/
handlers.go
269 lines (232 loc) · 6.85 KB
/
handlers.go
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package restservice
//TODO: Better use of errchan
import (
"encoding/json"
"errors"
"github.com/gorilla/mux"
"github.com/gorilla/sessions"
"github.com/howbazaar/loggo"
"github.com/nu7hatch/gouuid"
"github.com/straumur/straumur"
"io"
"net/http"
"strconv"
"time"
)
var (
ErrSaveExisting = errors.New("Save existing resource")
ErrUpdateNonExisting = errors.New("Update non-existing resource")
ErrMissingType = errors.New("Missing type param")
ErrInvalidEntity = errors.New("Invalid entity")
logger = loggo.GetLogger("straumur.rest")
sessionName = "straumur"
clientVarName = "client-id"
)
type RESTService struct {
Headers map[string]string
Store sessions.Store
databackend straumur.DataBackend
events chan *straumur.Event
WsServer *WebSocketServer
errchan chan error
}
// Returns the entity prefix
func getEntity(req *http.Request) (string, error) {
vars := mux.Vars(req)
entity := vars["entity"]
id := vars["id"]
if id == "" || entity == "" {
return "", ErrInvalidEntity
}
return entity + "/" + id, nil
}
// Parses a Query from the request
func getQuery(req *http.Request) (*straumur.Query, error) {
req.ParseForm()
return straumur.QueryFromValues(req.Form)
}
// Parses an event from the post body
func (r *RESTService) parseEvent(body io.ReadCloser) (straumur.Event, error) {
decoder := json.NewDecoder(body)
defer body.Close()
var e straumur.Event
err := decoder.Decode(&e)
return e, err
}
// Appends a unique session id to the request headers
func (r *RESTService) AddSessionIdHeader(f func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
return func(w http.ResponseWriter, req *http.Request) {
session, err := r.Store.Get(req, sessionName)
if err != nil {
logger.Errorf("%v", err)
}
cidi, ok := session.Values[clientVarName]
cid := ""
if !ok {
logger.Infof("New session")
u4, err := uuid.NewV4()
if err != nil {
logger.Errorf("%v", err)
}
cid = u4.String()
session.Values[clientVarName] = cid
session.Save(req, w)
} else {
cid = cidi.(string)
}
req.Header.Add("X-User-Id", cid)
f(w, req)
}
}
// Wraps http.HandlerFunc, adds error response and frequently used headers
func (r *RESTService) Middleware(f func(http.ResponseWriter, *http.Request) (error, int)) http.HandlerFunc {
v := func(w http.ResponseWriter, req *http.Request) {
for k, v := range r.Headers {
w.Header().Set(k, v)
}
t := time.Now()
err, status := f(w, req)
logger.Infof("Processed request: %s:%s in %f seconds", req.Method, req.URL, time.Now().Sub(t).Seconds())
if err != nil {
logger.Warningf("Error - [%s]%s, status: %d", req.Method, req.URL, status)
http.Error(w, err.Error(), status)
}
}
return r.AddSessionIdHeader(v)
}
// GET: /api/entity/id/
func (r *RESTService) entityHandler(w http.ResponseWriter, req *http.Request) (error, int) {
e, err := getEntity(req)
if err != nil {
return err, http.StatusBadRequest
}
q, err := getQuery(req)
if err != nil {
return err, http.StatusInternalServerError
}
q.Entities = append(q.Entities, e)
events, err := r.databackend.Query(*q)
if err != nil {
return err, http.StatusInternalServerError
}
enc := json.NewEncoder(w)
enc.Encode(events)
r.WsServer.Filters <- FilterPair{req.Header.Get("X-User-Id"), *q, 1}
return nil, http.StatusOK
}
// GET: /api/id/
func (r *RESTService) retrieveHandler(w http.ResponseWriter, req *http.Request) (error, int) {
vars := mux.Vars(req)
id := vars["id"]
idAsInt, err := strconv.Atoi(id)
if err != nil {
return err, http.StatusBadRequest
}
event, err := r.databackend.GetById(idAsInt)
if err != nil {
return err, http.StatusInternalServerError
}
enc := json.NewEncoder(w)
enc.Encode(event)
return nil, http.StatusOK
}
// POST: /
// PUT: /id/
// Save or update
func (r *RESTService) saveHandler(w http.ResponseWriter, req *http.Request) (error, int) {
vars := mux.Vars(req)
id := vars["id"]
e, err := r.parseEvent(req.Body)
if err != nil {
return err, http.StatusBadRequest
}
if id == "" && e.ID != 0 {
return ErrSaveExisting, http.StatusBadRequest
}
if id != "" && e.ID == 0 {
return ErrUpdateNonExisting, http.StatusBadRequest
}
if e.ID == 0 {
w.WriteHeader(http.StatusCreated)
} else {
w.WriteHeader(http.StatusAccepted)
}
logger.Infof("Saved event for key %s", e.Key)
//fix block on error
go func() { r.events <- &e }()
return nil, 0
}
// GET: /api/search
func (r *RESTService) searchHandler(w http.ResponseWriter, req *http.Request) (error, int) {
q, err := getQuery(req)
if err != nil {
return err, http.StatusBadRequest
}
events, err := r.databackend.Query(*q)
if err != nil {
return err, http.StatusInternalServerError
}
enc := json.NewEncoder(w)
enc.Encode(events)
r.WsServer.Filters <- FilterPair{req.Header.Get("X-User-Id"), *q, 1}
return nil, http.StatusOK
}
func (r *RESTService) aggregateHandler(w http.ResponseWriter, req *http.Request) (error, int) {
vars := mux.Vars(req)
agtype := vars["type"]
if agtype == "" {
return ErrMissingType, http.StatusBadRequest
}
q, err := getQuery(req)
if err != nil {
return err, http.StatusInternalServerError
}
m, err := r.databackend.AggregateType(*q, agtype)
if err != nil {
return err, http.StatusInternalServerError
}
enc := json.NewEncoder(w)
enc.Encode(m)
return nil, http.StatusOK
}
func (r *RESTService) ServeHTTP(w http.ResponseWriter, req *http.Request) {
router := r.getRouter()
router.ServeHTTP(w, req)
}
func (r *RESTService) getRouter() *mux.Router {
router := mux.NewRouter()
s := router.PathPrefix("/api").Subrouter()
s.HandleFunc("/{entity}/{id}/", r.Middleware(r.entityHandler)).Methods("GET")
s.HandleFunc("/", r.Middleware(r.saveHandler)).Methods("POST")
s.HandleFunc("/{id}/", r.Middleware(r.retrieveHandler)).Methods("GET")
s.HandleFunc("/{id}/", r.Middleware(r.saveHandler)).Methods("PUT")
s.HandleFunc("/search", r.Middleware(r.searchHandler)).Methods("GET")
s.HandleFunc("/aggregate/{type}", r.Middleware(r.aggregateHandler)).Methods("GET")
s.HandleFunc("/ws", r.AddSessionIdHeader(r.WsServer.GetHandler().ServeHTTP))
return router
}
// Creates a new REST dataservice
func NewRESTService(d straumur.DataBackend, errorChan chan error) *RESTService {
defaultHeaders := make(map[string]string)
defaultHeaders["Content-Type"] = "application/json; charset=utf-8"
defaultHeaders["Access-Control-Allow-Origin"] = "*"
defaultHeaders["Access-Control-Allow-Headers"] = "Origin, X-Requested-With, Content-Type, Accept"
rs := RESTService{
Headers: defaultHeaders,
WsServer: NewWebSocketServer(),
events: make(chan *straumur.Event),
databackend: d,
errchan: errorChan,
}
go rs.WsServer.Run(errorChan)
return &rs
}
//EventFeed interface
func (r *RESTService) Updates() <-chan *straumur.Event {
return r.events
}
func (r *RESTService) Close() error {
close(r.events)
//Investigate way to perform graceful shutdown of http
return nil
}