Plugins in Other Languages Javascript

    TypeScript is also supported in the following ways:

    • The PDK includes type definitions for PDK functions that allow type checking when developing plugins in TypeScript.
    • Plugins written in TypeScript can be loaded directly to Kong Gateway and transpiled.

    can be installed using . To install the plugin server binary globally:

    Development

    A valid JavaScript plugin implementation should export the following object:

    1. module.exports = {
    2.   Plugin: KongPlugin,
    3.   Schema: [
    4.     { message: { type: "string" } },
    5.   Version: '0.1.0',
    6.   Priority: 0,
    7. }
    • The Plugin attribute defines the class that implements this plugin.
    • The Schema defines the configuration schema of the plugin.
    • Version and Priority variables set to the version number and priority of execution.

    Note: contains examples of plugins built with JavaScript.

    You can implement custom logic to be executed at various points in the request processing lifecycle. To execute custom JavaScript code in the access phase, define a function named access:

    • certificate
    • access
    • response
    • preread
    • log

    The presence of the response handler automatically enables the buffered proxy mode.

    PDK functions

    Kong interacts with the PDK through network-based inter-rocess communication. Each function returns a promise instance. You can use async/await keywords in the phase handlers for better readability.

    1. class KongPlugin {
    2.     this.config = config
    3.   }
    4.   async access(kong) {
    5.     let host = await kong.request.getHeader("host")
    6.     // do something to host
    8. }

    Alternatively, use the then method to resolve a promise:

    When using the plugin server, plugins are allowed to have extra dependencies, as long as the directory that holds plugin source code also includes a node_modules directory.

    Assuming plugins are stored under /usr/local/kong/js-plugins, the extra dependencies are then defined in /usr/local/kong/js-plugins/package.json. Developers also need to run npm install under /usr/local/kong/js-plugins to install those dependencies locally into /usr/local/kong/js-plugins/node_modules.

    The JavaScript PDK provides a mock framework to test plugin code using .

    Install jest as a development dependency, then add the test script in package.json:

    1. npm install jest --save-dev

    The package.json contains information like this:

    Run the test through npm with:

    This repository contains examples of writing tests with jest.

    More Information