getMetadata.R

# Get metadta for .md files in a single directory
# Input: the directory path
# Output: a data.table with filename and metadata.  
# Currently, adding only ms.author and ms.reviewer

getMetadata <- function(path){
                        
library(data.table)

# get all the markdown files in the directory
files <- list.files(path=path, pattern=".md$", all.files=FALSE,
           full.names=FALSE)

metadata <- data.table()
# loop through files to get metadata and append to data.table
for (i in 1:length(files)) {
  fn <- paste(myrepo, files[i], sep="/") # get the filename
  tryCatch(               
    
    # Specifying expression
    expr = {                     
      yml_metadata <- rmarkdown::yaml_front_matter(fn) # read the metadata for this file
      
    },
    # Specifying error message
    error = function(e){         
      print(fn)
      print(e)
    },
    
    warning = function(w){      
      print(fn)
      print(w)
    },
    
    finally = {   
      # I'm appending the ms.author and ms.reviewer here - customize as you see fit!
      newrow <- data.table(filename =files[i], 
                           ms.author=yml_metadata[["ms.author"]], 
                           ms.reviewer=yml_metadata[["ms.reviewer"]],
                           ms.custom=yml_metadata[["ms.custom"]])
      metadata <- rbind(metadata, newrow, fill=T)
    }
  )
}

return (metadata)
}