| 1 | package provision |
| 2 | |
| 3 | import ( |
| 4 | "bytes" |
| 5 | "encoding/json" |
| 6 | "errors" |
| 7 | "io" |
| 8 | "strings" |
| 9 | |
| 10 | "github.com/carlosframework/platform/internal/maintenanceguard" |
| 11 | ) |
| 12 | |
| 13 | var ErrMaintenanceProjection = errors.New("provision: invalid maintenance projection or protected fields") |
| 14 | |
| 15 | // MaintenanceProjection retains a present projection, including invalid input. |
| 16 | // Its value receiver validates on marshal, so an ignored decode error cannot |
| 17 | // turn a present invalid projection into an absent one. An empty slice is absent. |
| 18 | type MaintenanceProjection []byte |
| 19 | |
| 20 | func (p *MaintenanceProjection) UnmarshalJSON(raw []byte) error { |
| 21 | *p = append((*p)[:0], raw...) |
| 22 | _, err := maintenanceguard.DecodeProjection(raw) |
| 23 | if err != nil { |
| 24 | return ErrMaintenanceProjection |
| 25 | } |
| 26 | return nil |
| 27 | } |
| 28 | func (p MaintenanceProjection) MarshalJSON() ([]byte, error) { |
| 29 | if _, err := maintenanceguard.DecodeProjection(p); err != nil { |
| 30 | return nil, ErrMaintenanceProjection |
| 31 | } |
| 32 | return append([]byte(nil), p...), nil |
| 33 | } |
| 34 | |
| 35 | // DecodeRecord is the bucket-record parser. API response views may use ordinary |
| 36 | // JSON decoding; they do not authorize writes. Keep this off Record's method |
| 37 | // set so embedding Record cannot swallow a wrapper's fields or Gate shadow. |
| 38 | func DecodeRecord(raw []byte) (Record, error) { |
| 39 | invalid := Record{Maintenance: MaintenanceProjection("null")} |
| 40 | dec := json.NewDecoder(bytes.NewReader(raw)) |
| 41 | first, e := dec.Token() |
| 42 | if e != nil || first != json.Delim('{') { |
| 43 | return invalid, ErrMaintenanceProjection |
| 44 | } |
| 45 | seen := false |
| 46 | for dec.More() { |
| 47 | key, e := dec.Token() |
| 48 | if e != nil { |
| 49 | return invalid, ErrMaintenanceProjection |
| 50 | } |
| 51 | name, ok := key.(string) |
| 52 | if !ok { |
| 53 | return invalid, ErrMaintenanceProjection |
| 54 | } |
| 55 | if strings.EqualFold(name, "maintenance") { |
| 56 | if name != "maintenance" || seen { |
| 57 | return invalid, ErrMaintenanceProjection |
| 58 | } |
| 59 | seen = true |
| 60 | } |
| 61 | var value json.RawMessage |
| 62 | if dec.Decode(&value) != nil { |
| 63 | return invalid, ErrMaintenanceProjection |
| 64 | } |
| 65 | } |
| 66 | if end, e := dec.Token(); e != nil || end != json.Delim('}') { |
| 67 | return invalid, ErrMaintenanceProjection |
| 68 | } |
| 69 | if _, e = dec.Token(); e != io.EOF { |
| 70 | return invalid, ErrMaintenanceProjection |
| 71 | } |
| 72 | var rec Record |
| 73 | if json.Unmarshal(raw, &rec) != nil { |
| 74 | return invalid, ErrMaintenanceProjection |
| 75 | } |
| 76 | return rec, nil |
| 77 | } |
| 78 | |
| 79 | // Equality preserves the projection, not permission to change a fenced record. |
| 80 | // Durable guard and lifecycle checks belong to the maintenance integration. |
| 81 | func protectedFieldsEqual(before, after Record) bool { |
| 82 | if before.RecordSeq != after.RecordSeq || before.Account != after.Account || before.App != after.App || before.Host != after.Host || !before.CreatedAt.Equal(after.CreatedAt) { |
| 83 | return false |
| 84 | } |
| 85 | if len(before.Maintenance) == 0 || len(after.Maintenance) == 0 { |
| 86 | return len(before.Maintenance) == len(after.Maintenance) |
| 87 | } |
| 88 | a, e := maintenanceguard.DecodeProjection(before.Maintenance) |
| 89 | if e != nil { |
| 90 | return false |
| 91 | } |
| 92 | b, e := maintenanceguard.DecodeProjection(after.Maintenance) |
| 93 | return e == nil && a == b |
| 94 | } |
| 95 | |
amadan