How to write result in a file by using node.js and express?
Question
I've built an application using node.js and express.js on top of elasticsearch. This is very simple application with a search box. When you search for a query, it prints result in JSON format. For eg, if I search for keyword "white", the output looks like this: http://i.stack.imgur.com/VHuWl.png
Now I want to store this result in a file(for eg output.json).This is my json file:
var fs = require('fs');
var path = "output.json";
var express = require('express'); //To make use of Express' routing capabilities you need to initiate a new Express Router.
var router = express.Router(); //To make use of Express' routing capabilities you need to initiate a new Express Router. get, put, post, delete, all
var searchModule = require('../search_module/search.js');
//There are two ways of using the router methods. You can define one route (for example /home) and attach the methods to it, or you can create a new method for each route.
/* GET home page. */
router.get('/', function(req, res) { //.get() - when you visit a website you make a GET request. You can get data from a URL in a GET request too.
res.render('index', { title: 'Express' });
});
router.post('/search-results', function(req, res) {//.post() is a method used everywhere for posting data to a server / app. You'll want to use this for submitting forms.
searchModule.search(req.body, function(data) {
res.render('index', { title: 'Express', results: data });
});
});
fs.writeFile(path,data,function(err){
if(err) console.error(err);
})
module.exports = router;
When I tried using writeFile method of node.js, I am getting an Reference error showing that "data" is not defined. My error looks like this: http://i.stack.imgur.com/lwXfW.png
I am not able to figure out this error. Is there any other way to write the output to a file by using node.js and express?
Edit: I edited my javascript
var fs = require('fs');
var path = "output.json";
var express = require('express'); //To make use of Express' routing capabilities you need to initiate a new Express Router.
var router = express.Router(); //To make use of Express' routing capabilities you need to initiate a new Express Router. get, put, post, delete, all
var searchModule = require('../search_module/search.js');
//There are two ways of using the router methods. You can define one route (for example /home) and attach the methods to it, or you can create a new method for each route.
/* GET home page. */
router.get('/', function(req, res) { //.get() - when you visit a website you make a GET request. You can get data from a URL in a GET request too.
res.render('index', { title: 'Express' });
});
router.post('/search-results', function(req, res) {//.post() is a method used everywhere for posting data to a server / app. You'll want to use this for submitting forms.
searchModule.search(req.body, function(data) {
fs.writeFile(path,data,function(err){
if(err) console.error(err);
})
res.render('index', { title: 'Express', results: data });
});
});
module.exports = router;
But when I ran this javascript, I got this output: http://i.stack.imgur.com/rfBq0.png
I am not getting the JSON output. My output should look like this: http://i.stack.imgur.com/VHuWl.png
I am also using an ejs file with my javascript for the frontend(index.ejs) which looks like this:
<!DOCTYPE html>
<html>
<head>
<title><%= title %></title>
</head>
<body>
<h1><%= title %></h1>
<form action='/search-results' method='post'>
<input type="text" name="searchTerm" placeholder="your search term here">
<button type="submit"> SEARCH </button>
</form>
<ul>
<% if(locals.results) { %>
<pre>
<%= JSON.stringify(results,null,2) %>
</pre>
<% results.forEach( function( result ) }) %>
<% } %>
</ul>
</body>
</html>
Do I need to get output from this file?
2 answers
solution1
1 2016-05-03 20:44:24
I'm looking at this block:
fs.writeFile(path,data,function(err){
if(err) console.error(err);
})
You've declared path at the top of your code, but data appears to be undefined in this context.
solution2
1 ACCPTED 2016-05-03 20:46:30
The data variable is not defined at this point. You can move your fs.writeFile function in the searchModule.search call like this:
searchModule.search(req.body, function(data) {
fs.writeFile(path,data,function(err){
if(err) console.error(err);
})
res.render('index', { title: 'Express', results: data });
});
or declare your variable before and set it in the searchModule.search call, to be disponible after in the scope to write your file:
var fileData;
searchModule.search(req.body, function(data) {
fileData = data;
res.render('index', { title: 'Express', results: data });
});
fs.writeFile(path,fileData,function(err){
if(err) console.error(err);
})
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