Hivemind App Cache Module

This module caches requests to the Hivemind IoT Platform for faster response time and fewer API calls.

For an example of how to use this module, check out Hivemind App Backend.

Entities

The entities submodule caches GET requests to the API for config.entityCacheTimeout milliseconds (defaults to 4 minutes).

If the response produces a list, a byId map will be added which allows access to individual entities using their id.

platform.entities.getEnvId(session, cbk)

Returns the ID of the (first) environment accessible using session.apiKey.

• session {Object}
  • apiKey {String} Key to access the platform API.
• cbk(err, envId) {Function}
  • err {Any}
  • envId {String}

platform.entities.getEntity(session, path, cbk)

Returns the response to the API call GET /v1/environments/{session.envId}{path}.

• session {Object}
  • apiKey {String}
  • envId {String}
• path {String}
• cbk(err, ans) {Function}
  • err {Any}
  • ans {Object}

platform.entities.getList(session, path, cbk)

Returns the data array from the response to the API call GET /v1/environments/{session.envId}{path}.

• session {Object}
  • apiKey {String}
  • envId {String}
• path {String}
• cbk(err, ans) {Function}
  • err {Any}
  • ans {Object}

platform.entities.getSingle(session, path, id, cbk)

Returns the entity with the given id when path points to a list. This call can improve response time since it requests all entities at once instead of individually.

• session {Object}
  • apiKey {String}
  • envId {String}
• path {String}
• id {String}
• cbk(err, ans) {Function}
  • err {Any}
  • ans {Object}

Samples

Samples are cached indefinitely. If a cursor tries to access older (not yet cached) samples, they are added to the cache transparently. New samples are added to the cache using WebSockets.

new platform.SampleCursor(session, devId, topic)

Returns a cursor to iterate over samples.

• session {Object}
  • apiKey {String}
  • envId {String}
• devId {String}
• topic {String}

SampleCursor.forEach(cbk, done)

Calls cbk for each sample, as long as the return value is true or there are no more samples available. And calls done after.

• cbk(sample) {Function}
  • sample {Object}
    • id {String}
    • timestamp {Date}
    • data {Object}
• done(err) {Function}
  • err {Any}

Events

platform.events.on('sampleInsert', cbk)

Emitted when a new sample is added to a sample cache.

• cbk(event) {Function}
  • event {Object}
    • envId {String}
    • devId {String}
    • topic {String}
    • sample {Object}
      • id {String}
      • timestamp {Date}
      • data {Object}

platform.events.on('sampleInvalidate', cbk)

Emitted when sample caches are destroyed. This can happen when samples are deleted, or a communication error occurs.

If topic is null, the sample caches of all topics are invalidated. If both devId and topic are null, the sample caches of all devices in the environment are invalidated.

After a sampleInvalidate event, no more sampleInsert events will be emitted for the affected caches (since they no longer exist). Access samples over a cursor to create a new cache.

• cbk(event) {Function}
  • event {Object}
    • envId {String}
    • devId {String}
    • topic {String}