From 5ae6078805bbbb7f1d2002af860e109928422800 Mon Sep 17 00:00:00 2001
From: Blallo <blallo@autistici.org>
Date: Thu, 8 Nov 2018 12:37:31 +0100
Subject: [PATCH] [http] Better handling of parameters and added LastMsg to
 Client

---
 cmd/circologd/http.go | 80 ++++++++++++++++++++++++++-----------------
 hub.go                |  1 +
 2 files changed, 49 insertions(+), 32 deletions(-)

diff --git a/cmd/circologd/http.go b/cmd/circologd/http.go
index c5d3432..718d4a2 100644
--- a/cmd/circologd/http.go
+++ b/cmd/circologd/http.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"log"
 	"net/http"
 	"strconv"
@@ -11,50 +12,65 @@ import (
 	"gopkg.in/mcuadros/go-syslog.v2/format"
 )
 
+type requestParams struct {
+	// Add here the expected request parameters
+	errorList         map[string]error
+	requestMessageLen int
+}
+
 func setupHTTP(hub circolog.Hub) {
 	http.HandleFunc("/", getHTTPHandler(hub))
 	http.HandleFunc("/ws", getWSHandler(hub))
 }
 
+func parseParameterL(r *http.Request) (int, error) {
+	var requestMessageLen int
+	var err error
+	if reqL, ok := r.Form["l"]; ok {
+		if len(reqL) == 1 {
+			requestMessageLen, err = strconv.Atoi(reqL[0])
+			if err != nil {
+				return 0, err
+			}
+			if requestMessageLen <= 0 {
+				return 0, errors.New("malformed request")
+			}
+		} else {
+			return 0, errors.New("malformed request")
+		}
+	}
+	return requestMessageLen, nil
+}
+
+func (p *requestParams) parseParameters(w http.ResponseWriter, r *http.Request) {
+	err := r.ParseForm()
+	if err != nil {
+		log.Println("error parsing http request", err)
+	}
+	p.errorList = make(map[string]error, 1)
+	p.requestMessageLen, p.errorList["l"] = parseParameterL(r)
+}
+
 func getHTTPHandler(hub circolog.Hub) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
+		// Looking for known parameter in the request
+		var params requestParams
+		params.parseParameters(w, r)
+		if params.errorList["l"] != nil {
+			log.Println("Request parameter \"l\":", params.errorList["l"])
+			w.WriteHeader(400)
+			return
+		}
+
 		client := circolog.Client{
 			Messages: make(chan format.LogParts, 20),
+			LastMsg:  params.requestMessageLen,
 			Nofollow: true}
 		hub.Register <- client
 
-		err := r.ParseForm()
-		if err != nil {
-			log.Println("error parsing http request", err)
-		}
-		// Looking for known parameter in the request
-		// TODO: write specialized function
-		var requestMessageLen int
-		if reqL, ok := r.Form["l"]; ok {
-			if len(reqL) == 1 {
-				requestMessageLen, err = strconv.Atoi(reqL[0])
-				if err != nil || requestMessageLen <= 0 {
-					log.Println("malformed request on parameter l")
-					requestMessageLen = -1
-					w.WriteHeader(400)
-				}
-			} else {
-				log.Println("malformed request on parameter l")
-				requestMessageLen = -1
-				w.WriteHeader(400)
-			}
-		}
-
-		if requestMessageLen >= 0 {
-			i := 1
-			for x := range client.Messages {
-				w.Write([]byte(circolog.FormatSyslog(x)))
-				w.Write([]byte("\n"))
-				if requestMessageLen != 0 && i >= requestMessageLen {
-					break
-				}
-				i++
-			}
+		for x := range client.Messages {
+			w.Write([]byte(circolog.FormatSyslog(x)))
+			w.Write([]byte("\n"))
 		}
 	}
 }
diff --git a/hub.go b/hub.go
index b653dc1..dfa0199 100644
--- a/hub.go
+++ b/hub.go
@@ -11,6 +11,7 @@ import (
 // new messages are sent.
 type Client struct {
 	Messages chan format.LogParts // only hub should write/close this
+	LastMsg  int                  // The number of last messages to display
 	Nofollow bool                 // if Nofollow is true, the hub will not keep this client permanently. Rather, it will send every message to "Messages" and close the channel. Use this if you want to get the messages one-shot
 }