Q:

How to use url-retrieve to download a tar.gz file in Emacs?

I'm using el-get and failed to el-get-install color-theme. After some research I found the file color-theme-6.6.0.tar.gz downloaded by el-get is incomplete. The size of the one downloaded using el-get is 124853, and the size would be 124858 if the file is downloaded by wget.
Then I found el-get is using url-retrieve to downloading packages. So I evaluated this code in *scratch* buffer.
(url-retrieve
 "http://download.savannah.gnu.org/releases/color-theme/color-theme-6.6.0.tar.gz"
 (lambda (s)
   (write-file "/home/jxq/data/tmp")))

The file /home/jxq/data/tmp now contains http header and body. The length of http header is 279 and the whole size is 125132. So the file size of tar.gz it retrieved is 124853. Where are the lost 5 bytes?
Is this a bug in url-retrieve or I'm using it incorrectly?

A:

You need to skip the HTTP headers (the documentation calls them "MIME headers") before writing:
(url-retrieve
 "http://download.savannah.gnu.org/releases/color-theme/color-theme-6.6.0.tar.gz"
 (lambda (s)
   (re-search-forward "\r?\n\r?\n")
   (write-region (point) (point-max) "/tmp/bla")))

This version saves the same contents as Wget.

