ServiceQuery: Dynamic Data Querying Over REST APIs

Overview

Welcome to ServiceQuery, the open-source library designed to revolutionize your data querying over REST APIs. Similar to OData and GraphQL, ServiceQuery harnesses the power of an expression builder and a straightforward model to serialize query instructions across service boundaries. It seamlessly supports a wide array of popular relational (SQL) and document (NoSQL) database engines, ensuring secure and efficient data querying by eliminating injection attacks. With ServiceQuery, your clients and front-end applications gain unprecedented querying capabilities through a standardized endpoint supporting polyglot data access.

Get Started

Installation is simple:

Install the NuGet Package ServiceQuery

Why ServiceQuery?

• Versatile: Supports numerous database engines including Azure Data Tables, Cosmos DB, MongoDB, MySQL, SQLite, SQL Server, PostgreSQL, Oracle, and more.
• Secure: Builds LINQ expressions using individually mapped functions and parsed data, eliminating injection attacks.
• Powerful: Provides clients and front-end applications with unprecedented querying capabilities.

Examples

Explore our examples folder for detailed implementations using the most popular database storage providers.

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Dynamic Querying Made Easy

Here's how you can dynamically query data using JavaScript: Make sure to include the following ServiceQuery.js javascript file to quickly build request queries in javascript.

<script src="/js/servicequery.js"></script>
<script type="text/javascript">

  function GetById() {

    // Build the request where id = 123
    var request = new ServiceQueryRequestBuilder().IsEqual("Id","123").Build();

    // Send ajax request to REST Controller
    $.ajax({
        url: '/ExampleServiceQuery',
        data: JSON.stringify(request),
        type: "POST",
        dataType: 'json',
        headers: { 'Content-Type': 'application/json' },
        success: function (result) {

          // Output the response
          alert(result.list.length + ' records returned');
        }
    });
  }
</script>

On the server side, convert the request into IQueryable expressions and return the result:

using ServiceQuery;

[HttpPost]
[Route("ExampleServiceQuery")]
public ServiceQueryResponse<ExampleTable> ExampleServiceQuery(ServiceQueryRequest request)
{
  var queryable = databaseContext.ExampleTable.AsQueryable();
  return request.Execute(queryable);
}

Documentation

Comprehensive documentation is available on our website at http://ServiceQuery.com including tables for supported data types and operations by .NET Framework version and database engine.

ServiceQuery.AzureDataTables

Azure Data Tables has certain limitations, like lack of support for aggregate functions, string comparisons and ordering. Our companion NuGet package ServiceQuery.AzureDataTables provides a solution to these limitations, allowing you to use standard operations and execute requests seamlessly. The solution is to download all records and then perform the query using an internal list. See our example project for more information.

Building and Executing a Query

Construct queries using the ServiceQueryRequestBuilder object:

using ServiceQuery;

public void Example()
{
  var request = new ServiceQueryRequestBuilder().Build();
  var queryable = databaseContext.ExampleTable.AsQueryable();
  var response = request.Execute(queryable);

  List<ExampleTable> list = response.List; // contains the list of objects returned from the query
  int? count = response.Count; // returns the count of the query (if requested)
  double? aggregate = response.Aggregate; // returns the aggregate (if requested)
}

Supported Operations

Aggregate Functions

• Average
• Count
• Maximum
• Minimum
• Sum

Comparison Functions

• Between
• Equal
• Not Equal
• Less Than
• Less Than or Equal
• Greater Than
• Greater Than or Equal
• In Set
• Not In Set

Comparison Functions (string)

• Contains
• StartsWith
• EndsWith

Grouping Functions

• And
• Or
• Begin
• End

Nullability Functions

• Null
• Not Null

Paging Functions

• Page Number
• Page Size
• Include Count

Selecting Functions

• Distinct
• Select

Sorting Functions

• Sort Ascending
• Sort Descending

Using Query Operations

If you are using javascript, make sure to download the ServiceQuery.js javascript file. This allows you to use the same syntax as the .NET code below!

  using ServiceQuery;

  var request = new ServiceQueryRequestBuilder().Build();

  // This is the same as just a new object
  request = new ServiceQueryRequestBuilder()
    .Paging(1, 1000, false)
    .Build();

  // Include the count of records with the response
  request = new ServiceQueryRequestBuilder()
    .IsGreaterThan("id","10")
    .IncludeCount()
    .Build();

  // Select only the properties you want
  request = new ServiceQueryRequestBuilder()
    .Select("Id","FirstName","LastName")
    .Build();
  
  // Build AND expressions 
  request = new ServiceQueryRequestBuilder()
    .IsEqual("Id","1")
    .And()
    .StartsWith("FirstName", "John")    
    .Build();

  // Build OR expressions
  request = new ServiceQueryRequestBuilder()
    .Between("Id","1", "5")
    .Or()
    .Contains("LastName", "Smith")    
    .Build();

  // Group expressions with BEGIN, END, AND and OR. Nest as deeply as needed.
  request = new ServiceQueryRequestBuilder()
    .Begin()
      .IsEqual("Id","1")
      .And()
      .IsInSet("Status", "Created", "Open", "InProcess")
    .End()
    .Or()
    .Begin()
      .IsLessThanOrEqual("BirthDate","1/1/2000")
      .And()
      .IsNull("CloseDate")
    .End()
    .Build();

  // Sorting
  request = new ServiceQueryRequestBuilder()
    .IsEqual("Age", "21")
    .SortAsc("FirstName")
    .Build();

  // Aggregate functions
  request = new ServiceQueryRequestBuilder()
    .IsLessThan("Id", "200")
    .Sum("Price")
    .Build();

ServiceQuery Options

Customize server-side query processing with ServiceQueryOptions object:

    public class ServiceQueryOptions
    {
        public Dictionary<string, string> PropertyNameMappings { get; set; }
        public bool PropertyNameCaseSensitive { get; set; }
        public bool AllowMissingExpressions { get; set; }
    }

Advanced Usage Scenarios

Manipulate queries before executing them

Add to, change or remove filters from incoming queries for business reasons.

Restrict properties by user roles

Adjust property mappings based on user role for security.

Sharding data

Add expressions to queries to target specific data segments, ensuring efficient data retrieval and enhanced security.

About

I am a business executive and software architect with 25+ years professional experience. You can reach me via www.linkedin.com/in/danlogsdon or visit https://HoloModular.com