How can I get all post ids for a Facebook page? - facebook

Question

I am using https://graph.facebook.com/v2.4/page_id/posts?fields=id to get all post ids from a Facebook page, but I am running into an infinite loop issue with pagination due to paging.next property always returning a url. It looks like the last page points to the first page. How would I know I have reached the end of results.
Here is a code example:
public static Dictionary<string,string> GetPagePostIds(string accessToken, string pageId)
{
Dictionary<string, string> postIds = new Dictionary<string, string>();
StringBuilder sb = new StringBuilder(graphAPIURL);
sb.Append("/").Append(pageId).Append("/posts/?access_token=").Append(accessToken);
sb.Append("&fields=id");
string url = sb.ToString();
int pages = 0;
int rows = 0;
while (url != null)
{
System.Net.WebRequest req = System.Net.WebRequest.Create(url);
System.Net.WebResponse response = req.GetResponse();
string json = null;
using (System.IO.StreamReader sr = new System.IO.StreamReader(response.GetResponseStream()))
{
json = sr.ReadToEnd();
Console.WriteLine(json);
}
if (json != null)
{
pages++;
Dictionary<string, dynamic> data = (Dictionary<string, dynamic>)Newtonsoft.Json.JsonConvert.DeserializeObject(json, typeof(Dictionary<string, dynamic>));
if (data.ContainsKey("data"))
{
Newtonsoft.Json.Linq.JArray a = (Newtonsoft.Json.Linq.JArray)data["data"];
foreach (Newtonsoft.Json.Linq.JObject o in a)
{
rows++;
postIds.Add(o["id"].ToString(), o["id"].ToString());
}
}
if (data.ContainsKey("paging"))
{
try
{
if (data["paging"]["next"] == url)
{
//otherwise we will be stuck in the infinite loop, as next url of the last page is not null
break;
}
//if next link is present, there are more pages available
url = null;
url = data["paging"]["next"];
}
catch (Exception)
{
}
}
}
}
return postIds;
}

Answer 1

You can break the loop, if you reach to the point, where you only receive empty results.
So you just simply extend your while loop with a second condition. Here is some simple pseudocode:
while (url != null && resultsOnPage) {
[...]
if (data.ContainsKey("data") && data['data'].Count > 0 ) {
[...]
} else {
resultsOnPage = false;
}
[...]
}
Just leave the rest as it is.