added get bus even API request

also provided framework for extracting filters

cmd/gotelem/cli/server.go

@@ -11,6 +11,7 @@ import (
 	"log/slog"
 
 	"github.com/kschamplin/gotelem"
+	"github.com/kschamplin/gotelem/internal/api"
 	"github.com/kschamplin/gotelem/internal/db"
 	"github.com/kschamplin/gotelem/skylab"
 	"github.com/kschamplin/gotelem/xbee"
@@ -132,7 +133,6 @@ func serve(cCtx *cli.Context) error {
 	return nil
 }
 
-
 // xBeeService provides data over an Xbee device, either by serial or TCP
 // based on the url provided in the xbee flag. see the description for details.
 type xBeeService struct {
@@ -220,7 +220,7 @@ func (h *httpService) Start(cCtx *cli.Context, deps svcDeps) (err error) {
 	broker := deps.Broker
 	db := deps.Db
 
-	r := gotelem.TelemRouter(logger, broker, db)
+	r := api.TelemRouter(logger, broker, db)
 
 	//
 

internal/api/http.go

@@ -1,4 +1,4 @@
-package gotelem
+package api
 
 // this file defines the HTTP handlers and routes.
 
@@ -13,13 +13,14 @@ import (
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
 	"github.com/google/uuid"
+	"github.com/kschamplin/gotelem"
 	"github.com/kschamplin/gotelem/internal/db"
 	"github.com/kschamplin/gotelem/skylab"
 	"nhooyr.io/websocket"
 	"nhooyr.io/websocket/wsjson"
 )
 
-func TelemRouter(log *slog.Logger, broker *Broker, db *db.TelemDb) http.Handler {
+func TelemRouter(log *slog.Logger, broker *gotelem.Broker, db *db.TelemDb) http.Handler {
 	r := chi.NewRouter()
 
 	r.Use(middleware.RequestID)
@@ -41,7 +42,7 @@ func TelemRouter(log *slog.Logger, broker *Broker, db *db.TelemDb) http.Handler
 }
 
 // define API version 1 routes.
-func apiV1(broker *Broker, db *db.TelemDb) chi.Router {
+func apiV1(broker *gotelem.Broker, tdb *db.TelemDb) chi.Router {
 	r := chi.NewRouter()
 	// this API only accepts JSON.
 	r.Use(middleware.AllowContentType("application/json"))
@@ -56,7 +57,7 @@ func apiV1(broker *Broker, db *db.TelemDb) chi.Router {
 	})
 
 	r.Route("/packets", func(r chi.Router) {
-		r.Get("/subscribe", apiV1PacketSubscribe(broker, db))
+		r.Get("/subscribe", apiV1PacketSubscribe(broker, tdb))
 		r.Post("/", func(w http.ResponseWriter, r *http.Request) {
 			var pkgs []skylab.BusEvent
 			decoder := json.NewDecoder(r.Body)
@@ -65,25 +66,59 @@ func apiV1(broker *Broker, db *db.TelemDb) chi.Router {
 				return
 			}
 			// we have a list of packets now. let's commit them.
-			db.AddEvents(pkgs...)
+			tdb.AddEvents(pkgs...)
 		})
 		r.Get("/", func(w http.ResponseWriter, r *http.Request) {
 			// this should use http query params to return a list of packets.
+			bef, err := extractBusEventFilter(r)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			lim, err := extractLimitModifier(r)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+
+			// TODO: is the following check needed?
+			var res []skylab.BusEvent
+			if lim != nil {
+				res, err = tdb.GetPackets(r.Context(), *bef, lim)
+				if err != nil {
+					http.Error(w, err.Error(), http.StatusInternalServerError)
+					return
+				}
+
+			} else {
+				res, err = tdb.GetPackets(r.Context(), *bef)
+				if err != nil {
+					http.Error(w, err.Error(), http.StatusInternalServerError)
+					return
+				}
+			}
+			b, err := json.Marshal(res)
+			if err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+			w.Write(b)
 
 		})
 
 		// this is to get a single field
-		r.Get("/{name:[a-z_]+}/{field:[a-z_]+}", apiV1GetValues(db))
+		r.Get("/{name:[a-z_]+}/{field:[a-z_]+}", apiV1GetValues(tdb))
 
 	})
 
 	// records are driving segments/runs.
 	r.Route("/records", func(r chi.Router) {
-		r.Get("/", apiV1GetRecords(db))            // get all runs
-		r.Get("/active", apiV1GetActiveRecord(db)) // get current run (no end time)
-		r.Post("/", apiV1StartRecord(db))          // create a new run (with note). Ends active run if any, and creates new active run (no end time)
-		r.Get("/{id}", apiV1GetRecord(db))         // get details on a specific run
-		r.Put("/{id}", apiV1UpdateRecord(db))      // update a specific run. Can only be used to add notes/metadata, and not to change time/id.
+		r.Get("/", apiV1GetRecords(tdb))            // get all runs
+		r.Get("/active", apiV1GetActiveRecord(tdb)) // get current run (no end time)
+		r.Post("/", apiV1StartRecord(tdb))          // create a new run (with note). Ends active run if any, and creates new active run (no end time)
+		r.Get("/{id}", apiV1GetRecord(tdb))         // get details on a specific run
+		r.Put("/{id}", apiV1UpdateRecord(tdb))      // update a specific run. Can only be used to add notes/metadata, and not to change time/id.
 
 	})
 
@@ -100,7 +135,7 @@ type apiV1Subscriber struct {
 }
 
 // this is a websocket stream.
-func apiV1PacketSubscribe(broker *Broker, db *db.TelemDb) http.HandlerFunc {
+func apiV1PacketSubscribe(broker *gotelem.Broker, db *db.TelemDb) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		conn_id := r.RemoteAddr + uuid.New().String()
 		sub, err := broker.Subscribe(conn_id)

internal/api/utils.go

@@ -0,0 +1,59 @@
+package api
+// This file contains common behaviors that are used across various requests
+import (
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/kschamplin/gotelem/internal/db"
+)
+
+func extractBusEventFilter(r *http.Request) (*db.BusEventFilter, error) {
+
+	bef := &db.BusEventFilter{}
+
+	v := r.URL.Query()
+	bef.Names = v["name"] // put all the names in.
+	if el := v.Get("start"); el != "" {
+		// parse the start time query.
+		t, err := time.Parse(time.RFC3339, el)
+		if err != nil {
+			return bef, err
+		}
+		bef.TimerangeStart = t
+	}
+	if el := v.Get("end"); el != "" {
+		// parse the start time query.
+		t, err := time.Parse(time.RFC3339, el)
+		if err != nil {
+			return bef, err
+		}
+		bef.TimerangeStart = t
+	}
+	return bef, nil
+}
+
+func extractLimitModifier(r *http.Request) (*db.LimitOffsetModifier, error) {
+	lim := &db.LimitOffsetModifier{}
+	v := r.URL.Query()
+	if el := v.Get("limit"); el != "" {
+		val, err := strconv.ParseInt(el, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+		lim.Limit = int(val)
+		// next, we check if we have an offset.
+		// we only check offset if we also have a limit.
+		// offset without limit isn't valid and is ignored.
+		if el := v.Get("offset"); el != "" {
+			val, err := strconv.ParseInt(el, 10, 64)
+			if err != nil {
+				return nil, err
+			}
+			lim.Offset = int(val)
+		}
+		return lim, nil
+	}
+	// we use the nil case to indicate that no limit was provided.
+	return nil, nil
+}

internal/db/getters.go

@@ -104,6 +104,10 @@ func (tdb *TelemDb) GetPackets(ctx context.Context, filter BusEventFilter, optio
 	return events, err
 }
 
+
+// We now need a different use-case: we would like to extract a value from
+// a specific packet.
+
 // Datum is a single measurement - it is more granular than a packet.
 // the classic example is bms_measurement.current
 type Datum struct {