-
Notifications
You must be signed in to change notification settings - Fork 24
/
SSDPResponse.swift
236 lines (202 loc) · 8.06 KB
/
SSDPResponse.swift
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
//
// SSDPMessageScanner.swift
// SwiftSSDP
//
// Created by Paul Bates on 2/7/17.
// Copyright © 2017 Paul Bates. All rights reserved.
//
import Foundation
/// Types of responses from discovery or from joining the SSDP multicast group
public enum SSDPMessage {
/// A M-SEARCH request broadcast
case searchRequest
/// A M-SEARCH response for a discovered device or service
case searchResponse(response: SSDPMSearchResponse)
/// A NOTIFY broadcast
case notify
}
//
// MARK: -
//
/// Parses M-SEARCH and NOTIFY responses from M-SEARCH broadcasts or NOTIFY multicasts on the local area network
class SSDPMessageParser {
/// Parses an M-SEARCH request/response or a multicast NOTIFY broadcast
/// Note: NOTIFY currently not supported
///
/// - Parameters:
/// - response: Full response to parse
public static func parse(response: String) -> SSDPMessage? {
if response.isEmpty {
return nil
}
let scanner = Scanner(string: response)
scanner.charactersToBeSkipped = CharacterSet.newlines
// Scan first token to ensure we have an expected response
guard let token = scanInitialToken(scanner: scanner) else {
return nil
}
// Scan remaining headers to construct and init a response from
var headers: [String: String] = [:]
while(!scanner.isAtEnd) {
if let pair = scanKeyValuePair(scanner: scanner) {
headers[pair.key] = pair.value
}
}
return constructMessage(token: token, headers: headers)
}
//
// MARK: Private Functions
//
/// Scans an initial token from the response to determine what the response type is
///
/// - Parameters:
/// - scanner: Scanner to scan an initial token from
///
/// - Returns: An initial token or nil if the scanner has already reached the end
private static func scanInitialToken(scanner: Scanner) -> String? {
if scanner.isAtEnd {
return nil
}
var buffer: NSString? = nil
if scanner.scanUpToCharacters(from: CharacterSet.whitespacesAndNewlines, into: &buffer) {
// Scan to the end of the line
_ = scanLine(scanner: scanner)
return buffer as String?
}
return nil
}
/// Scans a single line from the response
///
/// - Parameters:
/// - scanner: Scanner to scan the next line from
///
/// - Returns: An entire line or nil if the scanner has already reached the end
private static func scanLine(scanner: Scanner) -> String? {
if scanner.isAtEnd {
return nil
}
var buffer: NSString? = nil
if scanner.scanUpToCharacters(from: CharacterSet.newlines, into: &buffer) {
return buffer as String?
}
return nil
}
/// Scans a single line's key/value pair in the form of "KEY: value"
///
/// - Parameters:
/// - scanner: Scanner to scan the pair from
///
/// - Returns: A tuple of the key/value pair or nil if no match could be found or the scanner has reached the end
private static func scanKeyValuePair(scanner: Scanner) -> (key: String, value: String)? {
if scanner.isAtEnd {
return nil
}
var buffer: NSString? = nil
let delimiterSet = CharacterSet(charactersIn: ":").union(CharacterSet.whitespaces)
if scanner.scanUpToCharacters(from: delimiterSet, into: &buffer), let key = buffer as String? {
if scanner.scanCharacters(from: delimiterSet, into: nil) && !scanner.isAtEnd {
if CharacterSet.newlines.contains(UnicodeScalar((scanner.string as NSString).character(at: scanner.scanLocation))!) {
return (key: key, value: "")
} else if let value = scanLine(scanner: scanner) {
return (key: key, value: value.trimmingCharacters(in: CharacterSet.whitespaces))
} else {
return nil
}
}
}
return nil
}
/// Constructs a message based on initial token of the raw response and the parsed headers.
///
/// - Parameters
/// - token: Initial token parses from the response
/// - headers: Parsed dictionary of headers to construct a response with
///
/// - Returns: A fully formed message
private static func constructMessage(token: String, headers: [String: String]) -> SSDPMessage? {
if token == "M-SEARCH" {
return nil
} else if token == "NOTIFY" {
return nil
} else if token == "HTTP/1.1" {
guard let response = SSDPMSearchResponse(fromHeaders: headers) else {
return nil
}
return .searchResponse(response: response)
}
return nil
}
}
//
// MARK: -
//
// Extension to support initializing an `SSDPMSearchResponse` from `SSDPMessageParser` parsed message
extension SSDPMSearchResponse {
/// Attempts to initialize a `SSDPMSearchResponse` from parsed response headers. If critical headers are missing or malformed the
/// response will not be initialized
///
/// - Parameters:
/// - fromHeaders: M-SEARCH response headers
init?(fromHeaders headers: [String: String]) {
var mutableHeaders = headers
// CACHE-CONTROL
if let cacheControlString = headers[SSDPHeaderKeys.cacheControl] {
let maxAgeRegEx = try! NSRegularExpression(pattern: "max\\-age[ \t]*=[ \t]*([0-9]+)")
var matches: [String] = []
for match in maxAgeRegEx.matches(in: cacheControlString, range: NSRange(location:0, length: cacheControlString.utf8.count)) {
let capturedRange = match.rangeAt(1)
if !NSEqualRanges(capturedRange, NSMakeRange(NSNotFound, 0)) {
let theResult = (cacheControlString as NSString).substring(with: capturedRange)
matches.append(theResult)
}
}
if matches.count > 0, let maxAgeSeconds = Int(matches[0], radix: 10) {
self.cacheControl = Date(timeIntervalSinceNow: TimeInterval(maxAgeSeconds) * 1000.0)
mutableHeaders.removeValue(forKey: SSDPHeaderKeys.cacheControl)
} else {
self.cacheControl = nil
}
} else {
self.cacheControl = nil
}
// DATE
if let dateString = headers[SSDPHeaderKeys.date], let date = DateFormatter().date(from: dateString) {
self.date = date
mutableHeaders.removeValue(forKey: SSDPHeaderKeys.date)
} else {
self.date = nil
}
// EXT
guard let _ = headers[SSDPHeaderKeys.ext] else {
return nil
}
self.ext = true
mutableHeaders.removeValue(forKey: SSDPHeaderKeys.ext)
// LOCATION
guard let location = headers[SSDPHeaderKeys.location], let locationUrl = URL(string: location) else {
return nil
}
self.location = locationUrl
mutableHeaders.removeValue(forKey: SSDPHeaderKeys.location)
// SERVER
if let server = headers[SSDPHeaderKeys.server] {
self.server = server
mutableHeaders.removeValue(forKey: SSDPHeaderKeys.server)
} else {
self.server = nil
}
// ST
guard let searchTargetString = headers[SSDPHeaderKeys.searchTarget], let searchTarget = SSDPSearchTarget(rawValue: searchTargetString) else {
return nil
}
self.searchTarget = searchTarget
mutableHeaders.removeValue(forKey: SSDPHeaderKeys.searchTarget)
// USN
guard let usn = headers[SSDPHeaderKeys.usn] else {
return nil
}
self.usn = usn
mutableHeaders.removeValue(forKey: SSDPHeaderKeys.usn)
self.otherHeaders = mutableHeaders
}
}