I'm currently learning about Spring Boot and am undertaking a project where users can make posts, view those posts, etc.
A user's post(s) can be viewed via http://localhost:8080/users/{user_id}/posts and http://localhost:8080/users/{user_id}/posts/{post_id}
As a result I have the following UserPostController
#RestController
#RequestMapping("/users")
public class UserPostController {
#Autowired
private UserPostService postService;
#GetMapping("/{user_id}/posts")
public List<Post> retrieveUserPosts(#PathVariable int user_id) {
return postService.retrieveUserPostList(user_id);
}
#GetMapping("/{user_id}/posts/{post_id}")
public EntityModel<Post> retrieveUserPost(#PathVariable int user_id, #PathVariable int post_id) {
return postService.retrieveUserPost(user_id, post_id);
}
#PostMapping("/{user_id}/posts")
public ResponseEntity<Object> createUserPost(#PathVariable int user_id, #Valid #RequestBody Post post) {
return postService.saveUserPost(user_id, post);
}
}
Every request to the links work correctly. For example a GET request to http://localhost:8080/users/1/posts returns [{"id":1,"description":"This is a post"},{"id":2,"description":"This is another post"}], which is the expected action.
However, for some reason I am able to visit http://localhost:8080/posts which then returns a list of all posts:
{
"_embedded" : {
"posts" : [ {
"description" : "This is a post",
"_links" : {
"self" : {
"href" : "http://localhost:8080/posts/1"
},
"post" : {
"href" : "http://localhost:8080/posts/1"
},
"user" : {
"href" : "http://localhost:8080/posts/1/user"
}
}
}, {
"description" : "This another post",
"_links" : {
"self" : {
"href" : "http://localhost:8080/posts/2"
},
"post" : {
"href" : "http://localhost:8080/posts/2"
},
"user" : {
"href" : "http://localhost:8080/posts/2/user"
}
}
}, {
"description" : "This is yet another post",
"_links" : {
"self" : {
"href" : "http://localhost:8080/posts/3"
},
"post" : {
"href" : "http://localhost:8080/posts/3"
},
"user" : {
"href" : "http://localhost:8080/posts/3/user"
}
}
} ]
},
"_links" : {
"self" : {
"href" : "http://localhost:8080/posts"
},
"profile" : {
"href" : "http://localhost:8080/profile/posts"
}
},
"page" : {
"size" : 20,
"totalElements" : 3,
"totalPages" : 1,
"number" : 0
}
}
Through HATEOAS I am able to also see available links of the format http://localhost:8080/posts/{user_id}/user which I have also not created methods for, but they still exist.
Is there a reason why these unwanted routes exist? If so how do I change this?
Thank you :)
I am new with Spring Data MongoDB and I am trying to implement an aggregation query in Java with Spring Data MongoDB. I have tried searching from this problem and approached it using MongoTemplate, but still to no result.
The format of my data:
[{
"_id" : ObjectId("5e1aea6c275360baf96bac29"),
"title" : "postim",
"upvotesBy" : [
"5e18b4c12753608718dfa007",
"5e19ac0f5161a4994ded1f35"
],
"file" : "test",
"description" : "description",
"postedBy" : "5e18b4c12753608718dfa007",
"createdAt" : ISODate("2020-01-12T09:44:12.119+0000"),
"_class" : "com.socialnetwork.post.Post"
},
{
"_id" : ObjectId("5e1aeaf8275360bb4bb47325"),
"title" : "postim2",
"upvotesBy" : [
"5e18b4c12753608718dfa007",
"5e19ac0f5161a4994ded1f35"
],
"file" : "test2",
"description" : "description2",
"postedBy" : "5e18b4c12753608718dfa007",
"createdAt" : ISODate("2020-01-12T09:46:32.909+0000"),
"_class" : "com.socialnetwork.post.Post"
}]
My query:
db.post.aggregate([
{
$match: {}
},
{
$lookup: {
from: "users",
localField: "postedBy",
foreignField: "_id",
as: "user"
}
},
{
$group: {
_id: {
username: "$user.name",
title: "$title",
description: "$description",
upvotes: { $size: "$upvotesBy" },
upvotesBy: "$upvotesBy",
isUpvoted: { $in: [req.query.userId, "$upvotesBy"] },
isPinned: {
$cond: {
if: { $gte: [{ $size: "$upvotesBy" }, 3] },
then: true,
else: false
}
},
file: "$file",
createdAt: {
$dateToString: {
format: "%H:%M %d-%m-%Y",
timezone: "+01",
date: "$createdAt"
}
},
id: "$_id"
}
}
},
{ $sort: { "_id.isPinned": -1, "_id.createdAt": -1 } }
])
This is the query I use in my Javascript backend and I can do this fairly easy with Mongoose. However I am having some difficulty with the Java implementation of it.
private LookupOperation getLookupOperation() {
return LookupOperation.newLookup().from("user")
.localField("postedBy")
.foreignField("_id")
.as("user");
}
#Override
public List<PostSummary> aggregate() {
LookupOperation lookupOperation = getLookupOperation();
return mongoTemplate.aggregate(Aggregation.newAggregation(lookupOperation, Aggregation.group("id")
.addToSet("user.name").as("username")
.addToSet("title").as("title")
.addToSet("description").as("description")
.addToSet("id").as("id")
.push("upvotesBy").as("upvotesBy")
.addToSet("file").as("file")
.addToSet("createdAt").as("createdAt")
), Post.class, PostSummary.class).getMappedResults();
}
When I try to run this I get the following error:
"Cannot convert [] of type class java.util.ArrayList into an instance of class java.lang.Object! Implement a custom Converter<class java.util.ArrayList, class java.lang.Object> and register it with the CustomConversions. Parent object was: com.socialnetwork.post.PostSummary#7159d908"
When I delete the .addToSet("user.name").as("username") from the group aggregation I also get an error from .push("upvotesBy").as("upvotesBy") as it can not convert [] of type class java.util.ArrayList into an instance of class java.lang.String
Also the implementation of the Post Class and the PostSummary Class is simple:
Post.java:
#Document
public class Post {
#Id
private String id;
private String title;
private List<String> upvotesBy;
private String file;
private String description;
private String postedBy;
private Date createdAt = new Date();
// ... Getters and Setters for each field
}
PostSummary.java:
public class PostSummary {
private String username;
private String title;
private String description;
private List<String> upvotesBy;
private String file;
private String createdAt;
private String id;
//... Getters and Setters for the class
}
I also need to implement the isUpvoted and isPinned part of the query, but getting the idea on how to approach the first problem would be a great start.
EDIT: My desired output:
[
{
"username" : "user1",
"title" : "postim2",
"upvotesBy" : [
"5e18b4c12753608718dfa007",
"5e19ac0f5161a4994ded1f35"
],
"file": "file1",
id: "5e18b4c12753608718dber01"
... Other fields of the original post
},
{
"username" : "user2",
"title" : "postim2",
"upvotesBy" : [
"5e18b4c12753608718dfa007",
"5e19ac0f5161a4994ded1f35"
],
id: "5e18b4c12753608718dber02",
"file": "file2",
... Other fields of the original post
}
]
So from the lookup operation I need only to get the name of the user.
Let's do it
We need to update your aggregation to make it work.
Errors:
users's _id is ObjectId type, but in your post you have stored as String, so $lookup should be changed to Uncorrelated sub-queries
We replace $group by '$addFields' which fits better
We add as last stage $project operator to exclude all unsed fields.
db.post.aggregate([
{
$match: {}
},
{
$lookup: {
from: "users",
let: {
postedBy: "$postedBy"
},
pipeline: [
{
$match: {
$expr: {
$eq: [
{
"$toString": "$_id"
},
"$$postedBy"
]
}
}
}
],
as: "user"
}
},
{
$unwind: "$user"
},
{
$addFields: {
id: {
$toString: "$_id"
},
username: "$user.name",
upvotes: {
$size: "$upvotesBy"
},
isUpvoted: {
$in: [
"5e18b4c12753608718dfa007",
"$upvotesBy"
]
},
isPinned: {
$cond: [
{
$gte: [
{
$size: "$upvotesBy"
},
3
]
},
true,
false
]
},
createdAt: {
$dateToString: {
format: "%H:%M %d-%m-%Y",
timezone: "+01",
date: "$createdAt"
}
}
}
},
{
$sort: {
"isPinned": -1,
"createdAt": -1
}
},
{
$project: {
_id: 0,
user: 0,
upvotesBy: 0,
_class: 0
}
}
])
Now, we transform this query to Spring-Data syntax.
Java Implementation
package postman;
import static org.springframework.data.mongodb.core.aggregation.Aggregation.match;
import static org.springframework.data.mongodb.core.aggregation.Aggregation.project;
import static org.springframework.data.mongodb.core.aggregation.Aggregation.sort;
import static org.springframework.data.mongodb.core.aggregation.Aggregation.unwind;
import java.util.Arrays;
import java.util.List;
import org.bson.Document;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Sort.Direction;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.aggregation.Aggregation;
import org.springframework.data.mongodb.core.aggregation.AggregationOperation;
import org.springframework.data.mongodb.core.aggregation.AggregationOperationContext;
import org.springframework.data.mongodb.core.query.Criteria;
import org.springframework.stereotype.Service;
#Service
public class PostmanService {
#Autowired
private MongoTemplate mongoTemplate;
public List<PostSummary> find(String userId){
Aggregation aggregation = Aggregation.newAggregation(
match(new Criteria()),
//lookup("users", "postedBy", "_id", "user")
new AggregationOperation() {
#Override
public Document toDocument(AggregationOperationContext context) {
return new Document("$lookup",
new Document("from", "users")
.append("let", new Document("postedBy", "$postedBy"))
.append("pipeline", Arrays.asList(
new Document("$match",
new Document("$expr",
new Document("$eq", Arrays.asList(
new Document("$toString", "$_id"),
"$$postedBy"
))))))
.append("as", "user"));
}
},
unwind("$user"),
new AggregationOperation() {
#Override
public Document toDocument(AggregationOperationContext context) {
return new Document("$addFields",
new Document("id", new Document("$toString", "$_id"))
.append("username", "$user.name")
.append("upvotes", new Document("$size", "$upvotesBy"))
.append("isUpvoted", new Document("$in", Arrays.asList(userId, "$upvotesBy")))
.append("isPinned", new Document("$cond",
Arrays.asList(new Document("$gte",
Arrays.asList(new Document("$size", "$upvotesBy"), 3)), Boolean.TRUE, Boolean.FALSE)))
.append("createdAt", new Document("$dateToString",
new Document("format", "%H:%M %d-%m-%Y")
.append("timezone", "+01")
.append("date", "$createdAt")
)));
}
},
sort(Direction.DESC, "isPinned", "createdAt"),
project().andExclude("user", "_class")
);
System.out.println("Aggregation: " + aggregation.toString());
return mongoTemplate.aggregate(aggregation, mongoTemplate.getCollectionName(Post.class), PostSummary.class).getMappedResults();
}
}
Now, we call aggregation pipeline:
List<PostSummary> l = postmanService.find("5e18b4c12753608718dfa007");
for(PostSummary post: l) {
ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
System.out.println(ow.writeValueAsString(post));
}
2020-01-12 16:15:22.043 INFO 11148 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2020-01-12 16:15:22.047 INFO 11148 --- [ main] Postman.PostmanApplication : Started PostmanApplication in 4.602 seconds (JVM running for 5.301)
Aggregation: { "aggregate" : "__collection__", "pipeline" : [{ "$match" : {}}, { "$lookup" : { "from" : "users", "let" : { "postedBy" : "$postedBy"}, "pipeline" : [{ "$match" : { "$expr" : { "$eq" : [{ "$toString" : "$_id"}, "$$postedBy"]}}}], "as" : "user"}}, { "$unwind" : "$user"}, { "$addFields" : { "id" : { "$toString" : "$_id"}, "username" : "$user.name", "upvotes" : { "$size" : "$upvotesBy"}, "isUpvoted" : { "$in" : ["5e18b4c12753608718dfa007", "$upvotesBy"]}, "isPinned" : { "$cond" : [{ "$gte" : [{ "$size" : "$upvotesBy"}, 3]}, true, false]}, "createdAt" : { "$dateToString" : { "format" : "%H:%M %d-%m-%Y", "timezone" : "+01", "date" : "$createdAt"}}}}, { "$sort" : { "isPinned" : -1, "createdAt" : -1}}, { "$project" : { "user" : 0, "_class" : 0}}]}
2020-01-12 16:15:22.161 INFO 11148 --- [ main] org.mongodb.driver.connection : Opened connection [connectionId{localValue:2, serverValue:277}] to localhost:27017
{
"username" : "user1",
"title" : "postim2",
"description" : "description2",
"upvotesBy" : [ "5e18b4c12753608718dfa007", "5e19ac0f5161a4994ded1f35" ],
"file" : "test2",
"createdAt" : "10:46 12-01-2020",
"id" : "5e1aeaf8275360bb4bb47325"
}
{
"username" : "user1",
"title" : "postim",
"description" : "description",
"upvotesBy" : [ "5e18b4c12753608718dfa007", "5e19ac0f5161a4994ded1f35" ],
"file" : "test",
"createdAt" : "10:44 12-01-2020",
"id" : "5e1aea6c275360baf96bac29"
}
Please find my mapping query below for the filename field.
PUT /articles
{
"settings" : {
"analysis" : {
"analyzer" : {
"filename_search" : {
"tokenizer" : "filename",
"filter" : ["lowercase"]
},
"filename_index" : {
"tokenizer" : "filename",
"filter" : ["lowercase","edge_ngram"]
}
},
"tokenizer" : {
"filename" : {
"pattern" : "[^\\p{L}\\d]+",
"type" : "pattern"
}
},
"filter" : {
"edge_ngram" : {
"side" : "front",
"max_gram" : 50,
"min_gram" : 1,
"type" : "edgeNGram"
}
}
}
},
"mappings" : {
"doc" : {
"properties" : {
"filename" : {
"type" : "text",
"search_analyzer" : "filename_search",
"analyzer" : "filename_index"
}
}
}
}
}
If am trying to query series1333372 doc623258 and am expecting karthik_series1333372_oracle_page_doc623258_v1_en-EU.pdf. But it's giving all the files which is having series1333372, not even checking for doc623258.
Please find my query below
get articles/_search
{
"query" : {
"match" : {
"filename" : "series1333372 doc623258"
}
}
}
I am inserting the following sample documents for testing from Kibana
POST articles/doc/1
{
"filename" : "karthik_series1333372_oracle_page_doc623258_v1_en-EU.pdf"
}
POST articles/doc/2
{
"filename" : "karthik_series1333372_sun_page_doc658_v1_en-EU.pdf"
}
POST articles/doc/3
{
"filename" : "series1333372_oracle_page_doc623_v1_en-US.pdf"
}
POST articles/doc/4
{
"filename" : "Engineering series1333372 valve_page doc6232 v1_en-US.pdf"
}
POST articles/doc/5
{
"filename" : "Machines_series1333372_page_doc62258_v1_en-US.pdf"
}
POST articles/doc/6
{
"filename" : "AIX series1333372 IBM page doc62358 v1_en-EU.pdf"
}
The default operator of match is OR. If you want all your terms to be present change it like this
GET articles/_search
{
"query" : {
"match" : {
"filename" : {
"query": "series1333372 doc623258",
"operator" : "and"
}
}
}
}
We are using haschild query to find the parent documents based on the condition.
We have two types
funnels
pages
funnels sample doc
{
"funnel_id": "12345",
"path": "a -> b -> c"
}
{
"funnel_id": "56789",
"path": "a -> d"
}
** pages sample doc**
{
"_parent": "12345",
"visited_page": "/home"
}
{
"_parent": "12345",
"visited_page": "/cart"
}
{
"_parent": "12345",
"visited_page": "/cart"
}
Condition1:
Find parent doc based child doc "visited_page" value contains "home".
"must" : {
"has_child" : {
"query" : {
"regexp" : {
"url" : {
"value" : ".*home.*",
"flags_value" : 65535
}
}
},
"child_type" : "session_pages"
}
}
It works perfectly.
Condition2
Find parent doc based child doc "visited_page" value does NOT contains "home".
"must_not" : {
"has_child" : {
"query" : {
"regexp" : {
"url" : {
"value" : ".*home.*",
"flags_value" : 65535
}
}
},
"child_type" : "session_pages"
}
}
But this query returned wrong results.
Output of the query
{
"funnel_id": "12345",
"path": "a -> b -> c"
}
{
"funnel_id": "56789",
"path": "a -> d"
}
You can see the parent id(funnel_id:12345) child doc contains visited page with value "home". But that also returns.
Expected Result
{
"funnel_id": "56789",
"path": "a -> d"
}
I believe you are "must_not"ing in the wrong spot
try:
"must" : {
"has_child" : {
"query" : {
"regexp" : {
"url" : {
"must_not": {
"value" : ".*home.*"
},
"flags_value" : 65535
}
}
},
"child_type" : "session_pages"
}
}
In my Android app I am using Google Firebase to store information in the database.
I need to iterate through the information, and below for-loop is being used
public void showDataLobReq(DataSnapshot dataSnapshot){
for(DataSnapshot ds : dataSnapshot.child("Lobby_Requests").getChildren()){
System.out.println("asdfasdfasdfasdfasdf"+ds.getValue());
game = ds.child(userID).child("game").getValue(String.class);
console = ds.child(userID).child("console").getValue(String.class);
mic = ds.child(userID).child("mic").getValue(String.class);
players = ds.child(userID).child("players").getValue(String.class);
}
}
You may notice that I put '.child("Lobby_Requests")' after dataSnapshot. this is because the dataSnapshot takes a snapshot of the whole database, so I must go into the subdirectory "Lobby_Requests" because that is where the information I need to iterate through is.
Putting this '.child()' in is being problematic.
I print to the console what the dataSnapshot contains in the first line of the for loop and with .child("Lobby_Requests") it is pulling information from the directory "Lobbies" in the actual database, which is a completely different directory.
Yet, when I remove the '.child()' completely it gives me a view of the whole database like it should. Why is it doing this?
Code for listener:
nRef = mFirebaseDatabase.getReference();
nRef.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()){
showDataLobReq(dataSnapshot);
} else {
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
Here is JSON:
{
"Games" : {
"Forza 6" : {
"Consoles" : {
"PC" : true,
"Xbox 1" : true,
"Xbox 360" : true
},
"FilePathName" : "forza6",
"Genres" : {
"Racing" : true
},
"Live Lobbies" : 0,
"Name" : "Forza 6"
},
"Minecraft" : {
"Consoles" : {
"PC" : true,
"Xbox 1" : true,
"Xbox 360" : true
},
"FilePathName" : "minecraft",
"Genres" : {
"Adventure" : true,
"Creation" : true,
"Open World" : true
},
"Live Lobbies" : 0,
"Name" : "Minecraft"
}
},
"Lobbies" : {
"Cd6lVd2XMUYoLH6b0xoHsrfXMud2" : {
"Messages" : {
"-Kq6-1HsMvElEXZZyCIk" : {
"messageText" : "hey",
"messageTime" : 1501208519771,
"messageUser" : ""
}
},
"console" : "Origin",
"game" : "Minecraft",
"leader" : "Cd6lVd2XMUYoLH6b0xoHsrfXMud2",
"mic" : "Mic",
"note" : "2345",
"players" : "4"
},
"KUWH5f1TmYfO1O1wgCJLli3XZFi2" : {
"console" : "Steam",
"game" : "Forza 6",
"mic" : "No Mic",
"note" : "Hey Join Here!",
"players" : "2"
},
"hpWkq0D8clPReUetOq9Xtmc4V582" : {
"Messages" : {
"-Kq5a0kX305lFCRTSM_G" : {
"messageText" : "hello",
"messageTime" : 1501201701014,
"messageUser" : ""
},
"-Kq5asufOWQwtmyNJrQ7" : {
"messageText" : "hey",
"messageTime" : 1501201926941,
"messageUser" : ""
}
},
"console" : "Xbox One",
"game" : "Minecraft",
"leader" : "hpWkq0D8clPReUetOq9Xtmc4V582",
"mic" : "Mic",
"note" : "kjhg",
"players" : "4"
}
},
"Lobby_Requests" : {
"Cd6lVd2XMUYoLH6b0xoHsrfXMud2" : {
"Cd6lVd2XMUYoLH6b0xoHsrfXMud2" : {
"console" : "Xbox One",
"game" : "Forza 6",
"mic" : "Mic",
"players" : "5"
}
},
"KUWH5f1TmYfO1O1wgCJLli3XZFi2" : {
"KUWH5f1TmYfO1O1wgCJLli3XZFi2" : {
"console" : "Steam",
"game" : "Forza 6",
"mic" : "No Mic",
"players" : "2"
}
},
"hpWkq0D8clPReUetOq9Xtmc4V582" : {
"hpWkq0D8clPReUetOq9Xtmc4V582" : {
"console" : "Xbox One",
"game" : "Minecraft",
"mic" : "Mic",
"players" : "4"
},
"players" : "4"
}
},
"users" : {
"8cHrNCybwjO3PIUKxyOLiAqxJBv1" : {
"gamertag" : "thedylan",
"uname" : "thedood"
},
"Cd6lVd2XMUYoLH6b0xoHsrfXMud2" : {
"gamertag" : "dmdylan",
"uname" : "ninja goat"
},
"KUWH5f1TmYfO1O1wgCJLli3XZFi2" : {
"gamertag" : "skaner",
"uname" : "asdf"
},
"YvYEIiCBUSYKTviVyWpLHdyDIFw1" : {
"gamertag" : "joejoe",
"uname" : "Jifflingly"
},
"ZmX9yIZ6MNguQa1S3MaYNcxfK2b2" : {
"gamertag" : "dmkaner",
"uname" : "dmkaner"
},
"hpWkq0D8clPReUetOq9Xtmc4V582" : {
"gamertag" : "dmkaner",
"uname" : "dmkaner"
},
"t21ncnuRmeV4F7RknETBisMrxS42" : {
"gamertag" : "asdf",
"uname" : "asdf"
}
}
}
The problem in your code is that you are pushing your data twice and there is no need for this.
"Lobby_Requests" : {
"Cd6lVd2XMUYoLH6b0xoHsrfXMud2" : {
"Cd6lVd2XMUYoLH6b0xoHsrfXMud2" : { //This is wrong
If you'll change the way in which you add data to the Firebase database by pushing that data only once, your code will work for fine. Your database should look like this:
"Lobby_Requests" : {
"Cd6lVd2XMUYoLH6b0xoHsrfXMud2" : {
"console" : "Xbox One",
"game" : "Forza 6",
"mic" : "Mic",
"players" : "5"
},
As you probably see, there is only one pushed key.