[enh] update async examples - gocolly#91

_examples/parallel/parallel.go

@@ -12,6 +12,7 @@ func main() {
 		// MaxDepth is 2, so only the links on the scraped page
 		// and links on those pages are visited
 		colly.MaxDepth(2),
+		colly.Async(true),
 	)
 
 	// Limit the maximum parallelism to 5
@@ -28,7 +29,7 @@ func main() {
 		// Print link
 		fmt.Println(link)
 		// Visit link found on page on a new thread
-		go e.Request.Visit(link)
+		e.Request.Visit(link)
 	})
 
 	// Start scraping on https://en.wikipedia.org

_examples/random_delay/random_delay.go

@@ -15,6 +15,7 @@ func main() {
 	c := colly.NewCollector(
 		// Attach a debugger to the collector
 		colly.Debugger(&debug.LogDebugger{}),
+		colly.Async(true),
 	)
 
 	// Limit the number of threads started by colly to two
@@ -27,7 +28,7 @@ func main() {
 
 	// Start scraping in four threads on https://httpbin.org/delay/2
 	for i := 0; i < 4; i++ {
-		go c.Visit(fmt.Sprintf("%s?n=%d", url, i))
+		c.Visit(fmt.Sprintf("%s?n=%d", url, i))
 	}
 	// Start scraping on https://httpbin.org/delay/2
 	c.Visit(url)

_examples/rate_limit/rate_limit.go

@@ -12,6 +12,8 @@ func main() {
 
 	// Instantiate default collector
 	c := colly.NewCollector(
+		// Turn on asynchronous requests
+		colly.Async(true),
 		// Attach a debugger to the collector
 		colly.Debugger(&debug.LogDebugger{}),
 	)
@@ -24,12 +26,10 @@ func main() {
 		//Delay:      5 * time.Second,
 	})
 
-	// Start scraping in four threads on https://httpbin.org/delay/2
-	for i := 0; i < 4; i++ {
-		go c.Visit(fmt.Sprintf("%s?n=%d", url, i))
+	// Start scraping in five threads on https://httpbin.org/delay/2
+	for i := 0; i < 5; i++ {
+		c.Visit(fmt.Sprintf("%s?n=%d", url, i))
 	}
-	// Start scraping on https://httpbin.org/delay/2
-	c.Visit(url)
 	// Wait until threads are finished
 	c.Wait()
 }