When I do a nested object update inside an array in a Document. Does Mongo DB Engine needs to fetch and parse the whole document update the field and reinsert the document ?
db.ControllerPointCollection.updateOne({
"_id": "Ashutosh Das_MigrationTest_0_1_0"
}, {
$set: {
"Tables.$[t].Blocks.$[b].Points.$[p].Description": "Hey You"
}
}, {
arrayFilters: [{
"t.ID": 32
}, {
"b.ID": 268
}, {
"p.PointDefinitionID": 280
}]
})
Behind the scene, mongodb has a class called Model and inside Model class compose other behaviours with initializing other classes and one of them, I call it Sync which is implemented like this. this is not exact code, but you get the idea:
interface HasId {
id?: number; //optional
}
export class ApiSync<T extends HasId> {
constructor(public rootUrl: string) {}
// if user has Id, that means it is already stored in db, so we make a put request, if it does not then we make post
// so in mongoose, saving means Http request to db
save(data: T): AxiosPromise {
const { id } = data;
if (id) {
return axios.put(this.rootUrl + id, data);
} else {
return axios.post(this.rootUrl, data);
}
}
fetch(id: number): AxiosPromise {
return axios.get(this.rootUrl + id);
}
}
Related
Is there a way to use different types for reading and writing data using the FirebaseDataConverter?
The typing of FirebaseDataConverter<T> suggest that there should only be a single type T, which is both what you would get back when querying and what you should provide when writing.
But in the scenario outlined below, I have two types, InsertComment which is what I should provide when creating a new comment, and Comment, which is an enriched object that has the user's current name and the firebase path of the object added to it.
But there is no way to express that I have these two types. Am I missing something?
type Comment = { userId: string, userName: string, comment: string, _firebasePath: string }
type InsertComment = { userId: string, comment: string }
function lookupName(_id: string) { return 'Steve' }
const commentConverter: FirestoreDataConverter<Comment> = {
fromFirestore(snapshot, options) {
const { userId, comment } = snapshot.data(options)
return {
userId,
comment,
name: lookupName(userId),
_firebasePath: snapshot.ref.path,
} as any as Comment
},
// Here I wish I could write the below, but it gives me a type error
// toFirestore(modelObject: InsertComment) {
toFirestore(modelObject) {
return modelObject
},
}
const commentCollection = collection(getFirestore(), 'Comments').withConverter(commentConverter)
// This works great and is typesafe
getDocs(commentCollection).then(snaps => {
snaps.docs.forEach(snap => {
const { comment, userName, _firebasePath } = snap.data()
console.info(`${userName} said "${comment}" (path: ${_firebasePath})`)
})
})
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// This gives me the type-error: that fields "userName, _firebasePath" are missing
addDoc(commentCollection, { comment: 'Hello World', userId: '123' })
I found a workaround, but I don't think this ought to be the way it should be done. It feels hacky.
Basically, I make two DataConverters, one for reading and one for writing.
I make the one for reading the default one, and when I need to write, I overwrite the read-converter with the write-converter.
function createReadFirestoreConverter<T>(validator: Validator<T>): FirestoreDataConverter<T> {
return {
fromFirestore(snapshot, options) {
return validator({ ...snapshot.data(options), _id: snapshot.id, _path: snapshot.ref.path })
},
toFirestore() {
throw new Error('Firestore converter not configured for writing')
},
}
}
function createWriteFirestoreConverter<T>(validator: Validator<T>) {
return {
fromFirestore() {
throw new Error('Firestore converter not configured for reading')
},
toFirestore(modelObject: any) {
return validator(modelObject)
},
} as FirestoreDataConverter<any>
}
const installedComponentConverterRead = createReadFirestoreConverter(installedComponentValidator)
const installedComponentConverterWrite = createWriteFirestoreConverter(newInstalledComponentValidator)
const readCollection = collection(getFirestore(), `MachineCards/${machineCard._id}/Components`).withConverter(installedComponentConverterRead)
// If I need to write
const docRef = doc(readCollection, 'newDocId').withConverter(installedComponentConverterWrite)
Let's say I have a database with two collections, kids and classes. Each kid belongs to one class.
Each class has a previously created integer id.
I want to replace the kid.class_id with the (ObjectID) _id of the class, not the (integer) id of the class.
However, when I run the script below, it doesn't reset the class_id with the class._id -- it remains the old integer id.
mongoose.connect(someMongodbUri, { useMongoClient: true }, (err, db) => {
let kidsCount = 0;
db.collection('kids').find({}).each((err, kid) => {
kidsCount++;
db.collection('classes')
.findOne({ id: kid.class_id })
.then((class, err) => {
let newClassId = class._id;
db.collection('kids').updateOne(
{ _id: kid._id },
{ $set: { class_id: newClassId } }
).then(() => {
console.info('Updated', kid.class_id);
kidsCount--;
if (kidsCount === 0) { db.close(); }
});
});
});
});
Am I missing something? Thanks for any help you can offer!
We can convert integerId to Object id.
var ObjectId = require('mongodb').ObjectID;
let newClassId = ObjectId(class._id);
There may be better or elegent ways that i don't know, but this works for me.
I am trying to figure out a clean way to work with queries and mongdb projections so I don't have to retrieve excessive information from the database.
So assuming I have:
// the query
type Query {
getUserByEmail(email: String!): User
}
And I have a User with an email and a username, to keep things simple. If I send a query and I only want to retrieve the email, I can do the following:
query { getUserByEmail(email: "test#test.com") { email } }
But in the resolver, my DB query still retrieves both username and email, but only one of those is passed back by apollo server as the query result.
I only want the DB to retrieve what the query asks for:
// the resolver
getUserByEmail(root, args, context, info) {
// check what fields the query requested
// create a projection to only request those fields
return db.collection('users').findOne({ email: args.email }, { /* projection */ });
}
Of course the problem is, getting information on what the client is requesting isn't so straightforward.
Assuming I pass in request as context - I considered using context.payload (hapi.js), which has the query string, and searching it through various .split()s, but that feels kind of dirty. As far as I can tell, info.fieldASTs[0].selectionSet.selections has the list of fields, and I could check for it's existence in there. I'm not sure how reliable this is. Especially when I start using more complex queries.
Is there a simpler way?
In case you don't use mongDB, a projection is an additional argument you pass in telling it explicitly what to retrieve:
// telling mongoDB to not retrieve _id
db.collection('users').findOne({ email: 'test#test.com' }, { _id: 0 })
As always, thanks to the amazing community.
2020-Jan answer
The current answer to getting the fields requested in a GraphQL query, is to use the graphql-parse-resolve-info library for parsing the info parameter.
The library is "a pretty complete solution and is actually used under the hood by postgraphile", and is recommended going forward by the author of the other top library for parsing the info field, graphql-fields.
Use graphql-fields
Apollo server example
const rootSchema = [`
type Person {
id: String!
name: String!
email: String!
picture: String!
type: Int!
status: Int!
createdAt: Float
updatedAt: Float
}
schema {
query: Query
mutation: Mutation
}
`];
const rootResolvers = {
Query: {
users(root, args, context, info) {
const topLevelFields = Object.keys(graphqlFields(info));
return fetch(`/api/user?fields=${topLevelFields.join(',')}`);
}
}
};
const schema = [...rootSchema];
const resolvers = Object.assign({}, rootResolvers);
// Create schema
const executableSchema = makeExecutableSchema({
typeDefs: schema,
resolvers,
});
Sure you can. This is actually the same functionality that is implemented on join-monster package for SQL based db's. There's a talk by their creator: https://www.youtube.com/watch?v=Y7AdMIuXOgs
Take a look on their info analysing code to get you started - https://github.com/stems/join-monster/blob/master/src/queryASTToSqlAST.js#L6-L30
Would love to see a projection-monster package for us mongo users :)
UPDATE:
There is a package that creates a projection object from info on npm: https://www.npmjs.com/package/graphql-mongodb-projection
You can generate MongoDB projection from info argument. Here is the sample code that you can follow
/**
* #description - Gets MongoDB projection from graphql query
*
* #return { object }
* #param { object } info
* #param { model } model - MongoDB model for referencing
*/
function getDBProjection(info, model) {
const {
schema: { obj }
} = model;
const keys = Object.keys(obj);
const projection = {};
const { selections } = info.fieldNodes[0].selectionSet;
for (let i = 0; i < keys.length; i++) {
const key = keys[i];
const isSelected = selections.some(
selection => selection.name.value === key
);
projection[key] = isSelected;
}
console.log(projection);
}
module.exports = getDBProjection;
With a few helper functions you can use it like this (typescript version):
import { parceGqlInfo, query } from "#backend";
import { GraphQLResolveInfo } from "graphql";
export const user = async (parent: unknown, args: unknown, ctx: unknown, info: GraphQLResolveInfo): Promise<User | null> => {
const { dbQueryStr } = parceGqlInfo(info, userFields, "id");
const [user] = await query(`SELECT ${dbQueryStr} FROM users WHERE id=$1;`, [1]);
return user;
};
Helper functions.
Few points:
gql_uid used as ID! string type from primary key to not change db types
required option is used for dataloaders (if field was not requested by user)
allowedFields used to filter additional fields from info like '__typename'
queryPrefix is used if you need to prefix selected fields like select u.id from users u
const userFields = [
"gql_uid",
"id",
"email"
]
// merge arrays and delete duplicates
export const mergeDedupe = <T>(arr: any[][]): T => {
// #ts-ignore
return ([...new Set([].concat(...arr))] as unknown) as T;
};
import { parse, simplify, ResolveTree } from "graphql-parse-resolve-info";
import { GraphQLResolveInfo } from "graphql";
export const getQueryFieldsFromInfo = <Required = string>(info: GraphQLResolveInfo, options: { required?: Required[] } = {}): string[] => {
const { fields } = simplify(parse(info) as ResolveTree, info.returnType) as { fields: { [key: string]: { name: string } } };
let astFields = Object.entries(fields).map(([, v]) => v.name);
if (options.required) {
astFields = mergeDedupe([astFields, options.required]);
}
return astFields;
};
export const onlyAllowedFields = <T extends string | number>(raw: T[] | readonly T[], allowed: T[] | readonly T[]): T[] => {
return allowed.filter((f) => raw.includes(f));
};
export const parceGqlInfo = (
info: GraphQLResolveInfo,
allowedFields: string[] | readonly string[],
gqlUidDbAlliasField: string,
options: { required?: string[]; queryPrefix?: string } = {}
): { pureDbFields: string[]; gqlUidRequested: boolean; dbQueryStr: string } => {
const fieldsWithGqlUid = onlyAllowedFields(getQueryFieldsFromInfo(info, options), allowedFields);
return {
pureDbFields: fieldsWithGqlUid.filter((i) => i !== "gql_uid"),
gqlUidRequested: fieldsWithGqlUid.includes("gql_uid"),
dbQueryStr: fieldsWithGqlUid
.map((f) => {
const dbQueryStrField = f === "gql_uid" ? `${gqlUidDbAlliasField}::Text AS gql_uid` : f;
return options.queryPrefix ? `${options.queryPrefix}.${dbQueryStrField}` : dbQueryStrField;
})
.join(),
};
};
I am trying to query a User collection with multiple nested objects, and I'm not sure how to properly use the projection operators (e.g. $) as they seem to work for arrays not objects.
Each user has a "booksRecords" object, with multiple book objects (e.g. hc_1_3, hc_1_4, etc). Each book object has a field called currLevel and I am trying to find kids that have at least one book object where currLevel: 'nursery'.
I tried doing
User.find({'booksRecords.$.currLevel': 'nursery'}), but that doesn't seem to be working and I wonder what is the correct way to query nested objects?
I checked Querying nested in mongoDB, but it is different from my case as I'm querying nested objects.
[
//first object
{
_id: "xxx",
booksRecords: {
hc_1_3: {
markedRead: false,
currLevel: "elementary"
},
hc_1_2: {
markedRead: false,
currLevel: "elementary"
}
}
},
//second object
{
_id: "xyz",
booksRecords: {
hc_1_3: {
markedRead: false,
currLevel: "elementary"
},
hc_1_2: {
markedRead: false,
currLevel: "nursery"
}
}
}
]
$ projection applies to array only.
You need to use $where to evaluate each document:
db.User.find( { $where: function() {
for (var i=0 in this.booksRecords) {
if (this.booksRecords[i].currLevel === 'nursery') {
return true;
}
}
return false;
} });
can you please this:
var userList = db.User.find();
var booksRecordsList={};
while(userList.hasNext()){
var user = userList.next();
for(var key in user.booksRecords){
if ( !( key in booksRecordsList ) ) {
booksRecordsList[key] = key;
}
}
};
db.User.find().forEach(function(doc){
for (var booksRecord in booksRecordsList){
var booksRecordItem = doc.booksRecords[booksRecord];
if(booksRecordItem.currLevel == "nursery"){
print(tojson(doc));
}
}
});
I am trying to setup a rest webservice (JSON) this is what I am getting:
{"name":"test","routines":[{"class":"Routine","id":1},{"class":"Routine","id":2}]}
This is what I want to get:
{"name":"test","routines":[{"name": "routine-1"},{"name": "routine-2"}]}
I have these domains:
class Program {
String name;
static hasMany = [routines: Routine]
}
class Routine {
String name
}
I have this controller:
class ProgramController extends RestfulController {
static responseFormats = ['json']
def show(Program program) {
respond program
}
}
I added this in the resources.groovy
programRenderer(JsonRenderer, Program) {
excludes = ['class', 'id']
}
routineRenderer(JsonRenderer, Routine) {
excludes = ['class', 'id']
}
How do I include the name property of Routine in the json response using the show method/action of ProgramController?
The ObjectMarshaller approach is the technically correct way. However, the code is cumbersome to write and it's a maintenance headache syncing the fields of the domain with the marshaller.
In the spirit of being Groovy and keeping things really simple, we've been quite happy just adding a little out() method to each REST domain.
Program.groovy
class Program {
String name
static hasMany = [routines: Routine]
def out() {
return [
name: name,
count: routines?.size(),
routines: routines?.collect { [name: it.name] }
]
}
}
ProgramController.groovy
import grails.converters.JSON
class ProgramController {
def show() {
def resource = Program.read(params.id)
render resource.out() as JSON
}
}
JSON Response
{
name: "test",
count: 2,
routines: [{ name: "routine-1" }, { name: "routine-2" }]
}
The out() method approach makes it easy to customize the response JSON, such as adding count for the number of routines.