| 1 | package sheets |
| 2 | |
| 3 | import ( |
| 4 | "encoding/json" |
| 5 | "net/http" |
| 6 | "strconv" |
| 7 | |
| 8 | "github.com/go-chi/chi/v5" |
| 9 | |
| 10 | "amadan.net/oficina/sheets/internal/sheets/live" |
| 11 | "amadan.net/oficina/sheets/internal/sheets/store" |
| 12 | ) |
| 13 | |
| 14 | // maxRawBytes caps one cell's input. |
| 15 | // |
| 16 | // A formula or a label, not a document. The engine would happily parse |
| 17 | // a megabyte of nesting and spend a long time doing it, and the cell |
| 18 | // that holds it is one nobody can read anyway. |
| 19 | const maxRawBytes = 8 << 10 |
| 20 | |
| 21 | // cellWrite is the POST body. |
| 22 | // |
| 23 | // An explicit struct, decoded field by field — never bound onto a GORM |
| 24 | // model (AGENTS.md), which would let a request set UpdatedBy, a version |
| 25 | // or a tab id. |
| 26 | type cellWrite struct { |
| 27 | R int `json:"r"` |
| 28 | C int `json:"c"` |
| 29 | Raw string `json:"raw"` |
| 30 | Client string `json:"client"` |
| 31 | |
| 32 | // FromR and FromC name the cell this input was COPIED FROM, and |
| 33 | // turn an ordinary write into spec §4.2's translation pass: every |
| 34 | // relative reference in Raw is offset by the destination minus the |
| 35 | // origin before anything is stored. Absent — the ordinary case, |
| 36 | // somebody typing — nothing is translated. |
| 37 | // |
| 38 | // Pointers, so "copied from row 0" and "not a copy" are different |
| 39 | // requests. With plain ints they are the same zero value, and every |
| 40 | // paste into row 0 or column A would translate by its full offset |
| 41 | // from a cell nobody copied. |
| 42 | FromR *int `json:"fromR"` |
| 43 | FromC *int `json:"fromC"` |
| 44 | } |
| 45 | |
| 46 | // origin validates the copy origin and returns the offset to apply. |
| 47 | // |
| 48 | // The bounds are the same ones the destination is checked against, and |
| 49 | // for the same reason: both come from the request. An unbounded origin |
| 50 | // asks calc to offset a reference by millions and Render to print a |
| 51 | // column label with six letters in it, which parses back as a name. |
| 52 | func (in cellWrite) origin() (dRow, dCol int, ok bool) { |
| 53 | if in.FromR == nil || in.FromC == nil { |
| 54 | return 0, 0, true |
| 55 | } |
| 56 | if !inCellRange(*in.FromR, *in.FromC) { |
| 57 | return 0, 0, false |
| 58 | } |
| 59 | return in.R - *in.FromR, in.C - *in.FromC, true |
| 60 | } |
| 61 | |
| 62 | // inCellRange is the one definition of "a coordinate this route will |
| 63 | // accept", used for the destination and for the copy origin. Two copies |
| 64 | // of it is two places for the bound to drift. |
| 65 | func inCellRange(r, c int) bool { |
| 66 | return r >= 0 && c >= 0 && r < maxWindowRows*10 && c < maxWindowCols*10 |
| 67 | } |
| 68 | |
| 69 | // handleCellsGet serves a window of a tab. |
| 70 | func (a *App) handleCellsGet(w http.ResponseWriter, r *http.Request) { |
| 71 | h, ok := a.openTab(w, r, SheetViewer) |
| 72 | if !ok { |
| 73 | return |
| 74 | } |
| 75 | defer h.Release() |
| 76 | |
| 77 | rows := clamp(intParam(r, "rows"), defaultWindowRows, maxWindowRows) |
| 78 | cols := clamp(intParam(r, "cols"), defaultWindowCols, maxWindowCols) |
| 79 | |
| 80 | firstRow, firstCol := intParam(r, "firstRow"), intParam(r, "firstCol") |
| 81 | if firstRow < 0 || firstCol < 0 || firstRow >= maxWindowRows || firstCol >= maxWindowCols { |
| 82 | http.Error(w, "Window out of range.", 400) |
| 83 | return |
| 84 | } |
| 85 | cells, styles, err := snapshotWindow(h, newPosIndex(h), firstRow, firstCol, rows, cols) |
| 86 | if err != nil { |
| 87 | a.fail(w, r, err) |
| 88 | return |
| 89 | } |
| 90 | // Sizes ride along with the window rather than needing a second |
| 91 | // round trip: they are layout, so a page that fetched them |
| 92 | // afterwards would visibly reflow every column once. |
| 93 | resp := gridResponse{ |
| 94 | Version: h.Version(), Rows: rows, Cols: cols, Cells: cells, Formats: styles, |
| 95 | } |
| 96 | if cw, rh, err := h.Sizes(); err == nil && (len(cw) > 0 || len(rh) > 0) { |
| 97 | resp.Sizes = &wireSizes{Cols: intKeys(cw), Rows: intKeys(rh)} |
| 98 | } |
| 99 | writeJSON(w, http.StatusOK, resp) |
| 100 | } |
| 101 | |
| 102 | // handleCellPost writes one cell and fans the result out. |
| 103 | func (a *App) handleCellPost(w http.ResponseWriter, r *http.Request) { |
| 104 | actor, ok := a.actor(r) |
| 105 | if !ok { |
| 106 | http.Error(w, "Sign in first.", http.StatusForbidden) |
| 107 | return |
| 108 | } |
| 109 | h, ok := a.openTab(w, r, SheetEditor) |
| 110 | if !ok { |
| 111 | return |
| 112 | } |
| 113 | defer h.Release() |
| 114 | |
| 115 | var in cellWrite |
| 116 | if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, maxRawBytes*2)).Decode(&in); err != nil { |
| 117 | // The body is not echoed. It is a cell's contents, and an error |
| 118 | // string is a log line waiting to happen (AGENTS.md). |
| 119 | http.Error(w, "Malformed request.", http.StatusBadRequest) |
| 120 | return |
| 121 | } |
| 122 | if !inCellRange(in.R, in.C) { |
| 123 | http.Error(w, "Cell out of range.", http.StatusBadRequest) |
| 124 | return |
| 125 | } |
| 126 | if len(in.Raw) > maxRawBytes { |
| 127 | http.Error(w, "Cell input too long.", http.StatusRequestEntityTooLarge) |
| 128 | return |
| 129 | } |
| 130 | // §4.2's translation pass, before the length check has any more |
| 131 | // work to do and before anything reaches the store: what is written |
| 132 | // and what the formula bar later shows must be the same string, so |
| 133 | // the rewrite happens here and not on the way back out. |
| 134 | dRow, dCol, ok := in.origin() |
| 135 | if !ok { |
| 136 | http.Error(w, "Cell out of range.", http.StatusBadRequest) |
| 137 | return |
| 138 | } |
| 139 | in.Raw = translateCopied(in.Raw, dRow, dCol) |
| 140 | // Re-checked AFTER translating. Render is not length-preserving — |
| 141 | // "A1" becomes "AA100" — so a formula that fitted on the way in can |
| 142 | // exceed the cap on the way to storage, and the check above would |
| 143 | // have passed it. Cheap, and the alternative is a stored cell |
| 144 | // larger than the limit this route advertises. |
| 145 | if len(in.Raw) > maxRawBytes { |
| 146 | http.Error(w, "Cell input too long.", http.StatusRequestEntityTooLarge) |
| 147 | return |
| 148 | } |
| 149 | |
| 150 | // EnsureRow/EnsureCol so typing into a cell nothing has touched |
| 151 | // works: a tab starts with no rows or columns at all, and a grid |
| 152 | // coordinate has to become a stable id before anything can be |
| 153 | // written to it. |
| 154 | rowID, err := h.EnsureRow(in.R) |
| 155 | if err != nil { |
| 156 | a.fail(w, r, err) |
| 157 | return |
| 158 | } |
| 159 | colID, err := h.EnsureCol(in.C) |
| 160 | if err != nil { |
| 161 | a.fail(w, r, err) |
| 162 | return |
| 163 | } |
| 164 | |
| 165 | rep, err := h.SetReport(rowID, colID, in.Raw, actor.ID) |
| 166 | if err != nil { |
| 167 | // A parse failure is the caller's fault and a storage failure is |
| 168 | // ours, but neither may quote the input, so both answer the same |
| 169 | // fixed string with the coordinate the caller already knows. |
| 170 | http.Error(w, "That cell could not be written.", http.StatusBadRequest) |
| 171 | return |
| 172 | } |
| 173 | |
| 174 | cells, styles := fromReport(rep, newPosIndex(h), h) |
| 175 | resp := gridResponse{ |
| 176 | Version: rep.Version, |
| 177 | Cells: cells, |
| 178 | Formats: styles, |
| 179 | Resync: rep.Capped, |
| 180 | Stamps: rep.Stamps, |
| 181 | Client: in.Client, |
| 182 | } |
| 183 | a.touchSheet(sheetIDFrom(r)) |
| 184 | a.publish(tabIDFrom(r), resp) |
| 185 | writeJSON(w, http.StatusOK, resp) |
| 186 | } |
| 187 | |
| 188 | // publish fans a write out to every other tab on this one. |
| 189 | // |
| 190 | // Marshalled once here rather than once per subscriber: with ten tabs |
| 191 | // open, encoding per subscriber is ten encodings of identical bytes. |
| 192 | func (a *App) publish(tabID uint64, resp gridResponse) { |
| 193 | if a.hub == nil || tabID == 0 { |
| 194 | return |
| 195 | } |
| 196 | data, err := marshalGrid(resp) |
| 197 | if err != nil { |
| 198 | return |
| 199 | } |
| 200 | a.hub.Publish(tabID, live.Message{Version: resp.Version, Data: data}) |
| 201 | } |
| 202 | |
| 203 | // openTab resolves {sheetID}/{tabID}, checks the viewer holds at least |
| 204 | // `need` on the sheet, and opens the tab's handle. It answers for |
| 205 | // itself if it cannot; the bool is whether the caller should carry on. |
| 206 | // |
| 207 | // The tab is checked against the sheet, not just looked up: both ids |
| 208 | // come from the URL, so without the pairing check any tab could be read |
| 209 | // through any sheet, and the sheet id in the path — the thing the grant |
| 210 | // is keyed on — would mean nothing. |
| 211 | // |
| 212 | // Every refusal here is a 404. A viewer asking to write, and a stranger |
| 213 | // asking to read, both get the same answer as a sheet that does not |
| 214 | // exist. Anything else lets somebody enumerate the team's sheets by |
| 215 | // status code. |
| 216 | func (a *App) openTab(w http.ResponseWriter, r *http.Request, need SheetRole) (*store.Handle, bool) { |
| 217 | if a.db == nil || a.sealer == nil { |
| 218 | a.fail(w, r, errNoSealer) |
| 219 | return nil, false |
| 220 | } |
| 221 | viewer, ok := a.actor(r) |
| 222 | if !ok { |
| 223 | a.notFound(w, r) |
| 224 | return nil, false |
| 225 | } |
| 226 | sheetID, tabID := sheetIDFrom(r), tabIDFrom(r) |
| 227 | if sheetID == 0 || tabID == 0 || !a.tabBelongsTo(sheetID, tabID) { |
| 228 | a.notFound(w, r) |
| 229 | return nil, false |
| 230 | } |
| 231 | if role, has := a.roleFor(sheetID, viewer); !has || !role.Allows(need) { |
| 232 | a.notFound(w, r) |
| 233 | return nil, false |
| 234 | } |
| 235 | h, err := store.Open(a.db, a.sealer, tabID) |
| 236 | if err != nil { |
| 237 | a.fail(w, r, err) |
| 238 | return nil, false |
| 239 | } |
| 240 | return h, true |
| 241 | } |
| 242 | |
| 243 | func sheetIDFrom(r *http.Request) uint64 { return uintParam(r, "sheetID") } |
| 244 | func tabIDFrom(r *http.Request) uint64 { return uintParam(r, "tabID") } |
| 245 | |
| 246 | // uintParam reads a path parameter. A malformed one is 0, which every |
| 247 | // caller treats as "not found" — a URL that was never ours. |
| 248 | func uintParam(r *http.Request, name string) uint64 { |
| 249 | v, err := strconv.ParseUint(chi.URLParam(r, name), 10, 64) |
| 250 | if err != nil { |
| 251 | return 0 |
| 252 | } |
| 253 | return v |
| 254 | } |
| 255 | |
| 256 | // intParam reads a query parameter, defaulting to 0 so clamp can apply |
| 257 | // the real default in one place. |
| 258 | func intParam(r *http.Request, name string) int { |
| 259 | v, err := strconv.Atoi(r.URL.Query().Get(name)) |
| 260 | if err != nil { |
| 261 | return 0 |
| 262 | } |
| 263 | return v |
| 264 | } |
| 265 | |
| 266 | // writeJSON sends a response. An encode failure means the connection is |
| 267 | // already gone, so there is nothing left to say about it. |
| 268 | func writeJSON(w http.ResponseWriter, status int, resp gridResponse) { |
| 269 | w.Header().Set("Cache-Control", "no-store") |
| 270 | w.Header().Set("Content-Type", "application/json; charset=utf-8") |
| 271 | w.WriteHeader(status) |
| 272 | _ = json.NewEncoder(w).Encode(resp) |
| 273 | } |
| 274 | |
amadan