DADI Web's Built-in Data Helpers

DADI Web's Built-in Data Helpers | Edge Blog

Over the last couple of years we've spent a lot of time debugging runtime issues with Events and the data they have access to.

After a short introduction to Web's Event system, we cover two built-in helpers that are part of the data context for each page request in DADI Web.

Events

The Event system in DADI Web provides developers with a way to perform tasks related to the current request, end the current request or extend the data context that is passed to the rendering engine.

An Event is a JavaScript file stored in your application's workspace folder and attached to a page.json file using the "events" array:

"events": [
  "my-event"
]

It is declared in the following way, receiving the original HTTP request, the response, the data context and a callback function to return control back to the controller that called it:

const Event = function (req, res, data, callback) {
 
}

The data context

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Tutorials

Last Updated:

September 2019

{
  "query": {},
  "params": {
    "category": "beauty",
    "subCategory": "makeup"
  },
  "pathname": "/beauty-hair/makeup/article-one",
  "host": "127.0.0.1:8000",
  "debug": true,
  "page": {
    "name": "article", 
    "description": "Article page",
    "language": "en"
  },
  "global": {
    "baseUrl": "http://localhost:8000",
    "environment": "development"
  }
  "article": {
    "results": [
      {
        "slug": "article-one",
        "title": "Article One",
        "category": "beauty"
      } 
    ],
    "metadata": {
      "limit": 1,
      "page": 1,
      "totalCount": 19,
      "totalPages": 19,
      "nextPage": 2
    }
  }
}

{
  "results": [
    {
      "slug": "article-one",
      "title": "Article One",
      "category": "beauty"
    } 
  ],
  "metadata": {
    "limit": 1,
    "page": 1,
    "totalCount": 19,
    "totalPages": 19,
    "nextPage": 2
  }
}

const Event = function (req, res, data, callback) {
  if (data.has('instagram')) {
    // do something with data.instagram
  } else {
    // no instagram property
    res.statusCode = 404
    res.end('Not found')
  }
  
  callback()
}

const Event = function (req, res, data, callback) {
  if (data.hasResults('people')) {
    // do something with people
    let mostRecentPerson = data.people.results[0]
  } else {
    // no people results
    res.statusCode = 404
    res.end('Not found')
  }
  
  callback()
}