Nginx+memcached produces odd Quotation mark!

When I tried to use nginx and memcached module,
the output always had a odd quotation mark
before the cached content.

I have tried nginx/0.6.32 and nginx 0.5.34
I used:
ruby 1.8.7 (2008-06-20 patchlevel 22) [i686-linux] and
ruby 1.8.7 (2008-06-20 patchlevel 22) [i686-darwin9]
with
memcached 1.2.5
libmemcached 0.22
memcached gem 0.11
or
memcached-client 1.5.0

here is my nginx conf file:
worker_processes 1;
pid /www/logs/nginx.pid;
events {
worker_connections 1024;
}
http {
server {
listen 80;
server_name localhost;
location / {
default_type text/html;
set $memcached_key $uri;
memcached_pass localhost:11211;
}
}
}

after I setup a cache:
irb(main):002:0> require ‘memcached’
=> true
irb(main):003:0> c = Memcached.new(‘localhost:11211’)
#…
irb(main):006:0> c.set ‘/test’, ‘hello’

when I opened 127.0.0.1/test with safari 3.0 or
Firefox 3, I didn’t get
hello
but:
"hello

I get no idea where the Quotation mark coming from!!!
Can anyone tell me how to fix it?

if you run memcached in verbose mode “memcached -vv” does it display
the quote upon retrieving the key?

I started memcached with “memcached -vv”, I saw no cache content being
shown:
memcached -vv
slab class 1: chunk size 88 perslab 11915

slab class 39: chunk size 489032 perslab 2
<6 server listening
<7 send buffer was 105472, now 268435456
<7 server listening (udp)
<8 new client connection
<8 get /test

8 END
<8 connection closed.
<8 new client connection
<8 get /favicon.ico
8 END
<8 connection closed.
<8 new client connection
<8 set /test 0 0 9
8 STORED
<9 new client connection
<9 get /test
9 sending key /test
9 END
<9 connection closed.

But I noticed an interesting thing: ‘/favicon.ico’ was requested now and
then. Do you think it may cause the problem?

I have just modified the nginx conf file and restarted nginx to filter
all
/favicon.ico request.worker_processes 1;
pid /www/logs/nginx.pid;
events {
worker_connections 1024;
}
http {
server {
listen 80;
server_name localhost;
#access_log /www/logs/loc.access.log;
location / {
default_type text/html;
set $memcached_key $uri;
memcached_pass localhost:11211;
}

    location /favicon.ico {
       root /www/loc/public/images;
    }


}

}

But the quotation mark didn’t go away.