Node.js API在终端中返回JSON,但在浏览器中不返回
问题描述:
有一个奇怪的问题。一直在寻找答案,但没有出现。我正在做一个节点api教程,当我执行任何GET请求时,它会从我的终端中的mongoDB数据库返回JSON,但在我的浏览器或邮递员中我什么都没有收回,只有在终端中才能得到任何响应。当我在postman中尝试POST时,它说它无法连接到后端。Node.js API在终端中返回JSON,但在浏览器中不返回
这里是我的代码:
var http = require('http');
var url = require('url');
var database = require('./database');
// Generic find methods (GET)
function findAllResources(resourceName, req, res) {
database.find('OrderBase', resourceName, {}, function (err, resources) {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resources));
});
};
var findResourceById = function (resourceName, id, req, res) {
database.find('OrderBase', resourceName, {'_id': id}, function (err, resource) {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resource));
});
};
// Product methods
var findAllProducts = function (req, res) {
findAllResources('Products', req, res);
};
var findProductById = function (id, req, res) {
findResourceById('Products', id, req, res);
};
// Generic insert/update methods (POST, PUT)
var insertResource = function (resourceName, resource, req, res) {
database.insert('OrderBase', resourceName, resource, function (err, resource) {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resource));
});
};
// Product methods
var insertProduct = function (product, req, res) {
insertResource('OrderBase', 'Product', product, function (err, result) {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(result));
});
};
var server = http.createServer(function (req, res) {
// Break down the incoming URL into its components
var parsedURL = url.parse(req.url, true);
// determine a response based on the URL
switch (parsedURL.pathname) {
case '/api/products':
if (req.method === 'GET') {
// Find and return the product with the given id
if (parsedURL.query.id) {
findProductById(id, req, res)
}
// There is no id specified, return all products
else {
findAllProducts(req, res);
}
}
else if (req.method === 'POST') {
//Extract the data stored in the POST body
var body = '';
req.on('data', function (dataChunk) {
body += dataChunk;
});
req.on('end', function() {
// Done pulling data from the POST body.
// Turn it into JSON and proceed to store it in the database.
var postJSON = JSON.parse(body);
insertProduct(postJSON, req, res);
});
}
break;
default:
res.end('You shall not pass!');
}
});
server.listen(8080);
console.log('Up and running, ready for action!');
答
你有几个回调与err
作为第一个参数,但你没有治疗任何潜在的错误。这意味着如果出现问题,您不会捕获并返回错误。我不知道这有什么关系,但作为一种实践(甚至没有“最好”的,但一般的做法),而不是做这个
function (err, resource) {
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resource));
}
做到这一点
function (err, resource) {
if(err){
// do something to warn the client and stop here
}
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resource));
}
尝试在试图输出答案之前,看看你是否真的遇到了错误。
答
https://nodejs.org/api/http.html#http_response_end_data_encoding_callback
响应端方法不将数据发送到响应插座。也许你改了它
res.writeHead(200, {'Content-Type': 'application/json'});
res.end(JSON.stringify(resource));
res.writeHead(200, {'Content-Type': 'application/json'});
res.write(JSON.stringify(resource));
res.end();
如果你想socket关闭做某事,你可以进入回调结束。
res.end(#logHandle());
答
var MongoClient = require('mongodb').MongoClient;
var assert = require('assert');
var connect = function (databaseName, callback) {
var url = 'mongodb://localhost:27017/' + databaseName;
MongoClient.connect(url, function (error, database) {
assert.equal(null, error);
console.log("Successfully connected to MongoDB instance!");
callback(database);
})
};
exports.find = function (databaseName, collectioName, query, callback) {
connect(databaseName, function (database) {
var collection = database.collection(collectioName);
collection.find(query).toArray(
function (err, documents) {
assert.equal(err, null);
console.log('MongoDB returned the following documents:');
console.dir(JSON.parse(JSON.stringify(documents)));
//console.dir(documents);
callback(null, documents);
}
)
database.close();
})
};
我认为我们正在经历同样的教程,这是我的“database.js”的解决方案,为我工作。