114 lines
4.3 KiB
Swift
114 lines
4.3 KiB
Swift
//
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// GeminiProtocol.swift
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// Gemini
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//
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// Created by Shadowfacts on 7/12/20.
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//
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import Network
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class GeminiProtocol: NWProtocolFramerImplementation {
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static let definition = NWProtocolFramer.Definition(implementation: GeminiProtocol.self)
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static let label = "Gemini"
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private var tempStatusCode: GeminiResponseHeader.StatusCode?
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private var tempMeta: String?
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required init(framer: NWProtocolFramer.Instance) {
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}
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func start(framer: NWProtocolFramer.Instance) -> NWProtocolFramer.StartResult {
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return .ready
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}
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func wakeup(framer: NWProtocolFramer.Instance) {
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}
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func stop(framer: NWProtocolFramer.Instance) -> Bool {
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return true
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}
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func cleanup(framer: NWProtocolFramer.Instance) {
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}
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func handleInput(framer: NWProtocolFramer.Instance) -> Int {
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if tempStatusCode == nil {
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_ = framer.parseInput(minimumIncompleteLength: 3, maximumLength: 3) { (buffer, isComplete) -> Int in
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guard let buffer = buffer,
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buffer.count == 3 else { return 0 }
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self.tempStatusCode = GeminiResponseHeader.StatusCode(buffer)
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return 3
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}
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}
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guard let statusCode = tempStatusCode else {
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return 3
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}
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var attemptedMetaLength: Int?
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if tempMeta == nil {
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// Minimum length is 2 bytes, spec does not say meta string is required
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_ = framer.parseInput(minimumIncompleteLength: 2, maximumLength: 1024 + 2) { (buffer, isComplete) -> Int in
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guard let buffer = buffer,
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buffer.count >= 2 else { return 0 }
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attemptedMetaLength = buffer.count
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let lastPossibleCRIndex = buffer.index(before: buffer.index(before: buffer.endIndex))
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var index = buffer.startIndex
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var found = false
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while index <= lastPossibleCRIndex {
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// <CR><LF>
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if buffer[index] == 13 && buffer[buffer.index(after: index)] == 10 {
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found = true
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break
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}
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index = buffer.index(after: index)
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}
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if !found {
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if buffer.count < 1026 {
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return 0
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} else {
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fatalError("Didn't find <CR><LF> in buffer. Meta string was longer than 1024 bytes")
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}
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}
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self.tempMeta = String(bytes: buffer[..<index], encoding: .utf8)
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return buffer.startIndex.distance(to: index) + 2
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}
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}
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guard let meta = tempMeta else {
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if let attempted = attemptedMetaLength {
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return attempted + 1
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} else {
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return 2
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}
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}
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let header = GeminiResponseHeader(status: statusCode, meta: meta)
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let message = NWProtocolFramer.Message(geminiResponseHeader: header)
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// What does the return value of deliverInputNoCopy mean, you ask? Why, I have no idea
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// It always returns true for a length of zero, so following the sample code and looping
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// infinitely until it returns false causes an infinite loop.
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// Additionally, calling deliverInput with an empty Data() causes an error inside Network.framework.
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// So, we just ignore the result since it doesn't seem to cause any problems ¯\_(ツ)_/¯
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_ = framer.deliverInputNoCopy(length: statusCode.isSuccess ? .max : 0, message: message, isComplete: true)
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return 0
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}
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func handleOutput(framer: NWProtocolFramer.Instance, message: NWProtocolFramer.Message, messageLength: Int, isComplete: Bool) {
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guard let request = message.geminiRequest else { fatalError("GeminiProtocol can't send message that doesn't have an associated GeminiRequest") }
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framer.writeOutput(data: request.data)
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}
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}
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fileprivate extension GeminiResponseHeader.StatusCode {
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init?(_ buffer: UnsafeMutableRawBufferPointer) {
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guard let str = String(bytes: buffer[...buffer.index(after: buffer.startIndex)], encoding: .utf8),
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let value = Int(str, radix: 10) else { return nil }
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self.init(rawValue: value)
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}
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}
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