/// <summary>
/// Initializes a new instance of the <see cref="EntityTagHeaderOptions"/> class.
/// </summary>
/// <remarks>
/// The following table shows the initial property values for an instance of <see cref="EntityTagHeaderOptions"/>.
/// <list type="table">
/// <listheader>
/// <term>Property</term>
/// <description>Initial Value</description>
/// </listheader>
/// <item>
/// <term><see cref="EntityTagParser"/></term>
/// <description>A delegate that computes a MD5 hash of the body and add or update the necessary HTTP response headers needed to provide entity tag header information.</description>
/// </item>
/// </list>
/// </remarks>
public EntityTagHeaderOptions()
{
EntityTagParser = (body, request, response) =>
{
var builder = new ChecksumBuilder(body.ComputeHash(o =>
{
o.AlgorithmType = HashAlgorithmType.MD5;
o.LeaveStreamOpen = true;
}).Value);
response.SetEntityTagHeaderInformation(request, builder);
};
}
public void Mutate_Stream_Test()
{
var thisAssemblyFilePath = Assembly.GetExecutingAssembly().Location;
using (var fileStream = File.OpenRead(thisAssemblyFilePath))
{
var checksum = new ChecksumBuilder()
.Mutate(fileStream)
.Calculate()
.ToString();
Assert.That(checksum, Is.Not.Null.Or.Empty);
}
}
/// <summary>
/// Initializes a new instance of the <see cref="HttpEntityTagHeaderOptions"/> class.
/// </summary>
/// <remarks>
/// The following table shows the initial property values for an instance of <see cref="HttpEntityTagHeaderOptions"/>.
/// <list type="table">
/// <listheader>
/// <term>Property</term>
/// <description>Initial Value</description>
/// </listheader>
/// <item>
/// <term><see cref="EntityTagProvider"/></term>
/// <description><code>
/// (integrity, context) =>
/// {
/// var builder = new ChecksumBuilder(integrity.Checksum.Value);
/// context.Response.SetEntityTagHeaderInformation(context.Request, builder, integrity.ChecksumStrength == ChecksumStrength.Weak);
/// };
/// </code></description>
/// </item>
/// <item>
/// <term><see cref="EntityTagResponseParser"/></term>
/// <description><code>
/// (body, request, response) =>
/// {
/// var builder = new ChecksumBuilder(body.ComputeHash(o =>
/// {
/// o.AlgorithmType = HashAlgorithmType.MD5;
/// o.LeaveStreamOpen = true;
/// }).Value);
/// response.SetEntityTagHeaderInformation(request, builder);
/// };
/// </code></description>
/// </item>
/// <item>
/// <term><see cref="UseEntityTagResponseParser"/></term>
/// <description><c>false</c></description>
/// </item>
/// </list>
/// </remarks>
public HttpEntityTagHeaderOptions()
{
EntityTagProvider = (integrity, context) =>
{
var builder = new ChecksumBuilder(integrity.Checksum.Value);
context.Response.SetEntityTagHeaderInformation(context.Request, builder, integrity.Validation == ChecksumStrength.Weak);
};
EntityTagResponseParser = (body, request, response) =>
{
var builder = new ChecksumBuilder(body.ComputeHash(o =>
{
o.AlgorithmType = HashAlgorithmType.MD5;
o.LeaveStreamOpen = true;
}).Value);
response.SetEntityTagHeaderInformation(request, builder);
};
UseEntityTagResponseParser = false;
}
/// <summary>
/// Determines whether a cached version of the requested resource is found client-side using the If-None-Match HTTP header.
/// </summary>
/// <param name="request">An instance of the <see cref="HttpRequest"/> object.</param>
/// <param name="builder">A <see cref="ChecksumBuilder"/> that represents the integrity of the client.</param>
/// <returns>
/// <c>true</c> if a cached version of the requested content is found client-side; otherwise, <c>false</c>.
/// </returns>
public static bool IsClientSideResourceCached(this HttpRequest request, ChecksumBuilder builder)
{
Validator.ThrowIfNull(request, nameof(request));
var headers = new RequestHeaders(request.Headers);
if (headers.IfNoneMatch != null)
{
var clientSideEntityTagHeader = headers.IfNoneMatch.FirstOrDefault();
var clientSideEntityTag = clientSideEntityTagHeader == null ? "" : clientSideEntityTagHeader.Tag.Value;
int indexOfStartQuote = clientSideEntityTag.IndexOf('"');
int indexOfEndQuote = clientSideEntityTag.LastIndexOf('"');
if (indexOfStartQuote == 0 &&
(indexOfEndQuote > 2 && indexOfEndQuote == clientSideEntityTag.Length - 1))
{
clientSideEntityTag = clientSideEntityTag.Remove(indexOfEndQuote, 1);
clientSideEntityTag = clientSideEntityTag.Remove(indexOfStartQuote, 1);
}
return(builder.Checksum.ToHexadecimal().Equals(clientSideEntityTag));
}
return(false);
}
/// <summary>
/// This method will either add or update the necessary HTTP response headers needed to provide entity tag header information.
/// </summary>
/// <param name="response">The <see cref="HttpResponse"/> to extend.</param>
/// <param name="request">An instance of the <see cref="HttpRequest"/> object.</param>
/// <param name="builder">A <see cref="ChecksumBuilder"/> that represents the integrity of the client.</param>
/// <param name="isWeak">A value that indicates if this entity-tag header is a weak validator.</param>
public static void SetEntityTagHeaderInformation(this HttpResponse response, HttpRequest request, ChecksumBuilder builder, bool isWeak = false)
{
Validator.ThrowIfNull(response, nameof(response));
Validator.ThrowIfNull(request, nameof(request));
Validator.ThrowIfNull(builder, nameof(builder));
builder = builder.CombineWith(request.Headers["Accept"]);
DateTime utcNow = DateTime.UtcNow;
if (request.IsClientSideResourceCached(builder))
{
response.StatusCode = StatusCodes.Status304NotModified;
}
else
{
response.Headers.AddOrUpdate(HeaderNames.LastModified, new StringValues(utcNow.ToString("R", DateTimeFormatInfo.InvariantInfo)));
}
response.Headers.AddOrUpdate(HeaderNames.ETag, new StringValues(builder.ToEntityTag(isWeak).ToString()));
}
/// <summary>
/// Creates an <see cref="EntityTagHeaderValue"/> from the specified <paramref name="builder"/>.
/// </summary>
/// <param name="builder">The <see cref="ChecksumBuilder"/> to extend.</param>
/// <param name="isWeak">A value that indicates if this entity-tag header is a weak validator.</param>
/// <returns>An <see cref="EntityTagHeaderValue"/> that is initiated with a hexadecimal representation of <see cref="ChecksumBuilder.Checksum"/> and a value that indicates if the tag is weak.</returns>
public static EntityTagHeaderValue ToEntityTag(this ChecksumBuilder builder, bool isWeak = false)
{
Validator.ThrowIfNull(builder, nameof(builder));
return(new EntityTagHeaderValue(string.Concat("\"", builder.Checksum.ToHexadecimal(), "\""), isWeak));
}
/// <summary>
/// This method will either add or update the necessary HTTP response headers needed to provide entity tag header information.
/// </summary>
/// <param name="response">The <see cref="HttpResponse"/> to extend.</param>
/// <param name="request">An instance of the <see cref="HttpRequest"/> object.</param>
/// <param name="builder">A <see cref="ChecksumBuilder"/> that represents the integrity of the client.</param>
/// <param name="isWeak">A value that indicates if this entity-tag header is a weak validator.</param>
public static void SetEntityTagHeaderInformation(this HttpResponse response, HttpRequest request, ChecksumBuilder builder, bool isWeak = false)
{
Validator.ThrowIfNull(response, nameof(response));
Validator.ThrowIfNull(request, nameof(request));
Validator.ThrowIfNull(builder, nameof(builder));
builder = builder.CombineWith(request.Headers[HeaderNames.Accept]);
if (response.IsSuccessStatusCode() && request.IsClientSideResourceCached(builder))
{
response.StatusCode = StatusCodes.Status304NotModified;
}
response.Headers.AddOrUpdate(HeaderNames.ETag, new StringValues(builder.ToEntityTag(isWeak).ToString()));
}
