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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.Routing;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Razor.TagHelpers;
using Microsoft.AspNetCore.Routing;
namespace Microsoft.AspNetCore.Mvc.TagHelpers;
/// <summary>
/// <see cref="ITagHelper"/> implementation targeting <button> elements and <input> elements with
/// their <c>type</c> attribute set to <c>image</c> or <c>submit</c>.
/// </summary>
[HtmlTargetElement("button", Attributes = ActionAttributeName)]
[HtmlTargetElement("button", Attributes = ControllerAttributeName)]
[HtmlTargetElement("button", Attributes = AreaAttributeName)]
[HtmlTargetElement("button", Attributes = PageAttributeName)]
[HtmlTargetElement("button", Attributes = PageHandlerAttributeName)]
[HtmlTargetElement("button", Attributes = FragmentAttributeName)]
[HtmlTargetElement("button", Attributes = RouteAttributeName)]
[HtmlTargetElement("button", Attributes = RouteValuesDictionaryName)]
[HtmlTargetElement("button", Attributes = RouteValuesPrefix + "*")]
[HtmlTargetElement("input", Attributes = ImageActionAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = ImageControllerAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = ImageAreaAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = ImagePageAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = ImagePageHandlerAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = ImageFragmentAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = ImageRouteAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = ImageRouteValuesDictionarySelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = ImageRouteValuesSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = SubmitActionAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = SubmitControllerAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = SubmitAreaAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = SubmitPageAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = SubmitPageHandlerAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = SubmitFragmentAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = SubmitRouteAttributeSelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = SubmitRouteValuesDictionarySelector, TagStructure = TagStructure.WithoutEndTag)]
[HtmlTargetElement("input", Attributes = SubmitRouteValuesSelector, TagStructure = TagStructure.WithoutEndTag)]
public class FormActionTagHelper : TagHelper
{
private const string ActionAttributeName = "asp-action";
private const string AreaAttributeName = "asp-area";
private const string ControllerAttributeName = "asp-controller";
private const string PageAttributeName = "asp-page";
private const string PageHandlerAttributeName = "asp-page-handler";
private const string FragmentAttributeName = "asp-fragment";
private const string RouteAttributeName = "asp-route";
private const string RouteValuesDictionaryName = "asp-all-route-data";
private const string RouteValuesPrefix = "asp-route-";
private const string FormAction = "formaction";
private const string ImageTypeSelector = "[type=image], ";
private const string ImageActionAttributeSelector = ImageTypeSelector + ActionAttributeName;
private const string ImageAreaAttributeSelector = ImageTypeSelector + AreaAttributeName;
private const string ImagePageAttributeSelector = ImageTypeSelector + PageAttributeName;
private const string ImagePageHandlerAttributeSelector = ImageTypeSelector + PageHandlerAttributeName;
private const string ImageFragmentAttributeSelector = ImageTypeSelector + FragmentAttributeName;
private const string ImageControllerAttributeSelector = ImageTypeSelector + ControllerAttributeName;
private const string ImageRouteAttributeSelector = ImageTypeSelector + RouteAttributeName;
private const string ImageRouteValuesDictionarySelector = ImageTypeSelector + RouteValuesDictionaryName;
private const string ImageRouteValuesSelector = ImageTypeSelector + RouteValuesPrefix + "*";
private const string SubmitTypeSelector = "[type=submit], ";
private const string SubmitActionAttributeSelector = SubmitTypeSelector + ActionAttributeName;
private const string SubmitAreaAttributeSelector = SubmitTypeSelector + AreaAttributeName;
private const string SubmitPageAttributeSelector = SubmitTypeSelector + PageAttributeName;
private const string SubmitPageHandlerAttributeSelector = SubmitTypeSelector + PageHandlerAttributeName;
private const string SubmitFragmentAttributeSelector = SubmitTypeSelector + FragmentAttributeName;
private const string SubmitControllerAttributeSelector = SubmitTypeSelector + ControllerAttributeName;
private const string SubmitRouteAttributeSelector = SubmitTypeSelector + RouteAttributeName;
private const string SubmitRouteValuesDictionarySelector = SubmitTypeSelector + RouteValuesDictionaryName;
private const string SubmitRouteValuesSelector = SubmitTypeSelector + RouteValuesPrefix + "*";
private IDictionary<string, string> _routeValues;
/// <summary>
/// Creates a new <see cref="FormActionTagHelper"/>.
/// </summary>
/// <param name="urlHelperFactory">The <see cref="IUrlHelperFactory"/>.</param>
public FormActionTagHelper(IUrlHelperFactory urlHelperFactory)
{
UrlHelperFactory = urlHelperFactory;
}
/// <inheritdoc />
public override int Order => -1000;
/// <summary>
/// Gets or sets the <see cref="Rendering.ViewContext"/> for the current request.
/// </summary>
[HtmlAttributeNotBound]
[ViewContext]
public ViewContext ViewContext { get; set; }
/// <summary>
/// Gets the <see cref="IUrlHelperFactory"/> used to create an <see cref="IUrlHelper"/> to generate links.
/// </summary>
protected IUrlHelperFactory UrlHelperFactory { get; }
/// <summary>
/// The name of the action method.
/// </summary>
[HtmlAttributeName(ActionAttributeName)]
public string Action { get; set; }
/// <summary>
/// The name of the controller.
/// </summary>
[HtmlAttributeName(ControllerAttributeName)]
public string Controller { get; set; }
/// <summary>
/// The name of the area.
/// </summary>
[HtmlAttributeName(AreaAttributeName)]
public string Area { get; set; }
/// <summary>
/// The name of the page.
/// </summary>
[HtmlAttributeName(PageAttributeName)]
public string Page { get; set; }
/// <summary>
/// The name of the page handler.
/// </summary>
[HtmlAttributeName(PageHandlerAttributeName)]
public string PageHandler { get; set; }
/// <summary>
/// Gets or sets the URL fragment.
/// </summary>
[HtmlAttributeName(FragmentAttributeName)]
public string Fragment { get; set; }
/// <summary>
/// Name of the route.
/// </summary>
/// <remarks>
/// Must be <c>null</c> if <see cref="Action"/> or <see cref="Controller"/> is non-<c>null</c>.
/// </remarks>
[HtmlAttributeName(RouteAttributeName)]
public string Route { get; set; }
/// <summary>
/// Additional parameters for the route.
/// </summary>
[HtmlAttributeName(RouteValuesDictionaryName, DictionaryAttributePrefix = RouteValuesPrefix)]
public IDictionary<string, string> RouteValues
{
get
{
if (_routeValues == null)
{
_routeValues = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
}
return _routeValues;
}
set
{
_routeValues = value;
}
}
/// <inheritdoc />
/// <remarks>Does nothing if user provides an <c>FormAction</c> attribute.</remarks>
/// <exception cref="InvalidOperationException">
/// Thrown if <c>FormAction</c> attribute is provided and <see cref="Action"/>, <see cref="Controller"/>,
/// <see cref="Fragment"/> or <see cref="Route"/> are non-<c>null</c> or if the user provided <c>asp-route-*</c> attributes.
/// Also thrown if <see cref="Route"/> and one or both of <see cref="Action"/> and <see cref="Controller"/>
/// are non-<c>null</c>
/// </exception>
public override void Process(TagHelperContext context, TagHelperOutput output)
{
ArgumentNullException.ThrowIfNull(context);
ArgumentNullException.ThrowIfNull(output);
// If "FormAction" is already set, it means the user is attempting to use a normal button or input element.
if (output.Attributes.ContainsName(FormAction))
{
if (Action != null ||
Controller != null ||
Area != null ||
Page != null ||
PageHandler != null ||
Fragment != null ||
Route != null ||
(_routeValues != null && _routeValues.Count > 0))
{
// User specified a FormAction and one of the bound attributes; can't override that FormAction
// attribute.
throw new InvalidOperationException(
Resources.FormatFormActionTagHelper_CannotOverrideFormAction(
FormAction,
output.TagName,
RouteValuesPrefix,
ActionAttributeName,
ControllerAttributeName,
AreaAttributeName,
FragmentAttributeName,
RouteAttributeName,
PageAttributeName,
PageHandlerAttributeName));
}
return;
}
var routeLink = Route != null;
var actionLink = Controller != null || Action != null;
var pageLink = Page != null || PageHandler != null;
if ((routeLink && actionLink) || (routeLink && pageLink) || (actionLink && pageLink))
{
var message = string.Join(
Environment.NewLine,
Resources.FormatCannotDetermineAttributeFor(FormAction, '<' + output.TagName + '>'),
RouteAttributeName,
ControllerAttributeName + ", " + ActionAttributeName,
PageAttributeName + ", " + PageHandlerAttributeName);
throw new InvalidOperationException(message);
}
RouteValueDictionary routeValues = null;
if (_routeValues != null && _routeValues.Count > 0)
{
routeValues = new RouteValueDictionary(_routeValues);
}
if (Area != null)
{
if (routeValues == null)
{
routeValues = new RouteValueDictionary();
}
// Unconditionally replace any value from asp-route-area.
routeValues["area"] = Area;
}
var urlHelper = UrlHelperFactory.GetUrlHelper(ViewContext);
string url;
if (pageLink)
{
url = urlHelper.Page(Page, PageHandler, routeValues, protocol: null, host: null, fragment: Fragment);
}
else if (routeLink)
{
url = urlHelper.RouteUrl(Route, routeValues, protocol: null, host: null, fragment: Fragment);
}
else
{
url = urlHelper.Action(Action, Controller, routeValues, protocol: null, host: null, fragment: Fragment);
}
output.Attributes.SetAttribute(FormAction, url);
}
}
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