In jimrothstein/yt_api: R functions to use Google Youtube API

This is alternaive .... use S3

======================================

001_get_comments, for GIVEN video

======================================

knitr::opts_chunk$set(
    echo = TRUE,
    comment = "      ##",
    error = TRUE, 
    collapse = TRUE)
load_all()

## initialize takes no args, returns list of params good for entire file
global_params <- initialize()
global_params

S3 to get query_params

##  S3 object: playlists
    playlists  <- structure(list(), class="playlists")

##  generic function:  get_query_params
    get_query_params  <- function(x) UseMethod("get_query_params")

S3 method for S3 object playlists

    get_query_params.playlists  <- function(x) {

    ## query_defaults (starter values)
    if (!exists("query_defaults")) query_defaults <- get_typical_values()

    ## put it all togehter
    list( 
      ## from global_params
      key = global_params$api$api_key,

    ## for playlists
    base_url = "https://www.googleapis.com/youtube/v3/playlists",
    part  =  "snippet",
    fields=paste(sep=",", "nextPageToken",
                  "items(id,snippet(title,description,publishedAt))"),


    ## from query_defaults (only what comments needs)
      channelId = query_defaults$channelId,
      #videoId = query_defaults$videoId,
      #maxResults = query_defaults$maxResults,

    ## don't forget 
      pageToken = NULL
    )
   } 


query_params  <- get_query_params(playlists)
query_params

Have everything, pack into bundle (3 elements)

bundle  <- list(
                url = query_params$base_url,
                config = global_params$config ,
                query = query_params
                )

}
bundle$url
bundle$config
bundle$query


# spare:
videoId  <- "Mec9sw1cJk8"  # carter
#playlistId  <- "PLbcglKxZP5PMZ7afIT7E2o9NwQIzqTI5l"

HELPER:

More batches? Helper function: Get next page token * Run GET again, return next r

get_batch  <- function(url = NULL,  query = NULL, config=NULL) {
  res <- httr::GET(url = url, query = query, config= config ) %>% 
  httr::stop_for_status()
}

1st batch

## reminder:  config has already processed the token
{
r  <- get_batch(url = bundle$url , 
                  query=bundle$query, 
                  config = bundle$config )
r
}


##  process_comments runs r through json  and content, which returns list of
##  nextPageToken and content 
playlists  <- process_playlists(r)

playlists %>% knitr::kable()

Main loop: remaining batches

## request uses pageToken, but the response returns nextPageToken
while ( !is.null(httr::content(r)$nextPageToken )) {
  bundle$query$pageToken  <- httr::content(r)$nextPageToken
  print(bundle$query$pageToken)
    r  <- get_batch(url = bundle$url, 
                  query=bundle$query, 
                  config = bundle$config )
    playlists  <- process_playlists(r, playlists)

} # end loop

## playlists
head(playlists)
saveRDS(playlists, file=here("data","playlists.RDS"))
View(playlists)

library(kableExtra)

## opens up firefox:
kbl(playlists) %>% kable_styling(full_width = F) %>% column_spec(2, width= "30em")

# TODO:  file is found when knitr runs (see above)

# file must be of form:
# dir/name_of_this_file    where dir is relative to project root
file <- "rmd/009ALT_ONE_video_ALL_comments.Rmd"

# in general, pdf will look nicer
rmarkdown::render(file,
                  #output_format = "pdf_document",
                  output_format = "html_document",
                  output_file = "~/Downloads/print_and_delete/out")