I am trying fetch records from mongoDB through mongoose
router.route('/testaa')
.get(function(req,res){
fisSite.find(function(err, retVal) {
var x = [];
for(var i =0;i<retVal.length;i++){
x.push(retVal[i].site);
}
res.json(x)
});
})
The above code is giving undefined values.
undefined
undefined
undefined
.....
Please help to run the for loop inside node.js so that i can use extract data from array.
Currently what you are doing is you are getting all the document fields and then using only one from it. You can optimize the query using select method which will only retrieve particular field only rather than all fields :
[Note : id field is added by default, hence to remove it in select we specifically mention it using -_id. You can remove -_id if you want to maintain ID inside the response document.]
fisSite.find({}).select('site -_id').exec(function(err, docs)){
if(err){
return res.json({ status : false, message : 'Error Occured.'} );
}
else if(!docs){
return res.json({ status : false, message : 'No documents found.'} );
}
else{
return res.json({ status : success, message : 'Documents found.', data : docs} );
}
}
Imagine you have 10 fields in each document and find results 100 documents, you only need site field from those 100 documents,however unnecessarily you are calling remaining 900 fields.
I have used Lean.exec within Mongoose.
router.route('/site')
.get(function(req,res){
fisSite.find().lean().exec(function(err, retVal) {
var x = [];
for(var i =0;i<retVal.length;i++){
x.push(retVal[i].site);
}
res.json(x)
})
});
Try to add an empty search query to select all documents
Try to change
From this:
fisSite.find(function(err, retVal)
To this:
fisSite.find({}, function(err, retVal)
Also try to do a console.log(retVal) to check if your find actually returns any values.
Related
I want to know the link which was used by the user to join the group and I try to get the invite_link derived from this variable :
But, when I used getUpdates() method to receive incoming updates (Update is the object on which ChatMemberUpdated is),it didn't include invite_link.
This is the code (nodejs):
await client.getUpdates({ offset : 0, allowed_updates : 'chat_member' }).then(async function(update) {
console.log(update)
if (update.length != 0){
fs.appendFile('update.txt', JSON.stringify(update), function (err) {
if (err) throw err
console.log('Saved!')
})
}
})
And this is the result:
[{"update_id":xx96xxxxx,"message":{"message_id":2xxxx,"from":{"id":x669xxxxxx,"is_bot":false,"first_name":"xx.nwxxx","language_code":"es"},"chat":{"id":-xxxx4506xxxxx,"title":"xxxxxxx","type":"supergroup"},"date":xxx195xxxx,"new_chat_participant":{"id":xxx9660xxx,"is_bot":false,"first_name":"xxxnwxxx","language_code":"es"},"new_chat_member":{"id":xxx9660xxx,"is_bot":false,"first_name":"xxxnwxxx","language_code":"es"},"new_chat_members":[{"id":xxx9660xxx,"is_bot":false,"first_name":"xxxnwxxx","language_code":"es"}]}}]
At the moment to create the invite_link, you need to specified "creates_join_request" as true. Otherwise, the bot cannot detect the link.
In a DocDb stored procedure, as the first step in a process retrieving data that I'm mutating, I read and then use the data iff it matches the etag like so:
collection.readDocument(reqSelf, function(err, doc) {
if (doc._etag == requestEtag) {
// Success - want to update
} else {
// CURRENTLY: Discard the read result I just paid lots of RUs to read
// IDEALLY: check whether response `options` or similar indicates retrieval
was skipped due to doc not being present with that etag anymore
...
// ... Continue with an alternate strategy
}
});
Is there a way to pass an options to the readDocument call such that the callback will be informed "It's changed so we didn't get it, as you requested" ?
(My real problem here is that I can't find any documentation other than the readDocument undocumentation in the js-server docs)
Technically you can do that by creating a responseOptions object and passing it to the call.
function sample(selfLink, requestEtag) {
var collection = getContext().getCollection();
var responseOptions = { accessCondition: { type: "IfMatch", condition: requestEtag } };
var isAccepted = collection.readDocument(selfLink, responseOptions, function(err, doc, options) {
if(err){
throw new Error('Error thrown. Check the status code for PreconditionFailed errors');
}
var response = getContext().getResponse();
response.setBody(doc);
});
if (!isAccepted) throw new Error('The query was not accepted by the server.');
}
However, even if the etag you provide is not the one that the document has, you won't get an error and you will properly get the document itself back. It's just not supposed to work with that using the readDocument function in a stored procedure.
Thanks to some pushing from #Nick Chapsas, and this self-answer from #Redman I worked out that in my case I can achieve my goal (either read the current document via the self-link, or the newer one that has replaced it bearing the same id) by instead generating an Alt link within the stored procedure like so:
var docId = collection.getAltLink() + "/docs/"+req.id;
var isAccepted = collection.readDocument(docId, {}, function (err, doc, options) {
if (err) throw err;
// Will be null or not depending on whether it exists
executeUpsert(doc);
});
if (!isAccepted) throw new Error("readDocument not Accepted");
I am attempting to perform an update to a MongoDB document (using mongoose) by first using .findById to get the document, then updating the fields in that document with new values. I am still a bit new to this so I used a tutorial to figure out how to get it working, then I have been updating my code for my needs. Here is the tutorial: MEAN App Tutorial with Angular 4. The original code had a schema defined, but my requirement is for a generic MongoDB interface that will simply take whatever payload is sent to it and send it along to MongoDB. The original tutorial had something like this:
exports.updateTodo = async function(todo){
var id = todo.id
try{
//Find the old Todo Object by the Id
var oldTodo = await ToDo.findById(id);
}catch(e){
throw Error("Error occured while Finding the Todo")
}
// If no old Todo Object exists return false
if(!oldTodo){
return false;
}
console.log(oldTodo)
//Edit the Todo Object
oldTodo.title = todo.title
oldTodo.description = todo.description
oldTodo.status = todo.status
console.log(oldTodo)
try{
var savedTodo = await oldTodo.save()
return savedTodo;
}catch(e){
throw Error("And Error occured while updating the Todo");
}
}
However, since I don't want a schema and want to allow anything through, I don't want to assign static values to specific field names like, title, description, status, etc. So, I came up with this:
exports.updateData = async function(update){
var id = update.id
// Check the existence of the query parameters, If they don't exist then assign a default value
var dbName = update.dbName ? update.dbName : 'test'
var collection = update.collection ? update.collection : 'testing';
const Test = mongoose.model(dbName, TestSchema, collection);
try{
//Find the existing Test object by the Id
var existingData = await Test.findById(id);
}catch(e){
throw Error("Error occurred while finding the Test document - " + e)
}
// If no existing Test object exists return false
if(!existingData){
return false;
}
console.log("Existing document is " + existingData)
//Edit the Test object
existingData = JSON.parse(JSON.stringify(update))
//This was another way to overwrite existing field values, but
//performs a "shallow copy" so it's not desireable
//existingData = Object.assign({}, existingData, update)
//existingData.title = update.title
//existingData.description = update.description
//existingData.status = update.status
console.log("New data is " + existingData)
try{
var savedOutput = await existingData.save()
return savedOutput;
}catch(e){
throw Error("An error occurred while updating the Test document - " + e);
}
}
My original problem with this was that I had a lot of issues getting the new values to overwrite the old ones. Now that that's been solved, I am getting the error of "TypeError: existingData.save is not a function". I am thinking the data type changed or something, and now it is not being accepted. When I uncomment the static values that were in the old tutorial code, it works. This is further supported by my console logging before and after I join the objects, because the first one prints the actual data and the second one prints [object Object]. However, I can't seem to figure out what it's expecting. Any help would be greatly appreciated.
EDIT: I figured it out. Apparently Mongoose has its own data type of "Model" which gets changed if you do anything crazy to the underlying data by using things like JSON.stringify. I used Object.prototype.constructor to figure out the actual object type like so:
console.log("THIS IS BEFORE: " + existingData.constructor);
existingData = JSON.parse(JSON.stringify(update));
console.log("THIS IS AFTER: " + existingData.constructor);
And I got this:
THIS IS BEFORE: function model(doc, fields, skipId) {
model.hooks.execPreSync('createModel', doc);
if (!(this instanceof model)) {
return new model(doc, fields, skipId);
}
Model.call(this, doc, fields, skipId);
}
THIS IS AFTER: function Object() { [native code] }
Which showed me what was actually going on. I added this to fix it:
existingData = new Test(JSON.parse(JSON.stringify(update)));
On a related note, I should probably just use the native MongoDB driver at this point, but it's working, so I'll just put it on my to do list for now.
You've now found a solution but I would suggest using the MongoDB driver which would make your code look something along the lines of this and would make the origional issue disappear:
// MongoDB Settings
const MongoClient = require(`mongodb`).MongoClient;
const mongodb_uri = `mongodb+srv://${REPLACE_mongodb_username}:${REPLACE_mongodb_password}#url-here.gcp.mongodb.net/test`;
const db_name = `test`;
let db; // allows us to reuse the database connection once it is opened
// Open MongoDB Connection
const open_database_connection = async () => {
try {
client = await MongoClient.connect(mongodb_uri);
} catch (err) { throw new Error(err); }
db = client.db(db_name);
};
exports.updateData = async update => {
// open database connection if it isn't already open
try {
if (!db) await open_database_connection();
} catch (err) { throw new Error(err); }
// update document
let savedOutput;
try {
savedOutput = await db.collection(`testing`).updateOne( // .save() is being depreciated
{ // filter
_id: update.id // the '_id' might need to be 'id' depending on how you have set your collection up, usually it is '_id'
},
$set: { // I've assumed that you are overwriting the fields you are updating hence the '$set' operator
update // update here - this is assuming that the update object only contains fields that should be updated
}
// If you want to add a new document if the id isn't found add the below line
// ,{ upsert: true }
);
} catch (err) { throw new Error(`An error occurred while updating the Test document - ${err}`); }
if (savedOutput.matchedCount !== 1) return false; // if you add in '{ upsert: true }' above, then remove this line as it will create a new document
return savedOutput;
}
The collection testing would need to be created before this code but this is only a one-time thing and is very easy - if you are using MongoDB Atlas then you can use MongoDB Compass / go in your online admin to create the collection without a single line of code...
As far as I can see you should need to duplicate the update object. The above reduces the database calls from 2 to one and allows you to reuse the database connection, potentially anywhere else in the application which would help to speed things up. Also don't store your MongoDB credentials directly in the code.
I am using firebase and I want to only retrieve childs with a specific value (activiteId) for a given key ("associationId")
What I tried:
firebase.database().ref().child("collectivites").child(collectiviteId).child("evenements").orderByChild("associationId").equalTo(activiteId).once("value", function (snapshotAssociationEvenements) {
const data = snapshotAssociationEvenements.val();
if (data){
console.log(data);
}
});
The problem :
The child is displayed in the console but if I do console.log(snapshotAssociationEvenements.val().associationId); the console returns undefined
What have I done wrong ?
My db
Thank you !
Try the following:
firebase.database().ref().child("collectivites").child(collectiviteId).child("evenements").orderByChild("associationId").equalTo(activiteId).once("value", function (snapshotAssociationEvenements) {
snapshotAssociationEvenements.forEach(function(childSnapshot) {
var associateId=childSnapshot.val().associationId;
});
Your snapshot is at the child evenements, then you loop inside the random id using the forEach and you will be able to access the children under that id.
Getting TypeError: Object has no method 'find' whenever i use find() to check inside the returned object.
I don't have any idea how to get else in the object, I get the same error whenever using findOne(), forEach() etc. etc.
getChannels.findOne(query, function(err, data){
if(data){
data.banlist.find(function(list){
var currentTime = Date.now();
var banTime = list ? list.bantime : "";
if(currentTime >= banTime){
var index = data.banlist.indexOf(list);
data.banlist.splice(index, 1)
data.save();
}
})
}
})
})
Documents can be retrieved through several static helper methods of
models.
in the above quote document means the database record.
when you do .findOne(query, function(err, data) you get returned documents or a document. findOne in this case is one document(one record). You see, your getting back a document not a Model. to use a query method you need to use it on a Model.
I'm assuming getChannels is a Model so when your return a document. you could get something else from getChannels in the callback.
some thing like this. not working code.
getChannels.findOne(query, function(err, data){
if(data){
//query anyother Model or collection
getChannels.find(function(list){
var currentTime = Date.now();
var banTime = list ? list.bantime : "";
if(currentTime >= banTime){
var index = data.banlist.indexOf(list);
data.banlist.splice(index, 1)
data.save();
}
})
}
})
})