feat: Add MaxRequests parameter

Signed-off-by: Guilhem Lettron <guilhem@barpilot.io>

colly.go

@@ -115,6 +115,9 @@ type Collector struct {
 	// Context is the context that will be used for HTTP requests. You can set this
 	// to support clean cancellation of scraping.
 	Context context.Context
+	// MaxRequests limit the number of requests done by the instance.
+	// Set it to 0 for infinite requests (default).
+	MaxRequests uint32
 
 	store                    storage.Storage
 	debugger                 debug.Debugger
@@ -228,6 +231,8 @@ var (
 	ErrAbortedAfterHeaders = errors.New("Aborted after receiving response headers")
 	// ErrQueueFull is the error returned when the queue is full
 	ErrQueueFull = errors.New("Queue MaxSize reached")
+	// ErrMaxRequests is the error returned when exceeding max requests
+	ErrMaxRequests = errors.New("Max Requests limit reached")
 )
 
 var envMap = map[string]func(*Collector, string){
@@ -268,6 +273,12 @@ var envMap = map[string]func(*Collector, string){
 			c.MaxDepth = maxDepth
 		}
 	},
+	"MAX_REQUESTS": func(c *Collector, val string) {
+		maxRequests, err := strconv.ParseUint(val, 0, 32)
+		if err == nil {
+			c.MaxRequests = uint32(maxRequests)
+		}
+	},
 	"PARSE_HTTP_ERROR_RESPONSE": func(c *Collector, val string) {
 		c.ParseHTTPErrorResponse = isYesString(val)
 	},
@@ -320,6 +331,13 @@ func MaxDepth(depth int) CollectorOption {
 	}
 }
 
+// MaxDepth limits the recursion depth of visited URLs.
+func MaxRequests(max uint32) CollectorOption {
+	return func(c *Collector) {
+		c.MaxRequests = max
+	}
+}
+
 // AllowedDomains sets the domain whitelist used by the Collector.
 func AllowedDomains(domains ...string) CollectorOption {
 	return func(c *Collector) {
@@ -449,6 +467,7 @@ func (c *Collector) Init() {
 	c.UserAgent = "colly - https://github.com/gocolly/colly/v2"
 	c.Headers = nil
 	c.MaxDepth = 0
+	c.MaxRequests = 0
 	c.store = &storage.InMemoryStorage{}
 	c.store.Init()
 	c.MaxBodySize = 10 * 1024 * 1024
@@ -717,6 +736,9 @@ func (c *Collector) requestCheck(parsedURL *url.URL, method string, getBody func
 	if c.MaxDepth > 0 && c.MaxDepth < depth {
 		return ErrMaxDepth
 	}
+	if c.MaxRequests > 0 && c.requestCount >= c.MaxRequests {
+		return ErrMaxRequests
+	}
 	if err := c.checkFilters(u, parsedURL.Hostname()); err != nil {
 		return err
 	}
@@ -1278,6 +1300,7 @@ func (c *Collector) Clone() *Collector {
 		IgnoreRobotsTxt:        c.IgnoreRobotsTxt,
 		MaxBodySize:            c.MaxBodySize,
 		MaxDepth:               c.MaxDepth,
+		MaxRequests:            c.MaxRequests,
 		DisallowedURLFilters:   c.DisallowedURLFilters,
 		URLFilters:             c.URLFilters,
 		CheckHead:              c.CheckHead,

colly_test.go

@@ -1495,6 +1495,25 @@ func TestCollectorDepth(t *testing.T) {
 	}
 }
 
+func TestCollectorRequests(t *testing.T) {
+	ts := newTestServer()
+	defer ts.Close()
+	maxRequests := uint32(5)
+	c1 := NewCollector(
+		MaxRequests(maxRequests),
+		AllowURLRevisit(),
+	)
+	requestCount := 0
+	c1.OnResponse(func(resp *Response) {
+		requestCount++
+		c1.Visit(ts.URL)
+	})
+	c1.Visit(ts.URL)
+	if requestCount != 5 {
+		t.Errorf("Invalid number of requests: %d (expected 5) with MaxRequests", requestCount)
+	}
+}
+
 func TestCollectorContext(t *testing.T) {
 	// "/slow" takes 1 second to return the response.
 	// If context does abort the transfer after 0.5 seconds as it should,