osm-p2p-timestamp-index

Maintain an index of OSM documents' creation time.

background details relevant to understanding what this module does

Usage

var osmP2pTimestampIndex = require('osm-p2p-timestamp-index')
var OsmP2p = require('osm-p2p')

var osmdb = OsmP2p('/tmp/my-db')
var index = osmP2pTimestampIndex(osmdb)

var pending = 3
osmdb.put('foo', { type: 'node', lon: 0, lat: 0, timestamp: new Date().getTime() }, onWritten)
osmdb.put('bar', { type: 'node', lon: 1, lat: 1, timestamp: new Date().getTime() }, onWritten)
osmdb.put('baz', { type: 'node', lon: 2, lat: 2, timestamp: new Date().getTime() }, onWritten)

function onWritten (err, doc) {
  if (--pending !== 0) return

  index.ready(function () {
    var stream = index.getDocumentStream()
    stream.on('data', console.log)
  })
}

outputs the version IDs of the documents:

ae4faa3c17ff4e6ee50471bbc629188c45098fa77124382d08e0e4fbd77e5c94
324e841fbe4daf470a148cd1b65a9a91dab7f9255ffbe4000fa298fe63023ff1
664058630b0da6ea9b119e3af1ff9cd98d52d3318a6d79216e7192063a73b610

API

var osmP2pTimestampIndex = require('osm-p2p-timestamp-index')

var index = osmP2pTimestampIndex(osmdb)

Accepts an osm-p2p-db instance. You can use osm-p2p-db directly, or a helper module like osm-p2p.

index.ready(done)

Calls the callback function done exactly once, when the indexer has finished indexing all documents in osmdb.

var stream = index.getDocumentStream([opts])

Retrieves OSM documents by timestamp as a Readable stream. Valid options for opts are

• opts.gt, opts.gte: No documents older than this time. Defaults to -Infinity.
• opts.lt, opts.lte: No documents newer than this time. Defaults to Infinity.
• opts.limit: The upper bound on number of documents to be returned.
• opts.reverse: If true, the oldest documents will be returned first. Default is false (newest docs first).

The format to use for time depends on what format was used for the documents in the database. Good formats include e.g. 2017-05-21T16:18:54.436Z or milliseconds since Epoch.

Errors are emitted to the stream, so remember to listen to stream.on('error', function (err) { ... }).

Install

With npm installed, run

$ npm install osm-p2p-timestamp-index

See Also

• osm-p2p-db

License

ISC