[HTTP]レンジリクエスト - としきの日記

ヘッダフィールドRangeで指定すると、範囲を指定して一部分だけリクエストを送れます。
telnetで接続して試してみます。
まずは普通にリクエストを送ってみます。

$ telnet localhost 80
Trying ::1...
Connected to localhost.
Escape character is '^]'.

GET /test.html HTTP/1.1
Host: localhost

HTTP/1.1 200 OK
Date: Sun, 09 Mar 2008 00:51:52 GMT
Server: Apache/2.2.6 (Unix) mod_ssl/2.2.6 OpenSSL/0.9.7l DAV/2
Content-Location: index.html.en
Vary: negotiate,accept-language,accept-charset
TCN: choice
Last-Modified: Sun, 25 Nov 2007 04:49:49 GMT
ETag: "ee64-5b0-43fb993dbd540;4460bc0daec40"
Accept-Ranges: bytes
Content-Length: 1456
Content-Type: text/html
Content-Language: en

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Test Page for Apache Installation</title>
</head>
<!-- Background white, links blue (unvisited), navy (visited), red
(active) -->
<body bgcolor="#FFFFFF" text="#000000" link="#0000FF"
vlink="#000080" alink="#FF0000">
<p>If you can see this, it means that the installation of the <a
href="http://www.apache.org/foundation/preFAQ.html">Apache web
server</a> software on this system was successful. You may now add
content to this directory and replace this page.</p>

<hr width="50%" size="8" />
<h2 align="center">Seeing this instead of the website you
expected?</h2>

<p>This page is here because the site administrator has changed the
configuration of this web server. Please <strong>contact the person
responsible for maintaining this server with questions.</strong>
The Apache Software Foundation, which wrote the web server software
this site administrator is using, has nothing to do with
maintaining this site and cannot help resolve configuration
issues.</p>

</body>
</html>

Connection closed by foreign host.

次に、範囲を指定してリクエストを送ります。
Range:bytes=201-500で、リソースの201バイトから500バイトのバイトレンジだけリクエストします。

$ telnet localhost 80                             
Trying ::1...
Connected to localhost.
Escape character is '^]'.

GET /test.html HTTP/1.1
Host: localhost
Range:bytes=201-500

HTTP/1.1 206 Partial Content
Date: Sun, 09 Mar 2008 01:08:36 GMT
Server: Apache/2.2.6 (Unix) mod_ssl/2.2.6 OpenSSL/0.9.7l DAV/2
Content-Location: index.html.en
Vary: negotiate,accept-language,accept-charset
TCN: choice
Last-Modified: Sun, 25 Nov 2007 04:49:49 GMT
ETag: "ee64-5b0-43fb993dbd540;4460bc0daec40"
Accept-Ranges: bytes
Content-Length: 300
Content-Range: bytes 201-500/1456
Content-Type: text/html
Content-Language: en

che Installation</title>
</head>
<!-- Background white, links blue (unvisited), navy (visited), red
(active) -->
<body bgcolor="#FFFFFF" text="#000000" link="#0000FF"
vlink="#000080" alink="#FF0000">
<p>If you can see this, it means that the installation of the <a
href="http://www.apache.org/foundatConnection closed by foreign host.

レンジリクエストに対するレスポンスはステータスコード206 Partial Contentが返ります。
また、サーバがレンジリクエストに対応していない場合、ステータスコード200 OK のレスポンスで完全なエンティティが返されます。

Range:で指定する範囲ですが、Range:bytes=201- とすると201バイトより後をすべてを要求し、
Range:bytes=-200, 301-400とすると、200バイトまでと301バイトから400バイトまでの複数の範囲を要求できます。