119 lines
3.2 KiB
JavaScript
119 lines
3.2 KiB
JavaScript
/**
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* Processes DataApi return data as JSON
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*
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* Copyright (C) 2014, 2015 R-T Specialty, LLC.
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*
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* This file is part of the Liza Data Collection Framework
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*
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* Liza is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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var Trait = require( 'easejs' ).Trait,
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DataApi = require( '../DataApi' );
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/**
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* Processes DataApi return data as JSON
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*/
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module.exports = Trait( 'JsonResponse' )
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.implement( DataApi )
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.extend(
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{
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/**
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* Processes response as JSON
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*
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* If the response is not valid JSON, an error will be returned. The
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* output value will be an object with a single
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* property---`text`---containing the response text that failed to
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* parse.
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*
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* If a request error occurs in conjunction with a parse error, then
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* both errors will be returned in a single error object under the
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* `list` property.
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*
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* @param {string} data binary data to transmit
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* @param {function(?Error,*)} callback continuation upon reply
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*
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* @return {DataApi} self
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*/
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'virtual abstract override public request': function( data, callback )
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{
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var _self = this;
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this.__super( data, function( err, resp )
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{
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_self._tryParse( err, resp, callback );
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} );
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return this;
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},
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/**
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* Attempt to parse SRC as JSON and invoke callback according to the
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* rules of `#request`
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*
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* @param {?Error} err response error
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* @param {string} src JSON string
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* @param {function(?Error,*)} callback continuation
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*
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* @return {undefined}
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*/
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'private _tryParse': function( err, src, callback )
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{
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try
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{
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var data = JSON.parse( src );
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}
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catch ( e )
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{
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// parsing failed; provide response text in addition to
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// original data so that the caller can handle how they
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// please
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callback(
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this._getReturnError( err, e ),
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{ text: src }
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);
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return;
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}
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callback( err, data );
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},
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/**
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* Produce the parse error, or a combined error containing both the
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* original and parse errors
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*
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* @param {?Error} orig response error
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* @param {Error} parse parse error
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*
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* @return {Error} parse error or combined error
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*/
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'private _getReturnError': function( orig, parse )
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{
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if ( !orig )
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{
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return parse;
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}
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var e = Error( "Multiple errors occurred; see `list` property" );
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e.list = [ orig, parse ];
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return e;
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}
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} );
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