[#217,backend/ckan][m]: functional CKAN backend (read-only).

* limited tests so far (only use mocks so have not tested querying properly)
2012-08-18 02:01:13 +01:00
parent 83fa3dcf29
commit 74132d36d7
3 changed files with 254 additions and 0 deletions
--- a/src/backend.ckan.js
+++ b/src/backend.ckan.js
@@ -0,0 +1,88 @@
+this.recline = this.recline || {};
+this.recline.Backend = this.recline.Backend || {};
+this.recline.Backend.Ckan = this.recline.Backend.Ckan || {};
+
+(function($, my) {
+  // ## CKAN Backend
+  //
+  // This provides connection to the CKAN DataStore (v2)
+  //
+  // General notes
+  // 
+  // * Every dataset must have an id equal to its resource id on the CKAN instance
+  // * You should set the CKAN API endpoint for requests by setting API_ENDPOINT value on this module (recline.Backend.Ckan.API_ENDPOINT)
+
+  my.__type__ = 'ckan';
+
+  // Default CKAN API endpoint used for requests (you can change this but it will affect every request!)
+  my.API_ENDPOINT = 'http://datahub.io/api';
+
+  // ### fetch
+  my.fetch = function(dataset) {
+    var wrapper = my.DataStore();
+    var dfd = $.Deferred();
+    var jqxhr = wrapper.search({resource_id: dataset.id, limit: 0});
+    jqxhr.done(function(results) {
+      // map ckan types to our usual types ...
+      var fields = _.map(results.result.fields, function(field) {
+        field.type = field.type in CKAN_TYPES_MAP ? CKAN_TYPES_MAP[field.type] : field.type;
+        return field;
+      });
+      var out = {
+        fields: fields,
+        useMemoryStore: false
+      };
+      dfd.resolve(out);  
+    });
+    return dfd.promise();
+  };
+
+  my.query = function(dataset, queryObj) {
+    var wrapper = my.DataStore(dataset.url);
+    var actualQuery = {
+      resource_id: dataset.id,
+      q: queryObj.q,
+      limit: queryObj.size,
+      offset: queryObj.from
+    };
+    var dfd = $.Deferred();
+    var jqxhr = wrapper.search(actualQuery);
+    jqxhr.done(function(results) {
+      var out = {
+        total: results.result.total,
+        hits: results.result.records,
+      };
+      dfd.resolve(out);  
+    });
+    return dfd.promise();
+  };
+
+  // ### DataStore
+  //
+  // Simple wrapper around the CKAN DataStore API
+  //
+  // @param endpoint: CKAN api endpoint (e.g. http://datahub.io/api)
+  my.DataStore = function(endpoint) { 
+    var that = {
+      endpoint: endpoint || my.API_ENDPOINT
+    };
+    that.search = function(data) {
+      var searchUrl = my.endpoint + '/3/action/datastore_search';
+      var jqxhr = $.ajax({
+        url: searchUrl,
+        data: data,
+        dataType: 'json'
+      });
+      return jqxhr;
+    }
+
+    return that;
+  }
+
+  var CKAN_TYPES_MAP = {
+    'int4': 'integer',
+    'float8': 'float',
+    'text': 'string'
+  };
+
+}(jQuery, this.recline.Backend.Ckan));