#!/usr/bin/python

# This module contains some helper functions to keep the length of the
# files that use this module within reasonable bounds. The functions
# all provide standard functionality needed to work with ceXML and
# xml.apache.org's Xalan parser and Xerces XSLT processor.

import tempfile
import os

# initialise tempfile's first part of the temporary filenames
tempfile.template = "cexmlhelper"
# Start a list containing the generated temporary files, allowing for
# a clean-up when they're not needed anymore
list_of_tempfiles = []

def set_linux_classpath():
    # Sets the classpath. This is a specific implementation for my
    # personal linux system, someday this will be more
    # generic. Perhaps I'll even write a nice wrapper for more
    # systems :-)
    os.putenv("CLASSPATH","/usr/lib/jdk1.1/lib/classes.zip:"+
    "/usr/share/java/xerces.jar:/usr/share/java/xalan.jar")

def process_with_xslt(in_file, xslt_file, parameters=[]):
    # feeds "in_file" to "xslt_file" using the optional
    # "parameters". The "parameters" must be a python list of
    # key-value tuples. The return value is the name of the temporary
    # file containing the output.
    commandline = "java org.apache.xalan.xslt.Process"
    # Add the in_file
    commandline = commandline + " -in %s" % in_file
    # Add the xslt_file
    commandline = commandline + " -xsl %s" % xslt_file
    # Generate a temporary filename and add it as the process' output
    out_file = tempfile.mktemp()
    list_of_tempfiles.append(out_file)
    commandline = commandline + " -out %s" % out_file
    if len(parameters) > 0:
        i = 0
        while i < len(parameters):
            commandline=commandline+" -param %s %s" % parameters[i]
            i=i+1
    # add some stuff to suppress annoying output
    commandline = commandline + " -Q -QC"
    # run the commandline
    os.system(commandline)
    # return the output filename (a temporary one)
    return out_file

def print_xml_header():
    # Prints the header needed to send the file over HTTP. Normally
    # not needed, because print_xml_file() calls it automatically, but
    # you never know...
    os.system("echo Content-type: text/xml")
    os.system("echo")

def print_html_header():
    # Prints the header needed to send the file over HTTP. Normally
    # not needed, because print_html_file() calls it automatically, but
    # you never know...
    os.system("echo Content-type: text/html")
    os.system("echo")

def print_xml_file(xml_file):
    # Prints the xml header and the xml_file
    print_xml_header()
    os.system("cat %s" % xml_file)
    
def print_html_file(html_file):
    # Prints the html header and the html_file
    print_html_header()
    os.system("cat %s" % html_file)
    
def remove_temporary_files():
    i = 0
    while i < len(list_of_tempfiles):
        os.system("rm %s" % list_of_tempfiles[i])
        i=i+1