为Web Api版本控制自定义MapHttpAttributeRoutes

Question

我正在实现Web API版本控制中的Web API版本控制.我的控制器位于2个独立的命名空间中,我使用了一个自定义的SelectController方法来根据查询参数选择要使用的版本.例如

http://myapi/api/values?version=1.0

这一切都很好,但控制器中的一些操作使用Route属性

[Route("api/values/getNames")]
public HttpResponseMessage Get() { ... }

默认使用哪些映射到正确的控制器

config.MapHttpAttributeRoutes();

在WebApiConfig.cs中

如果我有多个版本的API具有相同的路由,这将不起作用.我是否能够为config.MapHttpAttributeRoutes()提供自定义实现,以便我可以选择要使用的API的正确版本,或者有更好的方法吗？

Answer 1

在Codeplex上的官方WebApi 2.1 examplex中有一个例子.它依赖于请求标头值来存储版本.

我认为它更好,因为它允许所有版本的路由保持不变.客户端只需在请求中包含HTTP标头(在本例中为版本号)即可选择版本.

此示例演示如何使用ASP.NET Web API中的属性路由和约束来通过"api-version"HTTP标头动态过滤控制器.当路由使用约束时,每个约束都有机会阻止路由匹配给定的请求.在此示例中,自定义RouteFactoryAttribute(VersionedRoute)为每个属性路由添加约束.

...

自定义约束实现(VersionConstraint)是基于匹配整数值的'api-version'的值实现的.约束的允许版本的值由放置在每个控制器上的VersionedRoute属性提供.当请求进入时,'api-version'的标头值与预期版本匹配.此示例使用标头,但约束实现可以使用任何条件来确定请求是否对路由有效.

无论如何,最终的结果将最终看起来像这样:

[VersionedRoute("api/Customer", 1)]
public class CustomerVersion1Controller : ApiController
{
    // controller code goes here
}
[VersionedRoute("api/Customer", 2)]
public class CustomerVersion2Controller : ApiController
{
    // controller code goes here
}

Answer 2

除了查询参数支持之外,这是一个允许您使用Web API 2版本化路由(标题)的解决方案(即使用名为'api-version'的标头或名为'？api-version = XXX的查询字符串参数".

HTTP Route约束完成工作:

/// <summary>
/// Add a route constraint to detect version header or by query string
/// </summary>
public class RouteVersionHttpConstraint : IHttpRouteConstraint
{
    public const string VersionHeaderName = "api-version";
    private const int DefaultVersion = 1;
    /// <summary>
    /// Add a route constraint to detect version header or by query string
    /// </summary>
    /// <param name="allowedVersion"></param>
    public RouteVersionHttpConstraint(int allowedVersion)
    {
        AllowedVersion = allowedVersion;
    }

    public int AllowedVersion
    {
        get;
        private set;
    }

    /// <summary>
    /// Perform the controller match
    /// </summary>
    /// <param name="request"></param>
    /// <param name="route"></param>
    /// <param name="parameterName"></param>
    /// <param name="values"></param>
    /// <param name="routeDirection"></param>
    /// <returns></returns>
    public bool Match(HttpRequestMessage request, IHttpRoute route, string parameterName, IDictionary<string, object> values, HttpRouteDirection routeDirection)
    {
        if (routeDirection == HttpRouteDirection.UriResolution)
        {
            int version = GetVersionHeaderOrQuery(request) ?? DefaultVersion;
            if (version == AllowedVersion)
            {
                return true;
            }
        }
        return false;
    }

    /// <summary>
    /// Check the request header, and the query string to determine if a version number has been provided
    /// </summary>
    /// <param name="request"></param>
    /// <returns></returns>
    private int? GetVersionHeaderOrQuery(HttpRequestMessage request)
    {
        string versionAsString;
        IEnumerable<string> headerValues;
        if (request.Headers.TryGetValues(VersionHeaderName, out headerValues) && headerValues.Count() == 1)
        {
            versionAsString = headerValues.First();
            int version;
            if (versionAsString != null && Int32.TryParse(versionAsString, out version))
            {
                return version;
            }
        }
        else
        {
            var query = System.Web.HttpUtility.ParseQueryString(request.RequestUri.Query);
            string versionStr = query[VersionHeaderName];
            int version = 0;
            int.TryParse(versionStr, out version);
            if (version > 0)
                return version;
        }
        return null;
    }
}

和路线工厂:

/// <summary>
/// Versioning support for the WebAPI controllers
/// </summary>
public class RouteVersionAttribute : RouteFactoryAttribute
{
    public int Version { get; private set; }

    public RouteVersionAttribute() : this(null, 1) 
    { 
    }
    /// <summary>
    /// Specify a version for the WebAPI controller
    /// </summary>
    /// <param name="version"></param>
    public RouteVersionAttribute(int version) : this(null, version)
    {
    }

    public RouteVersionAttribute(string template, int version)
        : base(template)
    {
        Version = version;
    }

    public override IDictionary<string, object> Constraints
    {
        get
        {
            var constraints = new HttpRouteValueDictionary();
            constraints.Add("version", new RouteVersionHttpConstraint(Version));
            return constraints;
        }
    }

    public override IDictionary<string, object> Defaults
    {
        get
        {
            var defaults = new HttpRouteValueDictionary();
            defaults.Add("version", 1);
            return defaults;
        }
    }

}

用法:

[RouteVersion("api/versiontest", 1)]
public class Version1TestController : BaseApiController
{
    // get: api/versiontest
    [HttpGet]
    public HttpResponseMessage get()
    {
        return Request.CreateResponse(HttpStatusCode.OK, new { Version = "API Version 1 selected" });
    }

}

[RouteVersion("api/versiontest", 2)]
public class Version2TestController : ApiController
{
    // get: api/versiontest
    [HttpGet]
    public HttpResponseMessage get()
    {
        return Request.CreateResponse(HttpStatusCode.OK, new { Version = "API Version 2 selected" });
    }

}