11 KiB
Sieve
⚗️ Sieve is a simple, clean, and extensible framework for .NET Core that adds sorting, filtering, and pagination functionality out of the box. Most common use case would be for serving ASP.NET Core GET queries.
Usage for ASP.NET Core
In this example, consider an app with a Post
entity.
We'll use Sieve to add sorting, filtering, and pagination capabilities when GET-ing all available posts.
1. Add required services
Inject the SieveProcessor
service. So in Startup.cs
add:
services.AddScoped<SieveProcessor>();
2. Tell Sieve which properties you'd like to sort/filter in your models
Sieve will only sort/filter properties that have the attribute [Sieve(CanSort = true, CanFilter = true)]
on them (they don't have to be both true).
So for our Post
entity model example:
public int Id { get; set; }
[Sieve(CanFilter = true, CanSort = true)]
public string Title { get; set; }
[Sieve(CanFilter = true, CanSort = true)]
public int LikeCount { get; set; }
[Sieve(CanFilter = true, CanSort = true)]
public int CommentCount { get; set; }
[Sieve(CanFilter = true, CanSort = true, Name = "created")]
public DateTimeOffset DateCreated { get; set; } = DateTimeOffset.UtcNow;
There is also the Name
parameter that you can use to have a different name for use by clients.
Alternatively, you can use Fluent API to do the same. This is especially useful if you don't want to use attributes or have multiple APIs.
3. Get sort/filter/page queries by using the Sieve model in your controllers
In the action that handles returning Posts, use SieveModel
to get the sort/filter/page query.
Apply it to your data by injecting SieveProcessor
into the controller and using its Apply<TEntity>
method. So for instance:
[HttpGet]
public JsonResult GetPosts(SieveModel sieveModel)
{
var result = _dbContext.Posts.AsNoTracking(); // Makes read-only queries faster
result = _sieveProcessor.Apply(sieveModel, result); // Returns `result` after applying the sort/filter/page query in `SieveModel` to it
return Json(result.ToList());
}
You can also explicitly specify if only filtering, sorting, and/or pagination should be applied via optional arguments.
4. Send a request
Add custom sort/filter methods
If you want to add custom sort/filter methods, inject ISieveCustomSortMethods
or ISieveCustomFilterMethods
with the implementation being a class that has custom sort/filter methods that Sieve will search through.
For instance:
services.AddScoped<ISieveCustomSortMethods, SieveCustomSortMethods>();
services.AddScoped<ISieveCustomFilterMethods, SieveCustomFilterMethods>();
Where SieveCustomSortMethodsOfPosts
for example is:
public class SieveCustomSortMethods : ISieveCustomSortMethods
{
public IQueryable<Post> Popularity(IQueryable<Post> source, bool useThenBy, bool desc) // The method is given an indicator of weather to use ThenBy(), and if the query is descending
{
var result = useThenBy ?
((IOrderedQueryable<Post>)source).ThenBy(p => p.LikeCount) : // ThenBy only works on IOrderedQueryable<TEntity>
source.OrderBy(p => p.LikeCount)
.ThenBy(p => p.CommentCount)
.ThenBy(p => p.DateCreated);
return result; // Must return modified IQueryable<TEntity>
}
}
And SieveCustomFilterMethods
:
public class SieveCustomFilterMethods : ISieveCustomFilterMethods
{
public IQueryable<Post> IsNew(IQueryable<Post> source, string op, string[] values) // The method is given the {Operator} & {Value}
{
var result = source.Where(p => p.LikeCount < 100 &&
p.CommentCount < 5);
return result; // Must return modified IQueryable<TEntity>
}
}
Configure Sieve
Use the ASP.NET Core options pattern with SieveOptions
to tell Sieve where to look for configuration. For example:
services.Configure<SieveOptions>(Configuration.GetSection("Sieve"));
Then you can add the configuration:
{
"Sieve": {
"CaseSensitive": "boolean: should property names be case-sensitive? Defaults to false",
"DefaultPageSize": "int number: optional number to fallback to when no page argument is given. Set <=0 to disable paging if no pageSize is specified (default).",
"MaxPageSize": "int number: maximum allowed page size. Set <=0 to make infinite (default)",
"ThrowExceptions": "boolean: should Sieve throw exceptions instead of silently failing? Defaults to false"
}
}
Send a request
With all the above in place, you can now send a GET request that includes a sort/filter/page query. An example:
GET /GetPosts
?sorts= LikeCount,CommentCount,-created // sort by likes, then comments, then descendingly by date created
&filters= LikeCount>10, Title@=awesome title, // filter to posts with more than 10 likes, and a title that contains the phrase "awesome title"
&page= 1 // get the first page...
&pageSize= 10 // ...which contains 10 posts
More formally:
sorts
is a comma-delimited ordered list of property names to sort by. Adding a-
before the name switches to sorting descendingly.filters
is a comma-delimited list of{Name}{Operator}{Value}
where{Name}
is the name of a property with the Sieve attribute or the name of a custom filter method for TEntity- You can also have multiple names (for OR logic) by enclosing them in brackets and using a pipe delimiter, eg.
(LikeCount|CommentCount)>10
asks ifLikeCount
orCommentCount
is>10
- You can also have multiple names (for OR logic) by enclosing them in brackets and using a pipe delimiter, eg.
{Operator}
is one of the Operators{Value}
is the value to use for filtering- You can also have multiple values (for OR logic) by using a pipe delimiter, eg.
Title@=new|hot
will return posts with titles that contain the text "new
" or "hot
"
- You can also have multiple values (for OR logic) by using a pipe delimiter, eg.
page
is the number of page to returnpageSize
is the number of items returned per page
Notes:
- You can use backslashes to escape commas and pipes within value fields
- You can have spaces anywhere except within
{Name}
or{Operator}
fields - If you need to look at the data before applying pagination (eg. get total count), use the optional paramters on
Apply
to defer pagination (an example) - Here's a good example on how to work with enumerables
- Another example on how to do OR logic
Nested objects
You can filter/sort on a nested object's property by marking the property using the Fluent API. Marking via attributes not currently supported.
For example, using this object model:
public class Post {
public User Creator { get; set; }
}
public class User {
public string Name { get; set; }
}
Mark Post.User
to be filterable:
// in MapProperties
mapper.Property<Post>(p => p.Creator.Name)
.CanFilter();
Now you can make requests such as: filters=User.Name==specific_name
.
Creating your own DSL
You can replace this DSL with your own (eg. use JSON instead) by implementing an ISieveModel. You can use the default SieveModel for reference.
Operators
Operator | Meaning |
---|---|
== |
Equals |
!= |
Not equals |
> |
Greater than |
< |
Less than |
>= |
Greater than or equal to |
<= |
Less than or equal to |
@= |
Contains |
_= |
Starts with |
!@= |
Does not Contains |
!_= |
Does not Starts with |
@=* |
Case-insensitive string Contains |
_=* |
Case-insensitive string Starts with |
==* |
Case-insensitive string Equals |
!=* |
Case-insensitive string Not equals |
!@=* |
Case-insensitive string does not Contains |
!_=* |
Case-insensitive string does not Starts with |
Handle Sieve's exceptions
Sieve will silently fail unless ThrowExceptions
in the configuration is set to true. 3 kinds of custom exceptions can be thrown:
SieveMethodNotFoundException
with aMethodName
SieveIncompatibleMethodException
with aMethodName
, anExpectedType
and anActualType
SieveException
which encapsulates any other exception types in itsInnerException
It is recommended that you write exception-handling middleware to globally handle Sieve's exceptions when using it with ASP.NET Core.
Example project
You can find an example project incorporating most Sieve concepts in SieveTests.
Fluent API
To use the Fluent API instead of attributes in marking properties, setup an alternative SieveProcessor
that overrides MapProperties
. For example:
public class ApplicationSieveProcessor : SieveProcessor
{
public ApplicationSieveProcessor(
IOptions<SieveOptions> options,
ISieveCustomSortMethods customSortMethods,
ISieveCustomFilterMethods customFilterMethods)
: base(options, customSortMethods, customFilterMethods)
{
}
protected override SievePropertyMapper MapProperties(SievePropertyMapper mapper)
{
mapper.Property<Post>(p => p.Title)
.CanFilter()
.HasName("a_different_query_name_here");
mapper.Property<Post>(p => p.CommentCount)
.CanSort();
mapper.Property<Post>(p => p.DateCreated)
.CanSort()
.CanFilter()
.HasName("created_on");
return mapper;
}
}
Now you should inject the new class instead:
services.AddScoped<ISieveProcessor, ApplicationSieveProcessor>();
Find More on Sieve's Fluent API here.
Upgrading to v2.2.0
2.2.0 introduced OR logic for filter values. This means your custom filters will need to accept multiple values rather than just the one.
- In all your custom filter methods, change the last argument to be a
string[] values
instead ofstring value
- The first value can then be found to be
values[0]
rather thanvalue
- Multiple values will be present if the client uses OR logic
Upgrading from v1.* to v2.*
- Changes to the
SieveProcessor
API:ApplyAll
is nowApply
ApplyFiltering
,ApplySorting
, andApplyPagination
are now depricated - instead you can use optional arguments onApply
to achieve the same
- Instead of just removing commas from
{Value}
s, you'll also need to remove brackets and pipes
License & Contributing
Sieve is licensed under Apache 2.0. Any contributions highly appreciated!