Hands-on Node.js: Working with MarkLogic's Node.js Client API

This project is used for hands-on sessions, guided by someone who is familiar with the MarkLogic Node.js Client API. The goal is that, after going through the exercises, a developer will be comfortable using the API to interact with MarkLogic.

Knowledge of JavaScript is assumed.

Introduction

MarkLogic is a document- and triple-store database. One of the features in MarkLogic 8 is a client API for Node.js developers. The exercises presented here will give you a taste of how the Node Client API works. Note that it is intended to get you started and show the power of the API, but it is not a full replacement for MarkLogic University's class on the subject.

Setup

1. Download and Install MarkLogic 8.

2. Clone the Geophoto repository.

3. cd to a directory where you want to project to be

4. git clone https://github.com/marklogic/Geophoto

5. Follow Geophoto's setup instructions, including data import.

6. In the hands-on-node directory, run npm install.

Geophoto

This session is based on the Geophoto application. Once you've cloned and set up the application and imported the data, start the application (see Geophoto's README for instructions).

See MarkLogic University's Using Node.js: The Geophoto App On Demand video for an overview of the Geophoto application.

Features

Things to note in the Geophoto application:

• map view
  • click a marker
  • edit the image metadata
  • see the semantic info
• geo search
  • circle search
  • MarkLogic also supports arbitrary polygons

Data Model

The database holds three types of data: binary images, metadata to describe them, and triples to provide context.

Execution

Trace the steps of editing the title of an image.

• views/partials/edit.jade
• public/js/editor/photoeditor.controller.js (updateTitle)
• public/js/data/photofactory.js (update)
• POST /api/image/update/:id/:update
• routes.js: update -> apiupdate -> updateDocument (read, edit, write)

Debugging

Browser-based Debugging

The Node Inspector package lets you debug Node.js code using Chrome's debugger tools.

To work with the browser-based debugger, run these commands:

• npm-debug unit-01/01-read-promise.js

From there, you'll be able to set breakpoints, step into, out of, and over function calls, inspect and even change variables.

REPL

Node.js provides a REPL: read/evaluate/print loop. By simply running node at the command line, you start up the Node.js REPL and can experiment with commands.

Built-in Debugging

Harder to use, but always available. Built-in debugging uses the Node REPL. You can dynamically set breakpoints using the sb() command, which sets a breakpoint on the current line, or by inserting the debugger; command into your code (a static breakpoint). See Node's documentation about the debugger for more capabilities.

• node debug unit-01/01-read-promise.js

Notice that there is a space between "node" and "debug", rather than the hyphen we saw with browser-based debugging.

Additional Resources

• MarkLogic University has an instructor-led course on using MarkLogic with the Node.js Client API