How to access data of another persisted model of loopback from remote method of one persisted model? - loopbackjs

'use strict';
module.exports = function (City) {
City.GetCurrentPopulation = function (req) {
var population;
City.app.models.Pupulation.find({where{id:req.id}}, //This line //gives me an error that cannot read property 'find' of undefined
function(req.res){
population=res.population;
});
response='Population for ' +req.cname ' is' +population;
req(null, response);
};
City.remoteMethod(
'GetCurrentPopulation', {
http: {
path: '/GetCurrentPopulation',
verb: 'GetCurrentPopulation'
},
returns: {
arg: 'startdate',
type: 'string'
}
}
);
There is a model city and i want to access another model like "population.find(some filters)" How to do this?
I have a remote method written in city model. Where i am trying to access population record as
var countryp=population.find(where{id:4});
var currentpopulation=countryp.Totalpopulation;
It gives an error population.find is not a function.
Please suggest way to do this.

City.app.models.Population can only work if you defined some relation between City & Population models. Otherwise it wont work that way. If there is no relation to the other model. You need to get a reference to the app object using
Try like this:
var app = require('../../server/server');
module.exports = function (City) {
var Population = app.models.Population;
City.GetCurrentPopulation = function(req) {
Population.find({where{id:req.id}}, function (err) {
if (err) {
return console.log(err);
} else {
// do something here
});
}
You can refer to the documentation here https://loopback.io/doc/en/lb3/Working-with-LoopBack-objects.html#using-model-objects

Related

Flutter aws amplify not returning data when calling graphql api

On button click I have programmed to call a graphql api which is connected to a Lambda function and the function is pulling data from a dynamodb table. The query does not produce any error, but it doesn't give me any results as well. I have also checked the cloudwatch logs and I dont see any traces of the function being called. Not sure on the careless mistake I am making here.
Here is my api
void findUser() async {
try {
String graphQLDocument = '''query getUserById(\$userId: ID!) {
getUserById(userId: \$id) {
id
name
}
}''';
var operation = Amplify.API.query(
request: GraphQLRequest<String>(
document: graphQLDocument,
variables: {'id': 'USER-14160000000'}));
var response = await operation.response;
var data = response.data;
print('Query result: ' + data);
} on ApiException catch (e) {
print('Query failed: $e');
}
}
Here is my lambda function -
const getUserById = require('./user-queries/getUserById');
exports.handler = async (event) => {
var userId = event.arguments.userId;
var name = event.arguments.name;
var avatarUrl = event.arguments.avatarUrl;
//console.log('Received Event - ', JSON.stringify(event,3));
console.log(userId);
switch(event.info.fieldName) {
case "getUserById":
return getUserById(userId);
}
};
const AWS = require('aws-sdk');
const docClient = new AWS.DynamoDB.DocumentClient({region: 'ca-central-1'});
async function getUserById(userId) {
const params = {
TableName:"Bol-Table",
KeyConditionExpression: 'pk = :hashKey and sk = :sortKey',
ExpressionAttributeValues: {
':hashKey': userId,
':sortKey': 'USER'
}
};
try {
const Item = await docClient.query(params).promise();
console.log(Item);
return {
id: Item.Items[0].pk,
name: Item.Items[0].details.displayName,
avatarUrl: Item.Items[0].details.avatarUrl,
createdAt: Item.Items[0].details.createdAt,
updatedAt: Item.Items[0].details.updatedAt
};
} catch(err) {
console.log("BOL Error: ", err);
}
}
module.exports = getUserById;
Upon button click I get this
Moving my comment to an answer:
Can you try changing your graphQLDocumnet to
String graphQLDocument = '''query getUserById(\$id: ID!) {
getUserById(userId: \$id) {
id
name
}
}''';
Your variable is $userId and then $id. Try calling it $id in both places like in your variables object.
Your flutter code is working fine but in lambda from the aws is returning blank string "" to not to print anything

Apollo GraphQL client doesn't return cached nested types in a query

I'm performing a query to get PowerMeter details in which contains another type inside called Project. I write the query this way:
query getPowerMeter($powerMeterId: ID!) {
powerMeter: powerMeter(powerMeterId: $powerMeterId) {
id
name
registry
project {
id
name
}
}
}
When I perform the query for the first time, project is successfully returned. The problem is that when I perform subsequent queries with the same parameters and default fetchPolicy (cache-first), project isn't returned anymore.
How may I solve this problem?
Also, I call readFragment to check how powerMeter is saved in the cache and the response shows that powerMeter has project saved.
const frag = client.readFragment({
fragment: gql`
fragment P on PowerMeter {
id
name
registry
project {
id
name
}
}
`,
id: 'PowerMeter:' + powerMeterId,
});
Power Meter returned first time
{
"powerMeter":{
"id":"7168adb4-4198-443e-ab76-db0725be2b18",
"name":"asd123123",
"registry":"as23",
"project":{
"id":"41d8e71b-d1e9-41af-af96-5b4ae9e492c1",
"name":"ProjectName",
"__typename":"Project"
},
"__typename":"PowerMeter"
}
}
Fragment after calling power meter first time
{
"id":"7168adb4-4198-443e-ab76-db0725be2b18",
"name":"asd123123",
"registry":"as23",
"project":{
"id":"41d8e71b-d1e9-41af-af96-5b4ae9e492c1",
"name":"ProjectName",
"__typename":"Project"
},
"__typename":"PowerMeter"
}
Power Meter returned second time
{
"powerMeter":{
"id":"7168adb4-4198-443e-ab76-db0725be2b18",
"name":"asd123123",
"registry":"as23",
"__typename":"PowerMeter"
}
}
Fragment after calling power meter second time
{
"id":"7168adb4-4198-443e-ab76-db0725be2b18",
"name":"asd123123",
"registry":"as23",
"project":{
"id":"41d8e71b-d1e9-41af-af96-5b4ae9e492c1",
"name":"ProjectName",
"__typename":"Project"
},
"__typename":"PowerMeter"
}
Edit 1: Fetching Query
The code below is how I'm fetching data. I'm using useApolloClient and not a query hook because I'm using AWS AppSync and it doesn't support query hook yet.
import { useApolloClient } from '#apollo/react-hooks';
import gql from 'graphql-tag';
import { useEffect, useState } from 'react';
export const getPowerMeterQuery = gql`
query getPowerMeter($powerMeterId: ID!) {
powerMeter: powerMeter(powerMeterId: $powerMeterId) {
id
name
registry
project {
id
name
}
}
}
`;
export const useGetPowerMeter = (powerMeterId?: string) => {
const client = useApolloClient();
const [state, setState] = useState<{
loading: boolean;
powerMeter?: PowerMeter;
error?: string;
}>({
loading: true,
});
useEffect(() => {
if (!powerMeterId) {
return setState({ loading: false });
}
client
.query<GetPowerMeterQueryResponse, GetPowerMeterQueryVariables>({
query: getPowerMeterQuery,
variables: {
powerMeterId,
},
})
.then(({ data, errors }) => {
if (errors) {
setState({ loading: false, error: errors[0].message });
}
console.log(JSON.stringify(data));
const frag = client.readFragment({
fragment: gql`
fragment P on PowerMeter {
id
name
registry
project {
id
name
}
}
`,
id: 'PowerMeter:' + powerMeterId,
});
console.log(JSON.stringify(frag));
setState({
loading: false,
powerMeter: data.powerMeter,
});
})
.catch(err => setState({ loading: false, error: err.message }));
}, [powerMeterId]);
return state;
};
Edit 2: Fetching Policy Details
When I use fetchPolice equals cache-first or network-only, the error persists. When I use no-cache, I don't get the error.
I think this might have been the solution:
https://github.com/apollographql/apollo-client/issues/7050
Probably way too late, but it could help people coming to this issue in the future.
When using apollo client's InMemoryCache it seems you need to provide a list of possible types so the fragment matching can be done correctly when using the InMemoryCache.
You can do that manually when having few union types and a pretty stable API which doesn't change very often.
Or you automatically generate these types into a json file, which you can use directly in the InMemoryCache's possibleTypes config directly.
Visit this link to the official docs to find out how to do it.
Cheers.

Invariant Violation error when updating apollo cache after mutation

I try update my list after item remove by this article
but get Invariant Violation error.
my mutation:
const deleteFn = useMutation<FeaturedPlaylistGroupDelete, FeaturedPlaylistGroupDeleteVariables>(deleteQuery, {
update: (cache, mutationResult) => {
console.log('mutationResult', mutationResult)
const data = cache.readQuery({ query: featuredPlaylistsGroupsQuery })
console.log('cache', cache)
console.log('cacheData', data)
cache.writeQuery({
query: featuredPlaylistsGroupsQuery,
data: data.filter((item) => item.id !== mutationResult.data.featuredPlaylistGroupDelete.id),
})
},
})
featuredPlaylistsGroupsQuery:
export const featuredPlaylistsGroupsQuery = gql`
query FeaturedPlaylistGroups(
$active: Boolean
$noCategory: Boolean
$dateFrom: String
$dateTo: String
$title: String
$regions: [String!]
$categories: [String!]
) {
featuredPlaylistGroups(
active: $active
noCategory: $noCategory
dateFrom: $dateFrom
dateTo: $dateTo
regions: $regions
title: $title
categories: $categories
) {
active
category {
title
}
datetime
id
region
title
}
}
`
deleteQuery:
const deleteQuery = gql`
mutation FeaturedPlaylistGroupDelete($id: String!) {
featuredPlaylistGroupDelete(id: $id) {
active
categoryId
category {
title
}
datetime
id
region
title
}
}
`
error:
Invariant Violation: Can't find field
featuredPlaylistGroups({}) on object {
...
When you use readQuery, what's returned is what would have been returned in the data part of the response for that query. This is always an object. So for a query like
query {
foo
bar
}
You get an object like
{
"foo": "FOO",
"bar": "BAR"
}
When you call readQuery using your featuredPlaylistsGroupsQuery, you'll get an object with a single property named featuredPlaylistGroups. So your code should look more like:
const cached = cache.readQuery({ query: featuredPlaylistsGroupsQuery })
const featuredPlaylistGroups = cached.featuredPlaylistGroups.filter(item => {
return item.id !== mutationResult.data.featuredPlaylistGroupDelete.id
})
const data = {
...cached,
featuredPlaylistGroups,
}
cache.writeQuery({
query: featuredPlaylistsGroupsQuery,
data: data,
})
However, this still will not work because featuredPlaylistsGroupsQuery takes a number of variables. We need those variables in order to read and write from the cache, since each combination of variable that has been queries is stored separately in the cache. So you will either need to keep track of the variables used and call readQuery/writeQuery on all used combinations, or use something like apollo-link-watched-mutation

How to set relation foreign key to be required

I have two models. Company and Booking.
In the relation part of model Company
"bookings": {
"type": "hasMany",
"model": "Booking",
"foreignKey": "companyId"
}
The issue is, it is possible to post a Booking without companyId which is not ok.
From the explorer.
Booking {
bookingId (string, optional),
name (string),
location (string),
companyId (string, optional)
}
You actually can't enforce this particular validation out-of-the-box. Instead you have a couple different options:
a) You can enforce the creation of Booking through company through the endpoint, POST /api/Company/{id}/Bookings by disabling Booking.disableRemoteMethod('create', ...) along with any other methods that have the ability to create records from the Booking model.
b) You can add a remote hook to check whether or not the company record exists and throw an error accordingly.
Booking.beforeRemote('create', function(ctx, booking, next) {
var Company = Booking.app.models.Company;
var companyId = ctx.req.body.companyId;
if (companyId) {
errorMsg = 'Company with id=' + companyId + ' does not exist.';
var noCompany = new Error(errorMsg);
Company.findById(companyId, function(err, company) {
if (err) next(err);
if (!company) {
ctx.res.statusCode = 400;
next(noCompany);
} else {
next();
}
});
} else {
next();
}
});
You will also have to do the same thing for any other endpoints that allow record create such as PUT /api/Bookings.
Hope that helps!
You can add the companyId property explicitly in the booking.json file, and add the required:true property. It would look like
{
"properties": {
"companyId": {
"type": "number",
"required": true
},
... //other properties
}
}
In richardpringle's answer part b booking was an empty object for me.
I was able to get this answer to work by adding app to the booking.js file like below:
'use strict';
var app = require('../../server/server');
module.exports = function(Booking) {
Booking.beforeRemote('create', function(ctx, booking, next) {
var Company = app.models.Company;
var companyId = ctx.req.body.companyId;
if (companyId) {
errorMsg = 'Company with id=' + companyId + ' does not exist.';
var noCompany = new Error(errorMsg);
Company.findById(companyId, function(err, company) {
if (err) next(err);
if (!company) {
ctx.res.statusCode = 400;
next(noCompany);
} else {
next();
}
});
} else {
next();
}
});
};
line 2 is new
line 6 is modified from richardpringle's answer
From: var Company = Booking.app.models.Company;
To: var Company = app.models.Company;

Ember - Within action, result is defined, returnvalue of same action logged in parent action is undefined? Why?

Quick and shortly I have following problem:
I have following two actions within a component in Ember:
createData: function(user) {
let collection = [];
for (let i = 0; i < user.posts.length; i++) {
let data = this.send('createSingleData',user.posts[i], user, 'post');
console.log(data);
collection.push(data);
}
return collection;
},
createSingleData: function(data, user, type) {
let entitySkeleton = {
name: data.place.name,
belongsTo: user.id,
position: {
data.place.location.longitude,
data.place.location.latitude
}
};
console.log(entitySkeleton);
return entitySkeleton;
}
the first log - within createSingleData, right before returning the logged value - writes the entitySkeleton as Object into the console - as expected.
However, the console.log(data) - within createData - writes 'undefined' to the console.
Is there any aspect of asynchrounosity I didn't respect?
P.S.:
I also logged any paramater within createSingleData, they are all set properly.
The variable collection also only gets pushed 'undefined'.
You cannot return the value from action, instead you can set property from the action.
how to return values from actions in emberjs
actions: {
PrintSomething: function() {
let obj = [{a: 'raj'}, {a: 'Prudvi'}, {a : 'thimappa'}]
console.log('before', obj);
this.send('returnSomething', obj);
console.log('after calling action', this.get('returnvalue'));
},
returnSomething: function(obj) {
obj.push({a: 'FSDFSDF'})
var data = obj;
this.set('returnvalue', data);
}
}