Class HeaderDictionaryDecoratorExtensions

Namespace

Cuemon.AspNetCore.Http

Assembly

Cuemon.AspNetCore.dll

Extension methods for the IHeaderDictionary interface hidden behind the IDecorator<T> interface.

public static class HeaderDictionaryDecoratorExtensions

Inheritance

object

HeaderDictionaryDecoratorExtensions

Examples

HeaderDictionaryDecoratorExtensions provides extension methods on Decorator.Enclose for merging, sanitizing, and updating IHeaderDictionary instances. This example creates a target HeaderDictionary with "X-Existing" and a source with both "X-Existing" and "X-New", then calls AddRange to selectively add only non-existing headers. It also demonstrates AddOrUpdateHeader with control-character sanitization (removing \r\n from a value) and AddOrUpdateHeaders to copy HttpResponseMessage response headers into the target. Console output confirms "X-Existing" retains its original value, "X-New" is added, sanitized headers are cleaned to "helloworld", and response headers are merged as "alpha,beta".

using System;
using System.Net.Http;
using Cuemon;
using Cuemon.AspNetCore.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Primitives;

namespace MyApp.AspNetCore.Http
{
    public class HeaderDictionaryDecoratorExtensionsExample
    {
        public void Demonstrate()
        {
            // Add non-existing headers from one dictionary into another
            var target = new HeaderDictionary
            {
                { "X-Existing", "value1" }
            };

            var source = new HeaderDictionary
            {
                { "X-Existing", "value1" },
                { "X-New", "value2" }
            };

            // Only adds headers that do not already exist in target
            Decorator.Enclose<IHeaderDictionary>(target).AddRange(source);

            Console.WriteLine(target["X-Existing"]); // "value1"
            Console.WriteLine(target["X-New"]);      // "value2"

            // Add or update a single header with control-character sanitization
            Decorator.Enclose<IHeaderDictionary>(target).AddOrUpdateHeader(
                "X-Sanitized", new StringValues("hello\r\nworld"), useAsciiEncodingConversion: false);

            Console.WriteLine(target["X-Sanitized"]); // "helloworld"

            // Copy response headers into an IHeaderDictionary
            using var response = new HttpResponseMessage();
            response.Headers.Add("X-Custom", new[] { "alpha", "beta" });

            Decorator.Enclose<IHeaderDictionary>(target).AddOrUpdateHeaders(response.Headers);

            Console.WriteLine(target["X-Custom"]); // "alpha,beta"

}}
}

Methods

AddOrUpdateHeader(IDecorator<IHeaderDictionary>, string, StringValues, bool)

Attempts to add or update an existing element with the provided key and value to the enclosed IHeaderDictionary of the decorator.

public static void AddOrUpdateHeader(this IDecorator<IHeaderDictionary> decorator, string key, StringValues value, bool useAsciiEncodingConversion = true)

Parameters

decorator IDecorator<IHeaderDictionary>

The IDecorator<T> to extend.

key string

The string to use as the key of the element to add.

value StringValues

The string to use as the value of the element to add.

useAsciiEncodingConversion bool

if set to true an ASCII encoding conversion is applied to the value.

Exceptions

ArgumentNullException

decorator cannot be null.

AddOrUpdateHeaders(IDecorator<IHeaderDictionary>, HttpResponseHeaders)

Attempts to add or update one or more elements from the provided collection of responseHeaders to the enclosed IHeaderDictionary of the decorator.

public static void AddOrUpdateHeaders(this IDecorator<IHeaderDictionary> decorator, HttpResponseHeaders responseHeaders)

Parameters

decorator IDecorator<IHeaderDictionary>

The IDecorator<T> to extend.

responseHeaders HttpResponseHeaders

The HttpResponseHeaders to copy.

AddRange(IDecorator<IHeaderDictionary>, IHeaderDictionary, Func<KeyValuePair<string, StringValues>, IHeaderDictionary, bool>)

Adds a range of headers to the enclosed IHeaderDictionary.

public static IHeaderDictionary AddRange(this IDecorator<IHeaderDictionary> decorator, IHeaderDictionary headers, Func<KeyValuePair<string, StringValues>, IHeaderDictionary, bool> predicate = null)

Parameters

decorator IDecorator<IHeaderDictionary>

The IDecorator<T> to extend.

headers IHeaderDictionary

The IHeaderDictionary to populate.

predicate Func<KeyValuePair<string, StringValues>, IHeaderDictionary, bool>

The function delegate that specifies what elements to populate from headers. Default is only non-existing headers.

Returns

IHeaderDictionary

A reference to decorator.Inner.Inner so that additional calls can be chained.

Remarks

When predicate is null, only new headers are added to the enclosed IHeaderDictionary.

See Also

IDecorator<T>

Decorator<T>