问题
I want to know the best way to return a bunch of JSON that is the result of some dependent mysql queries.
app.get('/viewing/:id', function (req, res){
if(!req.cookies.user) {
res.end('Requires Authenticated User');
} else {
connection.query('SELECT blah blah where userId='+req.params.id,
function (error, rows, fields) {
Now we have a bunch of rows -- lets say 5. I need to go through each one and make another mysql query based on the data I just got. So I end up needing to repeat call (do I loop?)
connection.query('SELECT id, firstName, lastName from users where id='+AN_ID_FROM_PRIOR_QUERY,
function (error2, rows2, fields2) {
});
}
}
How do I combine the rows from each of the repeated selects of the second query into a single object that can be returned as JSON?
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end(JSON.stringify(results));
}
});
}
});
回答1:
Asked and answered.
The Async.js utility has lots of good stuff including a map function and underscores.js helps tidy anything up!
app.get('/viewing/:id', function (req, res){
if(!req.cookies.user) {
res.end('Requires Authenticated User');
}
else {
connection.query('SELECT something,somethingelse from mytable where userId = ?',[req.params.id], function (error, rows, fields) {
async.map(rows, getUsers, function(err, results){
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end(JSON.stringify(_.flatten(_.compact(results))));
});
});
}
});
function getUsers(user, callback) {
connection.query('SELECT id,firstName,lastName FROM users WHERE id = '+ user.otherId, function(err, info) {
if(err) {
console.log(err);
return callback(err);
}
else {
return callback(null, info);
}
});
}
来源：https://stackoverflow.com/questions/17913916/combining-node-mysql-result-rows-into-single-json-return-for-node-js