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| author | Denis Vlasenko <vda.linux@googlemail.com> | 2007-02-11 14:52:07 +0000 |
|---|---|---|
| committer | Denis Vlasenko <vda.linux@googlemail.com> | 2007-02-11 14:52:07 +0000 |
| commit | 136f42f503cb3e9588e62332d043e92b7475ec4e (patch) | |
| tree | 81c556d1a136112be07bbd2c19293e65fad03cdd /docs/cgi/out.html | |
| parent | ad67a3925c78e7c9f8e61248f640c5cc7a5cf186 (diff) | |
| download | busybox-w32-136f42f503cb3e9588e62332d043e92b7475ec4e.tar.gz busybox-w32-136f42f503cb3e9588e62332d043e92b7475ec4e.tar.bz2 busybox-w32-136f42f503cb3e9588e62332d043e92b7475ec4e.zip | |
Add CGI docs
Diffstat (limited to 'docs/cgi/out.html')
| -rw-r--r-- | docs/cgi/out.html | 126 |
1 files changed, 126 insertions, 0 deletions
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| 1 | <html><head><title>CGI Script output</title></head><body><h1><img alt="" src="out_files/CGIlogo.gif"> CGI Script Output</h1> | ||
| 2 | <hr> | ||
| 3 | |||
| 4 | <h2>Script output</h2> | ||
| 5 | |||
| 6 | The script sends its output to stdout. This output can either be a | ||
| 7 | document generated by the script, or instructions to the server for | ||
| 8 | retrieving the desired output. <p> | ||
| 9 | </p><hr> | ||
| 10 | |||
| 11 | <h2>Script naming conventions</h2> | ||
| 12 | |||
| 13 | Normally, scripts produce output which is interpreted and sent back to | ||
| 14 | the client. An advantage of this is that the scripts do not need to | ||
| 15 | send a full HTTP/1.0 header for every request. <p> | ||
| 16 | <a name="nph"> | ||
| 17 | Some scripts may want to avoid the extra overhead of the server | ||
| 18 | parsing their output, and talk directly to the client. In order to | ||
| 19 | distinguish these scripts from the other scripts, CGI requires that | ||
| 20 | the script name begins with nph- if a script does not want the server | ||
| 21 | to parse its header. In this case, it is the script's responsibility | ||
| 22 | to return a valid HTTP/1.0 (or HTTP/0.9) response to the client. </a></p><p> | ||
| 23 | |||
| 24 | </p><hr> | ||
| 25 | <h2><a name="nph">Parsed headers</a></h2> | ||
| 26 | |||
| 27 | <a name="nph">The output of scripts begins with a small header. This header consists | ||
| 28 | of text lines, in the same format as an </a><a href="http://www.w3.org/hypertext/WWW/Protocols/HTTP/Object_Headers.html"> | ||
| 29 | HTTP header</a>, terminated by a blank line (a line with only a | ||
| 30 | linefeed or CR/LF). <p> | ||
| 31 | |||
| 32 | Any headers which are not server directives are sent directly back to | ||
| 33 | the client. Currently, this specification defines three server | ||
| 34 | directives:</p><p> | ||
| 35 | |||
| 36 | </p><ul> | ||
| 37 | <li> <code>Content-type</code> <p> | ||
| 38 | |||
| 39 | This is the MIME type of the document you are returning. </p><p> | ||
| 40 | |||
| 41 | </p></li><li> <code>Location</code> <p> | ||
| 42 | |||
| 43 | This is used to specify to the server that you are returning a | ||
| 44 | reference to a document rather than an actual document. </p><p> | ||
| 45 | |||
| 46 | If the argument to this is a URL, the server will issue a redirect | ||
| 47 | to the client. </p><p> | ||
| 48 | |||
| 49 | If the argument to this is a virtual path, the server will | ||
| 50 | retrieve the document specified as if the client had requested | ||
| 51 | that document originally. ? directives will work in here, but # | ||
| 52 | directives must be redirected back to the client.</p><p> | ||
| 53 | |||
| 54 | |||
| 55 | </p></li><li> <a name="status"><code>Status</code></a><p> | ||
| 56 | |||
| 57 | This is used to give the server an HTTP/1.0 <a href="http://www.w3.org/hypertext/WWW/Protocols/HTTP/HTRESP.html">status | ||
| 58 | line</a> to send to the client. The format is <code>nnn xxxxx</code>, | ||
| 59 | where <code>nnn</code> is the 3-digit status code, and | ||
| 60 | <code>xxxxx</code> is the reason string, such as "Forbidden".</p><p> | ||
| 61 | |||
| 62 | </p></li></ul> | ||
| 63 | |||
| 64 | <hr> | ||
| 65 | <h2>Examples</h2> | ||
| 66 | |||
| 67 | Let's say I have a fromgratz to HTML converter. When my converter is | ||
| 68 | finished with its work, it will output the following on stdout (note | ||
| 69 | that the lines beginning and ending with --- are just for illustration | ||
| 70 | and would not be output): <p> | ||
| 71 | |||
| 72 | </p><pre>--- start of output --- | ||
| 73 | Content-type: text/html | ||
| 74 | |||
| 75 | --- end of output --- | ||
| 76 | </pre> | ||
| 77 | |||
| 78 | Note the blank line after Content-type. <p> | ||
| 79 | |||
| 80 | Now, let's say I have a script which, in certain instances, wants to | ||
| 81 | return the document <code>/path/doc.txt</code> from this server just | ||
| 82 | as if the user had actually requested | ||
| 83 | <code>http://server:port/path/doc.txt</code> to begin with. In this | ||
| 84 | case, the script would output: </p><p> | ||
| 85 | </p><pre>--- start of output --- | ||
| 86 | Location: /path/doc.txt | ||
| 87 | |||
| 88 | --- end of output --- | ||
| 89 | </pre> | ||
| 90 | |||
| 91 | The server would then perform the request and send it to the client. | ||
| 92 | <p> | ||
| 93 | |||
| 94 | Let's say that I have a script which wants to reference our gopher | ||
| 95 | server. In this case, if the script wanted to refer the user to | ||
| 96 | <code>gopher://gopher.ncsa.uiuc.edu/</code>, it would output: </p><p> | ||
| 97 | |||
| 98 | </p><pre>--- start of output --- | ||
| 99 | Location: gopher://gopher.ncsa.uiuc.edu/ | ||
| 100 | |||
| 101 | --- end of output --- | ||
| 102 | </pre> | ||
| 103 | |||
| 104 | Finally, I have a script which wants to talk to the client directly. | ||
| 105 | In this case, if the script is referenced with <a href="http://hoohoo.ncsa.uiuc.edu/cgi/env.html#protocol"><code>SERVER_PROTOCOL</code></a> of HTTP/1.0, | ||
| 106 | the script would output the following HTTP/1.0 response: <p> | ||
| 107 | |||
| 108 | </p><pre>--- start of output --- | ||
| 109 | HTTP/1.0 200 OK | ||
| 110 | Server: NCSA/1.0a6 | ||
| 111 | Content-type: text/plain | ||
| 112 | |||
| 113 | This is a plaintext document generated on the fly just for you. | ||
| 114 | |||
| 115 | --- end of output --- | ||
| 116 | </pre> | ||
| 117 | |||
| 118 | |||
| 119 | <hr> | ||
| 120 | |||
| 121 | <a href="http://hoohoo.ncsa.uiuc.edu/cgi/interface.html"><img alt="[Back]" src="out_files/back.gif">Return to the | ||
| 122 | interface specification</a> <p> | ||
| 123 | |||
| 124 | CGI - Common Gateway Interface | ||
| 125 | </p><address><a href="http://hoohoo.ncsa.uiuc.edu/cgi/mailtocgi.html">cgi@ncsa.uiuc.edu</a></address> | ||
| 126 | </body></html> \ No newline at end of file | ||