Handlers

Here is the code for the different API router handlers.

Root resource

  1. private void apiRoot(RoutingContext context) {
  2.   dbService.fetchAllPagesData(reply -> {
  3.     JsonObject response = new JsonObject();
  4.     if (reply.succeeded()) {
  5.       List<JsonObject> pages = reply.result()
  6.         .stream()
  7.         .map(obj -> new JsonObject()
  8.           .put("id", obj.getInteger("ID"))  (1)
  9.           .put("name", obj.getString("NAME")))
  10.         .collect(Collectors.toList());
  11.       response
  12.         .put("success", true)
  13.         .put("pages", pages); (2)
  14.       context.response().setStatusCode(200);
  15.       context.response().putHeader("Content-Type", "application/json");
  16.       context.response().end(response.encode()); (3)
  17.     } else {
  18.       response
  19.         .put("success", false)
  20.         .put("error", reply.cause().getMessage());
  21.       context.response().setStatusCode(500);
  22.       context.response().putHeader("Content-Type", "application/json");
  23.       context.response().end(response.encode());
  24.     }
  25.   });
  26. }

  1. We just remap database results in page information entry objects.

  2. The resulting JSON array becomes the value for the pages key in the response payload.

  3. JsonObject#encode() gives a compact String representation of the JSON data.

Getting a page

  1. private void apiGetPage(RoutingContext context) {
  2.   int id = Integer.valueOf(context.request().getParam("id"));
  3.   dbService.fetchPageById(id, reply -> {
  4.     JsonObject response = new JsonObject();
  5.     if (reply.succeeded()) {
  6.       JsonObject dbObject = reply.result();
  7.       if (dbObject.getBoolean("found")) {
  8.         JsonObject payload = new JsonObject()
  9.           .put("name", dbObject.getString("name"))
  10.           .put("id", dbObject.getInteger("id"))
  11.           .put("markdown", dbObject.getString("content"))
  12.           .put("html", Processor.process(dbObject.getString("content")));
  13.         response
  14.           .put("success", true)
  15.           .put("page", payload);
  16.         context.response().setStatusCode(200);
  17.       } else {
  18.         context.response().setStatusCode(404);
  19.         response
  20.           .put("success", false)
  21.           .put("error", "There is no page with ID " + id);
  22.       }
  23.     } else {
  24.       response
  25.         .put("success", false)
  26.         .put("error", reply.cause().getMessage());
  27.       context.response().setStatusCode(500);
  28.     }
  29.     context.response().putHeader("Content-Type", "application/json");
  30.     context.response().end(response.encode());
  31.   });
  32. }

Creating a page

  1. private void apiCreatePage(RoutingContext context) {
  2.   JsonObject page = context.getBodyAsJson();
  3.   if (!validateJsonPageDocument(context, page, "name", "markdown")) {
  4.     return;
  5.   }
  6.   dbService.createPage(page.getString("name"), page.getString("markdown"), reply -> {
  7.     if (reply.succeeded()) {
  8.       context.response().setStatusCode(201);
  9.       context.response().putHeader("Content-Type", "application/json");
  10.       context.response().end(new JsonObject().put("success", true).encode());
  11.     } else {
  12.       context.response().setStatusCode(500);
  13.       context.response().putHeader("Content-Type", "application/json");
  14.       context.response().end(new JsonObject()
  15.         .put("success", false)
  16.         .put("error", reply.cause().getMessage()).encode());
  17.     }
  18.   });
  19. }

This handler and other handlers need to deal with incoming JSON documents. The following validateJsonPageDocument method is a helper for doing validation and early error reporting, so that the remainder of the processing assume the presence of certain JSON entries:

  1. private boolean validateJsonPageDocument(RoutingContext context, JsonObject page, String... expectedKeys) {
  2.   if (!Arrays.stream(expectedKeys).allMatch(page::containsKey)) {
  3.     LOGGER.error("Bad page creation JSON payload: " + page.encodePrettily() + " from " + context.request().remoteAddress());
  4.     context.response().setStatusCode(400);
  5.     context.response().putHeader("Content-Type", "application/json");
  6.     context.response().end(new JsonObject()
  7.       .put("success", false)
  8.       .put("error", "Bad request payload").encode());
  9.     return false;
  10.   }
  11.   return true;
  12. }

Updating a page

  1. private void apiUpdatePage(RoutingContext context) {
  2.   int id = Integer.valueOf(context.request().getParam("id"));
  3.   JsonObject page = context.getBodyAsJson();
  4.   if (!validateJsonPageDocument(context, page, "markdown")) {
  5.     return;
  6.   }
  7.   dbService.savePage(id, page.getString("markdown"), reply -> {
  8.     handleSimpleDbReply(context, reply);
  9.   });
  10. }

The handleSimpleDbReply method is a helper for finishing the request processing:

  1. private void handleSimpleDbReply(RoutingContext context, AsyncResult<Void> reply) {
  2.   if (reply.succeeded()) {
  3.     context.response().setStatusCode(200);
  4.     context.response().putHeader("Content-Type", "application/json");
  5.     context.response().end(new JsonObject().put("success", true).encode());
  6.   } else {
  7.     context.response().setStatusCode(500);
  8.     context.response().putHeader("Content-Type", "application/json");
  9.     context.response().end(new JsonObject()
  10.       .put("success", false)
  11.       .put("error", reply.cause().getMessage()).encode());
  12.   }
  13. }

Deleting a page

  1. private void apiDeletePage(RoutingContext context) {
  2.   int id = Integer.valueOf(context.request().getParam("id"));
  3.   dbService.deletePage(id, reply -> {
  4.     handleSimpleDbReply(context, reply);
  5.   });
  6. }