openapi: add custom context path for redoc/swagger ui

- fix #3574

Author: jknack

jooby/src/main/java/io/jooby/OpenAPIModule.java

@@ -122,6 +122,7 @@ public static Format from(@NonNull String filePath) {
   private String redocPath = "/redoc";
   private EnumSet<Format> format = EnumSet.of(Format.JSON, Format.YAML);
   private final Set<String> customFiles = new LinkedHashSet<>();
+  private String contextPath;
 
   /**
    * Creates an OpenAPI module. The path is used to route the open API files. For example:
@@ -153,11 +154,23 @@ public OpenAPIModule() {
    * @param path Path.
    * @return This module.
    */
-  public @NonNull OpenAPIModule file(String path) {
+  public @NonNull OpenAPIModule file(@NonNull String path) {
     customFiles.add(path);
     return this;
   }
 
+  /**
+   * Set/override context path of OpenAPI resource. Helps when it runs behind a proxy on a different
+   * context path or path prefix.
+   *
+   * @param contextPath Context path/Path prefix.
+   * @return This module.
+   */
+  public @NonNull OpenAPIModule setContextPath(@NonNull String contextPath) {
+    this.contextPath = contextPath;
+    return this;
+  }
+
   /**
    * Customize the swagger-ui path. Defaults is <code>/swagger</code>.
    *
@@ -251,8 +264,7 @@ private void configureUI(Jooby application) {
 
   private void redoc(Jooby application, AssetSource source) throws Exception {
 
-    String openAPIJSON =
-        fullPath(fullPath(application.getContextPath(), openAPIPath), "/openapi.json");
+    String openAPIJSON = fullPath(fullPath(contextPath(application), openAPIPath), "/openapi.json");
 
     AssetSource customSource =
         new OpenAPISource()
@@ -265,14 +277,13 @@ private void redoc(Jooby application, AssetSource source) throws Exception {
                     "${openAPIPath}",
                     openAPIJSON,
                     "${redocPath}",
-                    fullPath(application.getContextPath(), redocPath)));
+                    fullPath(contextPath(application), redocPath)));
 
     application.assets(redocPath + "/?*", customSource, source);
   }
 
   private void swaggerUI(Jooby application, AssetSource source) throws Exception {
-    String openAPIJSON =
-        fullPath(fullPath(application.getContextPath(), openAPIPath), "/openapi.json");
+    String openAPIJSON = fullPath(fullPath(contextPath(application), openAPIPath), "/openapi.json");
 
     AssetSource customSource =
         new OpenAPISource()
@@ -283,7 +294,7 @@ private void swaggerUI(Jooby application, AssetSource source) throws Exception {
                     MediaType.html,
                     "index.html",
                     "${swaggerPath}",
-                    fullPath(application.getContextPath(), swaggerUIPath)))
+                    fullPath(contextPath(application), swaggerUIPath)))
             .put(
                 "swagger-initializer.js",
                 processAsset(
@@ -311,4 +322,8 @@ private static Asset processAsset(
   private static String fullPath(String contextPath, String path) {
     return Router.noTrailingSlash(Router.normalizePath(contextPath + path));
   }
+
+  private String contextPath(Jooby application) {
+    return contextPath == null ? application.getContextPath() : contextPath;
+  }
 }

modules/jooby-redoc/src/test/java/io/jooby/redoc/RedocResourceTest.java

@@ -5,6 +5,7 @@
  */
 package io.jooby.redoc;
 
+import static java.util.Objects.requireNonNull;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -29,6 +30,7 @@ public void shouldCheckBundle() throws IOException {
   }
 
   private String asset(String resource) throws IOException {
-    return IOUtils.toString(getClass().getResource("/redoc/" + resource), StandardCharsets.UTF_8);
+    return IOUtils.toString(
+        requireNonNull(getClass().getResource("/redoc/" + resource)), StandardCharsets.UTF_8);
   }
 }

modules/jooby-swagger-ui/src/test/java/io.jooby.swagger/SwaggerResourceTest.java

@@ -9,6 +9,7 @@
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.util.Objects;
 
 import org.apache.commons.io.IOUtils;
 import org.junit.jupiter.api.Test;
@@ -30,6 +31,7 @@ public void shouldCheckSwaggerInitializer() throws IOException {
 
   private String asset(String resource) throws IOException {
     return IOUtils.toString(
-        getClass().getResource("/swagger-ui/" + resource), StandardCharsets.UTF_8);
+        Objects.requireNonNull(getClass().getResource("/swagger-ui/" + resource)),
+        StandardCharsets.UTF_8);
   }
 }