ckan

A Javascript client library for CKAN designed for both the browser and NodeJS.

The library provides full support for accessing both the CKAN Catalog and CKAN DataStore API.

It also provides a Recline compatible backend.

Installing

Browser

Just add the ckan.js to your page.

<script src="ckan.js"></script>

You can also use our hosted one:

<script src="http://okfnlabs.org/ckan.js/ckan.js"></script>

Node

npm install ckan

Then in your code:

var CKAN = require('ckan')

Usage

Usage is generally similar across Node and Browser versions.

Callback structure follows Node conventions, that is:

function(err, data)

Catalog

Set it up:

var client = new CKAN.Client('http://my-ckan-site.com');

// You can also provide an API key (for operations that require one)
var client = new CKAN.Client('http://my-ckan-site.com', 'my-api-key');

You can now use any part of the action API:

client.action('action_name', data, callback)

For example, to create a dataset using dataset_create action you would do:

client.action('dataset_create', { name: 'my-dataset' }, function(err, result) {
  console.log(err);
  console.log(result);
})

Here's a more complex example showing several commands to do a Dataset upsert (create if not exists, otherwise update):

var datasetInfo = {
  name: 'ckan.js-example',
  title: 'CKAN.JS Example',
  tags: ['amazing']
};
client.action('dataset_show', { id: datasetInfo.name }, function(err, out) {
  // dataset exists
  if (!err) {
    // TODO: you'd really want to extend the existing dataset object returned
    // in out with the datasetInfo we have but we are being simple here
    client.action('dataset_update', datasetInfo, cb);
  } else {
    client.action('dataset_create', datasetInfo, cb);
  }
});

DataStore

The DataStore feature of CKAN allows you to store structured data in CKAN and to create a rich API for it. It is also accessible via the action API - details in the docs here - and and you can therefore access using the CKAN client. Here are a few examples:

Store Data

Store data into the DataStore for an existing resource

// 2 rows or data (with columns/fields named 'A' and 'B'
var data = [
  { A: 1, B: 2 },
  { A: 10, B: 16}
];
// the id of a CKAN DataSet resource (the data that we store will be associated with that resource)
// this resource will need to already exist
resourceId = 'abc-efg';
client.action('datastore_create', {
    resource_id: resourceId,
    records: data
  },
  function(err) {
    if (err) console.log(err);
    console.log('All done');
  })

Store data into a new DataStore resource:

// the id of a CKAN dataset that already exists
packageId = 'the-best-dataset-ever';
client.action('datastore_create', {
    resource: {package_id: packageId},
    records: data
  },
  function(err) {
    if (err) console.log(err);
    console.log('All done');
  })

Here's an example of loading data from a CSV file into the DataStore:

// npm's csv file
var csv = require('csv');
csv()
  .from('path/to/csv-file.csv', {columns: true})
  .to.array(function(data, count) {
    client.action('datastore_create', {
        resource_id: resourceId,
        records: data
      },
      function(err) {
        if (err) console.log(err);
        console.log('All done');
      })
    })
    ;

Search Data

Search data using the Data API - see datastore_search for details of options:

client.action('datastore_search', {
    resource_id: '...',
    q: '...'
  },
  function(err, out) {
    if (err) console.log(err);
    console.log(out);
  })
});

Or using SQL support:

client.action('datastore_search_sql', {
    sql: '...'
  },
  function(err, out) {
    if (err) console.log(err);
    console.log(out);
  })
});

There are also a couple of nice wrapper methods:

// queryObj should be like the Recline Query structure
// http://okfnlabs.org/recline/docs/models.html#query
client.datastoreQuery(queryObj, function(err, out) {
  // out will follow recline structure, viz
  {
    total: ..
    fields: ... (fields will have Recline / JSON Table Schema types)
    hits: array of results ...
  }
});

And for SQL

client.datastoreSqlQuery(sql, function(err, out) {
  // out will follow recline structure, viz
  {
    total: ..
    fields: ... (fields will have Recline / JSON Table Schema types)
    hits: array of results ...
  }
});

Recline JS Backend

This module also provides a Recline compatible backend available as:

recline.backend.Ckan

The backend supports fetch and query but does not provide write support at the present time.