I'm having issues retrieving an entity from Google Datastore. Here's my code:
async function pushTaskIdToCurrentSession(taskId){
console.log(`Attempting to add ${taskId} to current Session: ${cloudDataStoreCurrentSession}`);
const transaction = datastore.transaction();
const taskKey = datastore.key(['Session', cloudDataStoreCurrentSession]);
try {
await transaction.run();
const [task] = await transaction.get(taskKey);
let sessionTasks = task.session_tasks;
sessionTasks.push(taskId);
task.session_tasks = sessionTasks;
transaction.save({
key: taskKey,
data: task,
});
transaction.commit();
console.log(`Task ${taskId} added to current Session successfully.`);
} catch (err) {
console.error('ERROR:', err);
transaction.rollback();
}
}
taskId is a string id of another entity that I want to store in an array of a property called session_tasks.
But it doesn't get that far. After this line:
const [task] = await transaction.get(taskKey);
The error is that task is undefined:
ERROR: TypeError: Cannot read property 'session_tasks' of undefined
at pushTaskIdToCurrentSession
Anything immediately obvious from this code?
UPDATE:
Using this instead:
const task = await transaction.get(taskKey).catch(console.error);
Gets me a task object, but it seems to be creating a new entity on the datastore:
I also get this error:
(node:19936) UnhandledPromiseRejectionWarning: Error: Unsupported field value, undefined, was provided.
at Object.encodeValue (/Users/.../node_modules/#google-cloud/datastore/build/src/entity.js:387:15)
This suggests the array is unsupported?
The issue here is that Datastore supports two kinds of IDs.
IDs that start with name= are custom IDs. And they are treated as strings
IDs that start with id= are numeric auto-generated IDs and are treated as integers
When you tried to updated the value in the Datastore, the cloudDataStoreCurrentSession was treated as a string. Since Datastore couldn't find an already created entity key with that custom name, it created it and added name= to specify that it is a custom name. So you have to pass cloudDataStoreCurrentSession as integer to save the data properly.
If I understand correctly, you are trying to load an Array List of Strings from Datastore, using a specific Entity Kind and Entity Key. Then you add one more Task and updated the value of the Datastore for the specific Entity Kind and Entity Key.
I have create the same case scenario as yours and done a little bit of coding myself. In this GitHub code you will find my example that does the following:
Goes to Datastore Entity Kind Session.
Retrieves all the data from Entity Key id=5639456635748352 (e.g.).
Get's the Array List from key: session_tasks.
Adds the new task that passed from the function's arguments.
Performs the transaction to Datastore and updates the values.
All steps are logged in the code and there are a lot of comments explaining exactly how the code works. Also there are two examples of currentSessionID. One for custom names and other one for automatically generated IDs. You can test the code to understand the usage of it and modify it according to your needs.
Related
Is it possible to reference a newly created DynamoDB record in AWS Lambda? For example, retrieving and using the ID of the newly created record. Hoping this is possible without a query to retrieve the new record from DynamoDB.
const docClient = new AWS.DynamoDB.DocumentClient();
... // Omitting the rest of the code in this example
const params = {
TableName : 'ExampleTableName',
Item: {
id: uuid.v1()
}
}
try {
await docClient.put(params).promise();
} catch (err) {
return err;
}
// Reference newly created record to retrieve the ID.
Of course you can achieve it using ReturnValues Paramter.
ReturnValues:- return the item's attribute values in the same operation.
But I am afraid that if you want to achieve your purpose you need to use an alternative API which UpdateItem
From the Docs
Use ReturnValues if you want to get the item attributes as they appear before or after they are updated. For UpdateItem, the valid values are:
NONE - If ReturnValues is not specified, or if its value is NONE, then nothing is returned. (This setting is the default for ReturnValues.)
ALL_OLD - Returns all of the attributes of the item, as they appeared before the UpdateItem operation.
UPDATED_OLD - Returns only the updated attributes, as they appeared before the UpdateItem operation.
ALL_NEW - Returns all of the attributes of the item, as they appear after the UpdateItem operation.
UPDATED_NEW - Returns only the updated attributes, as they appear after the UpdateItem operation.
There is no additional cost associated with requesting a return value aside from the small network and processing overhead of receiving a larger response. No read capacity units are consumed.
The values returned are strongly consistent.
Why you can use returnValue with putItem? Reason -> https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_PutItem.html#API_PutItem_RequestSyntax which wont solve your purpose.
You can store return values in variable and add custom logic to proceed further. :)
const generatedEvent = await Event.create(req.body);
res.send(generatedEvent);
I am getting some data from the request body and I can generate a new Event. And I'm returning the event to client when it has generated. But I don't want to return all fields with event. I want to make filter operation like how we are using select function like this: Event.find().select({title:1,description:1})
How can i use this select func with Model.create?
If you take a look at the mongoose-source code, you can see that Model.create returns a promise with the created/inserted documents. There's no way to specify a filtering-options to return only specific fields.
Of course you could do a .find() in combination with a .select() call after creating/inserting a new record but that would result in one extra DB-query for each insert which does not make a lot of sense.
You could instead just return the desired properties from the returned document, since you know that a new document was inserted successfully with the provided data, when the promise resolved. So you could simply do:
res.send({title: generatedEvent.title, description: generatedEvent.description});
Model.create() internally doesn't fetch the document from the database, rather it actually returns the result whether it's inserted successfully or not. If successful, mongoose will return the original mongoose document that mongoose created before sending to the database.
So you could just select the fields by yourself. Using es2015 Object destructuring assignment and Object shorthand property names would help writing more concise code.
const { title, description } = await Event.create(req.body); // Object destructuring
res.send({ title, description }); // Object shorthand property names
I am using Cloud Function to send a notification to mobile device. I have two collection in Firestore clientDetail and clientPersonalDetail. I have clientID same in both of the collection but the date is stored in clientDetail and name is stored in clientPersonal.
Take a look:
ClientDetail -- startDate
-- clientID
.......
ClientPersonalDetail -- name
-- clientID
.........
Here is My full Code:
exports.sendDailyNotifications = functions.https.onRequest( (request, response) => {
var getApplicants = getApplicantList();
console.log('getApplicants', getApplicants);
cors(request, response, () => {
admin
.firestore()
.collection("clientDetails")
//.where("clientID", "==", "wOqkjYYz3t7qQzHJ1kgu")
.get()
.then(querySnapshot => {
const promises = [];
querySnapshot.forEach(doc => {
let clientObject = {};
clientObject.clientID = doc.data().clientID;
clientObject.monthlyInstallment = doc.data().monthlyInstallment;
promises.push(clientObject);
});
return Promise.all(promises);
}) //below code for notification
.then(results => {
response.send(results);
results.forEach(user => {
//sendNotification(user);
});
return "";
})
.catch(error => {
console.log(error);
response.status(500).send(error);
});
});
}
);
Above function is showing an object like this
{clienId:xxxxxxxxx, startDate:23/1/2019}
But I need ClientID not name to show in notification so I'll have to join to clientPersonal collection in order to get name using clientID.
What should do ?
How can I create another function which solely return name by passing clientID as argument, and waits until it returns the name .
Can Anybody please Help.?
But I need ClientID not name to show in notification so I'll have to join to clientPersonal collection in order to get name using clientID. What should do ?
Unfortunately, there is no JOIN clause in Firestore. Queries in Firestore are shallow. This means that they only get items from the collection that the query is run against. There is no way to get documents from two top-level collection in a single query. Firestore doesn't support queries across different collections in one go. A single query may only use properties of documents in a single collection.
How can I create another function which solely return name by passing clientID as argument, and waits until it returns the name.
So the most simple solution I can think of is to first query the database to get the clientID. Once you have this id, make another database call (inside the callback), so you can get the corresponding name.
Another solution would be to add the name of the user as a new property under ClientDetail so you can query the database only once. This practice is called denormalization and is a common practice when it comes to Firebase. If you are new to NoQSL databases, I recommend you see this video, Denormalization is normal with the Firebase Database for a better understanding. It is for Firebase realtime database but same rules apply to Cloud Firestore.
Also, when you are duplicating data, there is one thing that need to keep in mind. In the same way you are adding data, you need to maintain it. With other words, if you want to update/detele an item, you need to do it in every place that it exists.
The "easier" solution would probably be the duplication of data. This is quite common in NoSQL world.
More precisely you would add in your documents in the ClientDetail collection the value of the client name.
You can use two extra functions in this occasion to have your code clear. One function that will read all the documents form the collection ClientDetail and instead of getting all the fields, will get only the ClientID. Then call the other function, that will be scanning all the documents in collection ClientPersonalDetail and retrieve only the part with the ClientID. Compare if those two match and then do any operations there if they do so.
You can refer to Get started with Cloud Firestore documentation on how to create, add and load documents from Firestore.
Your package,json should look something like this:
{
"name": "sample-http",
"version": "0.0.1",
"dependencies": {
"firebase-admin": "^6.5.1"
}
}
I have did a little bit of coding myself and here is my example code in GitHub. By deploying this Function, will scan all the documents form one Collection and compare the ClientID from the documents in the other collection. When it will find a match it will log a message otherwise it will log a message of not matching IDs. You can use the idea of how this function operates and use it in your code.
I have been working with the google cloud library, and I can successfully save data in DataStore, specifically from my particle electron device (Used their tutorial here https://docs.particle.io/tutorials/integrations/google-cloud-platform/)
The problem I am now having is retrieving the data again.
I am using this code, but it is not returning anything
function getData(){
var data = [];
const query = datastore.createQuery('ParticleEvent').order('created');
datastore.runQuery(query).then(results => {
const event = results[0];
console.log(results);
event.forEach(data => data.push(data.data));
});
console.log(data)
}
But each time it is returning empty specifically returning this :
[ [], { moreResults: 'NO_MORE_RESULTS', endCursor: 'CgA=' } ]
, and I can't figure out why because I have multiple entities saved in this Datastore.
Thanks
In the tutorial.js from the repo mentioned in the tutorial I see the ParticleEvent entities are created using this data:
var obj = {
gc_pub_sub_id: message.id,
device_id: message.attributes.device_id,
event: message.attributes.event,
data: message.data,
published_at: message.attributes.published_at
}
This means the entities don't have a created property. I suspect that ordering the query by such property name is the reason for which the query doesn't return results. From Datastore Queries (emphasis mine):
The results include all entities that have at least one value for
every property named in the filters and sort orders, and whose
property values meet all the specified filter criteria.
I'd try ordering the query by published_at instead, that appears to be the property with a meaning closest to created.
I am running into following error but I unable to completely grasp the understanding behind the error.
CastError: Cast to ObjectId failed for value "XYZ" at path "_id" for model "Partner"
I have my schema defined as following
var partnerList = new Schema (
{
partnerName: String,
supportedProducts: [String]
},
{
collection: 'partnerList'
}
);
module.exports = mongoose.model('Partner', partnerList);
The functionality of my delete function
delete: function (req, res) {
var removePartner = req.params.partnerName;
var promise = Partner.findByIdAndRemove(removePartner).exec();
promise.then(function removePartner(val) {
console.log('partner value removed');
res.send(val);
}).catch(function catchError(err){
console.error(err);
throw err;
});
}
I am trying to making a request to my node app service using
localhost:8443/data/XYZ, where i am passing the value 'XYZ' as the parameter. This value is used to delete the appropriate object from the database.
Basically the error means that whatever you pass as your "XYZ" url param is not a valid ObjectId.
Guessing from your code you use the "partner name" (probably some arbitrary string) instead of the database id of the partner. However findByIdAndRemove() requires you to specify an ObjectId as it uses this to identify which document to delete:
Model.findByIdAndRemove(id, [options], [callback])
Your delete API call could then look something like this: http://localhost:8443/data/59558ccd7acc4dd63ea88988. However for this the client needs to know the ObjectId of the partner.
So you have to either use the ObjectId of a partner in the URL, or use remove() to implement your custom delete query instead, for example like this (if name is the property you use to store your partner names):
Partner.remove({ name: partnerName }).exec();
Be careful however that this might remove multiple documents if your partner name is not unique, as remove will delete all documents matching the query.
In order to prevent this you can also use findOneAndRemove() using the same query. This would only remove one document at a time. If there are multiple partners with the same name it would remove the first one (depending on your sort order).