Added JsonDataApi

src/dapi/format/JsonDataApi.js

@@ -0,0 +1,91 @@
+/**
+ * Processes DataApi return data as JSON
+ *
+ *  Copyright (C) 2014 LoVullo Associates, Inc.
+ *
+ *  This file is part of the Liza Data Collection Framework
+ *
+ *  Liza is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+var Class   = require( 'easejs' ).Class,
+    DataApi = require( '../DataApi' );
+
+
+/**
+ * Processes DataApi return data as JSON
+ */
+module.exports = Class( 'JsonDataApi' )
+    .implement( DataApi )
+    .extend(
+{
+    /**
+     * DataAPI to decorate
+     * @type {DataApi}
+     */
+    'private _dapi': null,
+
+
+    /**
+     * Decorate provided DataAPI to parse response data as JSON
+     *
+     * @param {DataApi} dapi DataApi to decorate
+     */
+    __construct: function( dapi )
+    {
+        if ( !( Class.isA( DataApi, dapi ) ) )
+        {
+            throw TypeError( "Expecting DataApi" );
+        }
+
+        this._dapi = dapi;
+    },
+
+
+    /**
+     * Proxies request to encapsulated DataApi and parses the result as JSON
+     *
+     * @param {string}             data     binary data to transmit
+     * @param {function(?Error,*)} callback continuation upon reply
+     *
+     * @return {DataApi} self
+     */
+    'public request': function( data, callback )
+    {
+        this._dapi.request( data, function( err, resp )
+        {
+            if ( err !== null )
+            {
+                callback( err, null );
+                return;
+            }
+
+            try
+            {
+                var data = JSON.parse( resp );
+            }
+            catch ( e )
+            {
+                // parsing failed
+                callback( e, null );
+                return;
+            }
+
+            callback( null, data );
+        } );
+
+        return this;
+    }
+} );
+

test/dapi/format/JsonDataApiTest.js

@@ -0,0 +1,116 @@
+/**
+ * Test case for JSON formatting of API result
+ *
+ *  Copyright (C) 2014 LoVullo Associates, Inc.
+ *
+ *  This file is part of the Liza Data Collection Framework
+ *
+ *  Liza is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+var dapi    = require( '../../../' ).dapi,
+    expect  = require( 'chai' ).expect,
+    Class   = require( 'easejs' ).Class,
+    DataApi = dapi.DataApi,
+    Sut     = dapi.format.JsonDataApi;
+
+
+describe( 'JsonDataApi', function()
+{
+    it( 'errors if not provided a DataApi', function()
+    {
+        expect( function()
+        {
+            Sut( {} );
+        } ).to.throw( TypeError, 'DataApi' );
+    } );
+
+
+    it( 'accepts a DataApi', function()
+    {
+        expect( function()
+        {
+            Sut( _createStubDapi( null, '' ) );
+        } ).to.not.throw( TypeError );
+    } );
+
+
+    describe( '.request', function()
+    {
+        it( 'passes data to encapsulated DataApi', function()
+        {
+            var stubs    = _createStubDapi( null, '0' ),
+                expected = {};
+
+            Sut( stubs ).request( expected, function() {} );
+            expect( stubs.given ).to.equal( expected );
+        } );
+
+
+        it( 'converts response to JSON', function( done )
+        {
+            var raw = '{"foo": "bar"}';
+            Sut( _createStubDapi( null, raw ) ).request( '', function( err, data )
+            {
+                // should have been converted to JSON
+                expect( data ).to.deep.equal( { foo: 'bar' } );
+                expect( err ).to.equal( null );
+                done();
+            } );
+        } );
+
+
+        it( 'returns error if JSON parsing fails', function( done )
+        {
+            Sut( _createStubDapi( null, 'ERR' ) )
+                .request( '', function( err, data )
+                {
+                    expect( err ).to.be.instanceOf( Error );
+                    expect( data ).to.equal( null );
+                    done();
+                } );
+        } );
+
+
+        it( 'proxy error from encapsulated DataApi', function( done )
+        {
+            var e = Error( 'foo' );
+
+            Sut( _createStubDapi( e, '0' ) )
+                .request( '', function( err, data )
+                {
+                    // data should also be cleared out
+                    expect( err ).to.equal( e );
+                    expect( data ).to.equal( null );
+                    done();
+                } );
+        } );
+    } );
+} );
+
+
+function _createStubDapi( err, resp )
+{
+    return Class.implement( DataApi ).extend(
+    {
+        given: null,
+
+        request: function( data, callback )
+        {
+            this.given = data;
+            callback( err, resp );
+        }
+    } )();
+}
+