Hcs.Extensions.OdataClient 1.1.0

Hcs.Extensions.OdataClient

C# simple odata client with no $metadata needed for someone only use OdataQueryOptions for Query api like me

Install package

Install-Package Hcs.Extensions.OdataClient

Use

var httpClient = new HttpClient { BaseAddress = new Uri("https://localhost:44326/") };
var maxId = 100;
var req = httpClient.GetOdataClient<File>("/api/FileManage")
            .Where(x => x.CategoryId.HasValue)
            .Where(x => x.CategoryId.HasValue && x.Category.Id + 10 < maxId)
            .OrderBy(x => x.Path).ThenBy(x => x.Name)
            .Take(100)
            .Select(x => new { brand_new_id_property = x.Id, x.Path, xxxx = new { x.Category.Name } });

Console.WriteLine(req.GetQueryString(encode: false));

foreach (var result in await req.SendReqeust())
{
    Console.WriteLine($"{result.brand_new_id_property} {result.xxxx.Name}");
}

excute result

?$filter=CategoryId ne null and (CategoryId ne null and (Category/Id add 10) lt 100)&$orderby=Path asc,Name asc&$top=100&$count=true&$select=Id,Path&$expand=Category($select=Name)

3 A
2 A
4 A
5 A

Limitations

for current version of this lib IS NOT IQueryable implementation

Take/Skip

use Take and Skip will give you new query instance but just simple replace skip/take value,behavior is not like linq (eq [1,2,3,4,5].Take(5).Take(3) will get [1,2,3])

OrderBy

same as Take/Skip but you still can use ThenBy/ThenByDesc for $orderby=A asc,B asc combine with take/skip will work like following

// if all data is [{a:1},{a:2},{a:3},{a:4},{a:5}]
query.Take(4) //this will not affect query result
.OrderBy(x=>x.a) //this will not affect query result
.Take(2) // replace $top value to 2
.Skip(1)
.OrderByDesc(x=>x.a) // replace old order expressions

will give you $orderby=a desc&$top=2&$skip=1 [{a=5},{a=4}]

Select

for reduce complexity of expression parser Select can only apply once to the query, select expression is only for generate odata $select/$expand,then lib compile the expression for local projection use(Enumerable.Select),lib will insert nested member access null check for you , for example

x = >new{ x.Category.Name }

will modify to

x => new { Name = x.Category != null ? x.Category.Name : default(string) }

when use on result projection, so don't worry about null check.

Server side configuration hints for .net core

Install package

Microsoft.AspNetCore.OData

Add services

services.AddOData();
services.AddODataQueryFilter();
services.AddSingleton<ODataUriResolver, StringAsEnumResolver>();
//for .net core 3.1 you need replace built in json serializer for odata $select/$expand working
services.AddControllersWithViews().AddNewtonsoftJson(options =>
{
    options.SerializerSettings.NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore;
    options.SerializerSettings.ContractResolver = new Newtonsoft.Json.Serialization.DefaultContractResolver();
    options.SerializerSettings.StringEscapeHandling = Newtonsoft.Json.StringEscapeHandling.EscapeHtml;
});

Config endpoint

app.UseEndpoints(endpoints =>
{
    endpoints.EnableDependencyInjectionForOdata();
    endpoints.Count().Filter().OrderBy().Expand().Select().MaxTop(100); //allow complex query function
    // ....
});

Controller

[Route("api/[controller]")]
[ApiController]
public class FileManageController : ControllerBase
{
    DbContext context;
    public FileManageController(DbContext context)
    {
        this.context = context;
    }
    [EnableQuery]
    public IActionResult Get()
    {
        return Ok(context.Set<File>().AsQueryable());
    }
}

Count

Default ResultParser get count from response header you can replace odata's EnableQueryAttribute to custom ActionFilter like this

public class HcsEnableQueryAttribute : EnableQueryAttribute
{
    public override void OnActionExecuted(ActionExecutedContext actionExecutedContext)
    {
        base.OnActionExecuted(actionExecutedContext);
        var odata = actionExecutedContext.HttpContext.ODataFeature();

        if (odata.TotalCount.HasValue)
        {
            actionExecutedContext.HttpContext.Response.Headers.Add("x-total-count", odata.TotalCount.Value.ToString("#0"));
        }
    }
}

you can parse other result parser to OdataClient constructor for your endpoint response format

new OdataClient<File>(httpClient,"/api/FileManage",resultParser:new PageResultParser<File>())

PageResultParser is built-in parser for starndard odata endpoint

WARNING

I wrote this lib in rush (about 20ish hours),so use with your own risk, feel free to file a PR if you encounter any bugs