Setup

First, create a services directory to store all your plugins and add it to config.json as servicesDirectory .

Next, in this directory, create a new npm module to keep track of your plugins and their dependencies and to ensure others using this code have an easy time with it.

If you follow the prompts, you’ll get a new package.json file, which describes the plugins. Later, this file can be used to upgrade dependencies - npm outdated and npm update .

More importantly, when you migrate plugins from this development environment to your production server, you can easily install all dependencies - some of which may be OS dependent - with npm install, just by copying your plugin file and package.json.

Creating your module

In your services directory, create a new JavaScript file named my-plugin.realtime.js. It’s important to end the filename with .realtime.js, this differentiates the file from other supported plugin types and unrelated files.

Open the file in your favorite editor, and let’s define the interface by adding the necessary exports:

Installing dependencies

You can use npm to install third party libraries to save time on common tasks, such as making requests, or authenticating. The first library you’ll need is a Promise library implementing the ES6 standard. Our recommendation is q.js . Th

This will fetch and install the q library from npmjs.org - this is the default registry - and save its details to the package.json manifest.

In my-plugin.realtime.js you can now load this module and make use of its API to create promises.

Now that the interface is implemented, you can check the plugin in Marvin Live, by restarting it and creating a room. If this is your first plugin, you will see the Add My Plugin button in the top right corner. Otherwise it’s a new menu entry in the Add property dropdown.

Template usage

The title of the plugin panel is automatically added, along with a close button and a progress bar visible during updates, so you all you need to take care of is a display for your results.

Calling a web service

Let’s calculate the solubility forecast index of this structure. This descriptor is easily calculable from logD and the number of aromatic rings. ChemAxon has a REST web services product that can calculated these descriptors. Once that's installed we can use its service "View Properties Without Storing" (documentation). We need a POST request with the following JSON structure:

NodeJS has a built in library handling all tasks related to networking, called http, but we’re going to use a higher level API that’s more convenient and requires less boilerplate code: request.

After this we can import it, as we did with Q, and construct the request. Please make sure the URL to the /rest-v0/util/detail service in the properties variable matches your setup:

The results are in a large data structure, so the template will be used to simplify it for the chemists. In Angular JS templates, we may perform simple arithmetic expressions too, such as adding two numbers to calculate SFI:

Adding data to the report

The most common formats for reports (SDF, PPTX) have no capabilities to display or interpret HTML code or complex data structures, so there’s a separate and optional way to specify what information to add to reports.

To add key numbers or identifiers to the report, you need to extend the fulfillment value of the promise. In the previous steps, it specified data only for the client, this should change to an object containing both a client and a report property. The client property should contain the data required by the template as earlier - this is the reason we name the root variable client in the template.

The report property should contain a map, simple key - value pairs, where each pair becomes a data field or column in the report. This is the common data structure that fits all report types, Marvin Live can easily print the values provided here to PowerPoint or SD files.

To add the SFI value to the report, let’s change the resolve part of the code:

Converting to other chemical file formats

In many cases you need to convert the structure from ChemAxon’s native MRV format to some other chemical file format before starting calculations or a search. In this example we’ll convert the structure to SMILES. JChem Web Services provides a converter service , its documentation shows the request needed:

With the request module installed earlier, we can easily send this request: