| 1 | package calendar |
| 2 | |
| 3 | import ( |
| 4 | "fmt" |
| 5 | "strings" |
| 6 | ) |
| 7 | |
| 8 | // MaxTitleLen and friends bound what a form may store. Not security — |
| 9 | // the columns are sealed and SQLite does not care — but a title nobody |
| 10 | // can read in a chip is a title nobody wanted, and an unbounded notes |
| 11 | // field is an unbounded row in a file that gets replicated. |
| 12 | const ( |
| 13 | MaxTitleLen = 200 |
| 14 | MaxLocationLen = 200 |
| 15 | MaxNotesLen = 4000 |
| 16 | ) |
| 17 | |
| 18 | // ValidationError is a message meant for the person who submitted the |
| 19 | // form, beside the field it is about. It carries no stored content. |
| 20 | type ValidationError struct { |
| 21 | Field string |
| 22 | Message string |
| 23 | } |
| 24 | |
| 25 | func (e ValidationError) Error() string { return e.Field + ": " + e.Message } |
| 26 | |
| 27 | // Invalid reports whether err is a ValidationError, so a handler can |
| 28 | // re-render the form with the message rather than answering 500. |
| 29 | func Invalid(err error) (ValidationError, bool) { |
| 30 | var v ValidationError |
| 31 | if err == nil { |
| 32 | return v, false |
| 33 | } |
| 34 | if ve, ok := err.(ValidationError); ok { |
| 35 | return ve, true |
| 36 | } |
| 37 | return v, false |
| 38 | } |
| 39 | |
| 40 | // ValidateEventInput normalises in place and reports the first problem. |
| 41 | // |
| 42 | // Normalising here rather than in the handler means the store cannot be |
| 43 | // handed an event with an unparseable time or a kind nothing renders, |
| 44 | // whatever calls it — including the ICS importer, which is the caller |
| 45 | // most likely to supply something strange. |
| 46 | func ValidateEventInput(in *EventInput) error { |
| 47 | in.Title = strings.TrimSpace(in.Title) |
| 48 | in.Location = strings.TrimSpace(in.Location) |
| 49 | in.Notes = strings.TrimSpace(in.Notes) |
| 50 | in.TZ = strings.TrimSpace(in.TZ) |
| 51 | in.RRule = strings.TrimSpace(in.RRule) |
| 52 | |
| 53 | if in.Title == "" { |
| 54 | return ValidationError{"title", "Give it a name."} |
| 55 | } |
| 56 | if len(in.Title) > MaxTitleLen { |
| 57 | return ValidationError{"title", fmt.Sprintf("Keep it under %d characters.", MaxTitleLen)} |
| 58 | } |
| 59 | if len(in.Location) > MaxLocationLen { |
| 60 | return ValidationError{"location", fmt.Sprintf("Keep it under %d characters.", MaxLocationLen)} |
| 61 | } |
| 62 | if len(in.Notes) > MaxNotesLen { |
| 63 | return ValidationError{"notes", fmt.Sprintf("Keep it under %d characters.", MaxNotesLen)} |
| 64 | } |
| 65 | |
| 66 | switch in.Kind { |
| 67 | case KindMeeting, KindCommitment, KindNote: |
| 68 | case "": |
| 69 | in.Kind = KindMeeting |
| 70 | default: |
| 71 | return ValidationError{"kind", "Pick a meeting, a commitment or a note."} |
| 72 | } |
| 73 | switch in.Status { |
| 74 | case StatusConfirmed, StatusTentative, StatusCancelled: |
| 75 | case "": |
| 76 | in.Status = StatusConfirmed |
| 77 | default: |
| 78 | return ValidationError{"status", "Pick a status."} |
| 79 | } |
| 80 | |
| 81 | // A timed event needs a zone; an all-day one must not have its zone |
| 82 | // consulted at all, and carrying one would invite a later reader to |
| 83 | // use it. |
| 84 | if in.AllDay { |
| 85 | in.TZ = "" |
| 86 | } else if in.TZ == "" { |
| 87 | return ValidationError{"tz", "Say which time zone this is in."} |
| 88 | } |
| 89 | if !in.AllDay { |
| 90 | if _, err := Zone(in.TZ); err != nil { |
| 91 | return ValidationError{"tz", "That is not a time zone we know."} |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | start, err := ToUTC(in.StartLocal, in.TZ, in.AllDay) |
| 96 | if err != nil { |
| 97 | return ValidationError{"start", "That is not a time we can read."} |
| 98 | } |
| 99 | if strings.TrimSpace(in.EndLocal) == "" { |
| 100 | return ValidationError{"end", "Say when it ends."} |
| 101 | } |
| 102 | end, err := ToUTC(in.EndLocal, in.TZ, in.AllDay) |
| 103 | if err != nil { |
| 104 | return ValidationError{"end", "That is not a time we can read."} |
| 105 | } |
| 106 | |
| 107 | // End is exclusive, so equal is empty and earlier is backwards. |
| 108 | // Both are refused rather than silently corrected: an event that |
| 109 | // quietly moved its own end is a worse surprise than a rejected |
| 110 | // form. |
| 111 | if end < start { |
| 112 | return ValidationError{"end", "It cannot end before it starts."} |
| 113 | } |
| 114 | if end == start && in.AllDay { |
| 115 | return ValidationError{"end", "An all-day event ends on the following day."} |
| 116 | } |
| 117 | return nil |
| 118 | } |
| 119 | |
amadan