Error from Rfacebook 'getPage' with since&until - r

Question

I am using Rfacebook version 0.6.
When I call getPage with since and until dates as following, I get the following error. What I am doing wrong, or if there's something that need be updated in the package itself?
Note: <facebook_page_name>, <my_app_id>, <my_app_secret> are placeholders for illustration, without using the actual values.
Here are the details:
content<-get_fb_data("<facebook_page_name>",since="2016/01/01",until="2016/01/20",condition=2)
get_fb_data<-function(page_name,no_of_records,since_date,until_date,condition)
{
#get data from facebook page
library("Rfacebook")
fb_oauth <- fbOAuth(app_id="<my_app_id>", app_secret="<my_app_secret>",
extended_permissions = FALSE)
if (condition == 1)
{
content<-getPage(page_name, fb_oauth, no_of_records, feed = TRUE)
}
else
{
since_date<-paste(since_date,"00:00:00 IST",sep=" ")
until_date<-paste(until_date,"23:59:59 IST",sep=" ")
from_value<-as.numeric(as.POSIXct(since_date))
to_value<-as.numeric(as.POSIXct(until_date))
content<-getPage(page_name, fb_oauth,
since = from_value,
until = to_value,
feed = TRUE)
}
return(content)
}
Error displayed:
Error in as.Date.numeric(since) : 'origin' must be supplied
Per debug, this is from function as.Date called in getPage.

Answer 1

This should work:
library("Rfacebook")
fb_oauth <- fbOAuth(app_id="<my_app_id>", app_secret="<my_app_secret>",
extended_permissions = FALSE)
get_fb_data <- function(page_name, no_of_records, since_date,
until_date, condition){
if (condition == 1){
content<-getPage(page_name, fb_oauth, no_of_records, feed = TRUE)
} else{
content <- getPage(page_name, fb_oauth,
since = since_date,
until = until_date,
feed = TRUE)
}
content
}
content <- get_fb_data("humansofnewyork",
since_date="2016/01/01",
until_date="2016/01/2",
condition=2)
I do not really understand, why you are trying to change date format - it's unnecessary. What is more, you have a syntax error, because else should be written after } closing if. You shouldn't also load packages inside your function. What for loading it each time? The same with your fb_oauth.