streamline connection to WRDS in "connect_WRDS.R"

code/R/connect_WRDS.R

@@ -0,0 +1,49 @@
+# --- Header -------------------------------------------------------------------
+# See LICENSE file for details 
+#
+# This code establishes a connection to WRDS
+# ------------------------------------------------------------------------------
+#
+#
+library(RPostgres)
+library(DBI)
+#
+#
+message("Trying to establish connection to WRDS")
+#
+#
+# --- WRDS Credentials ----------------------------------------------------------
+if(file.exists("config.csv")){
+  df <- readr::read_csv("config.csv", col_type = readr::cols(), comment = "#")
+  cfg <- as.list(df$value)
+  names(cfg) <- df$variable
+  rm(df) 
+  wrds_user <- cfg$wrds_user
+  wrds_pwd <- cfg$wrds_pwd
+  rm(cfg)
+} else if(rstudioapi::isAvailable()) {
+    wrds_user <- rstudioapi::askForPassword(prompt="Enter your WRDS username")
+    wrds_pwd   <- rstudioapi::askForPassword()
+} else if(!rstudioapi::isAvailable()) {
+      stop("
+          cannot establish connection to WRDS (connect_WRDS.R) 
+          - missing WRDS credentials (wrds_user & wrds_pwd)
+          - see _config.csv for troubleshooting")
+} 
+#
+#
+# --- WRDS Connection ----------------------------------------------------------
+wrds <- dbConnect(
+  Postgres(),
+  host = 'wrds-pgdata.wharton.upenn.edu',
+  port = 9737,
+  user = wrds_user,
+  password = wrds_pwd,
+  sslmode = 'require',
+  dbname = 'wrds'
+)
+rm(wrds_user)
+rm(wrds_pwd)
+message("Logged on to WRDS!")
+#
+#

code/R/pull_wrds_data.R

@@ -3,13 +3,11 @@
 #
 # This code pulls data from WRDS 
 # ------------------------------------------------------------------------------
-
+#
 library(RPostgres)
 library(DBI)
-
-if (!exists("cfg")) source("code/R/read_config.R")
-
-save_wrds_data <- function(df, fname) {
+#
+save_rds_versionctrl <- function(df, fname) {
   if(file.exists(fname)) {
     file.rename(
       fname,
@@ -21,23 +19,13 @@ save_wrds_data <- function(df, fname) {
   }
   saveRDS(df, fname)
 }
-
-# --- Connect to WRDS ----------------------------------------------------------
-
-wrds <- dbConnect(
-  Postgres(),
-  host = 'wrds-pgdata.wharton.upenn.edu',
-  port = 9737,
-  user = cfg$wrds_user,
-  password = cfg$wrds_pwd,
-  sslmode = 'require',
-  dbname = 'wrds'
-)
-
-message("Logged on to WRDS ...")
-
+#
+# --- Connection to WRDS -------------------------------------------------------
+source("code/R/connect_WRDS.R")
+#
+#
 # --- Specify filters and variables --------------------------------------------
-
+#
 dyn_vars <- c(
   "gvkey", "conm", "cik", "fyear", "datadate", "indfmt", "sich",
   "consol", "popsrc", "datafmt", "curcd", "curuscn", "fyr", 
@@ -49,25 +37,25 @@ dyn_vars <- c(
   "recch", "invch", "apalch", "txach", "aoloch",
   "gdwlip", "spi", "wdp", "rcp"
 )
-
+#
 dyn_var_str <- paste(dyn_vars, collapse = ", ")
-
+#
 stat_vars <- c("gvkey", "loc", "sic", "spcindcd", "ipodate", "fic")
 stat_var_str <- paste(stat_vars, collapse = ", ")
-
+#
 cs_filter <- "consol='C' and (indfmt='INDL' or indfmt='FS') and datafmt='STD' and popsrc='D'"
-
-
+#
+#
 # --- Pull Compustat data ------------------------------------------------------
-
+#
 message("Pulling dynamic Compustat data ... ", appendLF = FALSE)
 res <- dbSendQuery(wrds, paste(
   "select", 
   dyn_var_str, 
   "from COMP.FUNDA",
   "where", cs_filter
 ))
-
+#
 wrds_us_dynamic <- dbFetch(res, n=-1)
 dbClearResult(res)
 message("done!")
@@ -76,13 +64,15 @@ message("Pulling static Compustat data ... ", appendLF = FALSE)
 res2<-dbSendQuery(wrds, paste(
   "select ", stat_var_str, "from COMP.COMPANY"
 ))
-
+#
 wrds_us_static <- dbFetch(res2,n=-1)
 dbClearResult(res2)
 message("done!")
-
+#
 wrds_us <- merge(wrds_us_static, wrds_us_dynamic, by="gvkey")
-save_wrds_data(wrds_us, "data/pulled/cstat_us_sample.rds")
-
+save_rds_versionctrl(wrds_us, "data/pulled/cstat_us_sample.rds")
+#
 dbDisconnect(wrds)
+rm(wrds)
 message("Disconnected from WRDS")
+#