Class EntityTagValue

Namespace

Trellis

Assembly

Trellis.Results.dll

Represents an RFC 9110 §8.8.1 entity tag (ETag) value with explicit weak/strong semantics.

public sealed record EntityTagValue : IEquatable<EntityTagValue>

Inheritance

object

EntityTagValue

Implements

IEquatable<EntityTagValue>

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

Extension Methods

MaybeExtensions.AsMaybe<T>(T)

MaybeExtensions.ToResult<TValue>(TValue)

NullableExtensions.ToResult<T>(T?, Func<Error>)

NullableExtensions.ToResult<T>(T?, Error)

AggregateTestMutator.ClearMaybeField<TEntity, TValue>(TEntity, Expression<Func<TEntity, Maybe<TValue>>>)

AggregateTestMutator.SetMaybeField<TEntity, TValue>(TEntity, Expression<Func<TEntity, Maybe<TValue>>>, TValue?)

Examples

var strong = EntityTagValue.Strong("abc123");
var weak = EntityTagValue.Weak("abc123");

// Parse from header
var parsed = EntityTagValue.TryParse("W/\"abc123\"");

// RFC 9110 §8.8.3.2 comparison
strong.StrongEquals(EntityTagValue.Strong("abc123")); // true
strong.WeakEquals(weak); // true

Remarks

An entity tag consists of an opaque quoted string, optionally prefixed with a weakness indicator (W/). Entity tags are used for conditional requests and cache validation.

Create instances using Strong(string) or Weak(string) factory methods, or parse from header values using TryParse(string?). Compare using StrongEquals(EntityTagValue) or WeakEquals(EntityTagValue) per RFC 9110 §8.8.3.2. Format for HTTP headers using ToHeaderValue().

Properties

IsWeak

Gets whether this is a weak entity tag.

public bool IsWeak { get; }

Property Value

bool

true if weak; false if strong.

IsWildcard

Gets whether this instance represents the RFC 9110 wildcard token (as opposed to a literal ETag with opaque-tag ).

public bool IsWildcard { get; }

Property Value

bool

OpaqueTag

Gets the raw opaque tag string without quotes or W/ prefix.

public string OpaqueTag { get; }

Property Value

string

Methods

Strong(string)

Creates a strong entity tag.

public static EntityTagValue Strong(string opaqueTag)

Parameters

opaqueTag string

The opaque tag string.

Returns

EntityTagValue

A new strong EntityTagValue.

StrongEquals(EntityTagValue)

Performs a strong comparison per RFC 9110 §8.8.3.2. Both tags must be strong and their opaque tags must match character-by-character. Wildcards never match in entity tag comparison — they are a precondition token, not a tag.

public bool StrongEquals(EntityTagValue other)

Parameters

other EntityTagValue

Returns

bool

ToHeaderValue()

Formats this entity tag for use in an HTTP header. Returns * for the wildcard, "tag" for strong tags, or W/"tag" for weak tags.

public string ToHeaderValue()

Returns

string

The formatted HTTP header value.

ToString()

Returns a string that represents the current object.

public override string ToString()

Returns

string

A string that represents the current object.

TryParse(string?)

Parses an entity tag from its HTTP header representation.

public static Result<EntityTagValue> TryParse(string? headerValue)

Parameters

headerValue string

The header value to parse. Expected formats: "tag" for strong or W/"tag" for weak.

Returns

Result<EntityTagValue>

A Result<TValue> containing the parsed EntityTagValue on success, or a BadRequestError on failure.

Examples

var strong = EntityTagValue.TryParse("\"abc123\"");
var weak = EntityTagValue.TryParse("W/\"abc123\"");

Weak(string)

Creates a weak entity tag.

public static EntityTagValue Weak(string opaqueTag)

Parameters

opaqueTag string

The opaque tag string.

Returns

EntityTagValue

A new weak EntityTagValue.

WeakEquals(EntityTagValue)

Performs a weak comparison per RFC 9110 §8.8.3.2. Only the opaque tags must match; the weakness indicator is ignored. Wildcards never match in entity tag comparison — they are a precondition token, not a tag.

public bool WeakEquals(EntityTagValue other)

Parameters

other EntityTagValue

Returns

bool

Wildcard()

Creates the RFC 9110 wildcard entity tag (), which matches any current entity. This is semantically distinct from Strong(""), which is a literal ETag with opaque-tag *.

public static EntityTagValue Wildcard()

Returns

EntityTagValue

A wildcard EntityTagValue.