mockResponse.js

'use strict';

/**
 * File: mockResponse
 *
 *  This file implements node.js's implementation of a 'response' object.
 *  Like all good mocks, the response file that can be called and used in
 *  place of a real HTTP response object.
 *
 * @author Howard Abrams <howard.abrams@gmail.com>
 */

/**
 * Function: createResponse
 *
 *    Creates a new mock 'response' instance. All values are reset to the
 *    defaults.
 *
 * Parameters:
 *
 *   options - An object of named parameters.
 *
 * Options:
 *
 *   encoding - The default encoding for the response
 */

var WritableStream = require('./mockWritableStream');
var EventEmitter = require('./mockEventEmitter');
var mime = require('mime');
var http = require('./node/http');
var utils = require('./utils');
var path = require('path');
var contentDisposition = require('content-disposition');

function createResponse(options) {

    if (!options) {
        options = {};
    }

    var _endCalled = false;
    var _data = '';
    var _buffer = Buffer.alloc(0);
    var _chunks = [];
    var _size = 0;
    var _encoding = options.encoding;

    var _redirectUrl = '';
    var _renderView = '';
    var _renderData = {};

    if (options.writableStream) {
        WritableStream = options.writableStream;
    }
    if (options.eventEmitter) {
        EventEmitter = options.eventEmitter;
    }
    var writableStream = new WritableStream();

    var mockRequest = options.req;
    // create mockResponse

    var mockResponse = Object.create(EventEmitter.prototype);
    EventEmitter.call(mockResponse);

    mockResponse._headers = {};

    mockResponse.cookies = {};
    mockResponse.finished = false;
    mockResponse.writableEnded = false;
    mockResponse.writableFinished = false;
    mockResponse.headersSent = false;
    mockResponse.statusCode = 200;
    mockResponse.statusMessage = 'OK';

    // http://expressjs.com/en/api.html#res.locals
    mockResponse.locals = options.locals || {};

    mockResponse.cookie = function(name, value, opt) {

        mockResponse.cookies[name] = {
            value: value,
            options: opt
        };

        return this;
    };

    mockResponse.clearCookie = function(name, opt) {
        var opts = opt || {};
        opts.expires = new Date(1);
        opts.path = '/';

        return this.cookie(name, '', opts);
    };

    mockResponse.status = function(code) {
        mockResponse.statusCode = code;
        return this;
    };

    /**
     * Function: writeHead
     *
     *  The 'writeHead' function from node's HTTP API.
     *
     * Parameters:
     *
     *  statusCode - A number to send as a the HTTP status
     *  headers    - An object of properties that will be used for
     *               the HTTP headers.
     */
    mockResponse.writeHead = function(statusCode, statusMessage, headers) {

        if (_endCalled) {
            throw new Error('The end() method has already been called.');
        }

        if (mockResponse.headersSent) {
            // Node docs: "This method must only be called once on a message"
            // but it doesn't error if you do call it after first chunk of body is sent
            // so we shouldn't throw here either (although it's a bug in the code).
            // We return without updating since in real life it's just possible the double call didn't
            // completely corrupt the response (for example not using chunked encoding due to HTTP/1.0 client)
            // and in this case the client will see the _original_ headers.
            return this;
        }

        mockResponse.statusCode = statusCode;

        // resolve statusMessage and headers as optional
        if (Object.prototype.toString.call(statusMessage) === '[object Object]') {
            headers = statusMessage;
            statusMessage = null;
        }

        if (statusMessage) {
            mockResponse.statusMessage = statusMessage;
        }

        // The headers specified earlier (been set with `mockResponse.setHeader`)
        // should not be overwritten but be merged with the headers
        // passed into `mockResponse.writeHead`.
        if (headers) {
            Object.assign(mockResponse._headers, utils.convertKeysToLowerCase(headers));
        }

        return this;
    };

    /**
     *  The 'send' function from restify's Response API that returns data
     *  to the client. Can be called multiple times.
     *
     *  @see http://mcavage.me/node-restify/#response-api
     *
     * @param data The data to return. Must be a string.
     */
    mockResponse.send = function(a, b, c) {

        var _formatData = function(data) {

            if (typeof data === 'object') {

                if (data.statusCode) {
                    mockResponse.statusCode = data.statusCode;
                } else if (data.httpCode) {
                    mockResponse.statusCode = data.httpCode;
                }

                if (data.body) {
                    _data = data.body;
                } else {
                    _data = data;
                }

            } else {
                _data += data;
            }

        };

        switch (arguments.length) {
            case 1:
                if (typeof a === 'number') {
                    mockResponse.statusCode = a;
                } else {
                    _formatData(a);
                }
                break;

            case 2:
                if (typeof a === 'number') {
                    _formatData(b);
                    mockResponse.statusCode = a;
                } else if (typeof b === 'number') {
                    _formatData(a);
                    mockResponse.statusCode = b;
                    console.warn('WARNING: Called send() with deprecated parameter order');
                } else {
                    _formatData(a);
                    _encoding = b;
                }
                break;

            case 3:
                _formatData(a);
                mockResponse._headers = utils.convertKeysToLowerCase(b);
                mockResponse.statusCode = c;
                console.warn('WARNING: Called send() with deprecated three parameters');
                break;

            default:
                break;
        }

        mockResponse.headersSent = true;

        mockResponse.emit('send');
        mockResponse.end();

        return mockResponse;
    };

    /**
     * Send given HTTP status code.
     *
     * Sets the response status to `statusCode` and the body of the
     * response to the standard description from node's http.STATUS_CODES
     * or the statusCode number if no description.
     *
     * Examples:
     *
     *     mockResponse.sendStatus(200);
     *
     * @param {number} statusCode
     * @api public
     */

    mockResponse.sendStatus = function sendStatus(statusCode) {
        var body = http.STATUS_CODES[statusCode] || String(statusCode);

        mockResponse.statusCode = statusCode;
        mockResponse.type('txt');

        return mockResponse.send(body);
    };


    /**
     * Function: json
     *
     *   The 'json' function from node's HTTP API that returns JSON
     *   data to the client.
     *
     *  Parameters:
     *
     *   a - Either a statusCode or string containing JSON payload
     *   b - Either a statusCode or string containing JSON payload
     *
     *  If not specified, the statusCode defaults to 200.
     *  Second parameter is optional.
     */
    mockResponse.json = function(a, b) {

        mockResponse.setHeader('Content-Type', 'application/json');
        if (typeof a !== 'undefined') {
            if (typeof a === 'number' && typeof b !== 'undefined') {
                mockResponse.statusCode = a;
                mockResponse.write(JSON.stringify(b), 'utf8');
            } else if(typeof b !== 'undefined' && typeof b === 'number') {
                mockResponse.statusCode = b;
                mockResponse.write(JSON.stringify(a), 'utf8');
            } else {
                mockResponse.write(JSON.stringify(a), 'utf8');
            }
        }
        mockResponse.emit('send');
        mockResponse.end();

        return mockResponse;
    };

    /**
     * Function: jsonp
     *
     *   The 'jsonp' function from node's HTTP API that returns JSON
     *   data to the client.
     *
     *  Parameters:
     *
     *   a - Either a statusCode or string containing JSON payload
     *   b - Either a statusCode or string containing JSON payload
     *
     *  If not specified, the statusCode defaults to 200.
     *  Second parameter is optional.
     */
    mockResponse.jsonp = function(a, b) {

        mockResponse.setHeader('Content-Type', 'text/javascript');
        if (typeof a !== 'undefined') {
            if (typeof a === 'number' && typeof b !== 'undefined') {
                mockResponse.statusCode = a;
                _data += JSON.stringify(b);
            } else if(typeof b !== 'undefined' && typeof b === 'number') {
                mockResponse.statusCode = b;
                _data += JSON.stringify(a);
            } else {
                _data += JSON.stringify(a);
            }
        }
        mockResponse.emit('send');
        mockResponse.end();

        return mockResponse;
    };

    /**
     * Set "Content-Type" response header with `type` through `mime.lookup()`
     * when it does not contain "/", or set the Content-Type to `type` otherwise.
     *
     * Examples:
     *
     *     res.type('.html');
     *     res.type('html');
     *     res.type('json');
     *     res.type('application/json');
     *     res.type('png');
     *
     * @param {String} type
     * @return {ServerResponse} for chaining
     * @api public
     */
    mockResponse.contentType = mockResponse.type = function(type) {
        return mockResponse.set('Content-Type', type.indexOf('/') >= 0 ? type : mime.lookup(type));
    };

    /**
     * Set 'Location' response header.
     *
     * @see http://expressjs.com/en/api.html#res.location
     *
     * @param  {String}         location The location to set in the header.
     * @return {ServerResponse}          For chaining
     */
    mockResponse.location = function(location) {
        return mockResponse.set('Location', location);
    };

    /**
     * Function: write
     *
     *    This function has the same behavior as the 'send' function.
     *
     * Parameters:
     *
     *  data - The data to return. Must be a string. Appended to
     *         previous calls to data.
     *  encoding - Optional encoding value.
     */

    mockResponse.write = function(data, encoding) {

        mockResponse.headersSent = true;

        if (data instanceof Buffer) {
            _chunks.push(data);
            _size += data.length;
        } else {
            _data += data;
        }

        if (encoding) {
            _encoding = encoding;
        }

    };
    
    /**
     *  Function: getEndArguments
     *
     *  Utility function that parses and names parameters for the various
     *  mockResponse.end() signatures. Reference:
     *  https://nodejs.org/api/http.html#http_response_end_data_encoding_callback
     *  
     */
    function getEndArguments(args) {
        var data, encoding, callback;
        if (args[0]) {
            if (typeof args[0] === 'function') {
                callback = args[0];
            } else {
                data = args[0];
            }
        }
        if (args[1]) {
            var type = typeof args[1];
            if (type === 'function') {
                callback = args[1];
            } else if (type === 'string' || args[1] instanceof String){
                encoding = args[1];
            }
        }
        if (args[2] && typeof args[2] === 'function') {
            callback = args[2];
        }
        return { data: data, encoding: encoding, callback: callback };
    }

    /**
     *  Function: end
     *
     *  The 'end' function from node's HTTP API that finishes
     *  the connection request. This must be called.
     *  
     *  Signature: response.end([data[, encoding]][, callback])
     *
     *  Parameters:
     *
     *  data - Optional data to return. Must be a string or Buffer instance. 
     *         Appended to previous calls to <send>.
     *  encoding - Optional encoding value.
     *  callback - Optional callback function, called once the logic has run
     *
     */
    mockResponse.end = function() {
        if (_endCalled) {
            // Do not emit this event twice.
            return;
        }

        mockResponse.finished = true;
        mockResponse.writableEnded = true;
        mockResponse.headersSent = true;

        _endCalled = true;
        
        var args = getEndArguments(arguments);
        
        if (args.data) {
            if (args.data instanceof Buffer) {
                _chunks.push(args.data);
                _size += args.data.length;
            } else {
                _data += args.data;
            }
        }

        if (_chunks.length) {
            switch (_chunks.length) {
                case 1:
                    _buffer = _chunks[0];
                    break;
                default:
                    _buffer = Buffer.alloc(_size);
                    for (var i = 0, pos = 0, l = _chunks.length; i < l; i++) {
                        var chunk = _chunks[i];
                        chunk.copy(_buffer, pos);
                        pos += chunk.length;
                    }
                    break;
            }
        }

        if (args.encoding) {
            _encoding = args.encoding;
        }
        
        mockResponse.emit('end');
        mockResponse.writableFinished = true; //Reference: https://nodejs.org/docs/latest-v12.x/api/http.html#http_request_writablefinished
        mockResponse.emit('finish');
        
        if (args.callback) {
            args.callback();
        }
    };
    

    /**
     * Function: vary
     *
     *   Adds the field/s to the Vary response header
     *
     * Examples:
     *
     *    res.vary('A-B-Test');
     *    res.vary(['A-B-Test', 'Known-User']);
     */
    mockResponse.vary = function(fields) {
        var header = mockResponse.getHeader('Vary') || '';
        var values = header.length ? header.split(', ') : [];

        fields = Array.isArray(fields) ? fields : [ fields ];

        fields = fields.filter(function(field) {
            var regex = new RegExp(field, 'i');

            var matches = values.filter(function(value) {
                return value.match(regex);
            });

            return !matches.length;
        });

        values = values.concat(fields);

        return mockResponse.setHeader('Vary', values.join(', '));
    };

    /**
     * Set _Content-Disposition_ header to _attachment_ with optional `filename`.
     * 
     * Example:
     * 
     *      res.attachment('download.csv')
     *
     * @param {String} filename
     * @return {ServerResponse}
     * @api public
     */

    mockResponse.attachment = function attachment(filename) {
        if (filename) {
            mockResponse.type(path.extname(filename));
        }
    
        mockResponse.set('Content-Disposition', contentDisposition(filename));
    
        return this;
    };

    /**
     * Append additional header `field` with value `val`.
     *
     * Example:
     *
     *    res.append('Link', ['<http://localhost/>', '<http://localhost:3000/>']);
     *    res.append('Set-Cookie', 'foo=bar; Path=/; HttpOnly');
     *    res.append('Warning', '199 Miscellaneous warning');
     *
     * @param {String} field
     * @param {String|Array} val
     * @return {ServerResponse} for chaining
     * @api public
     */
    mockResponse.append = function append(field, val) {
        var prev = mockResponse.get(field);
        var value = val;

        if (prev) {
            // concat the new and prev vals
            value = Array.isArray(prev) ? prev.concat(val)
                : Array.isArray(val) ? [prev].concat(val)
                    : [prev, val];
        }

        return mockResponse.set(field, value);
    };

    /**
     * Set header `field` to `val`, or pass
     * an object of header fields.
     *
     * Examples:
     *
     *    res.set('Foo', ['bar', 'baz']);
     *    res.set('Accept', 'application/json');
     *    res.set({ Accept: 'text/plain', 'X-API-Key': 'tobi' });
     *
     * Aliased as `mockResponse.header()`.
     *
     * @param {String|Object|Array} field
     * @param {String} val
     * @return {ServerResponse} for chaining
     * @api public
     */
    mockResponse.set = mockResponse.header = function header(field, val) {
        if (arguments.length === 2) {
            if (Array.isArray(val)) {
                val = val.map(String);
            } else {
                val = String(val);
            }
            mockResponse.setHeader(field, val);
        } else if (typeof field === 'string') {
            return mockResponse.getHeader(field);
        } else { // eslint-disable-line
            for (var key in field) {
                mockResponse.setHeader(key, field[key]);
            }
        }
        return mockResponse;
    };

    /**
     * Function: getHeaders
     *
     *   Returns a shallow copy of the current outgoing headers.
     */
    mockResponse.getHeaders = function() {
        return JSON.parse(JSON.stringify(mockResponse._headers));
    };

    /**
     * Function: getHeader
     * Function: get
     *
     *   Returns a particular header by name.
     */
    mockResponse.get = mockResponse.getHeader = function(name) {
        return mockResponse._headers[name.toLowerCase()];
    };

    /**
     * Function: getHeaderNames
     *
     *   Returns an array containing the unique names of the current outgoing headers.
     */
    mockResponse.getHeaderNames = function() {
        return Object.keys(mockResponse._headers); // names are already stored in lowercase
    };

    /**
     * Function: hasHeader
     *
     *   Returns `true` if the header identified by `name` is currently set.
     */
    mockResponse.hasHeader = function(name) {
        return name.toLowerCase() in mockResponse._headers;
    };

    /**
     * Function: setHeader
     * Function: set
     *
     *   Set a particular header by name.
     */
    mockResponse.setHeader = function(name, value) {
        mockResponse._headers[name.toLowerCase()] = value;
        return this;
    };

    /**
     * Function: removeHeader
     *
     *   Removes an HTTP header by name.
     */
    mockResponse.removeHeader = function(name) {
        delete mockResponse._headers[name.toLowerCase()];
    };

    /**
     * Function: setEncoding
     *
     *    Sets the encoding for the data. Generally 'utf8'.
     *
     * Parameters:
     *
     *   encoding - The string representing the encoding value.
     */
    mockResponse.setEncoding = function(encoding) {
        _encoding = encoding;
    };

    mockResponse.getEncoding = function() {
        return _encoding;
    };

    /**
     * Function: redirect
     *
     *     Redirect to a url with response code
     */
    mockResponse.redirect = function(a, b) {
        switch (arguments.length) {
            case 1:
                mockResponse.statusCode = 302;
                _redirectUrl = a;
                break;

            case 2:
                if (typeof a === 'number') {
                    mockResponse.statusCode = a;
                    _redirectUrl = b;
                }
                break;

            default:
                break;
        }
        mockResponse.end();
    };

    /**
     * Function: render
     *
     *     Render a view with a callback responding with the
     *     rendered string.
     */
    mockResponse.render = function(a, b, c) {
        _renderView = a;

        var data = b;
        var done = c;

        // support callback function as second arg
        if (typeof b === 'function') {
            done = b;
            data = {};
        }

        switch (arguments.length) {
            case 2:
            case 3:
                _renderData = data;
                break;

            default:
                break;
        }

        if (typeof done === 'function') {
            done(null, '');
        } else {
            mockResponse.emit('render');
            mockResponse.end();
        }
    };

    /**
     * Chooses the correct response function from the given supported types.
     * This method requires that the mockResponse object be initialized with a
     * mockRequest object reference, otherwise it will throw. @see createMocks.
     *
     * @param  {Object} supported Object with formats to handler functions.
     * @return {Object}           Whatever handler function returns.
     */
    mockResponse.format = function(supported) {
        supported = supported || {};
        var types = Object.keys(supported);

        if (types.length === 0) {
            return mockResponse.sendStatus(406);
        }

        if (!mockRequest) {
            throw new Error(
                'Request object unavailable. Use createMocks or pass in a ' +
                    'request object in createResponse to use format.'
            );
        }

        var accepted = mockRequest.accepts(types);

        if (accepted) {
            return supported[accepted]();
        }

        if (supported.default) {
            return supported.default();
        }

        return mockResponse.sendStatus(406);
    };

    // WritableStream.writable is not a function
    // mockResponse.writable = function() {
    //     return writableStream.writable.apply(this, arguments);
    // };

    // mockResponse.end = function(){
    //  return writableStream.end.apply(this, arguments);
    // };

    mockResponse.destroy = function() {
        return writableStream.destroy.apply(this, arguments);
    };

    mockResponse.destroySoon = function() {
        return writableStream.destroySoon.apply(this, arguments);
    };

    //This mock object stores some state as well
    //as some test-analysis functions:

    /**
     * Function: _isEndCalled
     *
     *  Since the <end> function must be called, this function
     *  returns true if it has been called. False otherwise.
     */
    mockResponse._isEndCalled = function() {
        return _endCalled;
    };

    /**
     * Function: _getHeaders
     *
     *  Returns all the headers that were set. This may be an
     *  empty object, but probably will have "Content-Type" set.
     */
    mockResponse._getHeaders = function() {
        return mockResponse._headers;
    };

    /**
     *  Function: _getLocals
     *
     *  Returns all the locals that were set.
     */
    mockResponse._getLocals = function() {
        return mockResponse.locals;
    };

    /**
     * Function: _getData
     *
     *  The data sent to the user.
     */
    mockResponse._getData = function() {
        return _data;
    };

    /**
     * Function: _getJSONData
     *
     *  The data sent to the user as JSON.
     */
    mockResponse._getJSONData = function() {
        return JSON.parse(_data);
    };

    /**
     * Function: _getBuffer
     *
     *  The buffer containing data to be sent to the user.
     *  Non-empty if Buffers were given in calls to write() and end()
     */
    mockResponse._getBuffer = function() {
        return _buffer;
    };


    /**
     * Function: _getChunks
     *
     *  The buffer containing data to be sent to the user.
     *  Non-empty if Buffers were given in calls to write() and end()
     */
    mockResponse._getChunks = function() {
        return _chunks;
    };

    /**
     * Function: _getStatusCode
     *
     *  The status code that was sent to the user.
     */
    mockResponse._getStatusCode = function() {
        return mockResponse.statusCode;
    };

    /**
     * Function: _getStatusMessage
     *
     *  The status message that was sent to the user.
     */
    mockResponse._getStatusMessage = function() {
        return mockResponse.statusMessage;
    };

    /**
     * Function: _isJSON
     *
     *  Returns true if the data sent was defined as JSON.
     *  It doesn't validate the data that was sent.
     */
    mockResponse._isJSON = function() {
        return mockResponse.getHeader('Content-Type') === 'application/json';
    };

    /**
     * Function: _isUTF8
     *
     *    If the encoding was set, and it was set to UTF-8, then
     *    this function return true. False otherwise.
     *
     * Returns:
     *
     *   False if the encoding wasn't set and wasn't set to "utf8".
     */
    mockResponse._isUTF8 = function() {
        if (!_encoding) {
            return false;
        }
        return _encoding === 'utf8';
    };

    /**
     * Function: _isDataLengthValid
     *
     *    If the Content-Length header was set, this will only
     *    return true if the length is actually the length of the
     *    data that was set.
     *
     * Returns:
     *
     *   True if the "Content-Length" header was not
     *   set. Otherwise, it compares it.
     */
    mockResponse._isDataLengthValid = function() {
        if (mockResponse.getHeader('Content-Length')) {
            return mockResponse.getHeader('Content-Length').toString() === _data.length.toString();
        }
        return true;
    };

    /**
     * Function: _getRedirectUrl
     *
     *     Return redirect url of redirect method
     *
     * Returns:
     *
     *     Redirect url
     */
    mockResponse._getRedirectUrl = function() {
        return _redirectUrl;
    };

    /**
     * Function: _getRenderView
     *
     *     Return render view of render method
     *
     * Returns:
     *
     *     render view
     */
    mockResponse._getRenderView = function() {
        return _renderView;
    };

    /**
     * Function: _getRenderData
     *
     *     Return render data of render method
     *
     * Returns:
     *
     *     render data
     */
    mockResponse._getRenderData = function() {
        return _renderData;
    };

    return mockResponse;

}

module.exports.createResponse = createResponse;