EDITED
I'm searching users in facebook using graph api in my asp.net mvc 3 application.
public void AsyncSearch(ICollection<JSonObject> result, string query, string objectType)
{
var fbClient = new FacebookClient(FacebookTokens.AccessToken);
var searchUri = string.Format("/search?q={0}&type={1}, query, objectType);
var tempResult = (JsonObject)fbClient.Get(searchUri);
var elements = (JsonArray)tempResult.Values.ToArray()[0];
elements.ForEach(element =>
{
result.Add(element);
});
var next = (JsonObject)tempResult.Values.ToList()[1];
while (next.Keys.Contains("next"))
{
tempResult = (JsonObject)fbClient.Get((string)next["next"]);
elements = (JsonArray)tempResult.Values.ToArray()[0];
elements.ForEach(element =>
{
result.Add(element);
});
next = (JsonObject)tempResult.Values.ToList()[1];
}
}
But result contains at most 600 objects(each search returns different number of objects).
I think, if i put, for example, "anna" in query parameter - result must be over 10000.
Why is that? Is there any way to retrieve all users by some keyword?
For performance concerns Facebook will paginate their results. If you look at the end of the JSON object, there should be a pageing object that has next and previous links in it. So, to get all results you will need to run multiple queries and aggregate them up on your side.
Related
I am trying to construct a MongoDB equivalent of an SQL WHERE IN clause by iterating over a Java Object List and using one field in that list to fill in the IN data. Using generic example, I would like to build the following command in MongoDB syntax:
SELECT title FROM albums WHERE recorded_year IN ('1967','1968','1969','1970');
The SQL command IN data is extracted from the Album object recordedYear value using the following loop:
if (albums.size() <= 1000) {
sb.append("SELECT title FROM albums WHERE recorded_year");
sb.append(" IN (");
for (int i = 0; i < albums.size(); i++) {
sb.append("'");
sb.append(albums.get(i).getRecordedYear());
sb.append("'");
if (i < albums.size() - 1) {
sb.append(",");
} else {
sb.append(")");
}
}
}
Most Mongo/Java sites I visited seem to deal with command structures using hard-coded values which, while helpful, is completely impractical in real world applications. Any help in pointing to a good tutorial, or if someone has the actual code itself would be greatly appreciated.
Thanks.
But the issue I am having is understanding how to pass a Java Object
list to the to the getAllDocuments...
Make an array of elements which you want to match with the field using the in operator. For example, If you have a someObject.year field, then the array will have the year values; int [] matchYears = { 1989, 2001, 2012 }. Instead of an array you can also use a List collection.
The query:
Bson queryFilter = in("recordedYear", matchYears);
List<Document> result = new ArrayList<>();
collection.find(queryFilter).into(result);
result.forEach(System.out::println);
The queryFilter is built using the com.mongodb.client.model.Filters factory class.
The MongoDB documentation on using the $in operator.
NOTE: The int [] matchYears = { 1989, 2001, 2012 } can be also be created as
int [] matchYears = { javaObject1.recorded_year, javaObject2.recorded_year, ... }.
I didn't quite implement it with BSON, but the logic in the method appears to be working with the code below. Thank you again for your help.
public void getAlbumYears(MongoCollection<Document> collection, List<Album> albums) {
BasicDBObject inQuery = new BasicDBObject();
List<String> year = new ArrayList<>();
for(Album album : albums) {
year.add(album.getYear());
}
inQuery.put("year", new BasicDBObject("$in", year));
for (Document document : collection.find(inQuery)) {
System.out.println(document.toJson());
}
}
I am lambda querying models (I make projection with other classes-GameBankVM, GameCouponBankVM) and at the end, I would like to loop throuh query result and update the model field. But I am getting The entity or complex type 'EPINMiddleWareAPI.Models.GameBankVM' cannot be constructed in a LINQ to Entities query.
Here is my sample code:
var gameBankResult = await (context.GameBanks.Where(g => g.productCode == initiate.productCode)
.Take(initiate.quantity)
.Select(g => new GameBankVM
{
quantity = g.quantity,
currency = g.currency,
initiationResultCode = g.initiationResultCode,
productCode = g.productCode,
productDescription = g.productDescription,
referenceId = g.referenceId,
responseDateTime = g.responseDateTime,
unitPrice = g.unitPrice,
totalPrice = g.totalPrice,
coupons = g.coupons.Select(c => new GameCouponBankVM
{
Pin = c.Pin,
Serial = c.Serial,
expiryDate = c.expiryDate
}).ToList()
})).ToListAsync();
if (gameBankResult.Count() != 0)
{
foreach (var item in gameBankResult)
{
item.referenceId = initiate.referenceId;
context.Entry(item).State = System.Data.Entity.EntityState.Modified;
}
await context.SaveChangesAsync();
return Ok(gameBankResult);
}
How can I update referenceId on my GameBank model/table?
In this scenario, your data won't be updated because your query is returning a List of GameBankVM and not a List of GameBank, now technically speaking, you are breaking SRP, you should either update your data or query your data not both in the same method, you may want to refactor your method like this :
1.- Create a private method for data update, in this case, you query directly GameBank iterate thru list entries, make your changes and save them to the database, this same method can return List of GameBank to avoid another database roundtrip.
2.- In the controller after you call your new method, you can run the transformation query to convert List of GameBank to List of GameBankVM and return it to the view.
There are many other ways to do this, I'm just recommending this as a less impact way to make your controller work. But if you are willing to make things better, you can create a business layer where you resolve all your business rules, or you can use patterns like CQS or CQRS.
I have mongo DB and I am using C#.Net to interact with mongo db. C# API has methods for finding a single document and updating it at the same time. For example FindOneAndUpdateAsync.
However I couldn't find any method to find multiple documents and update them at the same time asynchronously.
The code below finding and processing each document asynchronously. How do I also update that document at the same time?
public async Task<IList<IDictionary<string, string>>> DoWork()
{
var collection = _mongoDatabase.GetCollection<BsonDocument>("units");
var filterBuilder = Builders<BsonDocument>.Filter;
var filter = filterBuilder.Ne<string>("status", "INIT") &
(filterBuilder.Exists("isDone", false) |
filterBuilder.Eq<bool>("isDone", false));
// I want to pass this update filter to update the document. But not sure how
var update = Builders<BsonDocument>.Update
.CurrentDate("startTime");
var sort = Builders<BsonDocument>.Sort.Ascending("startTime");
var projection = Builders<BsonDocument>.Projection
.Include("_id")
.Include("fileName"); // for bravity i have removed other projection elements
var output = new List<IDictionary<string, string>>();
// How do i pass update filter and update the document at the same time??
await collection
.Find(filter)
.Sort(sort)
.Project(projection)
.ForEachAsync((unit) =>
{
var dictionary = new Dictionary<string, string>();
Recurse(unit, dictionary);
output.Add(dictionary);
});
return output.Count > 0 ? output : null;
}
That doesn't exist in the mongo .Net api see here.
Just use a combination of Find and UpdateManyAsync.
I'm having a very simple setup with _User entity having a likes Relation with itself (reflective).
A common use case is list users.
I'm listing very few users (ex: 15), but i would also like to display the amount of likes he has.
Following standard suggested technique from Parse.com that would require a query for each of the 15 _User(s).
I don't think this is acceptable, maybe 2 queries are enough:
first one getting the first 15 _User(s)
second one getting the amount of likes each of the _User haves
But I have no idea if that's even possible with Parse API, so I'm asking for help ;)
If the column is a relation, then yes, getting the count will require a query per user.
If you expect the number of likes per user to be low (<100 is my semi-arbitrary rule of thumb), you could instead model likes as an array of pointers.
With that, you can know the count just by having the record in hand (i.e. someUser.get("likes").length). Even better, query include will eagerly fetch the related users...
userQuery.include("likes");
userQuery.find().then(function(users) {
if (users.length) {
var someUser = users[0];
var likes = someUser.get("likes");
if (likes.length) { // see, we can get the count without query
var firstLike = likes[0]; // we can even get those other users!
var firstLikeEmail = firstLike.get("email");
}
}
});
Otherwise, using relations, you're stuck with another query...
userQuery.find().then(function(users) {
if (users.length) {
var someUser = users[0];
var likes = someUser.get("likes");
return likes.query().count();
} else {
return 0;
}
}).then(function(count) {
console.log("the first user has " + count + " likes");
});
I need to select User Name from the collection of Users. I do it in a such way:
MongoCollection<Enums> coll = Db.GetCollection<Enums>("Users");
var query = Query.EQ("_id", id);
var res = coll.FindOne(query);
var name = res.Name;
var url = res.UserUrl; //or some more fields, not just Name
Assuming that User document can contain a lot of data, and there is no need to transfer the whole user document, how to select only a few distinct fields, using official C# driver?
You'll have to use a function that returns a MongoCursor.
In the MongoCursor you can specify the fields you want to return.
var result = Db.GetCollection<Enums>("Users").FindAll();
result.Fields = Fields.Include(new [] {"Name"});;
foreach (var user in result)
{
Console.WriteLine(user.Name);
}