#!/usr/bin/python

#
#  TBPY by Mark Paschal <markpasc@markpasc.org>
#  Trackback server CGI for the rest of your web site.
#
#  See http://markpasc.org/code/tbpy/ for installing and configuring
#  instructions.
#
#
#  Copyright 2002 Mark Paschal
#
#  Permission is hereby granted, free of charge, to any person obtaining a
#  copy of this software and associated documentation files (the "Software"),
#  to deal in the Software without restriction, including without limitation
#  the rights to use, copy, modify, merge, publish, distribute, sublicense,
#  and/or sell copies of the Software, and to permit persons to whom the
#  Software is furnished to do so, subject to the following conditions:
#
#  The above copyright notice and this permission notice shall be included in
#  all copies or substantial portions of the Software.
#
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
#  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
#  DEALINGS IN THE SOFTWARE.
#


import cgi
import sys
import os
from os.path import dirname, join
from xml.dom.minidom import parse, Document
from time import strftime


def tbError(err):
	"""Print the appropriate Trackback error response and exit."""
	print """Content-type: text/xml

<?xml version="1.0"?>
<response>
	<error>1</error>
	<message>%s</message>
</response>""" % err
	sys.exit(0)

def getInnerText(node):
	"""Get the text from inside a node."""
	return ''.join([x.toxml() for x in node.childNodes])


try:
	resource = None  # so what is it?
	if os.environ["REQUEST_URI"].startswith(os.environ["SCRIPT_NAME"]):
		if os.environ.has_key("PATH_INFO"):
			resource = os.environ["PATH_INFO"]
		else:
			tbError("You didn't say what resource you wanted to ping.")
	else:
		resource = os.environ["REQUEST_URI"]
	if resource.endswith("index.html"): resource = resource[:-10]


	# Load existing TrackBack content.
	resourceUri = "http://%s%s" % (os.environ["SERVER_NAME"], resource)
	tbUri = "http://%s%s%s" % (os.environ["SERVER_NAME"], os.environ["SCRIPT_NAME"], resource)
	dataFilename = "%s.xml" % resource[1:].replace(os.sep, "_").replace(".", "_")
	dataFile = join(dirname(os.environ["SCRIPT_FILENAME"]), "data", dataFilename)

	tb_data = None  # so what is it?
	try:
		tb_data = parse(dataFile)
	except IOError:
		# Make a new document.
		tb_data = Document()

		rss = tb_data.createElement("rss")
		tb_data.appendChild(rss)
		rss.setAttribute("version", "0.91")

		channel = tb_data.createElement("channel")
		rss.appendChild(channel)

		chTitle = tb_data.createElement("title")
		chTitle.appendChild(tb_data.createTextNode("TrackBack for %s" % (resourceUri)))
		channel.appendChild(chTitle)

		chLink = tb_data.createElement("link")
		chLink.appendChild(tb_data.createTextNode(resourceUri))
		channel.appendChild(chLink)

		chDesc = tb_data.createElement("description")
		chDesc.appendChild(tb_data.createTextNode("What some people have pung me with."))
		channel.appendChild(chDesc)

		chLang = tb_data.createElement("language")
		chLang.appendChild(tb_data.createTextNode("en-us"))
		channel.appendChild(chLang)

	tb_channel = tb_data.documentElement.firstChild


	# Pinging or fetching?
	if "POST" == os.environ["REQUEST_METHOD"]:
		# Pinging.

		ping = cgi.FieldStorage()

		# Add this ping.
		pingItem = tb_data.createElement("item")

		if ping.has_key("title"):
			itemTitle = pingItem.appendChild(tb_data.createElement("title"))
			itemTitle.appendChild(tb_data.createTextNode(ping.getvalue("title")))
		if ping.has_key("url"):
			itemLink = pingItem.appendChild(tb_data.createElement("link"))
			itemLink.appendChild(tb_data.createTextNode(ping.getvalue("url")))
		if ping.has_key("excerpt"):
			excerpt = ping.getvalue("excerpt")
			if 255 < len(excerpt):
				excerpt = "%s..." % excerpt[:252]
			itemDesc = pingItem.appendChild(tb_data.createElement("description"))
			itemDesc.appendChild(tb_data.createTextNode(excerpt))
		if ping.has_key("blog_name"):
			itemBN = pingItem.appendChild(tb_data.createElement("blogName"))
			itemBN.appendChild(tb_data.createTextNode(ping.getvalue("blog_name")))

		itemDate = tb_data.createElementNS("http://purl.org/dc/elements/1.1/", "date")
		itemDate.appendChild(tb_data.createTextNode(strftime("%Y-%m-%dT%H:%MZ")))
		pingItem.appendChild(itemDate)

		tb_channel.appendChild(pingItem)

		# Write it back out.
		xmlout = open(dataFile, "w")
		xmlout.write(tb_data.toxml())
		xmlout.close()

		print """Content-type: text/xml

<?xml version="1.0"?>
<response>
	<error>0</error>
</response>"""

	else:
		# Fetching.

		# RSS?
		req = cgi.FieldStorage()
		if req.has_key("__mode") and "rss" == req.getvalue("__mode"):
			# Yes, RSS. Good thing it's already built.
			respDoc = Document()
			respTag = respDoc.appendChild(respDoc.createElement("response"))
			respTag.appendChild(respDoc.createElement("error")).appendChild(respDoc.createTextNode("0"))
			respTag.appendChild(tb_data.documentElement)

			print "Content-type: text/xml"
			print
			print response.toxml()

			sys.exit(0)

		# No, includable HTML.

		template = None  # so what is it?
		try:
			templateFile = open(join(dirname(os.environ["SCRIPT_FILENAME"]), "template.html"), "r")
			template = templateFile.readlines()
			templateFile.close()
			# Turn ("first", "middle", "middle", "middle", "last") into ("first", "middle\nmiddle\nmiddle", "last").
			if 3 > len(template): raise IOError, "Not enough lines in template file"
			template[1:-1] = ["\n".join(template[1:-1])]
		except IOError:
			template = ["<div class='tb'><h4>Trackbacks (<a href='%(dataUri)s'>RSS</a>)</h4>",
				"<h5><a href='%(link)s'>%(title)s</a></h5>\n<p>%(description)s</p>\n<p class='about'>by %(blogName)s at %(date)s</p>",
				"</div>"]

		metadata = {
			'dataUri':"http://%s%s/%s" % (os.environ["SERVER_NAME"], '/'.join(os.environ["SCRIPT_NAME"].split("/")[:-1] + ["data"]), dataFilename),
			'title':getInnerText(tb_channel.getElementsByTagName("title")[0]),
			'description':getInnerText(tb_channel.getElementsByTagName("description")[0]),
			'resourceUri':resourceUri, 'tbUri':tbUri
		}

		print """Content-type: text/html

<!--
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
		 xmlns:dc="http://purl.org/dc/elements/1.1/"
		 xmlns:trackback="http://madskills.com/public/xml/rss/module/trackback/">
<rdf:Description rdf:about="%(resourceUri)s" dc:identifier="%(resourceUri)s"
				 dc:title="%(title)s" dc:description="%(description)s"
				 trackback:ping="%(tbUri)s" />
</rdf:RDF>
-->
""" % metadata  # Here's a " for TextPad's broken syntax coloring.

		print template[0] % metadata

		tb_data.normalize()
		items = tb_data.getElementsByTagName("item")
		items.reverse()
		for item in items:
			data = {}
			for datum in ("title", "description", "link", "date", "blogName"):
				try:
					data[datum] = getInnerText(item.getElementsByTagName(datum)[0])
				except IndexError, x:
					# No 0th element by that name.
					data[datum] = "<!-- no %s for this ping -->" % (datum,)
			print template[1] % data
			print

		print template[2] % metadata

except Exception, x:
	tbError("%s: %s" % (x.__class__.__name__, x))