Changed exec for spawn, added better params handling & parsing multiple files

Readme.md

@@ -2,24 +2,49 @@
 
 Image meta-information (EXIF, IPTC, XMP...) extraction using [exiftool](http://www.sno.phy.queensu.ca/~phil/exiftool/)
 
-__NOTE__: This fork from https://github.com/visionmedia/node-exif has a DIFFERENT (improved !) API.
- It uses [precise tags](http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/index.html) for field access.
+__NOTE__: This fork from https://github.com/Yvem/node-exif has a DIFFERENT
+(improved !) API.
+
+ Mayor Changes:
+ Instead of calling 'exiftool' through 'child_process.exec', it calls:
+ [child_process.spawn](https://nodejs.org/api/child_process
+   .html#child_process_child_process_spawn_command_args_options) which avoids buffer limitations.
+ It also allows to send specific arguments to the 'exiftool' shell command
+ and to read EXIF info from multiple files at once.
 
 ## Installation
 
-    $ npm install Yvem/node-exif
+    $ npm install jmunox/node-exif
 
 ## Usage
 
+ * Fetch EXIF data from `file` and invoke `fn(err, data)`.
+ It spawns a child process (see child_process.spawn) and executes [exiftool]
+ (http://www.sno.phy.queensu.ca/%7Ephil/exiftool/)
+
+ Params:
+
+   @param {String} file or path to folder
+
+   @param {Array} args [optional] List of string arguments to pass to
+   [exiftool](http://www.sno.phy.queensu.ca/~phil/exiftool/exiftool_pod.html)
+
+   @param {Object} opts [optional] Object that is passed to the
+   child_process.spawn method as the `options` argument. See options of
+   [child_process.spawn](https://nodejs.org/api/child_process
+  .html#child_process_child_process_spawn_command_args_options)
+
+  @param {function} fn callback function to invoke `fn(err, data)`
+
 ```javascript
 var exif = require('exif2');
 
-exif(file, function(err, obj){
+exif(file, args, opts function(err, obj){
   console.log(obj);
 
   // see available tags http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/index.html
-  console.log(o['FileName']);
-  console.log(o['Caption-Abstract']); // IPTC Caption [2,120]
+  console.log(obj['FileName']);
+  console.log(obj['Caption-Abstract']); // IPTC Caption [2,120]
 })
 ```
 
@@ -150,23 +175,110 @@ exif(file, function(err, obj){
 
 ## Advanced usage
 
-### Errors
-node-exif may throw custom errors :
+### Parsing specific TagNames
+It is possible to parse specific EXIF metadata from a file by defining the
+TagNames in the Arguments:
+
+```javascript
+var exif = require('exif2');
+var file = 'test/fixtures/forest.jpg';
+var exifParams = ['-FileName', '-ImageHeight', '-ImageWidth', '-Orientation',
+  '-DateTimeOriginal', '-CreateDate', '-ModifyDate', '-FileAccessDate',
+  '-FileType', '-MIMEType'];
+
+   exif(file, exifParams,  function(err, metadata){
 
-* `Metadata too big !` when metadata are too big to be parsed with current buffer limitations
+     console.log(metadata.['ImageHeight']);
+     console.log(metadata.['ImageWidth']);
+   }
 
-### Special options
-For special cases, it is possible to provide exec options.
-`exif()` optional second parameter may be an `exec()` option object as described here :
-http://nodejs.org/api/child_process.html#child_process_child_process_exec_command_options_callback
+```
 
-Example usage : augment stdout buffer size to handle images with huge metadata :
+```json
+{
+	"SourceFile": "test/fixtures/forest.jpeg",
+	"FileName": "forest.jpeg",
+	"ImageWidth": 900,
+    "ImageHeight": 596
+    "Orientation": "Horizontal (normal)",
+	"DateTimeOriginal": "2012:10:07 11:36:30",
+    "CreateDate": "2012:10:07 11:36:30",
+    "ModifyDate": "2012:10:08 19:10:63",
+	"FileAccessDate": "2014:03:24 15:27:05+01:00",
+	"FileType": "JPEG",
+	"MIMEType": "image/jpeg"
+}
+```
+
+### Parsing EXIF from several media files in path
+It is also possible to parse EXIF metadata from all the media file by setting
+ the path to a specific folder. The data is returned in an Array. This is
+ more efficient, instead of calling `exif` for each file in the folder.
 
 ```javascript
-// REM : default buffer value is 200*1024
-exif(file, { maxBuffer: 1024*1024 }, function(err, obj) {
+var exif = require('exif2');
+var path = 'test/fixtures/';
+var exifParams = ['-FileName', '-ImageWidth', '-ImageHeight', '-Orientation',
+  '-DateTimeOriginal', '-CreateDate', '-ModifyDate', '-FileAccessDate',
+  '-FileType', '-MIMEType'];
+
+exif(file, exifParams,  function(err, metadata){
+  console.log(metadata[0].['ImageWidth']);  // 900
+  console.log(metadata[0].['ImageHeight']); // 596
+  console.log(metadata[1].['ImageWidth']);  // 3776
+  console.log(metadata[1].['ImageHeight']); // 3129
+
+}
+```
+Result:
+```json
+[{
+	"SourceFile": "test/fixtures/forest.jpeg",
+    "FileName": "forest.jpeg",
+	"ImageWidth": 900,
+	"ImageHeight": 596,
+    "Orientation": "Horizontal (normal)",
+	"DateTimeOriginal": "2012:10:07 11:36:30",
+    "CreateDate": "2012:10:07 11:36:30",
+    "ModifyDate": "2012:10:08 19:10:63",
+	"FileAccessDate": "2014:03:24 15:27:05+01:00",
+	"FileType": "JPEG",
+	"MIMEType": "image/jpeg"
+},
+{
+    "SourceFile": "test/fixtures/le_livre_de_photographies_vol_III_Phaidon.jpg",
+    "FileName": "le_livre_de_photographies_vol_III_Phaidon.jpg",
+    "ImageWidth": 3776,
+    "ImageHeight": 3129,
+    "Orientation": "Horizontal (normal)",
+    "CreateDate": "2014:01:09 12:52:13+01:00",
+    "ModifyDate": "2014:01:09 15:36:23",
+    "FileAccessDate": "2016:10:31 16:24:05+01:00",
+    "FileType": "JPEG",
+    "MIMEType": "image/jpeg"
+}]
+```
+### No more known buffer limitation
+
+Since this version uses `child_process.spawn()` instead of
+`child_process.exec()`, the output is handled in a different way, avoiding
+buffer limitations.
+
+See [child_process.spawn](https://nodejs.org/api/child_process
+      .html#child_process_child_process_spawn_command_args_options)
+
+### Special execution
+For special cases, it is possible to provide options for the [spawn process]
+(https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options).
+`exif()` optional third parameter may be an `spawn()` option object as
+described here:
+
+```javascript
+var opts = { cwd: undefined, env: process.env };
+exif(file, args, opts, function(err, obj) {
   console.log(obj);
 })
+
 ```
 
 ## Test / contribute

index.js

@@ -3,37 +3,67 @@
  * Module dependencies.
  */
 
-var exec = require('child_process').exec;
-var command = require('shelly');
+const spawn = require('child_process').spawn;
+var shelly = require('shelly');
 
 /**
  * Fetch EXIF data from `file` and invoke `fn(err, data)`.
  *
  * @param {String} file
- * @param {Object} execOpts [optional] options to pass to exec() for a finer control
+ * @param {Array} args [optional] List of string arguments to pass to exiftool
  * @param {Function} fn
  * @api public
  */
 
-module.exports = function(file, execOpts, fn){
+/**
+ * Fetch EXIF data from `file` and invoke `fn(err, data)`. It spawns a child
+ * process (see child_process.spawn) and executes exiftool
+ * http://www.sno.phy.queensu.ca/%7Ephil/exiftool/
+ *
+ * @param {String} file
+ * @param {Array} args [optional] List of string arguments to pass to
+ * exiftool http://www.sno.phy.queensu.ca/~phil/exiftool/exiftool_pod.html
+ * @param {Object} opts [optional] Object that is passed to the
+ * child_process.spawn method as the `options` argument
+ * See options of child_process.spawn:
+ * https://nodejs.org/api/child_process.html#child_process_child_process_spawn_command_args_options
+ * @param {function} fn callback function to invoke `fn(err, data)`
+ */
+module.exports = function(file, args, opts, fn){
   // rationalize options
-  if(typeof execOpts === 'function') {
-    fn = execOpts;
-    execOpts = {};
+  if (typeof args === 'function') {
+    fn = args;
+    args = [];
+    opts = {};
+  } else if (typeof opts === 'function') {
+    fn = opts;
+    opts = {};
   }
+  args = args || [];
+
+  file = shelly(file);
   // REM : exiftool options http://www.sno.phy.queensu.ca/~phil/exiftool/exiftool_pod.html
   // -json : ask JSON output
-  var cmd = command('exiftool -json ?', file);
-  exec(cmd, execOpts, function(err, str)
-  {
-    if(err) {
-      if(err.message === 'stdout maxBuffer exceeded.')
-        err = new Error('Metadata too big !'); // convert to a clearer message
-      return fn(err);
-    }
+  var cmdArgs = ['-json', file].concat(args);
+  var stdout = '';
+  var exif = spawn('exiftool', cmdArgs , opts);
 
-    var obj = JSON.parse(str)[0]; // so easy
+  exif.stdout.on('data',  function (data) {
+    stdout += String(data);
+  });
+
+  exif.on('error', function (error) {
+    return fn(error);
+  });
 
-    fn(null, obj);
+  exif.on('close', function (code)  {
+    if (code === 0) {
+      var obj = JSON.parse(stdout); // so easy
+      return fn(null, obj.length > 1 ? obj : obj[0]); // array if multiple files
+    }
+    else {
+      // http://www.tldp.org/LDP/abs/html/exitcodes.html#EXITCODESREF
+      return fn('Command closed unexpectedly, Exit Status Code: ' + code);
+    }
   });
 };

package.json

@@ -1,6 +1,6 @@
 {
   "name": "exif2",
-  "version": "1.1.0",
+  "version": "1.3.0",
   "description": "EXIF extraction with exiftool",
   "keywords": [],
   "author": "TJ Holowaychuk <tj@vision-media.ca>",
@@ -20,5 +20,15 @@
   "scripts": {
     "test": "mocha test/index.js --reporter spec",
     "bench": "matcha bench/index.js"
-  }
+  },
+  "contributors": [
+    {
+      "name": "Yves-Emmanuel Jutard",
+      "email": "ye.jutard@gmail.com"
+    },
+    {
+      "name": "Jesús Muñoz Alcántara",
+      "email": "jmunoza@live.com"
+    }
+  ]
 }

test/index.js

@@ -5,7 +5,7 @@ var chai = require('chai');
 var expect = chai.expect;
 chai.config.includeStack = true; // defaults to false
 
-describe('exif(file, fn)', function(){
+describe('exif(file[, args, opts,] fn)', function(){
 
   it('respond with EXIF json data', function(done){
     exif('test/fixtures/forest.jpeg', function(err, data){
@@ -25,24 +25,62 @@ describe('exif(file, fn)', function(){
     });
   });
 
-  it('handles too big metadata with a clear error message', function(done){
+  it('extracts specific EXIF data defined in arguments', function(done){
+    exif('test/fixtures/forest.jpeg', ['-d', '\'%r %a, %B %e, %Y\'', '-DateTimeOriginal',
+      '-S', '-s'], function(err, data) {
+      if (err) return done(err);
+      expect(data, 'DateTimeOriginal').to.have.property('DateTimeOriginal', '\'11:36:30 AM Sun, October  7, 2012\'');
+      done();
+    });
+  });
+
+  it('handles too big metadata without buffer errors', function(done){
     // real case taken from :
     // http://fr.phaidon.com/store/photography/le-livre-de-photographies-une-histoire-vol-3-9780714867755/
-    exif('test/fixtures/le_livre_de_photographies_vol_III_Phaidon.jpg', function(err){
-      expect( err ).to.be.an.instanceof(Error);
-      expect( err ).to.have.property('message', 'Metadata too big !');
+    exif('test/fixtures/le_livre_de_photographies_vol_III_Phaidon.jpg', function(err, data){
+      if(err) return done(err);
+      expect(data).to.have.property('YCbCrSubSampling', 'YCbCr4:4:4 (1 1)');
+      done();
+    });
+  });
+
+  it('handles all media files contained in the folder at once', function(done){
+    exif('test/fixtures/', function(err, data) {
+      if (err) return done(err);
+      expect(data[0], 'FileName').to.have.property('FileName', 'forest.jpeg');
+      expect(data[1], 'FileName').to.have.property('FileName', 'le_livre_de_photographies_vol_III_Phaidon.jpg');
       done();
     });
   });
 
-  it('allows handling huge metadatas through special options', function(done){
-    // we use the special exec option to ease limitations
-    exif('test/fixtures/le_livre_de_photographies_vol_III_Phaidon.jpg', {
-      maxBuffer: 1024*1024
-    },
+  it('handles all media files contained in the path plus arguments', function(done){
+    exif('test/fixtures/', ['-common'], function(err, data) {
+      if (err) return done(err);
+      expect(data[0], 'Model').to.have.property('Model', 'NIKON D7000');
+      expect(data[1], 'ImageSize').to.have.property('ImageSize', '3129x3776');
+      done();
+    });
+  });
+
+  it('get specified info from all media files contained in the path', function(done){
+    exif('test/fixtures/', ['-ExifImageWidth', '-Megapixels'], function(err, data) {
+      if (err) return done(err);
+      expect(data[0], 'ExifImageWidth').to.have.property('ExifImageWidth', 1971);
+      expect(data[0], 'Megapixels').to.have.property('Megapixels', 0.536);
+      expect(data[0], 'ExifImageHeight').to.not.have.property('ExifImageHeight');
+      expect(data[1], 'ExifImageWidth').to.have.property('ExifImageWidth', 3129);
+      expect(data[1], 'Megapixels').to.have.property('Megapixels', 11.8);
+      expect(data[1], 'ExifImageHeight').to.not.have.property('ExifImageHeight');
+      done();
+    });
+  });
+
+  it('handles all media files in path plus arguments plus spawn options', function(done){
+    exif('test/fixtures/', ['-common'], { cwd: undefined, env: process.env },
     function(err, data) {
       if (err) return done(err);
-      expect(data).to.have.property('YCbCrSubSampling', 'YCbCr4:4:4 (1 1)');
+      expect(data[0], 'Model').to.have.property('Model', 'NIKON D7000');
+      expect(data[1], 'ImageSize').to.have.property('ImageSize', '3129x3776');
       done();
     });
   });