135 lines
4.8 KiB
TeX
135 lines
4.8 KiB
TeX
\section{Overview}\label{sec:intro}
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\subsection{What's in sunet?}
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The Scheme Underground Network Package contains a set of libraries for
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doing Net hacking from Scheme/scsh. It includes:
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\begin{description}
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\item{An smtp client library.}\\
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Forge mail from the comfort of your own Scheme process.
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\item{rfc822 header library}\\
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Read email-style headers. Useful in several contexts (smtp, http,
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etc.)
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\item{Simple structured HTML output library} \\
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Balanced delimiters, etc.
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\item{The SU Web server}\\
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This is a complete implementation of an HTTP 1.0 server in Scheme.
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The server contains other standalone packages that may separately be
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of use:
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\begin{itemize}
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\item URI and URL parsers and unparsers.
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\item A library to help writing CGI scripts in Scheme.
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\item Server extensions for interfacing to CGI scripts.
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\item Server extensions for uploading Scheme code.
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\end{itemize}
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The server has three main design goals:
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\begin{description}
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\item{Extensibility}\\
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The server is in fact nothing but extensions, using a mechanism
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called ``path handlers'' to define URL-specific services. It has a
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toolkit of services that can be used as-is, extended or built
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upon. User extensions have exactly the same status as the base
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services.
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The extension mechanism allows for easy implementation of new
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services without the overhead of the CGI interface. Since the
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server is written on top of the Scheme shell, the full set of Unix
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system calls and program tools is available to the implementor.
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\item{Mobile code}\\
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The server allows Scheme code to be uploaded for direct execution
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inside the server. The server has complete control over the code,
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and can safely execute it in restricted environments that do not
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provide access to potentially dangerous primitives (such as the
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``delete file'' procedure.)
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\item{Clarity}\\
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I\footnote{That's Olin Shivers (\ex{shivers@ai.mit.edu},
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\ex{http://www.\ob{}ai.\ob{}mit.\ob{}edu/\ob{}people/\ob{}shivers/}).
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For the rest of the documentation, if not mentioned otherwise,
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`I' refers to him.} wrote this server to help myself understand
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the Web. It is voluminously commented, and I hope it will prove to
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be an aid in understanding the low-level details of the Web
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protocols.
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The S.U. server has the ability to upload code from Web clients
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and execute that code on behalf of the client in a protected
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environment.
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Some simple documentation on the server is available.
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\end{description}
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\end{description}
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\subsection{Obtaining the system}
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The network code is available by
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ftp\footnote{\ex{ftp://ftp-swiss.ai.mit.edu/pub/scsh/contrib/net/net.tar.gz}}.
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To run the server, you need our 0.6 release of
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scsh\footnote{http://www.scsh.net}. Beyond actually running the
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server, the separate parser libraries and other utilites may be of use
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as separate modules.
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The sunet package contains following parts:
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%
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\begin{itemize}
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\item Several servers (HTTP, CGI, FTP)
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\item Several clients (to FTP, SMTP, POP3, NTP)
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\item procedures to handle URIs
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\item procedures to handle RFC822 headers
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\item analogue of \verb|ls| for scsh
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\item {\dots}
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\end{itemize}
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\subsection{What is in this docu?}
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%
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Unfortunately not all parts of sunet are documented here. If you miss
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something, have a look in the source files -- they are alle well
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documented (I hope so!).
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Currently the ftp server, the ftp client, the modules containing the
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procedures handling URIs and URLs, the module handling RFC~822
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headers, the netrc package, the save evaluation environment
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\ex{toothless\=eval} and the obsolete library for using strings are
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documented.
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\subsection{How to use the modules}
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%
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% I think it is a good idea to tell the people how to use
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% scsh / sunet as the docu of scsh does not really do this
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% (as long as concerning my experience). Additionally, possible
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% programmers should be introduced how to create own modules,
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% including those in sunet.
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%FIXME
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\FIXME{Does anybody have a good idea how to tell newbies how to use
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the packages? I do not feel capable enough for this.}
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For the time being, it may help to look at the following. Scsh is started
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in the sunet directory. Then, the description file of the modules is
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loaded and the ftp-module is opened (to use a ftp client). After the
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things are done, scsh is finished via the \verb|,exit| command.
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\begin{alltt}
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atari-2600[72] scsh-0.6
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Welcome to scsh 0.6.0 (Chinese Democracy)
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Type ,? for help.
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> ,config ,load modules.scm
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modules.scm
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> ,open ftp
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Load structure ftp (y/n)? y
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[ecm-utilities ecm-utilities.scm]
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[netrc netrc.scm]
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[ftp ftp.scm]
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> ; do something nasty
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> ,exit
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atari-2600[73]
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\end{alltt}
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%%% Local Variables:
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%%% mode: latex
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%%% TeX-master: man
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%%% End:
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