From 5578d70154187eddc4a5fd672533aa9cd44a04e6 Mon Sep 17 00:00:00 2001
From: Eden Kirin <eden@ekirin.com>
Date: Sat, 20 Jan 2024 19:49:42 +0100
Subject: [PATCH] Channels

---
 channels/Makefile |  2 ++
 channels/go.mod   |  3 +++
 channels/main.go  | 68 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+)
 create mode 100644 channels/Makefile
 create mode 100644 channels/go.mod
 create mode 100644 channels/main.go

diff --git a/channels/Makefile b/channels/Makefile
new file mode 100644
index 0000000..860613c
--- /dev/null
+++ b/channels/Makefile
@@ -0,0 +1,2 @@
+run:
+	@go run main.go
\ No newline at end of file
diff --git a/channels/go.mod b/channels/go.mod
new file mode 100644
index 0000000..ed6b342
--- /dev/null
+++ b/channels/go.mod
@@ -0,0 +1,3 @@
+module channelsdemo
+
+go 1.21.6
diff --git a/channels/main.go b/channels/main.go
new file mode 100644
index 0000000..68c6904
--- /dev/null
+++ b/channels/main.go
@@ -0,0 +1,68 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"sync"
+)
+
+var Urls = []string{
+	"https://www.index.hr",
+	"https://www.vecernji.hr",
+	"https://www.jutarnji.hr",
+	"https://www.jutarnji.hrxxx/",
+}
+
+func fetchUrl(url string) (*string, error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		return nil, err
+	}
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	bodyStr := string(body)
+
+	return &bodyStr, nil
+}
+
+func main() {
+	var wg sync.WaitGroup
+	chMessages := make(chan string)
+	chDone := make(chan bool)
+
+	wg.Add(len(Urls))
+
+	for _, url := range Urls {
+		go func(url string) {
+			defer wg.Done()
+
+			chMessages <- fmt.Sprintf("Fetching %s...", url)
+			body, err := fetchUrl(url)
+			if err != nil {
+				chMessages <- fmt.Sprintf("Error fetching %s. Length: %v", url, err)
+			} else {
+				chMessages <- fmt.Sprintf("Done fetching %s. Length: %d", url, len(*body))
+			}
+		}(url)
+	}
+
+	go func() {
+		for msg := range chMessages {
+			fmt.Println(msg)
+		}
+		// signal that message reader is done
+		chDone <- true
+	}()
+
+	wg.Wait()
+
+	// close messages channel to stop reading from message stream
+	close(chMessages)
+
+	// wait for chMessages reader to get done
+	<-chDone
+}