Adding MongoDB Atlas Vector Search to a .NET Blazor C# Application

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{
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  "fields": [
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    {
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      "type": "vector",
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      "path": "plot_embedding",
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      "numDimensions": 1536,
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      "similarity": "dotProduct"
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    }
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  ]
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}

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"OpenAPIKey": "<YOUR OPENAI API KEY>"

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var openAPIKey = builder.Configuration.GetValue<string>("OpenAPIKey");

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builder.Services.AddScoped(service => new MongoDBService(mongoDBSettings, openAPIKey));

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public IEnumerable<Movie> MovieSearch(string textToSearch);

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using System.Text; 
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using System.Text.Json;

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  private readonly string _openAPIKey;
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  private readonly HttpClient _httpClient = new HttpClient();

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public MongoDBService(MongoDBSettings settings, string openAPIKey)

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public MongoDBService(MongoDBSettings settings, string openAPIKey)
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{
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    _client = new MongoClient(settings.AtlasURI);
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    _mongoDatabase = _client.GetDatabase(settings.DatabaseName);
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    _movies = _mongoDatabase.GetCollection<Movie>("embedded_movies");
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    _openAPIKey = openAPIKey;
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}

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using MongoDB.Bson;
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using MongoDB.Bson.Serialization.Attributes;
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namespace SeeSharpMovies.Models;
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public class Movie
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{
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   [BsonId]
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   [BsonElement("_id")]
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   public ObjectId Id { get; set; }
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   [BsonElement("plot")]
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   public string Plot { get; set; }
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   [BsonElement("genres")]  
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   public string[] Genres { get; set; }
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   [BsonElement("runtime")]
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   public int Runtime { get; set; }
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   [BsonElement("cast")]
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   public string[] Cast { get; set; }
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   [BsonElement("num_mflix_comments")]
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   public int NumMflixComments { get; set; }
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   [BsonElement("poster")]
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   public string Poster { get; set; }
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   [BsonElement("title")]
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   public string Title { get; set; }
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   [BsonElement("fullplot")]
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   public string FullPlot { get; set; }
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   [BsonElement("languages")]
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   public string[] Languages { get; set; }
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   [BsonElement("directors")]
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   public string[] Directors { get; set; }
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   [BsonElement("writers")]
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   public string[] Writers { get; set; }
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   [BsonElement("awards")]
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   public Awards Awards { get; set; }
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   [BsonElement("year")]
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   public string Year { get; set; }
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   [BsonElement("imdb")]
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   public Imdb Imdb { get; set; }
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   [BsonElement("countries")]
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   public string[] Countries { get; set; }
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   [BsonElement("type")]
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   public string Type { get; set; }
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   [BsonElement("plot_embedding")]
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   public float[] PlotEmbedding { get; set; }
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}
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public class Awards
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{
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   [BsonElement("wins")]
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   public int Wins { get; set; }
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   [BsonElement("nominations")]
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   public int Nominations { get; set; }
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   [BsonElement("text")]
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   public string Text { get; set; }
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}
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public class Imdb
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{
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   [BsonElement("rating")]
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   public float Rating { get; set; }
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   [BsonElement("votes")]
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   public int Votes { get; set; }
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   [BsonElement("id")]
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   public int Id { get; set; }
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}

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namespace SeeSharpMovies.Models
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{
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    public class EmbeddingResponse
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    {
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        public string @object { get; set; }
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        public List<Data> data { get; set; }
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        public string model { get; set; }
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        public Usage usage { get; set; }
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    }
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    public class Data
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    {
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        public string @object { get; set; }
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        public int index { get; set; }
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        public List<double> embedding { get; set; }
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    }
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    public class Usage
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    {
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        public int prompt_tokens { get; set; }
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        public int total_tokens { get; set; }
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    }
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}

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private async Task<List<double>> GetEmbeddingsFromText(string text)
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{
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    Dictionary<string, object> body = new Dictionary<string, object>
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    {
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        { "model", "text-embedding-ada-002" },
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        { "input", text }
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    };
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    _httpClient.BaseAddress = new Uri("https://api.openai.com");
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    _httpClient.DefaultRequestHeaders.Add("Authorization", $"Bearer {_openAPIKey}");
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    string requestBody = JsonSerializer.Serialize(body);
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    StringContent requestContent =
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        new StringContent(requestBody, Encoding.UTF8, "application/json");
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    var response = await _httpClient.PostAsync("/v1/embeddings", requestContent)
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        .ConfigureAwait(false);
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    if (response.IsSuccessStatusCode)
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    {
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        string responseBody = await response.Content.ReadAsStringAsync();
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        EmbeddingResponse embeddingResponse = JsonSerializer.Deserialize<EmbeddingResponse>(responseBody);
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        return embeddingResponse.data[0].embedding;
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    }
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    return new List<double>();
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}

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public IEnumerable<Movie> MovieSearch(string textToSearch)
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{
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    var vector = GetEmbeddingsFromText(textToSearch).Result.ToArray();
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    var vectorOptions = new VectorSearchOptions<Movie>()
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    {
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        IndexName = "vector_index",
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        NumberOfCandidates = 150
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    };
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  var movies = _movies.Aggregate()
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    .VectorSearch(movie => movie.PlotEmbedding, vector, 150, vectorOptions)
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    .Project<Movie>(Builders<Movie>.Projection
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    .Include(m => m.Title)
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    .Include(m => m.Plot)
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    .Include(m => m.Poster))            
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    .ToList();
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    return movies;
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}

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 var movie = _movies.Find(movie => movie.Id.ToString() == id).FirstOrDefault();

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 string searchTerm;

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private void SearchMovies()
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{
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    if (string.IsNullOrWhiteSpace(searchTerm))
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    {
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        movies = MongoDBService.GetAllMovies();
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    }
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    else
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    {
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        movies = MongoDBService.MovieSearch(searchTerm);
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    }
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}

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<header class="top-bar">
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        <a href="/">See Sharp Movies</a>
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    <div class="form-inline search-bar">
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        <input class="form-control mr-sm-2"
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               type="search" placeholder="Search"
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               aria-label="Search"               
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               @bind="searchTerm">
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        <button class="btn btn-outline-success my-2 my-sm-0" @onclick="SearchMovies">Search</button>
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    </div>
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    </header>

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.search-bar {
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    padding: 5%;
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}
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.search-bar button {
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    padding: 4px;
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}