Initial Commit

.gitignore

@@ -20,3 +20,5 @@ _cgo_export.*
 _testmain.go
 
 *.exe
+
+pagechanges

config.json

@@ -0,0 +1 @@
+{"alerts":[{"url":"http://bullercodeworks.com"}],"refresh":60}

main.go

@@ -0,0 +1,125 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strconv"
+	"time"
+)
+
+// SiteAlertConfig is an instance of a site to be monitored
+// in the config file
+type SiteAlertConfig struct {
+	URL string `json:"url"`
+}
+
+// Config is the config that we're running with
+type Config struct {
+	RefreshInterval int               `json:"refresh"`
+	Alerts          []SiteAlertConfig `json:"alerts"`
+}
+
+var config *Config
+var allAlerts []Alert
+
+func main() {
+	loadConfig()
+	for {
+		fmt.Println("Kicking off refresh.")
+		for i := range allAlerts {
+			fmt.Println("Checking URL: " + allAlerts[i].url + "...")
+			if allAlerts[i].Refresh() {
+				for j := 0; j < 25; j++ {
+					fmt.Println(" CHANGE DETECTED!")
+				}
+			}
+		}
+		fmt.Println("Refresh Completed.")
+		time.Sleep(time.Minute)
+	}
+}
+
+func loadConfig() {
+	fmt.Print("Loading Config...")
+	jsonInp, err := ioutil.ReadFile("config.json")
+	assertError(err)
+	assertError(json.Unmarshal(jsonInp, &config))
+	t, e := json.Marshal(config)
+	if e != nil {
+		fmt.Println(e)
+	} else {
+		fmt.Println(string(t))
+	}
+	for i := range config.Alerts {
+		allAlerts = append(allAlerts, *CreateNewAlert(config.Alerts[i].URL))
+	}
+	fmt.Println("Found " + strconv.Itoa(len(allAlerts)) + " alerts")
+}
+
+// Alert is for monitoring a page
+type Alert struct {
+	url        string
+	contents   string
+	response   *http.Response
+	err        error
+	updateTime time.Time
+
+	lastChangeContents string
+	lastChangeResponse *http.Response
+	lastChangeError    error
+	lastChangeTime     time.Time
+}
+
+// CreateNewAlert returns an alert object for url 'u'
+func CreateNewAlert(u string) *Alert {
+	a := Alert{url: u}
+	a.response, a.err = http.Get(u)
+	return &a
+}
+
+// Refresh refetches the url for the alert and returns
+// true if it changed.
+func (a *Alert) Refresh() bool {
+	var changed bool
+	r, e := http.Get(a.url)
+	if e != a.err {
+		a.Update(r, "", e)
+		return true
+	}
+	if body, err := ioutil.ReadAll(r.Body); err == nil {
+		b := string(body)
+		if b != a.contents {
+			changed = true
+			a.Update(r, b, e)
+		}
+	} else {
+		e = err
+	}
+	r.Body.Close()
+	if e != a.err {
+		a.Update(r, "", e)
+		return true
+	}
+	return changed
+}
+
+// Update updates the contents of the alert with the new changes
+func (a *Alert) Update(r *http.Response, body string, e error) {
+	a.lastChangeContents = a.contents
+	a.lastChangeResponse = a.response
+	a.lastChangeError = a.err
+	a.lastChangeTime = a.updateTime
+
+	a.contents = body
+	a.response = r
+	a.err = e
+	a.updateTime = time.Now()
+}
+
+func assertError(err error) {
+	if err != nil {
+		panic(err)
+	}
+}