Push Notifications

Overview

The ccmjs cloud service for data management on ccm2.inf.h-brs.de supports push notifications. A client-side service worker can subscribe for push notifications. A push notification is triggered when a dataset in the server-side database has changed. The client-side can specify which datasets in which datastores are observed.

Example for POST params to subscribe for push notifications

{
  "sub": {
    "subscription": {...},  // subscription object from service worker
    "proxy": "...",         // proxy URL (default: no proxy)
    "db": "mongo|redis",    // database name (default: "mongo")
    "stores": [
      {
        "name": "...",      // datastore name (MongoDB: collection name)
        "observe": {...}    // key, keys or simple query to define observed datasets (default: all)
      }
    ],
    "token": "...",         // token of already logged in user (optional)
    "realm": "..."          // realm of already logged in user (only if a token is passed)
  }
}

Examples for observe

"dataset_A"

Observes the dataset with the unique key dataset_A.

[ "dataset_A", "dataset_B", ... ]

Observes all datasets whose unique key is specified in the array.

{ "key": "value" }

Observes all datasets that have the value value at property key. So this is a simple query.

[ "dataset_A", { "key": "value" }, ... ]

An array with a mix of given unique keys and simple queries can also be used.

Examples for stores

"store_A"

Observes all datasets in the datastore store_A.

{
  "name": "store_A",
  "observe": ...
}

Observes the datasets of the datastore store_A that are defined in observe.

[ "store_A", "store_B", ... ]

Observes all datasets of the datastores whose name is specified in the array.

[
  {
    "name": "store_A",
    "observe": ...
  },
  {
    "name": "store_B",
    "observe": ...
  },
  ...
]

The array can also contain objects to observe only specific datasets in different datastores.

[
  "store_A",
  {
    "name": "store_B",
    "observe": ...
  },
  ...
]

An array with a mix of given datastore names and objects can also be used.