Extracting All Emails Using GmailR - r

Question

I'm trying to extract all the emails from my gmail account to do some analysis. The end goal is a dataframe of emails. I'm using the gmailR package.
So far I've extracted all the email threads and "expanded" them by mapping all the thread IDs to gm_thread(). Here's the code for that:
threads <- gm_threads(num_results = 5)
thread_ids <- gm_id(threads)
#extract all the thread ids
threads_expanded <- map(thread_ids, gm_thread)
This returns a list of all the threads. The structure of this is a list of gmail_thread objects. When you drill down one level into the list of thread objects, str(threads_expanded[[1]], max.level = 1), you get a single thread object which looks like:
List of 3
$ id : chr "xxxx"
$ historyId: chr "yyyy"
$ messages :List of 3
- attr(*, "class")= chr "gmail_thread"
Then, if you drill down further into the messages composing the threads, you start to get the useful info. str(threads_expanded[[1]]$messages, max.level = 1) gets you a list of the gmail_message objects for that thread:
List of 3
$ :List of 8
..- attr(*, "class")= chr "gmail_message"
$ :List of 8
..- attr(*, "class")= chr "gmail_message"
$ :List of 8
..- attr(*, "class")= chr "gmail_message"
Where I'm stuck is actually extracting all the useful information from each email within all the threads. The end goal is a dataframe with a column for the message_id, thread_id, to, from, etc. I'm imagining something like this:
message_id | thread_id | to | from | ... |
-------------------------------------------------------------------------
1234 | abcd | me#gmail.com | pam#gmail.com | ... |
1235 | abcd | pam#gmail.com | me#gmail.com | ... |
1236 | abcf | me#gmail.com | tim#gmail.com | ... |

Answer 1

It's not the prettiest answer, but it works. I'm going to work on vectorizing it later:
threads <- gm_threads(num_results = 5)
thread_ids <- gm_id(threads)
#extract all the thread ids
threads_expanded <- map(thread_ids, gm_thread)
msgs <- vector()
for(i in (1:length(threads_expanded))){
msgs <- append(msgs, values = threads_expanded[[i]]$messages)
}
#extract all the individual messages from each thread
msg_ids <- unlist(map(msgs, gm_id))
#get the message id for each message
msg_body <- vector()
#get message body, store in vector
for(msg in msgs){
body <- gm_body(msg)
attchmnt <- nrow(gm_attachments(msg))
if(length(body) != 0 && attchmnt == 0){
#does not return a null value, rather an empty list or list
of length 0, so if,
#body is not 0 (there is something there) and there are no attachemts,
#add it to vector
msg_body <- append(msg_body, body)
#if there is no to info, fill that spot with an empty space
}
else{
msg_body <- append(msg_body, "")
#if there is no attachment but the body is also empty add "" to the list
}
}
msg_body <- unlist(msg_body)
msg_datetime <- msgs %>%
map(gm_date) %>%
unlist()%>%
dmy_hms()
#get datetime info, store in vector
message_df <- tibble(msg_ids, msg_datetime, msg_body)
#all the other possible categories, e.g., to, from, cc, subject, etc.,
#either use a similar for loop or a map call