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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2025 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
@available(FoundationPreview 6.2, *)
public extension FormatStyle where Self == Date.HTTPFormatStyle {
static var http: Self {
return Date.HTTPFormatStyle()
}
}
@available(FoundationPreview 6.2, *)
public extension ParseableFormatStyle where Self == Date.HTTPFormatStyle {
static var http: Self { .init() }
}
@available(FoundationPreview 6.2, *)
public extension ParseStrategy where Self == Date.HTTPFormatStyle {
@_disfavoredOverload
static var http: Self { .init() }
}
@available(FoundationPreview 6.2, *)
extension Date.HTTPFormatStyle : ParseStrategy {
public var parseStrategy: Date.HTTPFormatStyle { self }
}
@available(FoundationPreview 6.2, *)
extension Date.HTTPFormatStyle : FormatStyle {
}
@available(FoundationPreview 6.2, *)
extension Date {
/// Options for generating and parsing string representations of dates following the HTTP date format from [RFC 9110 ยง 5.6.7](https://www.rfc-editor.org/rfc/rfc9110.html#http.date).
public struct HTTPFormatStyle : Sendable, Hashable, Codable, ParseableFormatStyle {
let componentsStyle = DateComponents.HTTPFormatStyle()
public init() {}
public init(from decoder: any Decoder) throws {}
public func format(_ date: Date) -> String {
// <day-name>, <day> <month> <year> <hour>:<minute>:<second> GMT
let components = Calendar(identifier: .gregorian)._dateComponents([.weekday, .day, .month, .year, .hour, .minute, .second], from: date, in: .gmt)
return componentsStyle.format(components)
}
public func parse(_ value: String) throws -> Date {
guard let (_, date) = parse(value, in: value.startIndex..<value.endIndex) else {
throw parseError(value, exampleFormattedString: self.format(Date.now))
}
return date
}
fileprivate func parse(_ value: String, in range: Range<String.Index>) -> (String.Index, Date)? {
var v = value[range]
guard !v.isEmpty else {
return nil
}
let result = v.withUTF8 { buffer -> (Int, Date)? in
let view = BufferView(unsafeBufferPointer: buffer)!
guard let comps = try? componentsStyle.components(from: value, in: view) else {
return nil
}
// HTTP dates are always GMT
guard let date = Calendar(identifier: .gregorian).date(from: comps.components) else {
return nil
}
return (comps.consumed, date)
}
guard let result else {
return nil
}
let endIndex = value.utf8.index(v.startIndex, offsetBy: result.0)
return (endIndex, result.1)
}
}
}
// MARK: - Regex
@available(FoundationPreview 6.2, *)
extension Date.HTTPFormatStyle : CustomConsumingRegexComponent {
public typealias RegexOutput = Date
public func consuming(_ input: String, startingAt index: String.Index, in bounds: Range<String.Index>) throws -> (upperBound: String.Index, output: Date)? {
guard index < bounds.upperBound else {
return nil
}
// It's important to return nil from parse in case of a failure, not throw. That allows things like the firstMatch regex to work.
return self.parse(input, in: index..<bounds.upperBound)
}
}
@available(FoundationPreview 6.2, *)
extension RegexComponent where Self == Date.HTTPFormatStyle {
/// Creates a regex component to match an HTTP date and time, such as "2015-11-14'T'15:05:03'Z'", and capture the string as a `Date` using the time zone as specified in the string.
public static var http: Date.HTTPFormatStyle {
return Date.HTTPFormatStyle()
}
}
@available(FoundationPreview 6.2, *)
extension DateComponents.HTTPFormatStyle : CustomConsumingRegexComponent {
public typealias RegexOutput = DateComponents
public func consuming(_ input: String, startingAt index: String.Index, in bounds: Range<String.Index>) throws -> (upperBound: String.Index, output: DateComponents)? {
guard index < bounds.upperBound else {
return nil
}
// It's important to return nil from parse in case of a failure, not throw. That allows things like the firstMatch regex to work.
return self.parse(input, in: index..<bounds.upperBound)
}
}
@available(FoundationPreview 6.2, *)
extension RegexComponent where Self == DateComponents.HTTPFormatStyle {
/// Creates a regex component to match an HTTP date and time, such as "2015-11-14'T'15:05:03'Z'", and capture the string as a `DateComponents` using the time zone as specified in the string.
public static var httpComponents: DateComponents.HTTPFormatStyle {
return DateComponents.HTTPFormatStyle()
}
}
// MARK: - Components
@available(FoundationPreview 6.2, *)
public extension FormatStyle where Self == DateComponents.HTTPFormatStyle {
static var http: Self {
return DateComponents.HTTPFormatStyle()
}
}
@available(FoundationPreview 6.2, *)
public extension ParseableFormatStyle where Self == DateComponents.HTTPFormatStyle {
static var http: Self { .init() }
}
@available(FoundationPreview 6.2, *)
public extension ParseStrategy where Self == DateComponents.HTTPFormatStyle {
@_disfavoredOverload
static var http: Self { .init() }
}
@available(FoundationPreview 6.2, *)
extension DateComponents.HTTPFormatStyle : FormatStyle {
}
@available(FoundationPreview 6.2, *)
extension DateComponents.HTTPFormatStyle : ParseStrategy {
public var parseStrategy: DateComponents.HTTPFormatStyle { self }
}
@available(FoundationPreview 6.2, *)
extension DateComponents {
/// Converts `DateComponents` into RFC 9110-compatible "HTTP date" `String`, and parses in the reverse direction.
/// This parser does not do validation on the individual values of the components. An optional date can be created from the result using `Calendar(identifier: .gregorian).date(from: ...)`.
/// When formatting, missing or invalid fields are filled with default values: `Sun`, `01`, `Jan`, `2000`, `00:00:00`, `GMT`. Note that missing fields may result in an invalid date or time. Other values in the `DateComponents` are ignored.
public struct HTTPFormatStyle : Sendable, Hashable, Codable, ParseableFormatStyle {
public init() {
}
// MARK: - Format
public func format(_ components: DateComponents) -> String {
let capacity = 32 // It is believed no HTTP date can exceed this size (max should be 26)
return withUnsafeTemporaryAllocation(of: CChar.self, capacity: capacity + 1) { _buffer in
var buffer = OutputBuffer(initializing: _buffer.baseAddress!, capacity: _buffer.count)
switch components.weekday {
case 2:
buffer.appendElement(CChar(UInt8(ascii: "M")))
buffer.appendElement(CChar(UInt8(ascii: "o")))
buffer.appendElement(CChar(UInt8(ascii: "n")))
case 3:
buffer.appendElement(CChar(UInt8(ascii: "T")))
buffer.appendElement(CChar(UInt8(ascii: "u")))
buffer.appendElement(CChar(UInt8(ascii: "e")))
case 4:
buffer.appendElement(CChar(UInt8(ascii: "W")))
buffer.appendElement(CChar(UInt8(ascii: "e")))
buffer.appendElement(CChar(UInt8(ascii: "d")))
case 5:
buffer.appendElement(CChar(UInt8(ascii: "T")))
buffer.appendElement(CChar(UInt8(ascii: "h")))
buffer.appendElement(CChar(UInt8(ascii: "u")))
case 6:
buffer.appendElement(CChar(UInt8(ascii: "F")))
buffer.appendElement(CChar(UInt8(ascii: "r")))
buffer.appendElement(CChar(UInt8(ascii: "i")))
case 7:
buffer.appendElement(CChar(UInt8(ascii: "S")))
buffer.appendElement(CChar(UInt8(ascii: "a")))
buffer.appendElement(CChar(UInt8(ascii: "t")))
case 1:
// Sunday, or default / missing
fallthrough
default:
buffer.appendElement(CChar(UInt8(ascii: "S")))
buffer.appendElement(CChar(UInt8(ascii: "u")))
buffer.appendElement(CChar(UInt8(ascii: "n")))
}
buffer.appendElement(CChar(UInt8(ascii: ",")))
buffer.appendElement(CChar(UInt8(ascii: " ")))
let day = components.day ?? 1
buffer.append(day, zeroPad: 2)
buffer.appendElement(CChar(UInt8(ascii: " ")))
switch components.month {
case 2:
buffer.appendElement(CChar(UInt8(ascii: "F")))
buffer.appendElement(CChar(UInt8(ascii: "e")))
buffer.appendElement(CChar(UInt8(ascii: "b")))
case 3:
buffer.appendElement(CChar(UInt8(ascii: "M")))
buffer.appendElement(CChar(UInt8(ascii: "a")))
buffer.appendElement(CChar(UInt8(ascii: "r")))
case 4:
buffer.appendElement(CChar(UInt8(ascii: "A")))
buffer.appendElement(CChar(UInt8(ascii: "p")))
buffer.appendElement(CChar(UInt8(ascii: "r")))
case 5:
buffer.appendElement(CChar(UInt8(ascii: "M")))
buffer.appendElement(CChar(UInt8(ascii: "a")))
buffer.appendElement(CChar(UInt8(ascii: "y")))
case 6:
buffer.appendElement(CChar(UInt8(ascii: "J")))
buffer.appendElement(CChar(UInt8(ascii: "u")))
buffer.appendElement(CChar(UInt8(ascii: "n")))
case 7:
buffer.appendElement(CChar(UInt8(ascii: "J")))
buffer.appendElement(CChar(UInt8(ascii: "u")))
buffer.appendElement(CChar(UInt8(ascii: "l")))
case 8:
buffer.appendElement(CChar(UInt8(ascii: "A")))
buffer.appendElement(CChar(UInt8(ascii: "u")))
buffer.appendElement(CChar(UInt8(ascii: "g")))
case 9:
buffer.appendElement(CChar(UInt8(ascii: "S")))
buffer.appendElement(CChar(UInt8(ascii: "e")))
buffer.appendElement(CChar(UInt8(ascii: "p")))
case 10:
buffer.appendElement(CChar(UInt8(ascii: "O")))
buffer.appendElement(CChar(UInt8(ascii: "c")))
buffer.appendElement(CChar(UInt8(ascii: "t")))
case 11:
buffer.appendElement(CChar(UInt8(ascii: "N")))
buffer.appendElement(CChar(UInt8(ascii: "o")))
buffer.appendElement(CChar(UInt8(ascii: "v")))
case 12:
buffer.appendElement(CChar(UInt8(ascii: "D")))
buffer.appendElement(CChar(UInt8(ascii: "e")))
buffer.appendElement(CChar(UInt8(ascii: "c")))
case 1:
// Jan or default value
fallthrough
default:
buffer.appendElement(CChar(UInt8(ascii: "J")))
buffer.appendElement(CChar(UInt8(ascii: "a")))
buffer.appendElement(CChar(UInt8(ascii: "n")))
}
buffer.appendElement(CChar(UInt8(ascii: " ")))
let year = components.year ?? 2000
buffer.append(year, zeroPad: 4)
buffer.appendElement(CChar(UInt8(ascii: " ")))
let h = components.hour ?? 0
let m = components.minute ?? 0
let s = components.second ?? 0
buffer.append(h, zeroPad: 2)
buffer.appendElement(CChar(UInt8(ascii: ":")))
buffer.append(m, zeroPad: 2)
buffer.appendElement(CChar(UInt8(ascii: ":")))
buffer.append(s, zeroPad: 2)
buffer.appendElement(CChar(UInt8(ascii: " ")))
buffer.appendElement(CChar(UInt8(ascii: "G")))
buffer.appendElement(CChar(UInt8(ascii: "M")))
buffer.appendElement(CChar(UInt8(ascii: "T")))
// Null-terminate
buffer.appendElement(CChar(0))
// Make a string
let initialized = buffer.relinquishBorrowedMemory()
return String(validatingUTF8: initialized.baseAddress!)!
}
}
// MARK: - Parse
fileprivate struct ComponentsParseResult {
var consumed: Int
var components: DateComponents
}
public func parse(_ value: String) throws -> DateComponents {
guard let (_, components) = parse(value, in: value.startIndex..<value.endIndex) else {
throw parseError(value, exampleFormattedString: Date.HTTPFormatStyle().format(Date.now))
}
return components
}
private func parse(_ value: String, in range: Range<String.Index>) -> (String.Index, DateComponents)? {
var v = value[range]
guard !v.isEmpty else {
return nil
}
let result = v.withUTF8 { buffer -> (Int, DateComponents)? in
let view = BufferView(unsafeBufferPointer: buffer)!
guard let comps = try? components(from: value, in: view) else {
return nil
}
return (comps.consumed, comps.components)
}
guard let result else {
return nil
}
let endIndex = value.utf8.index(v.startIndex, offsetBy: result.0)
return (endIndex, result.1)
}
fileprivate func components(from inputString: String, in view: borrowing BufferView<UInt8>) throws -> ComponentsParseResult {
// https://www.rfc-editor.org/rfc/rfc9110.html#http.date
// <day-name>, <day> <month> <year> <hour>:<minute>:<second> GMT
var it = view.makeIterator()
var dc = DateComponents()
// Despite the spec, we allow the weekday name to be optional.
guard let maybeWeekday1 = it.peek() else {
throw parseError(inputString, exampleFormattedString: Date.HTTPFormatStyle().format(Date.now))
}
if isASCIIDigit(maybeWeekday1) {
// This is the first digit of the day. Weekday is not present.
} else {
// Anything else must be a day-name (Mon, Tue, ... Sun)
guard let weekday1 = it.next(), let weekday2 = it.next(), let weekday3 = it.next() else {
throw parseError(inputString, exampleFormattedString: Date.HTTPFormatStyle().format(Date.now))
}
dc.weekday = switch (weekday1, weekday2, weekday3) {
case (UInt8(ascii: "S"), UInt8(ascii: "u"), UInt8(ascii: "n")):
1
case (UInt8(ascii: "M"), UInt8(ascii: "o"), UInt8(ascii: "n")):
2
case (UInt8(ascii: "T"), UInt8(ascii: "u"), UInt8(ascii: "e")):
3
case (UInt8(ascii: "W"), UInt8(ascii: "e"), UInt8(ascii: "d")):
4
case (UInt8(ascii: "T"), UInt8(ascii: "h"), UInt8(ascii: "u")):
5
case (UInt8(ascii: "F"), UInt8(ascii: "r"), UInt8(ascii: "i")):
6
case (UInt8(ascii: "S"), UInt8(ascii: "a"), UInt8(ascii: "t")):
7
default:
throw parseError(inputString, exampleFormattedString: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Malformed weekday name")
}
// Move past , and space to weekday
try it.expectCharacter(UInt8(ascii: ","), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Missing , after weekday")
try it.expectCharacter(UInt8(ascii: " "), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Missing space after weekday")
}
dc.day = try it.digits(minDigits: 2, maxDigits: 2, input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Missing or malformed day")
try it.expectCharacter(UInt8(ascii: " "), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now))
// month-name (Jan, Feb, ... Dec)
guard let month1 = it.next(), let month2 = it.next(), let month3 = it.next() else {
throw parseError(inputString, exampleFormattedString: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Missing month")
}
dc.month = switch (month1, month2, month3) {
case (UInt8(ascii: "J"), UInt8(ascii: "a"), UInt8(ascii: "n")):
1
case (UInt8(ascii: "F"), UInt8(ascii: "e"), UInt8(ascii: "b")):
2
case (UInt8(ascii: "M"), UInt8(ascii: "a"), UInt8(ascii: "r")):
3
case (UInt8(ascii: "A"), UInt8(ascii: "p"), UInt8(ascii: "r")):
4
case (UInt8(ascii: "M"), UInt8(ascii: "a"), UInt8(ascii: "y")):
5
case (UInt8(ascii: "J"), UInt8(ascii: "u"), UInt8(ascii: "n")):
6
case (UInt8(ascii: "J"), UInt8(ascii: "u"), UInt8(ascii: "l")):
7
case (UInt8(ascii: "A"), UInt8(ascii: "u"), UInt8(ascii: "g")):
8
case (UInt8(ascii: "S"), UInt8(ascii: "e"), UInt8(ascii: "p")):
9
case (UInt8(ascii: "O"), UInt8(ascii: "c"), UInt8(ascii: "t")):
10
case (UInt8(ascii: "N"), UInt8(ascii: "o"), UInt8(ascii: "v")):
11
case (UInt8(ascii: "D"), UInt8(ascii: "e"), UInt8(ascii: "c")):
12
default:
throw parseError(inputString, exampleFormattedString: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Month \(String(describing: dc.month)) is out of bounds")
}
try it.expectCharacter(UInt8(ascii: " "), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now))
dc.year = try it.digits(minDigits: 4, maxDigits: 4, input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now))
try it.expectCharacter(UInt8(ascii: " "), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now))
let hour = try it.digits(minDigits: 2, maxDigits: 2, input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now))
if hour < 0 || hour > 23 {
throw parseError(inputString, exampleFormattedString: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Hour \(hour) is out of bounds")
}
dc.hour = hour
try it.expectCharacter(UInt8(ascii: ":"), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now))
let minute = try it.digits(minDigits: 2, maxDigits: 2, input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now))
if minute < 0 || minute > 59 {
throw parseError(inputString, exampleFormattedString: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Minute \(minute) is out of bounds")
}
dc.minute = minute
try it.expectCharacter(UInt8(ascii: ":"), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now))
let second = try it.digits(minDigits: 2, maxDigits: 2, input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now))
// second '60' is supported in the spec for leap seconds, but Foundation does not support leap seconds. 60 is adjusted to 59.
if second < 0 || second > 60 {
throw parseError(inputString, exampleFormattedString: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Second \(second) is out of bounds")
}
// Foundation does not support leap seconds. We convert 60 seconds into 59 seconds.
if second == 60 {
dc.second = 59
} else {
dc.second = second
}
try it.expectCharacter(UInt8(ascii: " "), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now))
// "GMT"
try it.expectCharacter(UInt8(ascii: "G"), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Missing GMT time zone")
try it.expectCharacter(UInt8(ascii: "M"), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Missing GMT time zone")
try it.expectCharacter(UInt8(ascii: "T"), input: inputString, onFailure: Date.HTTPFormatStyle().format(Date.now), extendedDescription: "Missing GMT time zone")
// Time zone is always GMT, calendar is always Gregorian
dc.timeZone = .gmt
dc.calendar = Calendar(identifier: .gregorian)
// Would be nice to see this functionality on BufferView, but for now we calculate it ourselves.
let utf8CharactersRead = it.curPointer - view.startIndex._rawValue
return ComponentsParseResult(consumed: utf8CharactersRead, components: dc)
}
}
}
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