Changes instagram parser to use their pagination

Limited to max 5 pages to avoid endless scanning on first start.
If the current page contains at least one media element not in
our database it will check the next page (max. 5 pages).

instagram/api.go

@@ -69,9 +69,15 @@ type InstagramPostResponse struct {
 	} `json:"media"`
 }
 
-func LoadList() (*InstagramListResponse, error) {
+func LoadList(token string) (*InstagramListResponse, error) {
 	var listResponse InstagramListResponse
-	res, err := GetHTTPResource("https://www.instagram.com/explore/tags/" + config.C.Instagram.Tag + "/?__a=1")
+	var url string
+	if token == "" {
+		url = "https://www.instagram.com/explore/tags/" + config.C.Instagram.Tag + "/?__a=1"
+	} else {
+		url = "https://www.instagram.com/explore/tags/" + config.C.Instagram.Tag + "/?__a=1&max_id=" + token
+	}
+	res, err := GetHTTPResource(url)
 	if err != nil {
 		return nil, err
 	}

instagram/main.go

@@ -8,16 +8,29 @@ import (
 
 func LoadNewInstas() {
 	log.Printf("Loading new Instas...")
-	list, err := LoadList()
-	if err != nil {
-		log.Printf("Can't load Instagram feed: %+v", err)
-		return
+	token := ""
+	for i := 0; i < 5; i++ {
+		list, err := LoadList(token)
+		if err != nil {
+			log.Printf("Can't load Instagram feed: %+v", err)
+			return
+		}
+		token = iterList(list)
+		if token == "" {
+			break
+		}
 	}
+	log.Printf("Finished looking for new Instas.")
+}
+
+func iterList(list *InstagramListResponse) string {
+	var token string
 	for _, image := range list.Tag.Media.Nodes {
 		var count int
 		if database.Db.Model(database.Item{}).Where("original_id = ?", image.Code).Count(&count); count > 0 {
 			continue
 		}
+		token = list.Tag.Media.PageInfo.EndCursor
 		post, err := LoadPost(image.Code)
 		if err != nil {
 			log.Printf("Can't load Instagram post %s: %+v", image.Code, err)
@@ -90,5 +103,5 @@ func LoadNewInstas() {
 			database.Db.Create(&IT)
 		}
 	}
-	log.Printf("Finished looking for new Instas.")
+	return token
 }