# @compassdigital/middleware > CDL Provider middleware module Latest version **5.0.3** (published 2022-10-14) · ISC license · 0 weekly downloads > **Deprecated.** This package is deprecated. ## Install ```sh npm install @compassdigital/middleware pnpm add @compassdigital/middleware yarn add @compassdigital/middleware bun add @compassdigital/middleware ``` ## Health **Score 10/100 (F)** — status: deprecated. Negative: deprecated. ## Facts | | | |---|---| | Version | 5.0.3 | | Published | 2022-10-14 | | First published | 2019-01-31 | | Weekly downloads | 0 | | License | ISC | | TypeScript types | none | | Module format | CommonJS | | Dependencies | 11 | | Unpacked size | 17.2 KB | | Known vulnerabilities | 0 | | Install scripts | no | | Author | Robert Pisani | | Maintainers | hiteshi.patel, gagandeepk, gaurangcompass, sitharam_t, sitharams_t, drashti_patel, mbkhan1995, ds-brian, pallavipulivarthy, rajanikandepucdl, svietz, vivien.igweze, shivani-aggarwal, darren.rahnemoon.cdl, sanjay_tech, brahmrshi_tech, tfox121, rachitaj, matthewclair, qihangsong, collinstonefromcompass, hermsidhu, ananthu.cdl, ospozito, cdl-samir-thaker, jitesh.tfpl, dhruv.seth, ricardodesimas, sbeaury-cdl, zach-cdl, jrodri, svtokarevsv, rcjpisani, danialhasan, lalityabijjam, astrit-cdl, keyur-cdl, roya-cdl, jpdemiranda, toronto.devops, brahmrshiraval, coreycosman, pberoy, andrei-cdl, alberttir, umeshprasad, kieranshb, eirabie, coreycosman.cdl, marlondc, bcardoso, eiston-cdl, icholy, brunnodatum | | Keywords | cdl | ## Links - npm: https://www.npmjs.com/package/@compassdigital/middleware - Repository: https://github.com/compassdigital/compassdigital.middleware - Homepage: https://github.com/compassdigital/compassdigital.middleware#readme - Issues: https://github.com/compassdigital/compassdigital.middleware/issues - npm.io page: https://npm.io/package/@compassdigital/middleware ## Dependencies (11) - [uuid](https://npm.io/package/uuid.md) ^7.0.2 - [aws-sdk](https://npm.io/package/aws-sdk.md) ^2.581.0 - [dynamoose](https://npm.io/package/dynamoose.md) ^1.6.5 - [redactyl.js](https://npm.io/package/redactyl.js.md) ^1.2.0 - [aws-xray-sdk](https://npm.io/package/aws-xray-sdk.md) ^2.5.0 - [lodash.merge](https://npm.io/package/lodash.merge.md) ^4.6.2 - [@compassdigital/id](https://npm.io/package/@compassdigital/id.md) ^3.6.0 - [@compassdigital/auth](https://npm.io/package/@compassdigital/auth.md) ^5.0.1 - [@splitsoftware/splitio](https://npm.io/package/@splitsoftware/splitio.md) ^10.15.5 - [@compassdigital/constant](https://npm.io/package/@compassdigital/constant.md) ^0.3.0 - [@compassdigital/superagent](https://npm.io/package/@compassdigital/superagent.md) ^0.0.8 ## Recent versions - 5.0.3 (latest) — 2022-10-14 - 5.0.2 — 2022-10-14 - 5.0.1 — 2022-10-14 - 5.0.0 — 2022-10-14 - 4.1.0 — 2022-06-08 - 4.0.2 — 2022-04-28 - 4.0.1 — 2022-01-06 - 4.0.0 — 2021-11-03 - 3.3.3 — 2021-08-30 - 3.3.2 — 2021-07-07 - 3.2.2 — 2021-05-07 - 3.2.1 — 2021-05-05 - 3.2.0 — 2021-05-03 - 3.1.0 — 2020-09-23 - 3.0.1 — 2020-04-30 - … 19 more at https://npm.io/package/@compassdigital/middleware/versions ## README # compassdigital.middleware ## CDL Provider middleware module - This middleware module extends the CDL core provider with the ability to run functions before requests get handled - This can be handled at the provider level (for every incoming request) or at the event level (for particular events, ex: "post_order") ### Usage Registering Provider-level middleware ```js const Middleware = require("@compassdigital/middleware").handler; const ActionLogger = require("@compassdigital/middleware").fn.ActionLogger; /** * Inside the Provider constructor. * The "bind" call is needed for this particular function but * is not needed to make any custom middleware work with this * package. */ this.middleware = new Middleware(ActionLogger.bind(this)); ``` Registering handler-level middleware ```js const Middleware = require("@compassdigital/middleware").handler; // Inside the domain-specific Provider function bodyLogger (req, res, next) { /** * req: the request object from the lambda event * res: the response object currently only holds a reference to user-defined local variables specific to the lifecycle of a single request * next: the callback function to call when the middleware is finished work. * - No parameters passes the middleware off to the next layer in the stack * - Passing an error will cause the provider's error handler to take over and send the appropiate response * - Passing true will skip the rest of the middleware for the current request / console.log(JSON.stringify(req.body)); return next(); } Provider.on("post_test", "*:*:*", [ bodyLogger, async function (req, next) { // Business logic here... }]); ``` #### Feature Flagging Feature flagging middleware provides an easy way to get state of flags in the req object. ```js const FeatureFlagging = require('@compassdigital/middleware').fn.FeatureFlagging; ``` You can register the middleware at the provider level with minimal boilerplate code. ```js UserProvider.use(FeatureFlagging.call(UserProvider)); ``` Or at the handler level ```js Provider.on("post_test", "*:*:*", [FeatureFlagging(), async function (req, next) { // Business logic here... }]); ``` From here on, a `feature_flags` property will be exposed on the `req` object. You can then use the flags as ```js Provider.on("post_test", "*:*:*", async function (req, next) { if (req.feature_flags.my_feature_1) doSomething(); }); ``` ##### Split API Key For the middleware to be able to contact Split, an environment variable must be set in the provider's `serverless.yml` file. ```yml provider: environment: SPLIT_KEY: ${config:SPLIT_KEY} ``` ##### Flag Caching Before the middleware hits Split to retrieve the flags, it gets a CDL config file that has a cache_time property. This tells the middleware how long it should hold on to the flags before getting them again from Split. This can be changed. ```json { "is_split_enabled": true, "cache_time": 10000 } ``` --- _Source: https://npm.io/package/@compassdigital/middleware · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._