Retrieve and edit a text/uri-list

gistfile1.txt

GET /favorites HTTP/1.1
User-Agent: curl/7.16.4 (i386-apple-darwin9.0) libcurl/7.16.4 OpenSSL/0.9.7l zlib/1.2.3
Host: www.example.com
Accept: text/uri-list;q=1.0, */*;q=0.9

...

HTTP/1.1 200 OK
Date: Mon, 16 Jul 2012 10:38:12 GMT
Content-Type: text/uri-list; charset=utf-8
Server: Apache/2.4.1 (Unix) OpenSSL/1.0.0g
ETag: "7ca4cd3a3b2dc09e389e1b89568428be"
Content-Length: 228

http://www.example.com/raindrops-on-roses
ftp://www.example.com/sleighbells
http://www.example.com/crisp-apple-strudel
http://www.example.com/doorbells
tag:foo@example.com,2012-07-01:bright-copper-kettles
urn:isbn:0-061-99881-8

...

PATCH /favorites HTTP/1.1
User-Agent: curl/7.16.4 (i386-apple-darwin9.0) libcurl/7.16.4 OpenSSL/0.9.7l zlib/1.2.3
Host: www.example.com
Accept: text/uri-list;q=1.0, */*;q=0.9
Content-Type: text/diff; charset=utf-8
Content-Length: 243
If-Match: "7ca4cd3a3b2dc09e389e1b89568428be"

--- favs.txt	2012-07-16 06:45:59.000000000 -0400
+++ favs-new.txt	2012-07-16 06:49:52.000000000 -0400
@@ -3,2 +3,3 @@
 http://www.example.com/crisp-apple-strudel
+http://www.example.com/schnitzel-with-noodles
 http://www.example.com/doorbells

...

HTTP/1.1 200 OK
Date: Mon, 16 Jul 2012 10:38:15 GMT
Content-Type: text/uri-list; charset=utf-8
Server: Apache/2.4.1 (Unix) OpenSSL/1.0.0g
ETag: "30bd0f03380afd045e00e570df810881"
Content-Length: 274

http://www.example.com/raindrops-on-roses
ftp://www.example.com/sleighbells
http://www.example.com/crisp-apple-strudel
http://www.example.com/schnitzel-with-noodles
http://www.example.com/doorbells
tag:foo@example.com,2012-07-01:bright-copper-kettles
urn:isbn:0-061-99881-8