add route to list rcpt_addr's mails as json

cmd/web_server/main.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"database/sql"
+	"encoding/json"
 	"fmt"
 	"log"
 	"net/http"
@@ -8,17 +10,89 @@ import (
 	"strconv"
 
 	"github.com/go-chi/chi"
+	_ "github.com/mattn/go-sqlite3"
 )
 
+type mail struct {
+	Id                   int
+	Arrived_at           int
+	Rcpt_addr, From_addr string
+	Data                 []byte
+}
+
 func main() {
+	db, err := sql.Open("sqlite3", "./db.db")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
 	router := chi.NewRouter()
 
-	router.Get("/", func(w http.ResponseWriter, r *http.Request) {
+	router.Get("/{rcpt-addr}", func(res http.ResponseWriter, req *http.Request) {
-		w.Write([]byte("Hello world"))
+		rcpt_addr := chi.URLParam(req, "rcpt-addr")
+		if len(rcpt_addr) == 0 {
+			res.WriteHeader(404)
+			res.Write([]byte("inbox not found"))
+			return
+		}
+
+		tx, err := db.Begin()
+		if err != nil {
+			res.WriteHeader(500)
+			res.Write([]byte("internal server error"))
+
+			log.Println("could not begin db transaction")
+			return
+		}
+
+		stmt, err := tx.Prepare("SELECT mails.id, mails.arrived_at, mails.rcpt_addr, mails.from_addr, mails.data FROM mails WHERE mails.rcpt_addr = ?")
+		if err != nil {
+			res.WriteHeader(500)
+			res.Write([]byte("internal server error"))
+
+			log.Println("could not prepare db stmt")
+			return
+		}
+		defer stmt.Close()
+
+		rows, err := stmt.Query(rcpt_addr)
+		if err != nil {
+			res.WriteHeader(500)
+			res.Write([]byte("internal server error"))
+
+			log.Println("could not query db stmt")
+			return
+		}
+		defer rows.Close()
+
+		var mails []mail
+		for rows.Next() {
+			var m mail
+			err = rows.Scan(&m.Id, &m.Arrived_at, &m.Rcpt_addr, &m.From_addr, &m.Data)
+			if err != nil {
+				res.WriteHeader(500)
+				res.Write([]byte("internal server error"))
+
+				log.Println("could not scan db row")
+				return
+			}
+
+            mails = append(mails, m)
+		}
+		b, err := json.Marshal(mails)
+		if err != nil {
+			res.WriteHeader(500)
+			res.Write([]byte("internal server error"))
+
+			log.Println("could not marshal json")
+			return
+		}
+
+		res.Write([]byte(b))
 	})
 
 	var port int
-    var err error
 	port_str, exists := os.LookupEnv("WEB_SERVER_PORT")
 	if exists {
 		port, err = strconv.Atoi(port_str)