @GET
    @Produces("application/yaml")
    @Path("/swagger")
    @ApiOperation(value = "The swagger definition in YAML", hidden = true)
    public Response getListingYaml(
            @Context Application app,
            @Context WebConfig sc,
            @Context HttpHeaders headers,
            @Context UriInfo uriInfo) {
        Swagger swagger = process(app, sc, headers, uriInfo);
        try {
            if (swagger != null) {
                String yaml = Yaml.mapper().writeValueAsString(swagger);
                StringBuilder b = new StringBuilder();
                String[] parts = yaml.split("\n");
                for (String part : parts) {
                    b.append(part);
                    b.append("\n");
                }
                return Response.ok().entity(b.toString()).type("application/yaml").build();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return Response.status(404).build();
    }

    protected Map<String, List<String>> getQueryParams(MultivaluedMap<String, String> params) {
        Map<String, List<String>> output = new HashMap<>();
        if (params != null) {
            for (String key : params.keySet()) {
                List<String> values = params.get(key);
                output.put(key, values);
            }
        }
        return output;
    }

    protected Map<String, String> getCookies(HttpHeaders headers) {
        Map<String, String> output = new HashMap<>();
        if (headers != null) {
            for (String key : headers.getCookies().keySet()) {
                Cookie cookie = headers.getCookies().get(key);
                output.put(key, cookie.getValue());
            }
        }
        return output;
    }

    protected Map<String, List<String>> getHeaders(HttpHeaders headers) {
        Map<String, List<String>> output = new HashMap<>();
        if (headers != null) {
            for (String key : headers.getRequestHeaders().keySet()) {
                List<String> values = headers.getRequestHeaders().get(key);
                output.put(key, values);
            }
        }
        return output;
    }

}