Let's say I have two events:
{"id":1, "name":"event1"},
{"id":2, "name":"event2"}
And I am writing a REST API to retrieve events. This API takes an optional parameter, id, which if present, returns events specific to that id only, and returns all events if null.
So api/events?id=1 should return event1 only, while api/events will return both event1 and event2. Currently I am using an if-else statement, but this is clearly not scalable if I have more optional parameters. Is there any way to express this as a MongoDB query instead?
Code:
app.get('/api/events', function (req, res) {
var _get = url.parse(req.url, true).query,
eventCollection = db.collection('events');
// Parameters passed in URL
var page = (_get.page) ? _get.page * 10 : 0,
org_id = (_get_id) ? parseInt(_get_id) : "";
if (org_id == "") {
eventCollection.find({
}, {
limit: 10,
skip: page
}).toArray(function(err, events) {
if (!err) {
res.json(
events
);
}
});
} else {
eventCollection.find({
org_id: org_id
}, {
limit: 10,
skip: page
}).toArray(function(err, events) {
if (!err) {
res.json(
events
);
}
});
}
});
P.S. I am using the Node.js Javascript driver for MongoDB.
Let's say I have two events:
{"id":1, "name":"event1"},
{"id":2, "name":"event2"}
And I am writing a REST API to retrieve events. This API takes an optional parameter, id, which if present, returns events specific to that id only, and returns all events if null.
So api/events?id=1 should return event1 only, while api/events will return both event1 and event2. Currently I am using an if-else statement, but this is clearly not scalable if I have more optional parameters. Is there any way to express this as a MongoDB query instead?
Code:
app.get('/api/events', function (req, res) {
var _get = url.parse(req.url, true).query,
eventCollection = db.collection('events');
// Parameters passed in URL
var page = (_get.page) ? _get.page * 10 : 0,
org_id = (_get_id) ? parseInt(_get_id) : "";
if (org_id == "") {
eventCollection.find({
}, {
limit: 10,
skip: page
}).toArray(function(err, events) {
if (!err) {
res.json(
events
);
}
});
} else {
eventCollection.find({
org_id: org_id
}, {
limit: 10,
skip: page
}).toArray(function(err, events) {
if (!err) {
res.json(
events
);
}
});
}
});
P.S. I am using the Node.js Javascript driver for MongoDB.
Share Improve this question asked Oct 25, 2013 at 1:47 Wei HaoWei Hao 2,8569 gold badges28 silver badges40 bronze badges1 Answer
Reset to default 14Single Parameter
One idea would be to set the query object with the ternary operator.
Something like the following:
app.get('/api/events', function (req, res) {
var _get = url.parse(req.url, true).query,
eventCollection = db.collection('events');
// Parameters passed in URL
var page = (_get.page) ? _get.page * 10 : 0,
query = (_get_id) ? {org_id:parseInt(_get_id)} : {};
eventCollection.find(query, {limit: 10, skip: page}).toArray(function(err, events){
if (!err) {
res.json(
events
);
}
});
});
Multiple Parameters
Having that been said, if you have multiple parameters to query, one way would be to build a JSON object like below:
app.get('/api/events', function (req, res) {
var _get = url.parse(req.url, true).query,
eventCollection = db.collection('events');
// Parameters passed in URL
var page = (_get.page) ? _get.page * 10 : 0,
query = {};
(_get_id) ? (query_id = parseInt(_get_id)) : "";
(_get.name) ? (query.name = _get.name) : "";
(_get.param3) ? (query.name = _get.param3) : "";
eventCollection.find(query, {limit: 10, skip: page}).toArray(function(err, events){
if (!err) {
res.json(
events
);
}
});
});
I'll leave it to you to take the block where the query parameters are defined and turn it into a for loop.
Unknown Parameters
If you don't know the number of parameters ahead of time, one option is to build a string and then convert it to a JSON object. However, I don't remend this. It's dangerous to let users define parameters.