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1 files changed, 308 insertions, 0 deletions
| -rw-r--r-- | homework/81013/go2html/sample.go | 308 |
diff --git a/homework/81013/go2html/sample.go b/homework/81013/go2html/sample.go new file mode 100644 index 0000000..9c76ea2 --- /dev/null +++ b/homework/81013/go2html/sample.go @@ -0,0 +1,308 @@ +package main + +import ( + "encoding/json" + "errors" + "io/ioutil" + "net/http" + "net/url" + "regexp" + "strconv" + "sync" + //"fmt" +) + +type Cell struct { + X int64 `json:"x"` + Y int64 `json:"y"` +} + +type GameOfLifeHandler struct { + Generation int + Board map[Cell]bool + Neighbours map[Cell]int + RespWriter http.ResponseWriter + BoardMutex sync.Mutex + NeighboursMutex sync.Mutex + RequestMutex sync.RWMutex +} + +/* util functions */ +func (g *GameOfLifeHandler) sendError(err error) { + g.RespWriter.Header().Set("Error", err.Error()) + g.RespWriter.WriteHeader(http.StatusBadRequest) +} + +func (g *GameOfLifeHandler) parseXYQuery(r *http.Request) (result Cell, err error) { + values, err := url.ParseQuery(r.URL.RawQuery) + if err != nil { + g.sendError(err) + return + } + + // validate + if len(values) != 2 { + err = errors.New("Invalid parameters query - invalid number of query parameters") + g.sendError(err) + return + } + + xString := values.Get("x") + yString := values.Get("y") + + if xString == "" || yString == "" { + err = errors.New("Invalid parameters query - x or y not set") + g.sendError(err) + return + } + + x, err := strconv.ParseInt(xString, 10, 64) + if err != nil { + g.sendError(err) + return + } + y, err := strconv.ParseInt(yString, 10, 64) + if err != nil { + g.sendError(err) + return + } + + result.X = x + result.Y = y + + return +} + +func updateNeighbours(cell Cell, neighbours *map[Cell]int) { + var neighbour Cell + + for i := cell.X - 1; i <= cell.X+1; i++ { + for j := cell.Y - 1; j <= cell.Y+1; j++ { + + if i == cell.X && j == cell.Y { + continue + } + + neighbour.X = i + neighbour.Y = j + + (*neighbours)[neighbour]++ + } + } +} + +/* url handlers */ +func (g *GameOfLifeHandler) addNewCells(r *http.Request) (err error) { + var cellSlice []Cell + cellSlice = make([]Cell, 0, 2) + + jsonBytes, err := ioutil.ReadAll(r.Body) + if err != nil { + g.sendError(err) + return + } + + err = json.Unmarshal(jsonBytes, &cellSlice) + if err != nil { + g.sendError(err) + return + } + + for _, cell := range cellSlice { + g.BoardMutex.Lock() + g.Board[cell] = true + g.BoardMutex.Unlock() + + g.NeighboursMutex.Lock() + updateNeighbours(cell, &g.Neighbours) + g.NeighboursMutex.Unlock() + } + + return err +} + +// writes json as a response +func (g *GameOfLifeHandler) checkCell(w http.ResponseWriter, cell Cell) (err error) { + alive := make(map[string]bool) + alive["alive"] = g.Board[cell] + + output, err := json.Marshal(alive) + if err != nil { + g.sendError(err) + return + } + + w.WriteHeader(http.StatusOK) + w.Write(output) + return +} + +// writes json as a response +func (g *GameOfLifeHandler) generation(w http.ResponseWriter) { + generation := make([]Cell, 0, len(g.Board)) + + for cell := range g.Board { + generation = append(generation, cell) + } + + currentGeneration := make(map[string]interface{}) + currentGeneration["generation"] = strconv.Itoa(g.Generation) + currentGeneration["living"] = generation + + output, err := json.Marshal(currentGeneration) + if err != nil { + g.sendError(err) + return + } + + w.WriteHeader(http.StatusOK) + w.Write(output) +} + +func (g *GameOfLifeHandler) evolve(w http.ResponseWriter) { + newBoard := make(map[Cell]bool) + newNeighbourBoard := make(map[Cell]int) + + for cell, neighbours := range g.Neighbours { + if g.Board[cell] { + if neighbours == 2 || neighbours == 3 { + newBoard[cell] = true + + updateNeighbours(cell, &newNeighbourBoard) + } + } else { + if neighbours == 3 { + newBoard[cell] = true + + updateNeighbours(cell, &newNeighbourBoard) + } + } + } + + g.BoardMutex.Lock() + g.Board = newBoard + g.BoardMutex.Unlock() + + g.NeighboursMutex.Lock() + g.Neighbours = newNeighbourBoard + g.NeighboursMutex.Unlock() + + g.Generation++ + + w.WriteHeader(http.StatusNoContent) +} + +func (g *GameOfLifeHandler) reset(w http.ResponseWriter) { + g.Generation = 0 + + g.BoardMutex.Lock() + g.Board = make(map[Cell]bool) + g.BoardMutex.Unlock() + + w.WriteHeader(http.StatusNoContent) +} + +func (g *GameOfLifeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { + path := r.URL.Path + + switch { + case regexp.MustCompile(`/generation/evolve/`).MatchString(path): + // POST + if r.Method != "POST" { + w.WriteHeader(http.StatusMethodNotAllowed) + } else { + g.RequestMutex.Lock() + + g.evolve(w) + + g.RequestMutex.Unlock() + } + + case regexp.MustCompile(`/generation/`).MatchString(path): + // GET + if r.Method != "GET" { + w.WriteHeader(http.StatusMethodNotAllowed) + } else { + g.RequestMutex.RLock() + + g.generation(w) + + g.RequestMutex.RUnlock() + } + + case regexp.MustCompile(`/cell/status/`).MatchString(path): + // GET + if r.Method != "GET" { + w.WriteHeader(http.StatusMethodNotAllowed) + } else { + g.RequestMutex.RLock() + + cell, err := g.parseXYQuery(r) + if err == nil { + g.checkCell(w, cell) + } + + g.RequestMutex.RUnlock() + } + + case regexp.MustCompile(`/cells/`).MatchString(path): + // POST + if r.Method != "POST" { + w.WriteHeader(http.StatusMethodNotAllowed) + } else { + g.RequestMutex.Lock() + + if err := g.addNewCells(r); err == nil { + w.WriteHeader(http.StatusCreated) + } + + g.RequestMutex.Unlock() + } + + case regexp.MustCompile(`/reset/`).MatchString(path): + // POST + if r.Method != "POST" { + w.WriteHeader(http.StatusMethodNotAllowed) + } else { + g.RequestMutex.Lock() + + g.reset(w) + + g.RequestMutex.Unlock() + } + + default: + w.WriteHeader(http.StatusNotFound) + } +} + +func NewGameOfLifeHandler(cells [][2]int64) *GameOfLifeHandler { + board := make(map[Cell]bool) + neighbours := make(map[Cell]int) + + var newCell Cell + + for _, cell := range cells { + newCell.X = cell[0] + newCell.Y = cell[1] + + board[newCell] = true + + updateNeighbours(newCell, &neighbours) + } + + gameOfLifeHandler := &GameOfLifeHandler{Generation: 0, Board: board, Neighbours: neighbours} + + return gameOfLifeHandler +} + +func main() { + gofh := NewGameOfLifeHandler([][2]int64{ + {2, 3}, + {2, 4}, + {-20, 4}, + {-42, 0}, + }) + + http.ListenAndServe(":8080", gofh) +} |