| 1 | package calendar |
| 2 | |
| 3 | import ( |
| 4 | "crypto/sha256" |
| 5 | "encoding/hex" |
| 6 | "strings" |
| 7 | ) |
| 8 | |
| 9 | // CommonZones is the settings page's zone list. |
| 10 | // |
| 11 | // A short list, not the whole IANA database. Six hundred names in a |
| 12 | // select is a control nobody can use, and the seam for the rest is a |
| 13 | // text field beside it — somebody in Pacific/Chatham types it and the |
| 14 | // server validates it against the real database, so the list being |
| 15 | // short costs them one field rather than the feature. |
| 16 | var CommonZones = []string{ |
| 17 | "UTC", |
| 18 | "Europe/Dublin", |
| 19 | "Europe/London", |
| 20 | "Europe/Lisbon", |
| 21 | "Europe/Madrid", |
| 22 | "Europe/Paris", |
| 23 | "Europe/Berlin", |
| 24 | "Europe/Amsterdam", |
| 25 | "Europe/Brussels", |
| 26 | "Europe/Zurich", |
| 27 | "Europe/Rome", |
| 28 | "Europe/Stockholm", |
| 29 | "Europe/Helsinki", |
| 30 | "Europe/Athens", |
| 31 | "Europe/Warsaw", |
| 32 | "Europe/Kyiv", |
| 33 | "Europe/Istanbul", |
| 34 | "Europe/Moscow", |
| 35 | "America/St_Johns", |
| 36 | "America/Halifax", |
| 37 | "America/New_York", |
| 38 | "America/Toronto", |
| 39 | "America/Chicago", |
| 40 | "America/Mexico_City", |
| 41 | "America/Denver", |
| 42 | "America/Phoenix", |
| 43 | "America/Los_Angeles", |
| 44 | "America/Vancouver", |
| 45 | "America/Anchorage", |
| 46 | "America/Sao_Paulo", |
| 47 | "America/Argentina/Buenos_Aires", |
| 48 | "America/Bogota", |
| 49 | "America/Lima", |
| 50 | "America/Santiago", |
| 51 | "Africa/Cairo", |
| 52 | "Africa/Lagos", |
| 53 | "Africa/Nairobi", |
| 54 | "Africa/Johannesburg", |
| 55 | "Asia/Jerusalem", |
| 56 | "Asia/Dubai", |
| 57 | "Asia/Karachi", |
| 58 | "Asia/Kolkata", |
| 59 | "Asia/Kathmandu", |
| 60 | "Asia/Dhaka", |
| 61 | "Asia/Bangkok", |
| 62 | "Asia/Jakarta", |
| 63 | "Asia/Singapore", |
| 64 | "Asia/Hong_Kong", |
| 65 | "Asia/Shanghai", |
| 66 | "Asia/Manila", |
| 67 | "Asia/Tokyo", |
| 68 | "Asia/Seoul", |
| 69 | "Australia/Perth", |
| 70 | "Australia/Adelaide", |
| 71 | "Australia/Brisbane", |
| 72 | "Australia/Sydney", |
| 73 | "Pacific/Auckland", |
| 74 | "Pacific/Honolulu", |
| 75 | } |
| 76 | |
| 77 | // commonZoneSet is CommonZones as a lookup, built once. |
| 78 | var commonZoneSet = func() map[string]bool { |
| 79 | m := make(map[string]bool, len(CommonZones)) |
| 80 | for _, z := range CommonZones { |
| 81 | m[z] = true |
| 82 | } |
| 83 | return m |
| 84 | }() |
| 85 | |
| 86 | // IsCommonZone reports whether name is on the CommonZones list. |
| 87 | // |
| 88 | // It is the bound on a zone a STRANGER may name: the public booking page |
| 89 | // accepts ?zone= only from this list (plus the host's own zone), so an |
| 90 | // unauthenticated request can never reach time.LoadLocation with a |
| 91 | // string of its choosing. |
| 92 | func IsCommonZone(name string) bool { return commonZoneSet[name] } |
| 93 | |
| 94 | // etagFor is the feed's cache validator: a hash of exactly the bytes |
| 95 | // being served, so it changes when and only when the file does. |
| 96 | // |
| 97 | // Not the calendar's updated_at, which would miss an occurrence rolling |
| 98 | // out of the window without anything being edited, and not a random |
| 99 | // value, which would defeat the 304 entirely. |
| 100 | func etagFor(body string) string { |
| 101 | sum := sha256.Sum256([]byte(body)) |
| 102 | return `"` + hex.EncodeToString(sum[:16]) + `"` |
| 103 | } |
| 104 | |
| 105 | // safeFilename reduces a calendar's name to something a Content- |
| 106 | // Disposition header and a filesystem will both accept. |
| 107 | // |
| 108 | // The name is content — it came out of a sealed column — so it must not |
| 109 | // be able to inject a header. Anything outside a conservative set |
| 110 | // becomes a dash rather than being escaped, because an escaped filename |
| 111 | // that round-trips through three operating systems is not worth the |
| 112 | // surface. |
| 113 | func safeFilename(name string) string { |
| 114 | var b strings.Builder |
| 115 | for _, r := range name { |
| 116 | switch { |
| 117 | case r >= 'a' && r <= 'z', r >= 'A' && r <= 'Z', r >= '0' && r <= '9': |
| 118 | b.WriteRune(r) |
| 119 | case r == ' ' || r == '-' || r == '_': |
| 120 | b.WriteRune('-') |
| 121 | } |
| 122 | } |
| 123 | out := strings.Trim(b.String(), "-") |
| 124 | if out == "" { |
| 125 | return "calendar" |
| 126 | } |
| 127 | if len(out) > 60 { |
| 128 | out = out[:60] |
| 129 | } |
| 130 | return out |
| 131 | } |
| 132 | |
amadan