Added support for stream-like downloads of existing files to force_download()

Based on code/ideas from PR #365, #1254

2 files changed, 11 insertions, 7 deletions

diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 6047f1c9c..e523c4cab 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -77,8 +77,10 @@ Release Date: Not Released
    -  :doc:`Inflector Helper <helpers/inflector_helper>` changes include:
 	 - Changed :php:func:`humanize()` to allow passing an input separator as its second parameter.
 	 - Refactored :php:func:`plural()` and :php:func:`singular()` to avoid double pluralization and support more words.
-   -  Added an optional third parameter to ``force_download()`` that enables/disables sending the actual file MIME type in the Content-Type header (disabled by default).
-   -  Added a work-around in ``force_download()`` for a bug Android <= 2.1, where the filename extension needs to be in uppercase.
+   -  :doc:`Download Helper <helpers/download_helper>` changes include:
+	 - Added an optional third parameter to :php:func:`force_download()` that enables/disables sending the actual file MIME type in the Content-Type header (disabled by default).
+	 - Added a work-around in :php:func:`force_download()` for a bug Android <= 2.1, where the filename extension needs to be in uppercase.
+	 - Added support for reading from an existing file path by passing NULL as the second parameter to :php:func:`force_download()` (useful for large files and/or safely transmitting binary data).
    -  :doc:`Form Helper <helpers/form_helper>` changes include:
 	 - :php:func:`form_dropdown()` will now also take an array for unity with other form helpers.
 	 - :php:func:`form_prep()`'s second argument now only accepts a boolean value, which determines whether the value is escaped for a <textarea> or a regular <input> element.
diff --git a/user_guide_src/source/helpers/download_helper.rst b/user_guide_src/source/helpers/download_helper.rst
index 1e9ec21ea..860c568b9 100644
--- a/user_guide_src/source/helpers/download_helper.rst
+++ b/user_guide_src/source/helpers/download_helper.rst
@@ -21,7 +21,7 @@ force_download()
 .. php:function:: force_download($filename = '', $data = '', $set_mime = FALSE)
 
 	:param	string	$filename: Filename
-	:param	string	$data: File contents
+	:param	mixed	$data: File contents
 	:param	bool	$set_mime: Whether to try to send the actual MIME type
 	:returns:	void
 
@@ -30,6 +30,9 @@ desktop. Useful with file downloads. The first parameter is the **name
 you want the downloaded file to be named**, the second parameter is the
 file data.
 
+If you set the second parameter to NULL and ``$filename`` is an existing, readable
+file path, then its content will be read instead.
+
 If you set the third parameter to boolean TRUE, then the actual file MIME type
 (based on the filename extension) will be sent, so that if your browser has a
 handler for that type - it can use it.
@@ -41,8 +44,7 @@ Example::
 	force_download($name, $data);
 
 If you want to download an existing file from your server you'll need to
-read the file into a string::
+do the following::
 
-	$data = file_get_contents('/path/to/photo.jpg'); // Read the file's contents
-	$name = 'myphoto.jpg';
-	force_download($name, $data);
\ No newline at end of file
+	// Contents of photo.jpg will be automatically read
+	force_download('/path/to/photo.jpg', NULL);
\ No newline at end of file