diff options
Diffstat (limited to 'Doc/libcgi.tex')
| -rw-r--r-- | Doc/libcgi.tex | 46 |
1 files changed, 23 insertions, 23 deletions
diff --git a/Doc/libcgi.tex b/Doc/libcgi.tex index 6b50ec8..f115263 100644 --- a/Doc/libcgi.tex +++ b/Doc/libcgi.tex @@ -7,7 +7,7 @@ \indexii{MIME}{headers} \index{URL} -\renewcommand{\indexsubitem}{(in module cgi)} +\setindexsubitem{(in module cgi)} Support module for CGI (Common Gateway Interface) scripts. @@ -40,20 +40,20 @@ by a blank line. The first section contains a number of headers, telling the client what kind of data is following. Python code to generate a minimal header section looks like this: -\bcode\begin{verbatim} +\begin{verbatim} print "Content-type: text/html" # HTML is following print # blank line, end of headers -\end{verbatim}\ecode +\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: -\bcode\begin{verbatim} +\begin{verbatim} print "<TITLE>CGI script output</TITLE>" print "<H1>This is my first CGI script</H1>" print "Hello, world!" -\end{verbatim}\ecode +\end{verbatim} % (It may not be fully legal HTML according to the letter of the standard, but any browser will understand it.) @@ -77,7 +77,7 @@ 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: -\bcode\begin{verbatim} +\begin{verbatim} form = cgi.FieldStorage() form_ok = 0 if form.has_key("name") and form.has_key("addr"): @@ -88,7 +88,7 @@ if not form_ok: print "Please fill in the name and addr fields." return ...further form processing here... -\end{verbatim}\ecode +\end{verbatim} % Here the fields, accessed through \code{form[key]}, are themselves instances of \code{FieldStorage} (or \code{MiniFieldStorage}, depending on the form encoding). @@ -101,7 +101,7 @@ 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: -\bcode\begin{verbatim} +\begin{verbatim} username = form["username"] if type(username) is type([]): # Multiple username fields specified @@ -116,7 +116,7 @@ if type(username) is type([]): else: # Single username field specified usernames = username.value -\end{verbatim}\ecode +\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 @@ -124,7 +124,7 @@ 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: -\bcode\begin{verbatim} +\begin{verbatim} fileitem = form["userfile"] if fileitem.file: # It's an uploaded file; count lines @@ -133,7 +133,7 @@ if fileitem.file: line = fileitem.file.readline() if not line: break linecount = linecount + 1 -\end{verbatim}\ecode +\end{verbatim} % The file upload draft standard entertains the possibility of uploading multiple files from one field (using a recursive \code{multipart/*} @@ -267,9 +267,9 @@ Make sure that your script is readable and executable by ``others''; the that the first line of the script contains \code{\#!} starting in column 1 followed by the pathname of the Python interpreter, for instance: -\bcode\begin{verbatim} +\begin{verbatim} #!/usr/local/bin/python -\end{verbatim}\ecode +\end{verbatim} % Make sure the Python interpreter exists and is executable by ``others''. @@ -289,11 +289,11 @@ 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, before importing other modules, e.g.: -\bcode\begin{verbatim} +\begin{verbatim} import sys sys.path.insert(0, "/usr/home/joe/lib/python") sys.path.insert(0, "/usr/local/lib/python") -\end{verbatim}\ecode +\end{verbatim} % (This way, the directory inserted last will be searched first!) @@ -327,9 +327,9 @@ Give it the right mode etc, and send it a request. If it's installed in the standard \file{cgi-bin} directory, it should be possible to send it a request by entering a URL into your browser of the form: -\bcode\begin{verbatim} +\begin{verbatim} http://yourhostname/cgi-bin/cgi.py?name=Joe+Blow&addr=At+Home -\end{verbatim}\ecode +\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 @@ -345,9 +345,9 @@ 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 -\bcode\begin{verbatim} +\begin{verbatim} cgi.test() -\end{verbatim}\ecode +\end{verbatim} % This should produce the same results as those gotten from installing the \file{cgi.py} file itself. @@ -380,7 +380,7 @@ Here are the rules: For example: -\bcode\begin{verbatim} +\begin{verbatim} import sys import traceback print "Content-type: text/html" @@ -391,7 +391,7 @@ try: except: print "\n\n<PRE>" traceback.print_exc() -\end{verbatim}\ecode +\end{verbatim} % Notes: The assignment to \code{sys.stderr} is needed because the traceback prints to \code{sys.stderr}. @@ -402,13 +402,13 @@ If you suspect that there may be a problem in importing the traceback module, you can use an even more robust approach (which only uses built-in modules): -\bcode\begin{verbatim} +\begin{verbatim} import sys sys.stderr = sys.stdout print "Content-type: text/plain" print ...your code here... -\end{verbatim}\ecode +\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 |