OfflineSearch

A small node library providing csMap with the option to create an index file of the static GeoJson and TopoJson files.

Installation

npm install cs-offline-search --save

Usage

  import offlineSearch = require('cs-offline-search');

  var offlineSearchManager = new offlineSearch('public/data/projects/projects.json', {
      propertyNames: ['Name', 'postcode', 'Postcode'],
      stopWords    : ['the', 'a', 'an', 'of', 'to']
  });

Tests

npm test

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code.

Release History

• 0.0.1 Initial release
• 0.0.2 Added test
• 0.0.3 Fixed bug when a property returns a number
• 0.0.4 Reorganized the output (added dist folder)
• 0.0.5 Updated documentation
• 0.0.7 Added fix for files that contain geometries without features
• 0.0.8 Excluded topojson files (not yet supported)

About the code

Normally, searching the website would mean that you do a query in a database or use a separate search engine to get back some results. However, this implies that you need to have such a service running on your server, making it less easy to create a standalone map application on a simple server that serves static HTML pages. For that reason, this offline search module is created.

How it works

The offline search module scans the projects.json solution file, looking for projects. For each project, a new file is created, offline_search_results.json, in the same folder as the project.json.

The OfflineSearchManager class (in index.ts):

• Runs when node.js starts up
• Scans the projects.json for local projects
• Starts an OfflineSearcher for each project in projects found

The OfflineSearcher

• Scans the project.json for local layers and parses each of them

• Builds an OfflineSearchResult with

• Saves the OfflineSearchResult.

  • An array with source layer files: layer_id, title (for display), path, file_size, last_write_date
  • Is configered with a list of stop words that should be excluded from the index.
  • Is configured with the property names it needs to include in the search. These property names are also saved.
  • Builds an index list based on these property names
  • Each entry in the index contains a reference to: the layer, the feature, and the property name

The OfflineSearchDirective

• Retreives the OfflineSearchResult file (async)
• Uses it for locating search requests: found results are returned using the layer name & feature name.