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
|
#' Find an open TCP port
#'
#' Finds a random available TCP port for listening on, within a specified range
#' of ports. The default range of ports to check is 1024 to 49151, which is the
#' set of TCP User Ports. This function automatically excludes some ports which
#' are considered unsafe by web browsers.
#'
#' @inheritParams runServer
#' @param min Minimum port number.
#' @param max Maximum port number.
#' @param n Number of ports to try before giving up.
#'
#' @return A port that is available to listen on.
#'
#' @examples
#' \dontrun{
#' s <- startServer("127.0.0.1", randomPort(), list())
#' browseURL(paste0("http://127.0.0.1:", s$getPort()))
#'
#' s$stop()
#' }
#'
#' @export
randomPort <- function(min = 1024L, max = 49151L, host = "127.0.0.1", n = 20) {
valid_ports <- setdiff(seq.int(min, max), unsafe_ports)
n <- min(n, length(valid_ports))
# Try up to n ports
for (port in sample(valid_ports, n)) {
s <- NULL
# Check if port is open
tryCatch(
s <- startServer(host, port, list(), quiet = TRUE),
error = function(e) { }
)
if (!is.null(s)) {
s$stop()
return(port)
}
}
stop("Cannot find an available port.")
}
# Ports that are considered unsafe by Chrome
# http://superuser.com/questions/188058/which-ports-are-considered-unsafe-on-chrome
# https://github.com/rstudio/shiny/issues/1784
unsafe_ports <- c(
1,
7,
9,
11,
13,
15,
17,
19,
20,
21,
22,
23,
25,
37,
42,
43,
53,
77,
79,
87,
95,
101,
102,
103,
104,
109,
110,
111,
113,
115,
117,
119,
123,
135,
139,
143,
179,
389,
427,
465,
512,
513,
514,
515,
526,
530,
531,
532,
540,
548,
556,
563,
587,
601,
636,
993,
995,
2049,
3659,
4045,
6000,
6665,
6666,
6667,
6668,
6669,
6697
)
|
