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Logical markup.

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Lots of nits in both.
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Fred Drake 1998-03-12 06:52:05 +00:00
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284
Doc/lib/libcgi.tex
View file

@ -7,7 +7,6 @@
\indexii{MIME}{headers}
\index{URL}
\setindexsubitem{(in module cgi)}
Support module for CGI (Common Gateway Interface) scripts.
@ -28,11 +27,11 @@ executes the script, and sends the script's output back to the client.
The script's input is connected to the client too, and sometimes the
form data is read this way; at other times the form data is passed via
the ``query string'' part of the URL. This module (\file{cgi.py}) is intended
the ``query string'' part of the URL. This module is intended
to take care of the different cases and provide a simpler interface to
the Python script. It also provides a number of utilities that help
in debugging scripts, and the latest addition is support for file
uploads from a form (if your browser supports it -- Grail 0.3 and
uploads from a form (if your browser supports it --- Grail 0.3 and
Netscape 2.0 do).
The output of a CGI script should consist of two sections, separated
@ -44,7 +43,7 @@ generate a minimal header section looks like this:
print "Content-type: text/html" # HTML is following
print # blank line, end of headers
\end{verbatim}
%
The second section is usually HTML, which allows the client software
to display nicely formatted text with header, in-line images, etc.
Here's Python code that prints a simple piece of HTML:
@ -54,28 +53,30 @@ print "<TITLE>CGI script output</TITLE>"
print "<H1>This is my first CGI script</H1>"
print "Hello, world!"
\end{verbatim}
%
(It may not be fully legal HTML according to the letter of the
standard, but any browser will understand it.)
\subsection{Using the cgi module}
\nodename{Using the cgi module}
Begin by writing \code{import cgi}. Don't use \code{from cgi import *} -- the
module defines all sorts of names for its own use or for backward
compatibility that you don't want in your namespace.
Begin by writing \samp{import cgi}. Do not use \samp{from cgi import
*} --- the module defines all sorts of names for its own use or for
backward compatibility that you don't want in your namespace.
It's best to use the \code{FieldStorage} class. The other classes define in this
module are provided mostly for backward compatibility. Instantiate it
exactly once, without arguments. This reads the form contents from
standard input or the environment (depending on the value of various
environment variables set according to the CGI standard). Since it may
consume standard input, it should be instantiated only once.
It's best to use the \class{FieldStorage} class. The other classes
defined in this module are provided mostly for backward compatibility.
Instantiate it exactly once, without arguments. This reads the form
contents from standard input or the environment (depending on the
value of various environment variables set according to the CGI
standard). Since it may consume standard input, it should be
instantiated only once.
The \code{FieldStorage} instance can be accessed as if it were a Python
The \class{FieldStorage} instance can be accessed as if it were a Python
dictionary. For instance, the following code (which assumes that the
\code{Content-type} header and blank line have already been printed) checks that
the fields \code{name} and \code{addr} are both set to a non-empty string:
\code{content-type} header and blank line have already been printed)
checks that the fields \code{name} and \code{addr} are both set to a
non-empty string:
\begin{verbatim}
form = cgi.FieldStorage()
@ -89,17 +90,20 @@ if not form_ok:
return
...further form processing here...
\end{verbatim}
%
Here the fields, accessed through \code{form[key]}, are themselves instances
of \code{FieldStorage} (or \code{MiniFieldStorage}, depending on the form encoding).
Here the fields, accessed through \samp{form[\var{key}]}, are
themselves instances of \class{FieldStorage} (or
\class{MiniFieldStorage}, depending on the form encoding).
If the submitted form data contains more than one field with the same
name, the object retrieved by \code{form[key]} is not a \code{(Mini)FieldStorage}
name, the object retrieved by \samp{form[\var{key}]} is not a
\class{FieldStorage} or \class{MiniFieldStorage}
instance but a list of such instances. If you expect this possibility
(i.e., when your HTML form comtains multiple fields with the same
name), use the \code{type()} function to determine whether you have a single
instance or a list of instances. For example, here's code that
concatenates any number of username fields, separated by commas:
name), use the \function{type()} function to determine whether you
have a single instance or a list of instances. For example, here's
code that concatenates any number of username fields, separated by
commas:
\begin{verbatim}
username = form["username"]
@ -117,12 +121,12 @@ else:
# Single username field specified
usernames = username.value
\end{verbatim}
%
If a field represents an uploaded file, the value attribute reads the
entire file in memory as a string. This may not be what you want. You can
test for an uploaded file by testing either the filename attribute or the
file attribute. You can then read the data at leasure from the file
attribute:
If a field represents an uploaded file, the value attribute reads the
entire file in memory as a string. This may not be what you want.
You can test for an uploaded file by testing either the filename
attribute or the file attribute. You can then read the data at
leasure from the file attribute:
\begin{verbatim}
fileitem = form["userfile"]
@ -134,40 +138,40 @@ if fileitem.file:
if not line: break
linecount = linecount + 1
\end{verbatim}
%
The file upload draft standard entertains the possibility of uploading
multiple files from one field (using a recursive \code{multipart/*}
encoding). When this occurs, the item will be a dictionary-like
FieldStorage item. This can be determined by testing its type
attribute, which should have the value \code{multipart/form-data} (or
perhaps another string beginning with \code{multipart/} It this case, it
can be iterated over recursively just like the top-level form object.
When a form is submitted in the ``old'' format (as the query string or as a
single data part of type \code{application/x-www-form-urlencoded}), the items
will actually be instances of the class \code{MiniFieldStorage}. In this case,
the list, file and filename attributes are always \code{None}.
The file upload draft standard entertains the possibility of uploading
multiple files from one field (using a recursive
\mimetype{multipart/*} encoding). When this occurs, the item will be
a dictionary-like \class{FieldStorage} item. This can be determined
by testing its \member{type} attribute, which should be
\mimetype{multipart/form-data} (or perhaps another MIME type matching
\mimetype{multipart/*}). It this case, it can be iterated over
recursively just like the top-level form object.
When a form is submitted in the ``old'' format (as the query string or
as a single data part of type
\mimetype{application/x-www-form-urlencoded}), the items will actually
be instances of the class \class{MiniFieldStorage}. In this case, the
list, file and filename attributes are always \code{None}.
\subsection{Old classes}
These classes, present in earlier versions of the \code{cgi} module, are still
supported for backward compatibility. New applications should use the
FieldStorage class.
These classes, present in earlier versions of the \module{cgi} module,
are still supported for backward compatibility. New applications
should use the \class{FieldStorage} class.
\code{SvFormContentDict}
single value form content as dictionary; assumes each
field name occurs in the form only once.
\class{SvFormContentDict} stores single value form content as
dictionary; it assumes each field name occurs in the form only once.
\code{FormContentDict}
multiple value form content as dictionary (the form
items are lists of values). Useful if your form contains multiple
fields with the same name.
\class{FormContentDict} stores multiple value form content as a
dictionary (the form items are lists of values). Useful if your form
contains multiple fields with the same name.
Other classes (\code{FormContent}, \code{InterpFormContentDict}) are present for
backwards compatibility with really old applications only. If you still
use these and would be inconvenienced when they disappeared from a next
version of this module, drop me a note.
Other classes (\class{FormContent}, \class{InterpFormContentDict}) are
present for backwards compatibility with really old applications only.
If you still use these and would be inconvenienced when they
disappeared from a next version of this module, drop me a note.
\subsection{Functions}
@ -178,78 +182,81 @@ some of the algorithms implemented in this module in other
circumstances.
\begin{funcdesc}{parse}{fp}
Parse a query in the environment or from a file (default \code{sys.stdin}).
Parse a query in the environment or from a file (default
\code{sys.stdin}).
\end{funcdesc}
\begin{funcdesc}{parse_qs}{qs}
parse a query string given as a string argument (data of type
\code{application/x-www-form-urlencoded}).
Parse a query string given as a string argument (data of type
\mimetype{application/x-www-form-urlencoded}).
\end{funcdesc}
\begin{funcdesc}{parse_multipart}{fp\, pdict}
parse input of type \code{multipart/form-data} (for
file uploads). Arguments are \code{fp} for the input file and
\code{pdict} for the dictionary containing other parameters of \code{content-type} header
Parse input of type \mimetype{multipart/form-data} (for
file uploads). Arguments are \var{fp} for the input file and
\var{pdict} for the dictionary containing other parameters of
\code{content-type} header
Returns a dictionary just like \code{parse_qs()}
keys are the field names, each
value is a list of values for that field. This is easy to use but not
much good if you are expecting megabytes to be uploaded -- in that case,
use the \code{FieldStorage} class instead which is much more flexible. Note
that \code{content-type} is the raw, unparsed contents of the \code{content-type}
header.
Returns a dictionary just like \function{parse_qs()} keys are the
field names, each value is a list of values for that field. This is
easy to use but not much good if you are expecting megabytes to be
uploaded --- in that case, use the \class{FieldStorage} class instead
which is much more flexible. Note that \code{content-type} is the
raw, unparsed contents of the \code{content-type} header.
Note that this does not parse nested multipart parts -- use \code{FieldStorage} for
that.
Note that this does not parse nested multipart parts --- use
\class{FieldStorage} for that.
\end{funcdesc}
\begin{funcdesc}{parse_header}{string}
parse a header like \code{Content-type} into a main
Parse a header like \code{content-type} into a main
content-type and a dictionary of parameters.
\end{funcdesc}
\begin{funcdesc}{test}{}
robust test CGI script, usable as main program.
Writes minimal HTTP headers and formats all information provided to
the script in HTML form.
Robust test CGI script, usable as main program.
Writes minimal HTTP headers and formats all information provided to
the script in HTML form.
\end{funcdesc}
\begin{funcdesc}{print_environ}{}
format the shell environment in HTML.
Format the shell environment in HTML.
\end{funcdesc}
\begin{funcdesc}{print_form}{form}
format a form in HTML.
Format a form in HTML.
\end{funcdesc}
\begin{funcdesc}{print_directory}{}
format the current directory in HTML.
Format the current directory in HTML.
\end{funcdesc}
\begin{funcdesc}{print_environ_usage}{}
print a list of useful (used by CGI) environment variables in
Print a list of useful (used by CGI) environment variables in
HTML.
\end{funcdesc}
\begin{funcdesc}{escape}{s\optional{\, quote}}
convert the characters
``\code{\&}'', ``\code{<}'' and ``\code{>}'' in string \var{s} to HTML-safe
sequences. Use this if you need to display text that might contain
such characters in HTML. If the optional flag \var{quote} is true,
the double quote character (\code{"}) is also translated; this helps
for inclusion in an HTML attribute value, e.g. in ``\code{<A HREF="...">}''.
Convert the characters
\character{\&}, \character{<} and \character{>} in string \var{s} to
HTML-safe sequences. Use this if you need to display text that might
contain such characters in HTML. If the optional flag \var{quote} is
true, the double quote character (\character{"}) is also translated;
this helps for inclusion in an HTML attribute value, e.g. in \code{<A
HREF="...">}.
\end{funcdesc}
\subsection{Caring about security}
There's one important rule: if you invoke an external program (e.g.
via the \code{os.system()} or \code{os.popen()} functions), make very sure you don't
pass arbitrary strings received from the client to the shell. This is
a well-known security hole whereby clever hackers anywhere on the web
can exploit a gullible CGI script to invoke arbitrary shell commands.
Even parts of the URL or field names cannot be trusted, since the
request doesn't have to come from your form!
via the \function{os.system()} or \function{os.popen()} functions),
make very sure you don't pass arbitrary strings received from the
client to the shell. This is a well-known security hole whereby
clever hackers anywhere on the web can exploit a gullible CGI script
to invoke arbitrary shell commands. Even parts of the URL or field
names cannot be trusted, since the request doesn't have to come from
your form!
To be on the safe side, if you must pass a string gotten from a form
to a shell command, you should make sure the string contains only
@ -263,27 +270,29 @@ system administrator to find the directory where CGI scripts should be
installed; usually this is in a directory \file{cgi-bin} in the server tree.
Make sure that your script is readable and executable by ``others''; the
\UNIX{} file mode should be 755 (use \code{chmod 755 filename}). Make sure
that the first line of the script contains \code{\#!} starting in column 1
followed by the pathname of the Python interpreter, for instance:
\UNIX{} file mode should be \code{0755} octal (use \samp{chmod 0755
filename}). Make sure that the first line of the script contains
\code{\#!} starting in column 1 followed by the pathname of the Python
interpreter, for instance:
\begin{verbatim}
#!/usr/local/bin/python
\end{verbatim}
%
Make sure the Python interpreter exists and is executable by ``others''.
Make sure that any files your script needs to read or write are
readable or writable, respectively, by ``others'' -- their mode should
be 644 for readable and 666 for writable. This is because, for
security reasons, the HTTP server executes your script as user
``nobody'', without any special privileges. It can only read (write,
execute) files that everybody can read (write, execute). The current
directory at execution time is also different (it is usually the
server's cgi-bin directory) and the set of environment variables is
also different from what you get at login. in particular, don't count
on the shell's search path for executables (\code{\$PATH}) or the Python
module search path (\code{\$PYTHONPATH}) to be set to anything interesting.
readable or writable, respectively, by ``others'' --- their mode
should be \code{0644} for readable and \code{0666} for writable. This
is because, for security reasons, the HTTP server executes your script
as user ``nobody'', without any special privileges. It can only read
(write, execute) files that everybody can read (write, execute). The
current directory at execution time is also different (it is usually
the server's cgi-bin directory) and the set of environment variables
is also different from what you get at login. In particular, don't
count on the shell's search path for executables (\envvar{PATH}) or
the Python module search path (\envvar{PYTHONPATH}) to be set to
anything interesting.
If you need to load modules from a directory which is not on Python's
default module search path, you can change the path in your script,
@ -294,7 +303,7 @@ import sys
sys.path.insert(0, "/usr/home/joe/lib/python")
sys.path.insert(0, "/usr/local/lib/python")
\end{verbatim}
%
(This way, the directory inserted last will be searched first!)
Instructions for non-\UNIX{} systems will vary; check your HTTP server's
@ -312,12 +321,12 @@ execute it at all, and the HTTP server will most likely send a cryptic
error to the client.
Assuming your script has no syntax errors, yet it does not work, you
have no choice but to read the next section:
have no choice but to read the next section.
\subsection{Debugging CGI scripts}
First of all, check for trivial installation errors -- reading the
First of all, check for trivial installation errors --- reading the
section above on installing your CGI script carefully can save you a
lot of time. If you wonder whether you have understood the
installation procedure correctly, try installing a copy of this module
@ -330,7 +339,7 @@ request by entering a URL into your browser of the form:
\begin{verbatim}
http://yourhostname/cgi-bin/cgi.py?name=Joe+Blow&addr=At+Home
\end{verbatim}
%
If this gives an error of type 404, the server cannot find the script
-- perhaps you need to install it in a different directory. If it
gives another error (e.g. 500), there's an installation problem that
@ -341,14 +350,14 @@ and ``name'' with value ``Joe Blow''), the \file{cgi.py} script has been
installed correctly. If you follow the same procedure for your own
script, you should now be able to debug it.
The next step could be to call the \code{cgi} module's \code{test()}
function from your script: replace its main code with the single
statement
The next step could be to call the \module{cgi} module's
\function{test()} function from your script: replace its main code
with the single statement
\begin{verbatim}
cgi.test()
\end{verbatim}
%
This should produce the same results as those gotten from installing
the \file{cgi.py} file itself.
@ -360,22 +369,23 @@ raises an exception, most likely the traceback will end up in one of
the HTTP server's log file, or be discarded altogether.
Fortunately, once you have managed to get your script to execute
*some* code, it is easy to catch exceptions and cause a traceback to
be printed. The \code{test()} function below in this module is an example.
Here are the rules:
\emph{some} code, it is easy to catch exceptions and cause a traceback
to be printed. The \function{test()} function below in this module is
an example. Here are the rules:
\begin{enumerate}
\item Import the traceback module (before entering the
try-except!)
\item Make sure you finish printing the headers and the blank
line early
\item Assign \code{sys.stderr} to \code{sys.stdout}
\item Wrap all remaining code in a try-except statement
\item In the except clause, call \code{traceback.print_exc()}
\item Import the traceback module before entering the \keyword{try}
... \keyword{except} statement
\item Assign \code{sys.stderr} to be \code{sys.stdout}
\item Make sure you finish printing the headers and the blank line
early
\item Wrap all remaining code in a \keyword{try} ... \keyword{except}
statement
\item In the except clause, call \function{traceback.print_exc()}
\end{enumerate}
For example:
@ -392,9 +402,9 @@ except:
print "\n\n<PRE>"
traceback.print_exc()
\end{verbatim}
%
Notes: The assignment to \code{sys.stderr} is needed because the traceback
prints to \code{sys.stderr}.
Notes: The assignment to \code{sys.stderr} is needed because the
traceback prints to \code{sys.stderr}.
The \code{print "{\e}n{\e}n<PRE>"} statement is necessary to
disable the word wrapping in HTML.
@ -409,7 +419,7 @@ print "Content-type: text/plain"
print
...your code here...
\end{verbatim}
%
This relies on the Python interpreter to print the traceback. The
content type of the output is set to plain text, which disables all
HTML processing. If your script works, the raw HTML will be displayed
@ -428,18 +438,18 @@ progress report on the client's display while the script is running.
\item Check the installation instructions above.
\item Check the HTTP server's log files. (\code{tail -f logfile} in a separate
window may be useful!)
\item Check the HTTP server's log files. (\samp{tail -f logfile} in a
separate window may be useful!)
\item Always check a script for syntax errors first, by doing something
like \code{python script.py}.
like \samp{python script.py}.
\item When using any of the debugging techniques, don't forget to add
\code{import sys} to the top of the script.
\samp{import sys} to the top of the script.
\item When invoking external programs, make sure they can be found.
Usually, this means using absolute path names -- \code{\$PATH} is usually not
set to a very useful value in a CGI script.
Usually, this means using absolute path names --- \envvar{PATH} is
usually not set to a very useful value in a CGI script.
\item When reading or writing external files, make sure they can be read
or written by every user on the system.

103
Doc/lib/liburllib.tex
View file

@ -5,59 +5,59 @@
\index{World-Wide Web}
\index{URL}
\setindexsubitem{(in module urllib)}
This module provides a high-level interface for fetching data across
the World-Wide Web. In particular, the \code{urlopen()} function is
similar to the built-in function \code{open()}, but accepts URLs
(Universal Resource Locators) instead of filenames. Some restrictions
apply --- it can only open URLs for reading, and no seek operations
are available.
the World-Wide Web. In particular, the \function{urlopen()} function
is similar to the built-in function \function{open()}, but accepts
Universal Resource Locators (URLs) instead of filenames. Some
restrictions apply --- it can only open URLs for reading, and no seek
operations are available.
It defines the following public functions:
\begin{funcdesc}{urlopen}{url}
Open a network object denoted by a URL for reading. If the URL does
not have a scheme identifier, or if it has \samp{file:} as its scheme
not have a scheme identifier, or if it has \file{file:} as its scheme
identifier, this opens a local file; otherwise it opens a socket to a
server somewhere on the network. If the connection cannot be made, or
if the server returns an error code, the \code{IOError} exception is
raised. If all went well, a file-like object is returned. This
supports the following methods: \code{read()}, \code{readline()},
\code{readlines()}, \code{fileno()}, \code{close()} and \code{info()}.
if the server returns an error code, the \exception{IOError} exception
is raised. If all went well, a file-like object is returned. This
supports the following methods: \method{read()}, \method{readline()},
\method{readlines()}, \method{fileno()}, \method{close()} and
\method{info()}.
Except for the last one, these methods have the same interface as for
file objects --- see the section on File Objects earlier in this
manual. (It's not a built-in file object, however, so it can't be
file objects --- see section \ref{bltin-file-objects} in this
manual. (It is not a built-in file object, however, so it can't be
used at those few places where a true built-in file object is
required.)
The \code{info()} method returns an instance of the class
\code{mimetools.Message} containing the headers received from the server,
if the protocol uses such headers (currently the only supported
protocol that uses this is HTTP). See the description of the
\code{mimetools} module.
\refstmodindex{mimetools}
The \method{info()} method returns an instance of the class
\class{mimetools.Message} containing the headers received from the
server, if the protocol uses such headers (currently the only
supported protocol that uses this is HTTP). See the description of
the \module{mimetools}\refstmodindex{mimetools} module.
\end{funcdesc}
\begin{funcdesc}{urlretrieve}{url}
Copy a network object denoted by a URL to a local file, if necessary.
If the URL points to a local file, or a valid cached copy of the
object exists, the object is not copied. Return a tuple (\var{filename},
\var{headers}) where \var{filename} is the local file name under which
the object can be found, and \var{headers} is either \code{None} (for
a local object) or whatever the \code{info()} method of the object
returned by \code{urlopen()} returned (for a remote object, possibly
cached). Exceptions are the same as for \code{urlopen()}.
object exists, the object is not copied. Return a tuple
\code{(\var{filename}, \var{headers})} where \var{filename} is the
local file name under which the object can be found, and \var{headers}
is either \code{None} (for a local object) or whatever the
\method{info()} method of the object returned by \function{urlopen()}
returned (for a remote object, possibly cached). Exceptions are the
same as for \function{urlopen()}.
\end{funcdesc}
\begin{funcdesc}{urlcleanup}{}
Clear the cache that may have been built up by previous calls to
\code{urlretrieve()}.
\function{urlretrieve()}.
\end{funcdesc}
\begin{funcdesc}{quote}{string\optional{\, addsafe}}
Replace special characters in \var{string} using the \code{\%xx} escape.
Letters, digits, and the characters ``\code{_,.-}'' are never quoted.
Replace special characters in \var{string} using the \samp{\%xx} escape.
Letters, digits, and the characters \character{_,.-} are never quoted.
The optional \var{addsafe} parameter specifies additional characters
that should not be quoted --- its default value is \code{'/'}.
@ -65,7 +65,7 @@ Example: \code{quote('/\~connolly/')} yields \code{'/\%7econnolly/'}.
\end{funcdesc}
\begin{funcdesc}{quote_plus}{string\optional{\, addsafe}}
Like \code{quote()}, but also replaces spaces by plus signs, as
Like \function{quote()}, but also replaces spaces by plus signs, as
required for quoting HTML form values.
\end{funcdesc}
@ -76,7 +76,7 @@ Example: \code{unquote('/\%7Econnolly/')} yields \code{'/\~connolly/'}.
\end{funcdesc}
\begin{funcdesc}{unquote_plus}{string}
Like \code{unquote()}, but also replaces plus signs by spaces, as
Like \function{unquote()}, but also replaces plus signs by spaces, as
required for unquoting HTML form values.
\end{funcdesc}
@ -87,13 +87,14 @@ Restrictions:
\item
Currently, only the following protocols are supported: HTTP, (versions
0.9 and 1.0), Gopher (but not Gopher-+), FTP, and local files.
\index{HTTP}
\index{Gopher}
\index{FTP}
\indexii{HTTP}{protocol}
\indexii{Gopher}{protocol}
\indexii{FTP}{protocol}
\item
The caching feature of \code{urlretrieve()} has been disabled until I
find the time to hack proper processing of Expiration time headers.
The caching feature of \function{urlretrieve()} has been disabled
until I find the time to hack proper processing of Expiration time
headers.
\item
There should be a function to query whether a particular URL is in
@ -105,29 +106,27 @@ but the file can't be opened, the URL is re-interpreted using the FTP
protocol. This can sometimes cause confusing error messages.
\item
The \code{urlopen()} and \code{urlretrieve()} functions can cause
arbitrarily long delays while waiting for a network connection to be
set up. This means that it is difficult to build an interactive
The \function{urlopen()} and \function{urlretrieve()} functions can
cause arbitrarily long delays while waiting for a network connection
to be set up. This means that it is difficult to build an interactive
web client using these functions without using threads.
\item
The data returned by \code{urlopen()} or \code{urlretrieve()} is the
raw data returned by the server. This may be binary data (e.g. an
image), plain text or (for example) HTML. The HTTP protocol provides
type information in the reply header, which can be inspected by
looking at the \code{Content-type} header. For the Gopher protocol,
The data returned by \function{urlopen()} or \function{urlretrieve()}
is the raw data returned by the server. This may be binary data
(e.g. an image), plain text or (for example) HTML. The HTTP protocol
provides type information in the reply header, which can be inspected
by looking at the \code{content-type} header. For the Gopher protocol,
type information is encoded in the URL; there is currently no easy way
to extract it. If the returned data is HTML, you can use the module
\code{htmllib} to parse it.
\index{HTML}%
\index{HTTP}%
\index{Gopher}%
\refstmodindex{htmllib}
\module{htmllib}\refstmodindex{htmllib} to parse it.
\index{HTML}
\indexii{HTTP}{protocol}
\indexii{Gopher}{protocol}
\item
Although the \code{urllib} module contains (undocumented) routines to
parse and unparse URL strings, the recommended interface for URL
manipulation is in module \code{urlparse}.
\refstmodindex{urlparse}
Although the \module{urllib} module contains (undocumented) routines
to parse and unparse URL strings, the recommended interface for URL
manipulation is in module \module{urlparse}\refstmodindex{urlparse}.
\end{itemize}

284
Doc/libcgi.tex
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@ -7,7 +7,6 @@
\indexii{MIME}{headers}
\index{URL}
\setindexsubitem{(in module cgi)}
Support module for CGI (Common Gateway Interface) scripts.
@ -28,11 +27,11 @@ executes the script, and sends the script's output back to the client.
The script's input is connected to the client too, and sometimes the
form data is read this way; at other times the form data is passed via
the ``query string'' part of the URL. This module (\file{cgi.py}) is intended
the ``query string'' part of the URL. This module is intended
to take care of the different cases and provide a simpler interface to
the Python script. It also provides a number of utilities that help
in debugging scripts, and the latest addition is support for file
uploads from a form (if your browser supports it -- Grail 0.3 and
uploads from a form (if your browser supports it --- Grail 0.3 and
Netscape 2.0 do).
The output of a CGI script should consist of two sections, separated
@ -44,7 +43,7 @@ generate a minimal header section looks like this:
print "Content-type: text/html" # HTML is following
print # blank line, end of headers
\end{verbatim}
%
The second section is usually HTML, which allows the client software
to display nicely formatted text with header, in-line images, etc.
Here's Python code that prints a simple piece of HTML:
@ -54,28 +53,30 @@ print "<TITLE>CGI script output</TITLE>"
print "<H1>This is my first CGI script</H1>"
print "Hello, world!"
\end{verbatim}
%
(It may not be fully legal HTML according to the letter of the
standard, but any browser will understand it.)
\subsection{Using the cgi module}
\nodename{Using the cgi module}
Begin by writing \code{import cgi}. Don't use \code{from cgi import *} -- the
module defines all sorts of names for its own use or for backward
compatibility that you don't want in your namespace.
Begin by writing \samp{import cgi}. Do not use \samp{from cgi import
*} --- the module defines all sorts of names for its own use or for
backward compatibility that you don't want in your namespace.
It's best to use the \code{FieldStorage} class. The other classes define in this
module are provided mostly for backward compatibility. Instantiate it
exactly once, without arguments. This reads the form contents from
standard input or the environment (depending on the value of various
environment variables set according to the CGI standard). Since it may
consume standard input, it should be instantiated only once.
It's best to use the \class{FieldStorage} class. The other classes
defined in this module are provided mostly for backward compatibility.
Instantiate it exactly once, without arguments. This reads the form
contents from standard input or the environment (depending on the
value of various environment variables set according to the CGI
standard). Since it may consume standard input, it should be
instantiated only once.
The \code{FieldStorage} instance can be accessed as if it were a Python
The \class{FieldStorage} instance can be accessed as if it were a Python
dictionary. For instance, the following code (which assumes that the
\code{Content-type} header and blank line have already been printed) checks that
the fields \code{name} and \code{addr} are both set to a non-empty string:
\code{content-type} header and blank line have already been printed)
checks that the fields \code{name} and \code{addr} are both set to a
non-empty string:
\begin{verbatim}
form = cgi.FieldStorage()
@ -89,17 +90,20 @@ if not form_ok:
return
...further form processing here...
\end{verbatim}
%
Here the fields, accessed through \code{form[key]}, are themselves instances
of \code{FieldStorage} (or \code{MiniFieldStorage}, depending on the form encoding).
Here the fields, accessed through \samp{form[\var{key}]}, are
themselves instances of \class{FieldStorage} (or
\class{MiniFieldStorage}, depending on the form encoding).
If the submitted form data contains more than one field with the same
name, the object retrieved by \code{form[key]} is not a \code{(Mini)FieldStorage}
name, the object retrieved by \samp{form[\var{key}]} is not a
\class{FieldStorage} or \class{MiniFieldStorage}
instance but a list of such instances. If you expect this possibility
(i.e., when your HTML form comtains multiple fields with the same
name), use the \code{type()} function to determine whether you have a single
instance or a list of instances. For example, here's code that
concatenates any number of username fields, separated by commas:
name), use the \function{type()} function to determine whether you
have a single instance or a list of instances. For example, here's
code that concatenates any number of username fields, separated by
commas:
\begin{verbatim}
username = form["username"]
@ -117,12 +121,12 @@ else:
# Single username field specified
usernames = username.value
\end{verbatim}
%
If a field represents an uploaded file, the value attribute reads the
entire file in memory as a string. This may not be what you want. You can
test for an uploaded file by testing either the filename attribute or the
file attribute. You can then read the data at leasure from the file
attribute:
If a field represents an uploaded file, the value attribute reads the
entire file in memory as a string. This may not be what you want.
You can test for an uploaded file by testing either the filename
attribute or the file attribute. You can then read the data at
leasure from the file attribute:
\begin{verbatim}
fileitem = form["userfile"]
@ -134,40 +138,40 @@ if fileitem.file:
if not line: break
linecount = linecount + 1
\end{verbatim}
%
The file upload draft standard entertains the possibility of uploading
multiple files from one field (using a recursive \code{multipart/*}
encoding). When this occurs, the item will be a dictionary-like
FieldStorage item. This can be determined by testing its type
attribute, which should have the value \code{multipart/form-data} (or
perhaps another string beginning with \code{multipart/} It this case, it
can be iterated over recursively just like the top-level form object.
When a form is submitted in the ``old'' format (as the query string or as a
single data part of type \code{application/x-www-form-urlencoded}), the items
will actually be instances of the class \code{MiniFieldStorage}. In this case,
the list, file and filename attributes are always \code{None}.
The file upload draft standard entertains the possibility of uploading
multiple files from one field (using a recursive
\mimetype{multipart/*} encoding). When this occurs, the item will be
a dictionary-like \class{FieldStorage} item. This can be determined
by testing its \member{type} attribute, which should be
\mimetype{multipart/form-data} (or perhaps another MIME type matching
\mimetype{multipart/*}). It this case, it can be iterated over
recursively just like the top-level form object.
When a form is submitted in the ``old'' format (as the query string or
as a single data part of type
\mimetype{application/x-www-form-urlencoded}), the items will actually
be instances of the class \class{MiniFieldStorage}. In this case, the
list, file and filename attributes are always \code{None}.
\subsection{Old classes}
These classes, present in earlier versions of the \code{cgi} module, are still
supported for backward compatibility. New applications should use the
FieldStorage class.
These classes, present in earlier versions of the \module{cgi} module,
are still supported for backward compatibility. New applications
should use the \class{FieldStorage} class.
\code{SvFormContentDict}
single value form content as dictionary; assumes each
field name occurs in the form only once.
\class{SvFormContentDict} stores single value form content as
dictionary; it assumes each field name occurs in the form only once.
\code{FormContentDict}
multiple value form content as dictionary (the form
items are lists of values). Useful if your form contains multiple
fields with the same name.
\class{FormContentDict} stores multiple value form content as a
dictionary (the form items are lists of values). Useful if your form
contains multiple fields with the same name.
Other classes (\code{FormContent}, \code{InterpFormContentDict}) are present for
backwards compatibility with really old applications only. If you still
use these and would be inconvenienced when they disappeared from a next
version of this module, drop me a note.
Other classes (\class{FormContent}, \class{InterpFormContentDict}) are
present for backwards compatibility with really old applications only.
If you still use these and would be inconvenienced when they
disappeared from a next version of this module, drop me a note.
\subsection{Functions}
@ -178,78 +182,81 @@ some of the algorithms implemented in this module in other
circumstances.
\begin{funcdesc}{parse}{fp}
Parse a query in the environment or from a file (default \code{sys.stdin}).
Parse a query in the environment or from a file (default
\code{sys.stdin}).
\end{funcdesc}
\begin{funcdesc}{parse_qs}{qs}
parse a query string given as a string argument (data of type
\code{application/x-www-form-urlencoded}).
Parse a query string given as a string argument (data of type
\mimetype{application/x-www-form-urlencoded}).
\end{funcdesc}
\begin{funcdesc}{parse_multipart}{fp\, pdict}
parse input of type \code{multipart/form-data} (for
file uploads). Arguments are \code{fp} for the input file and
\code{pdict} for the dictionary containing other parameters of \code{content-type} header
Parse input of type \mimetype{multipart/form-data} (for
file uploads). Arguments are \var{fp} for the input file and
\var{pdict} for the dictionary containing other parameters of
\code{content-type} header
Returns a dictionary just like \code{parse_qs()}
keys are the field names, each
value is a list of values for that field. This is easy to use but not
much good if you are expecting megabytes to be uploaded -- in that case,
use the \code{FieldStorage} class instead which is much more flexible. Note
that \code{content-type} is the raw, unparsed contents of the \code{content-type}
header.
Returns a dictionary just like \function{parse_qs()} keys are the
field names, each value is a list of values for that field. This is
easy to use but not much good if you are expecting megabytes to be
uploaded --- in that case, use the \class{FieldStorage} class instead
which is much more flexible. Note that \code{content-type} is the
raw, unparsed contents of the \code{content-type} header.
Note that this does not parse nested multipart parts -- use \code{FieldStorage} for
that.
Note that this does not parse nested multipart parts --- use
\class{FieldStorage} for that.
\end{funcdesc}
\begin{funcdesc}{parse_header}{string}
parse a header like \code{Content-type} into a main
Parse a header like \code{content-type} into a main
content-type and a dictionary of parameters.
\end{funcdesc}
\begin{funcdesc}{test}{}
robust test CGI script, usable as main program.
Writes minimal HTTP headers and formats all information provided to
the script in HTML form.
Robust test CGI script, usable as main program.
Writes minimal HTTP headers and formats all information provided to
the script in HTML form.
\end{funcdesc}
\begin{funcdesc}{print_environ}{}
format the shell environment in HTML.
Format the shell environment in HTML.
\end{funcdesc}
\begin{funcdesc}{print_form}{form}
format a form in HTML.
Format a form in HTML.
\end{funcdesc}
\begin{funcdesc}{print_directory}{}
format the current directory in HTML.
Format the current directory in HTML.
\end{funcdesc}
\begin{funcdesc}{print_environ_usage}{}
print a list of useful (used by CGI) environment variables in
Print a list of useful (used by CGI) environment variables in
HTML.
\end{funcdesc}
\begin{funcdesc}{escape}{s\optional{\, quote}}
convert the characters
``\code{\&}'', ``\code{<}'' and ``\code{>}'' in string \var{s} to HTML-safe
sequences. Use this if you need to display text that might contain
such characters in HTML. If the optional flag \var{quote} is true,
the double quote character (\code{"}) is also translated; this helps
for inclusion in an HTML attribute value, e.g. in ``\code{<A HREF="...">}''.
Convert the characters
\character{\&}, \character{<} and \character{>} in string \var{s} to
HTML-safe sequences. Use this if you need to display text that might
contain such characters in HTML. If the optional flag \var{quote} is
true, the double quote character (\character{"}) is also translated;
this helps for inclusion in an HTML attribute value, e.g. in \code{<A
HREF="...">}.
\end{funcdesc}
\subsection{Caring about security}
There's one important rule: if you invoke an external program (e.g.
via the \code{os.system()} or \code{os.popen()} functions), make very sure you don't
pass arbitrary strings received from the client to the shell. This is
a well-known security hole whereby clever hackers anywhere on the web
can exploit a gullible CGI script to invoke arbitrary shell commands.
Even parts of the URL or field names cannot be trusted, since the
request doesn't have to come from your form!
via the \function{os.system()} or \function{os.popen()} functions),
make very sure you don't pass arbitrary strings received from the
client to the shell. This is a well-known security hole whereby
clever hackers anywhere on the web can exploit a gullible CGI script
to invoke arbitrary shell commands. Even parts of the URL or field
names cannot be trusted, since the request doesn't have to come from
your form!
To be on the safe side, if you must pass a string gotten from a form
to a shell command, you should make sure the string contains only
@ -263,27 +270,29 @@ system administrator to find the directory where CGI scripts should be
installed; usually this is in a directory \file{cgi-bin} in the server tree.
Make sure that your script is readable and executable by ``others''; the
\UNIX{} file mode should be 755 (use \code{chmod 755 filename}). Make sure
that the first line of the script contains \code{\#!} starting in column 1
followed by the pathname of the Python interpreter, for instance:
\UNIX{} file mode should be \code{0755} octal (use \samp{chmod 0755
filename}). Make sure that the first line of the script contains
\code{\#!} starting in column 1 followed by the pathname of the Python
interpreter, for instance:
\begin{verbatim}
#!/usr/local/bin/python
\end{verbatim}
%
Make sure the Python interpreter exists and is executable by ``others''.
Make sure that any files your script needs to read or write are
readable or writable, respectively, by ``others'' -- their mode should
be 644 for readable and 666 for writable. This is because, for
security reasons, the HTTP server executes your script as user
``nobody'', without any special privileges. It can only read (write,
execute) files that everybody can read (write, execute). The current
directory at execution time is also different (it is usually the
server's cgi-bin directory) and the set of environment variables is
also different from what you get at login. in particular, don't count
on the shell's search path for executables (\code{\$PATH}) or the Python
module search path (\code{\$PYTHONPATH}) to be set to anything interesting.
readable or writable, respectively, by ``others'' --- their mode
should be \code{0644} for readable and \code{0666} for writable. This
is because, for security reasons, the HTTP server executes your script
as user ``nobody'', without any special privileges. It can only read
(write, execute) files that everybody can read (write, execute). The
current directory at execution time is also different (it is usually
the server's cgi-bin directory) and the set of environment variables
is also different from what you get at login. In particular, don't
count on the shell's search path for executables (\envvar{PATH}) or
the Python module search path (\envvar{PYTHONPATH}) to be set to
anything interesting.
If you need to load modules from a directory which is not on Python's
default module search path, you can change the path in your script,
@ -294,7 +303,7 @@ import sys
sys.path.insert(0, "/usr/home/joe/lib/python")
sys.path.insert(0, "/usr/local/lib/python")
\end{verbatim}
%
(This way, the directory inserted last will be searched first!)
Instructions for non-\UNIX{} systems will vary; check your HTTP server's
@ -312,12 +321,12 @@ execute it at all, and the HTTP server will most likely send a cryptic
error to the client.
Assuming your script has no syntax errors, yet it does not work, you
have no choice but to read the next section:
have no choice but to read the next section.
\subsection{Debugging CGI scripts}
First of all, check for trivial installation errors -- reading the
First of all, check for trivial installation errors --- reading the
section above on installing your CGI script carefully can save you a
lot of time. If you wonder whether you have understood the
installation procedure correctly, try installing a copy of this module
@ -330,7 +339,7 @@ request by entering a URL into your browser of the form:
\begin{verbatim}
http://yourhostname/cgi-bin/cgi.py?name=Joe+Blow&addr=At+Home
\end{verbatim}
%
If this gives an error of type 404, the server cannot find the script
-- perhaps you need to install it in a different directory. If it
gives another error (e.g. 500), there's an installation problem that
@ -341,14 +350,14 @@ and ``name'' with value ``Joe Blow''), the \file{cgi.py} script has been
installed correctly. If you follow the same procedure for your own
script, you should now be able to debug it.
The next step could be to call the \code{cgi} module's \code{test()}
function from your script: replace its main code with the single
statement
The next step could be to call the \module{cgi} module's
\function{test()} function from your script: replace its main code
with the single statement
\begin{verbatim}
cgi.test()
\end{verbatim}
%
This should produce the same results as those gotten from installing
the \file{cgi.py} file itself.
@ -360,22 +369,23 @@ raises an exception, most likely the traceback will end up in one of
the HTTP server's log file, or be discarded altogether.
Fortunately, once you have managed to get your script to execute
*some* code, it is easy to catch exceptions and cause a traceback to
be printed. The \code{test()} function below in this module is an example.
Here are the rules:
\emph{some} code, it is easy to catch exceptions and cause a traceback
to be printed. The \function{test()} function below in this module is
an example. Here are the rules:
\begin{enumerate}
\item Import the traceback module (before entering the
try-except!)
\item Make sure you finish printing the headers and the blank
line early
\item Assign \code{sys.stderr} to \code{sys.stdout}
\item Wrap all remaining code in a try-except statement
\item In the except clause, call \code{traceback.print_exc()}
\item Import the traceback module before entering the \keyword{try}
... \keyword{except} statement
\item Assign \code{sys.stderr} to be \code{sys.stdout}
\item Make sure you finish printing the headers and the blank line
early
\item Wrap all remaining code in a \keyword{try} ... \keyword{except}
statement
\item In the except clause, call \function{traceback.print_exc()}
\end{enumerate}
For example:
@ -392,9 +402,9 @@ except:
print "\n\n<PRE>"
traceback.print_exc()
\end{verbatim}
%
Notes: The assignment to \code{sys.stderr} is needed because the traceback
prints to \code{sys.stderr}.
Notes: The assignment to \code{sys.stderr} is needed because the
traceback prints to \code{sys.stderr}.
The \code{print "{\e}n{\e}n<PRE>"} statement is necessary to
disable the word wrapping in HTML.
@ -409,7 +419,7 @@ print "Content-type: text/plain"
print
...your code here...
\end{verbatim}
%
This relies on the Python interpreter to print the traceback. The
content type of the output is set to plain text, which disables all
HTML processing. If your script works, the raw HTML will be displayed
@ -428,18 +438,18 @@ progress report on the client's display while the script is running.
\item Check the installation instructions above.
\item Check the HTTP server's log files. (\code{tail -f logfile} in a separate
window may be useful!)
\item Check the HTTP server's log files. (\samp{tail -f logfile} in a
separate window may be useful!)
\item Always check a script for syntax errors first, by doing something
like \code{python script.py}.
like \samp{python script.py}.
\item When using any of the debugging techniques, don't forget to add
\code{import sys} to the top of the script.
\samp{import sys} to the top of the script.
\item When invoking external programs, make sure they can be found.
Usually, this means using absolute path names -- \code{\$PATH} is usually not
set to a very useful value in a CGI script.
Usually, this means using absolute path names --- \envvar{PATH} is
usually not set to a very useful value in a CGI script.
\item When reading or writing external files, make sure they can be read
or written by every user on the system.

103
Doc/liburllib.tex
View file

@ -5,59 +5,59 @@
\index{World-Wide Web}
\index{URL}
\setindexsubitem{(in module urllib)}
This module provides a high-level interface for fetching data across
the World-Wide Web. In particular, the \code{urlopen()} function is
similar to the built-in function \code{open()}, but accepts URLs
(Universal Resource Locators) instead of filenames. Some restrictions
apply --- it can only open URLs for reading, and no seek operations
are available.
the World-Wide Web. In particular, the \function{urlopen()} function
is similar to the built-in function \function{open()}, but accepts
Universal Resource Locators (URLs) instead of filenames. Some
restrictions apply --- it can only open URLs for reading, and no seek
operations are available.
It defines the following public functions:
\begin{funcdesc}{urlopen}{url}
Open a network object denoted by a URL for reading. If the URL does
not have a scheme identifier, or if it has \samp{file:} as its scheme
not have a scheme identifier, or if it has \file{file:} as its scheme
identifier, this opens a local file; otherwise it opens a socket to a
server somewhere on the network. If the connection cannot be made, or
if the server returns an error code, the \code{IOError} exception is
raised. If all went well, a file-like object is returned. This
supports the following methods: \code{read()}, \code{readline()},
\code{readlines()}, \code{fileno()}, \code{close()} and \code{info()}.
if the server returns an error code, the \exception{IOError} exception
is raised. If all went well, a file-like object is returned. This
supports the following methods: \method{read()}, \method{readline()},
\method{readlines()}, \method{fileno()}, \method{close()} and
\method{info()}.
Except for the last one, these methods have the same interface as for
file objects --- see the section on File Objects earlier in this
manual. (It's not a built-in file object, however, so it can't be
file objects --- see section \ref{bltin-file-objects} in this
manual. (It is not a built-in file object, however, so it can't be
used at those few places where a true built-in file object is
required.)
The \code{info()} method returns an instance of the class
\code{mimetools.Message} containing the headers received from the server,
if the protocol uses such headers (currently the only supported
protocol that uses this is HTTP). See the description of the
\code{mimetools} module.
\refstmodindex{mimetools}
The \method{info()} method returns an instance of the class
\class{mimetools.Message} containing the headers received from the
server, if the protocol uses such headers (currently the only
supported protocol that uses this is HTTP). See the description of
the \module{mimetools}\refstmodindex{mimetools} module.
\end{funcdesc}
\begin{funcdesc}{urlretrieve}{url}
Copy a network object denoted by a URL to a local file, if necessary.
If the URL points to a local file, or a valid cached copy of the
object exists, the object is not copied. Return a tuple (\var{filename},
\var{headers}) where \var{filename} is the local file name under which
the object can be found, and \var{headers} is either \code{None} (for
a local object) or whatever the \code{info()} method of the object
returned by \code{urlopen()} returned (for a remote object, possibly
cached). Exceptions are the same as for \code{urlopen()}.
object exists, the object is not copied. Return a tuple
\code{(\var{filename}, \var{headers})} where \var{filename} is the
local file name under which the object can be found, and \var{headers}
is either \code{None} (for a local object) or whatever the
\method{info()} method of the object returned by \function{urlopen()}
returned (for a remote object, possibly cached). Exceptions are the
same as for \function{urlopen()}.
\end{funcdesc}
\begin{funcdesc}{urlcleanup}{}
Clear the cache that may have been built up by previous calls to
\code{urlretrieve()}.
\function{urlretrieve()}.
\end{funcdesc}
\begin{funcdesc}{quote}{string\optional{\, addsafe}}
Replace special characters in \var{string} using the \code{\%xx} escape.
Letters, digits, and the characters ``\code{_,.-}'' are never quoted.
Replace special characters in \var{string} using the \samp{\%xx} escape.
Letters, digits, and the characters \character{_,.-} are never quoted.
The optional \var{addsafe} parameter specifies additional characters
that should not be quoted --- its default value is \code{'/'}.
@ -65,7 +65,7 @@ Example: \code{quote('/\~connolly/')} yields \code{'/\%7econnolly/'}.
\end{funcdesc}
\begin{funcdesc}{quote_plus}{string\optional{\, addsafe}}
Like \code{quote()}, but also replaces spaces by plus signs, as
Like \function{quote()}, but also replaces spaces by plus signs, as
required for quoting HTML form values.
\end{funcdesc}
@ -76,7 +76,7 @@ Example: \code{unquote('/\%7Econnolly/')} yields \code{'/\~connolly/'}.
\end{funcdesc}
\begin{funcdesc}{unquote_plus}{string}
Like \code{unquote()}, but also replaces plus signs by spaces, as
Like \function{unquote()}, but also replaces plus signs by spaces, as
required for unquoting HTML form values.
\end{funcdesc}
@ -87,13 +87,14 @@ Restrictions:
\item
Currently, only the following protocols are supported: HTTP, (versions
0.9 and 1.0), Gopher (but not Gopher-+), FTP, and local files.
\index{HTTP}
\index{Gopher}
\index{FTP}
\indexii{HTTP}{protocol}
\indexii{Gopher}{protocol}
\indexii{FTP}{protocol}
\item
The caching feature of \code{urlretrieve()} has been disabled until I
find the time to hack proper processing of Expiration time headers.
The caching feature of \function{urlretrieve()} has been disabled
until I find the time to hack proper processing of Expiration time
headers.
\item
There should be a function to query whether a particular URL is in
@ -105,29 +106,27 @@ but the file can't be opened, the URL is re-interpreted using the FTP
protocol. This can sometimes cause confusing error messages.
\item
The \code{urlopen()} and \code{urlretrieve()} functions can cause
arbitrarily long delays while waiting for a network connection to be
set up. This means that it is difficult to build an interactive
The \function{urlopen()} and \function{urlretrieve()} functions can
cause arbitrarily long delays while waiting for a network connection
to be set up. This means that it is difficult to build an interactive
web client using these functions without using threads.
\item
The data returned by \code{urlopen()} or \code{urlretrieve()} is the
raw data returned by the server. This may be binary data (e.g. an
image), plain text or (for example) HTML. The HTTP protocol provides
type information in the reply header, which can be inspected by
looking at the \code{Content-type} header. For the Gopher protocol,
The data returned by \function{urlopen()} or \function{urlretrieve()}
is the raw data returned by the server. This may be binary data
(e.g. an image), plain text or (for example) HTML. The HTTP protocol
provides type information in the reply header, which can be inspected
by looking at the \code{content-type} header. For the Gopher protocol,
type information is encoded in the URL; there is currently no easy way
to extract it. If the returned data is HTML, you can use the module
\code{htmllib} to parse it.
\index{HTML}%
\index{HTTP}%
\index{Gopher}%
\refstmodindex{htmllib}
\module{htmllib}\refstmodindex{htmllib} to parse it.
\index{HTML}
\indexii{HTTP}{protocol}
\indexii{Gopher}{protocol}
\item
Although the \code{urllib} module contains (undocumented) routines to
parse and unparse URL strings, the recommended interface for URL
manipulation is in module \code{urlparse}.
\refstmodindex{urlparse}
Although the \module{urllib} module contains (undocumented) routines
to parse and unparse URL strings, the recommended interface for URL
manipulation is in module \module{urlparse}\refstmodindex{urlparse}.
\end{itemize}