basic API handler

api.go

@@ -0,0 +1,134 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"faculty_media_report/dbi"
+	"github.com/golang-jwt/jwt/v5"
+)
+
+type jsonRPCRequest struct {
+	Jsonrpc string          `json:"jsonrpc"`
+	Method  string          `json:"method"`
+	Params  json.RawMessage `json:"params"`
+	ID      *int            `json:"id"`
+}
+
+type jsonRPCErrorBody struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}
+
+type jsonRPCResponse struct {
+	Jsonrpc string            `json:"jsonrpc"`
+	Result  interface{}       `json:"result,omitempty"`
+	Error   *jsonRPCErrorBody `json:"error,omitempty"`
+	ID      *int              `json:"id"`
+}
+
+func writeJSONRPC(w http.ResponseWriter, resp jsonRPCResponse) {
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(resp)
+}
+
+func jsonRPCErr(w http.ResponseWriter, code int, message string, id *int) {
+	writeJSONRPC(w, jsonRPCResponse{
+		Jsonrpc: "2.0",
+		Error:   &jsonRPCErrorBody{Code: code, Message: message},
+		ID:      id,
+	})
+}
+
+func handleAPI(w http.ResponseWriter, r *http.Request) {
+	authHeader := r.Header.Get("Authorization")
+	if !strings.HasPrefix(authHeader, "Bearer ") {
+		http.Error(w, "missing or invalid Authorization header", http.StatusUnauthorized)
+		return
+	}
+	tokenStr := strings.TrimPrefix(authHeader, "Bearer ")
+
+	db, err := dbi.GetDbConn()
+	if err != nil {
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	}
+	defer db.Close()
+
+	conn, err := db.Conn(context.Background())
+	if err != nil {
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	}
+	defer conn.Close()
+
+	var user dbi.User
+	token, err := jwt.Parse(tokenStr, func(t *jwt.Token) (interface{}, error) {
+		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method: %v", t.Header["alg"])
+		}
+		sub, err := t.Claims.GetSubject()
+		if err != nil {
+			return nil, fmt.Errorf("missing sub claim")
+		}
+		user, err = dbi.GetUser(conn, sub)
+		if err != nil {
+			return nil, fmt.Errorf("user not found")
+		}
+		return []byte(user.APIKey), nil
+	}, jwt.WithExpirationRequired())
+
+	if err != nil || !token.Valid {
+		if err != nil {
+			http.Error(w, "unauthorized: "+err.Error(), http.StatusUnauthorized)
+		} else {
+			http.Error(w, "unauthorized", http.StatusUnauthorized)
+		}
+		return
+	}
+
+	claims, ok := token.Claims.(jwt.MapClaims)
+	if !ok {
+		http.Error(w, "invalid token claims", http.StatusUnauthorized)
+		return
+	}
+
+	iat, err := claims.GetIssuedAt()
+	if err != nil || iat == nil {
+		http.Error(w, "missing iat claim", http.StatusUnauthorized)
+		return
+	}
+	if iat.After(time.Now()) {
+		http.Error(w, "iat is in the future", http.StatusUnauthorized)
+		return
+	}
+
+	var req jsonRPCRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		jsonRPCErr(w, -32700, "Parse error", nil)
+		return
+	}
+	if req.Jsonrpc != "2.0" {
+		jsonRPCErr(w, -32600, `Invalid Request: jsonrpc must be "2.0"`, req.ID)
+		return
+	}
+	if req.Method == "" {
+		jsonRPCErr(w, -32600, "Invalid Request: method is required", req.ID)
+		return
+	}
+	if req.Params == nil {
+		jsonRPCErr(w, -32600, "Invalid Request: params is required", req.ID)
+		return
+	}
+	if req.ID == nil {
+		jsonRPCErr(w, -32600, "Invalid Request: id is required", req.ID)
+		return
+	}
+
+	_ = user
+	jsonRPCErr(w, -32601, "Method not found", req.ID)
+}