storage: support file.compose - fixes #401

Author: stephenplusplus

lib/common/util.js

@@ -208,6 +208,52 @@ function getType(value) {
   return Object.prototype.toString.call(value).match(/\s(\w+)\]/)[1];
 }
 
+/**
+ * Used in an Array iterator usually, this will return the value of a property
+ * in an object by its name.
+ *
+ * @param {string} name - Name of the property to return.
+ * @return {function}
+ *
+ * @example
+ * var people = [
+ *   {
+ *     name: 'Stephen',
+ *     origin: 'USA',
+ *     beenToNYC: false
+ *   },
+ *   {
+ *     name: 'Ryan',
+ *     origin: 'Canada',
+ *     beenToNYC: true
+ *   }
+ * ];
+ *
+ * var names = people.map(prop('name'));
+ * // [
+ * //   'Stephen',
+ * //   'Ryan'
+ * // ]
+ *
+ * var peopleInUSA = people.filter(prop('beenToNYC'));
+ * // [
+ * //   {
+ * //     name: 'Ryan',
+ * //     origin: 'Canada',
+ * //     beenToNYC: true
+ * //   }
+ * // ]
+ */
+function prop(name) {
+  return function(item) {
+    if (name in item) {
+      return item[name];
+    }
+  };
+}
+
+module.exports.prop = prop;
+
 /**
  * Assign a value to a property in an Array iterator.
  *

lib/storage/bucket.js

@@ -202,6 +202,100 @@ function Bucket(storage, name) {
   /* jshint ignore:end */
 }
 
+/**
+ * Combine mutliple files into one new file.
+ *
+ * @throws if a non-array is provided as sources argument.
+ * @throws if less than two sources are provided.
+ * @throws if no destination is provided.
+ * @throws if a content type cannot be determined for the destination file.
+ *
+ * @param {string[]|module:storage/file[]} sources - The source files that will
+ *     be combined.
+ * @param {string|module:storage/file} destination - The file you would like the
+ *     source files combined into.
+ * @param {function=} callback - The callback function.
+ *
+ * @example
+ * var 2013logs = bucket.file('2013-logs.txt');
+ * var 2014logs = bucket.file('2014-logs.txt');
+ *
+ * var allLogs = bucket.file('all-logs.txt');
+ *
+ * bucket.combine([
+ *   2013logs,
+ *   2014logs
+ * ], allLogs, function(err, newFile) {
+ *   // newFile === allLogs
+ * });
+ */
+Bucket.prototype.combine = function(sources, destination, callback) {
+  if (!util.is(sources, 'array') || sources.length < 2) {
+    throw new Error('You must provide at least two source files.');
+  }
+
+  if (!destination) {
+    throw new Error('A destination file must be specified.');
+  }
+
+  var self = this;
+
+  sources = sources.map(convertToFile);
+  destination = convertToFile(destination);
+  callback = callback || util.noop;
+
+  if (!destination.metadata.contentType) {
+    var destinationContentType = mime.contentType(destination.name);
+
+    if (destinationContentType) {
+      destination.metadata.contentType = destinationContentType;
+    } else {
+      throw new Error(
+        'A content type could not be detected for the destination file.');
+    }
+  }
+
+  this.storage.makeAuthorizedRequest_({
+    method: 'POST',
+    uri: util.format('{base}/{destBucket}/o/{destFile}/compose', {
+      base: STORAGE_BASE_URL,
+      destBucket: destination.bucket.name,
+      destFile: encodeURIComponent(destination.name)
+    }),
+    json: {
+      destination: {
+        contentType: destination.metadata.contentType
+      },
+      sourceObjects: sources.map(function (source) {
+        var sourceObject = {
+          name: source.name
+        };
+
+        if (source.metadata && source.metadata.generation) {
+          sourceObject.generation = source.metadata.generation;
+        }
+
+        return sourceObject;
+      })
+    }
+  }, function(err) {
+    if (err) {
+      callback(err);
+      return;
+    }
+
+    callback(null, destination);
+  });
+
+  function convertToFile(file) {
+    if (file instanceof File) {
+      return file;
+    } else {
+      return self.file(file);
+    }
+  }
+};
+
 /**
  * Delete the bucket.
  *

regression/storage.js

@@ -25,8 +25,11 @@ var fs = require('fs');
 var request = require('request');
 var through = require('through2');
 var tmp = require('tmp');
+var util = require('../lib/common/util');
 var uuid = require('node-uuid');
 
+var prop = util.prop;
+
 var env = require('./env.js');
 var storage = require('../lib/storage')(env);
 
@@ -47,12 +50,14 @@ function deleteFiles(bucket, callback) {
       callback(err);
       return;
     }
-    async.map(files, function(file, next) {
-      file.delete(next);
-    }, callback);
+    async.map(files, deleteFile, callback);
   });
 }
 
+function deleteFile(file, callback) {
+  file.delete(callback);
+}
+
 function generateBucketName() {
   return 'gcloud-test-bucket-temp-' + uuid.v1();
 }
@@ -493,6 +498,41 @@ describe('storage', function() {
     });
   });
 
+  describe('combine files', function() {
+    it('should combine multiple files into one', function(done) {
+      var files = [
+        { file: bucket.file('file-one.txt'), contents: '123' },
+        { file: bucket.file('file-two.txt'), contents: '456' }
+      ];
+
+      async.each(files, createFile, function(err) {
+        assert.ifError(err);
+
+        var sourceFiles = files.map(prop('file'));
+        var destinationFile = bucket.file('file-one-and-two.txt');
+
+        bucket.combine(sourceFiles, destinationFile, function(err) {
+          assert.ifError(err);
+
+          destinationFile.download(function(err, contents) {
+            assert.ifError(err);
+
+            assert.equal(contents, files.map(prop('contents')).join(''));
+
+            async.each(sourceFiles.concat([destinationFile]), deleteFile, done);
+          });
+        });
+      });
+
+      function createFile(fileObject, cb) {
+        var ws = fileObject.file.createWriteStream();
+        ws.on('error', cb);
+        ws.on('complete', cb.bind(null, null));
+        ws.end(fileObject.contents);
+      }
+    });
+  });
+
   describe('list files', function() {
     var filenames = ['CloudLogo1', 'CloudLogo2', 'CloudLogo3'];
 

test/common/util.js

@@ -449,6 +449,18 @@ describe('common/util', function() {
     });
   });
 
+  describe('prop', function() {
+    it('should return objects that match the property name', function() {
+      var people = [
+        { name: 'Stephen', origin: 'USA', beenToNYC: false },
+        { name: 'Ryan', origin: 'Canada', beenToNYC: true }
+      ];
+
+      assert.deepEqual(people.map(util.prop('name')), ['Stephen', 'Ryan']);
+      assert.deepEqual(people.filter(util.prop('beenToNYC')), [people[1]]);
+    });
+  });
+
   describe('propAssign', function() {
     it('should assign a property and value to an object', function() {
       var obj = {};