add data to package

DESCRIPTION

@@ -5,8 +5,8 @@ Version: 0.1.0
 Date: 2016-08-12
 Author: Bob Rudis (@hrbrmstr), Christos Zoulas [libmagic]
 Maintainer: Bob Rudis <bob@rudis.net>
-Description: The 'libmagic' library provides functions to determine 
-    mime type and other metadata from files through their "magic" 
+Description: The 'libmagic' library provides functions to determine
+    mime type and other metadata from files through their "magic"
     attributes.
 URL: http://github.com/hrbrmstr/wand
 BugReports: https://github.com/hrbrmstr/wand/issues
@@ -16,7 +16,8 @@ Suggests:
     testthat,
     tibble,
     magrittr,
-    dplyr
+    dplyr,
+    rappdirs
 Depends:
     R (>= 3.0.0)
 Imports:

NAMESPACE

@@ -1,6 +1,8 @@
 # Generated by roxygen2: do not edit by hand
 
 export(incant)
+export(magic_wand_file)
 import(purrr)
+import(rappdirs)
 importFrom(Rcpp,sourceCpp)
 useDynLib(wand)

R/RcppExports.R

@@ -4,10 +4,15 @@
 #' Retrieve 'magic' attributes from files and directories
 #'
 #' @param path character vector of files to use magic on
+#' @param magic_db either "\code{system}" (the default) to use the system
+#'   \code{magic} database or an atomic character vector with a
+#'   colon-separated list of full paths to custom \code{magic} database(s).
 #' @return a \code{tibble} / \code{data.frame} of file magic attributes.
 #'   Specifically, mime type, encoding, possible file extensions and
 #'   type description are returned as colums in the data frame along
 #'   with \code{path}.
+#' @references See \url{http://openpreservation.org/blog/2012/08/09/magic-editing-and-creation-primer/}
+#'   for information on how to create your own \code{magic} database
 #' @export
 #' @examples
 #' library(magrittr)
@@ -17,7 +22,7 @@
 #'   list.files(full.names=TRUE) %>%
 #'   incant() %>%
 #'   glimpse()
-incant <- function(path) {
-    .Call('wand_incant', PACKAGE = 'wand', path)
+incant <- function(path, magic_db = "system") {
+    .Call('wand_incant', PACKAGE = 'wand', path, magic_db)
 }
 

R/wand-package.R

@@ -4,6 +4,7 @@
 #' @docType package
 #' @author Bob Rudis (@@hrbrmstr)
 #' @import purrr
+#' @import rappdirs
 #' @useDynLib wand
 #' @importFrom Rcpp sourceCpp
 NULL

R/zzz.r

@@ -0,0 +1,34 @@
+#' Use the "magic" file that comes with the package
+#'
+#' The \code{magic_load()} functon from \code{libmagic} can't take ZIP files
+#' and the \code{magic.mgc} file that ships with the package is too large to
+#' be shipped uncompressed. Using this function as the \code{magic_db}
+#' parameter will copy and uncompress the database to a cache directory and
+#' return the full path to the magic file. Subsequent calls will not have to
+#' perform the decompression unless \code{force} is \code{TRUE} or the
+#' cache directory has been cleared.
+#'
+#' @param force ensure the lastest copy of the pacakge "magic"
+#'   database is used.
+#' @export
+#' @examples
+# ' library(magrittr)
+# ' library(dplyr)
+#'
+#' system.file("img", package="filemagic") %>%
+#'   list.files(full.names=TRUE) %>%
+#'   incant(magic_wand_file()) %>%
+#'   glimpse()
+magic_wand_file <- function(force=FALSE) {
+
+  cache <- rappdirs::user_cache_dir("wandr")
+
+  if (!dir.exists(cache)) dir.create(cache, showWarnings=FALSE)
+  if (!dir.exists(cache)) return("system")
+
+  suppressWarnings(unzip(system.file("magic.mgc.zip", package="wand"),
+        exdir=cache, overwrite=force))
+
+  file.path(rappdirs::user_cache_dir("wandr"), "magic.mgc")
+
+}

README.Rmd

@@ -9,6 +9,7 @@ The `libmagic` library must be installed and available to use this. The package
 The following functions are implemented:
 
 - `incant` : returns the "magic" metadata of the files in the input vector (as a data frame)
+- `magic_wand_file` : provides a full path to the package-provided `magic` file
 
 ### Installation
 
@@ -32,6 +33,12 @@ system.file("img", package="wand") %>%
   incant() %>% 
   glimpse()
 
+system.file("img", package="wand") %>% 
+  list.files(full.names=TRUE) %>% 
+  incant(magic_wand_file()) %>% 
+  select(description) %>% 
+  unlist(use.names=FALSE)
+
 # current verison
 packageVersion("wand")
 

README.md

@@ -6,6 +6,7 @@ The `libmagic` library must be installed and available to use this. The package
 The following functions are implemented:
 
 -   `incant` : returns the "magic" metadata of the files in the input vector (as a data frame)
+-   `magic_wand_file` : provides a full path to the package-provided `magic` file
 
 ### Installation
 
@@ -35,6 +36,25 @@ system.file("img", package="wand") %>%
     ## $ description <chr> "directory", "C source, ASCII text", "HTML document, ASCII text, with CRLF line terminators", "...
 
 ``` r
+system.file("img", package="wand") %>% 
+  list.files(full.names=TRUE) %>% 
+  incant(magic_wand_file()) %>% 
+  select(description) %>% 
+  unlist(use.names=FALSE)
+```
+
+    ##  [1] "directory"                                                                                                                                                                                                        
+    ##  [2] "C source, ASCII text"                                                                                                                                                                                             
+    ##  [3] "HTML document, ASCII text, with CRLF line terminators"                                                                                                                                                            
+    ##  [4] "ASCII text, with no line terminators"                                                                                                                                                                             
+    ##  [5] "Rich Text Format data, version 1, ANSI"                                                                                                                                                                           
+    ##  [6] "JPEG image data, JFIF standard 1.01, aspect ratio, density 72x72, segment length 16, Exif Standard: [TIFF image data, big-endian, direntries=2, orientation=upper-left], baseline, precision 8, 800x700, frames 3"
+    ##  [7] "PDF document, version 1.3"                                                                                                                                                                                        
+    ##  [8] "PNG image data, 800 x 700, 8-bit/color RGBA, non-interlaced"                                                                                                                                                      
+    ##  [9] "ASCII text, with very long lines, with CRLF line terminators"                                                                                                                                                     
+    ## [10] "TIFF image data, big-endian"
+
+``` r
 # current verison
 packageVersion("wand")
 ```
@@ -50,7 +70,7 @@ library(testthat)
 date()
 ```
 
-    ## [1] "Fri Aug 12 22:23:39 2016"
+    ## [1] "Fri Aug 12 23:38:14 2016"
 
 ``` r
 test_dir("tests/")

man/incant.Rd

@@ -4,14 +4,14 @@
 \alias{incant}
 \title{Retrieve 'magic' attributes from files and directories}
 \usage{
-incant(path, magic_db = NA_character_)
+incant(path, magic_db = "system")
 }
 \arguments{
 \item{path}{character vector of files to use magic on}
 
-\item{magic_db}{either \code{NULL} (the default) to use the built-in
-\code{magic.mgc} database or an atomic character vector with a
-colon-separated list of full paths to custom \code{magic.mgc} database(s).}
+\item{magic_db}{either "\code{system}" (the default) to use the system
+\code{magic} database or an atomic character vector with a
+colon-separated list of full paths to custom \code{magic} database(s).}
 }
 \value{
 a \code{tibble} / \code{data.frame} of file magic attributes.
@@ -33,6 +33,6 @@ system.file("img", package="filemagic") \%>\%
 }
 \references{
 See \url{http://openpreservation.org/blog/2012/08/09/magic-editing-and-creation-primer/}
-  for information on how to create your own \code{magic.mgc} databases.
+  for information on how to create your own \code{magic} database
 }
 

man/magic_wand_file.Rd

@@ -0,0 +1,31 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/zzz.r
+\name{magic_wand_file}
+\alias{magic_wand_file}
+\title{Use the "magic" file that comes with the package}
+\usage{
+magic_wand_file(force = FALSE)
+}
+\arguments{
+\item{force}{ensure the lastest copy of the pacakge "magic"
+database is used.}
+}
+\description{
+The \code{magic_load()} functon from \code{libmagic} can't take ZIP files
+and the \code{magic.mgc} file that ships with the package is too large to
+be shipped uncompressed. Using this function as the \code{magic_db}
+parameter will copy and uncompress the database to a cache directory and
+return the full path to the magic file. Subsequent calls will not have to
+perform the decompression unless \code{force} is \code{TRUE} or the
+cache directory has been cleared.
+}
+\examples{
+library(magrittr)
+library(dplyr)
+
+system.file("img", package="filemagic") \%>\%
+  list.files(full.names=TRUE) \%>\%
+  incant(magic_wand_file()) \%>\%
+  glimpse()
+}
+

src/RcppExports.cpp

@@ -6,13 +6,14 @@
 using namespace Rcpp;
 
 // incant
-DataFrame incant(CharacterVector path);
-RcppExport SEXP wand_incant(SEXP pathSEXP) {
+DataFrame incant(CharacterVector path, std::string magic_db);
+RcppExport SEXP wand_incant(SEXP pathSEXP, SEXP magic_dbSEXP) {
 BEGIN_RCPP
     Rcpp::RObject __result;
     Rcpp::RNGScope __rngScope;
     Rcpp::traits::input_parameter< CharacterVector >::type path(pathSEXP);
-    __result = Rcpp::wrap(incant(path));
+    Rcpp::traits::input_parameter< std::string >::type magic_db(magic_dbSEXP);
+    __result = Rcpp::wrap(incant(path, magic_db));
     return __result;
 END_RCPP
 }

src/wand.cpp

@@ -7,10 +7,15 @@ using namespace Rcpp;
 //' Retrieve 'magic' attributes from files and directories
 //'
 //' @param path character vector of files to use magic on
+//' @param magic_db either "\code{system}" (the default) to use the system
+//'   \code{magic} database or an atomic character vector with a
+//'   colon-separated list of full paths to custom \code{magic} database(s).
 //' @return a \code{tibble} / \code{data.frame} of file magic attributes.
 //'   Specifically, mime type, encoding, possible file extensions and
 //'   type description are returned as colums in the data frame along
 //'   with \code{path}.
+//' @references See \url{http://openpreservation.org/blog/2012/08/09/magic-editing-and-creation-primer/}
+//'   for information on how to create your own \code{magic} database
 //' @export
 //' @examples
 //' library(magrittr)
@@ -21,7 +26,7 @@ using namespace Rcpp;
 //'   incant() %>%
 //'   glimpse()
 // [[Rcpp::export]]
-DataFrame incant(CharacterVector path) {
+DataFrame incant(CharacterVector path, std::string magic_db="system") {
 
   unsigned int input_size = path.size();
 
@@ -30,7 +35,15 @@ DataFrame incant(CharacterVector path) {
   StringVector extensions(input_size);
   StringVector description(input_size);
 
-  const char *mtype = NULL;
+  const char *mdb;
+  std::string mdbcpp;
+
+  if (magic_db == "system") {
+    mdb = NULL;
+  } else {
+    mdbcpp = magic_db;
+    mdb = mdbcpp.c_str();
+  }
 
   for (unsigned int i=0; i<input_size; i++) {
 
@@ -44,7 +57,8 @@ DataFrame incant(CharacterVector path) {
     if (cookie == NULL) {
       mime_type[i] = NA_STRING;
     } else {
-      magic_load(cookie, mtype);
+      int val = magic_load(cookie, mdb);
+      if (val < 0) magic_load(cookie, NULL);
       const char *magic_result = magic_file(cookie, fullPath.c_str());
       if (magic_result == NULL) {
         mime_type[i] = NA_STRING;
@@ -59,7 +73,8 @@ DataFrame incant(CharacterVector path) {
     if (cookie == NULL) {
       encoding[i] = NA_STRING;
     } else {
-      magic_load(cookie, mtype);
+      int val = magic_load(cookie, mdb);
+      if (val < 0) magic_load(cookie, NULL);
       const char *magic_result = magic_file(cookie, fullPath.c_str());
       if (magic_result == NULL) {
         encoding[i] = NA_STRING;
@@ -74,7 +89,8 @@ DataFrame incant(CharacterVector path) {
     if (cookie == NULL) {
       extensions[i] = NA_STRING;
     } else {
-      magic_load(cookie, mtype);
+      int val = magic_load(cookie, mdb);
+      if (val < 0) magic_load(cookie, NULL);
       const char *magic_result = magic_file(cookie, fullPath.c_str());
       if (magic_result == NULL) {
         extensions[i] = NA_STRING;
@@ -89,7 +105,8 @@ DataFrame incant(CharacterVector path) {
     if (cookie == NULL) {
       description[i] = NA_STRING;
     } else {
-      magic_load(cookie, mtype);
+      int val = magic_load(cookie, mdb);
+      if (val < 0) magic_load(cookie, NULL);
       const char *magic_result = magic_file(cookie, fullPath.c_str());
       if (magic_result == NULL) {
         description[i] = NA_STRING;