the-screenless-office/screenless/bureau/publications/publications.py

# publications office for reading and writing
from base64 import b64encode
from datetime import datetime
import io
import json
import os
import random
import string
import threading
import urllib.request, urllib.parse, urllib.error

import bleach
import code128
import feedparser
import lxml.html
import PIL
from readability import readability
import requests

from bureau import Bureau, add_command, add_api


class Publications(Bureau):
    """
    The Publications Office serves as a kind of screenless content management
    system.  Create, update and organize your sites while doing most of the work
    on paper or anything you can photograph.
    """

    name = "Publications Office"
    prefix = "PB"
    version = 0

    def __init__(self):
        Bureau.__init__(self)

        # set up db for published sites
        # TODO: rename this to something less ambiguous
        self.db = os.path.expanduser("~/.screenless/PB.data")
        if not os.path.exists(self.db):
            os.mkdir(self.db)

        # set up urldb for short-codes
        self.urldb = self.dbenv.open_db(b"urldb")
        self.rev_urldb = self.dbenv.open_db(b"rev_urldb")

    def _make_shorturl(self, url):
        def _shortcode():
            return ''.join(random.choice(string.ascii_letters + string.digits)
                            for _ in range(5))
        
        # we only have about a billion so make sure we don't collide keys
        with self.dbenv.begin(write=True, db=self.urldb) as txn:
            res = "not None"
            while res is not None:
              tmpcode = _shortcode()
              res = txn.get(tmpcode.encode())
            txn.put(tmpcode.encode(), url.encode())

        # chop wierdly long urls to be 500 chars (LMDB limit for keys)
        # TODO: make sure we're not truncating some multi-byte unicode
        if len(url.encode()) > 500:
            url_key = url.encode()[0:500]
        else:
            url_key = url.encode()
        with self.dbenv.begin(write=True, db=self.rev_urldb) as txn:
            txn.put(url_key, tmpcode.encode())

        return tmpcode


    def _get_url(self, shortcode):
        """look up a URL from a shortcode
        returns full unicode url
        """
        with self.dbenv.begin(db=self.urldb) as txn:
            return txn.get(shortcode.encode()).decode()

    @add_command("new", "Create a new Publication/Site")
    def new_site(self):
        """
        Create a new Publication/Site, set up config and tace a picture from
        the document camera as the index page.  Finally, it will print out
        the main page with commands for working with the site.
        """
        site_dir = os.path.join(self.db, "1")
        site_id = 1
        while os.path.exists(site_dir):
            site_id += 1
            site_dir = os.path.join(self.db, str(site_id))
        os.mkdir(site_dir)

        root_d = {"template": "default", "id": site_id}
        with open(os.path.join(site_dir, "root.json", "w")) as root_json:
            root_json.write(json.dumps(root_d))

        photo = self.send("PX", "photo")["photo"]

        # TODO: come up with a generic set of img form operations for Bureau
        #       should map regions defined with percentages to names
        form_img = PIL.Image.open(photo)
        fx, fy = form_img.size
        title_region = (0, 0, 0.5 * fx, 0.125 * fy)
        title_img = form_img.crop(title_region)
        content_region = (0, 0.125 * fy, fx, fy)
        content_img = form_img.crop(content_region)

    def _update_page(self, site, page):
        pass

    @add_command("news", "Print a personalized daily newspaper")
    def daily_news(self):
        """
        Print out a selection of up-to-the-minute news items culled from various
        sources on the internet. Current unread Post, weather and finance 
        information can also be shown.
        """
        news = self._get_news()
        # TODO: get weather
        # TODO: get finance
        inbox = self.send("PO", "unread")
        date = datetime.today().strftime("%A %B %e, %Y")
        if inbox is None:
            inbox = []  # if IMAP times out just move on...
        self.print_full("news.html", news=news, inbox=inbox, date=date)

    @add_command("r", "Print a web page for reading")
    def print_url(self, data):
        """
        Print out a web page for reading.  The command requires a short-code,
        typically referenced via barcode.  Short-codes refer to full resource
        URIs recorded in the Publications office 'urldb' database.
        """
        shortcode, _ = data.split(".")
        with self.dbenv.begin(db=self.urldb) as txn:
            self.log.debug("looking up short-code:" + shortcode)
            url = txn.get(shortcode.encode('utf-8'))

        if not url:
            self.log.warning("no valid URL in db for short code: " + shortcode)
            return
        else:
            url = url.decode()

        # download page with requests
        headers = {'User-Agent': 'Mozilla/5.0'}
        try:
            resp = requests.get(url, timeout=20.0, headers=headers)
        except requests.ReadTimeout:
            self.log.warning("Timeout reading RSS feed %s", url)
            return  # TODO: do we need to spit out an error?

        # re-render with readability
        doc = readability.Document(resp.text,
                                   url=url)
        timestamp = datetime.now().strftime("Sourced %d %B, %Y at %H:%M")
        html = lxml.html.document_fromstring(doc.summary())

        notecount = 0
        # store links then make corresponding svg barcodes
        for link in html.findall(".//a"):
            if "href" in link.attrib:
                notecount += 1
            else:
                continue  # skip bogus links
            tmpcode = self._make_shorturl(link.attrib["href"])

            svg = code128.svg("PBr." + tmpcode)

            footnote = html.makeelement("div")
            footnote.attrib["class"] = "footnote"
            notetext = html.makeelement("div")
            notetext.text = str(notecount) + ". " + link.attrib["href"]
            footnote.append(notetext)
            #TODO: make this barcode inline thing a util method
            encoded_svg = b64encode(bytes(svg, 'utf-8')).decode()
            encoded_data = "data:image/svg+xml;charset=utf-8;base64," + encoded_svg
            svg = '<img src="%s"/>' % encoded_data
            footnote.append(lxml.html.fromstring(svg))
            html.append(footnote)

        self.print_full("article.html", title=doc.title(),
                        article=lxml.html.tostring(html).decode("utf-8"),
                        url=url, date=timestamp)

    def _get_ogdata(self, url):
        """
        returns an object with OpenGraph metadata if available
        """
        ogdata = {}

        # download page with requests
        headers = {'User-Agent': 'Mozilla/5.0'}
        try:
            resp = requests.get(url, timeout=20.0, headers=headers)
        except (requests.ReadTimeout, requests.exceptions.ReadTimeout):
            self.log.warning("Timeout fetching OpenGraph data from document %s",
                             url)
            return ogdata
        except (requests.exceptions.ConnectionError):
            self.log.warning("Connection errors fetching OpenGraph from %s",
                             url)
            return ogdata
        except requests.exceptions.MissingSchema:
            self.log.warning("Can't get OpenGraph data from bogus URL %s", url)
            return ogdata

        html = lxml.html.document_fromstring(resp.text)

        #find all elements with property="og:<something>"
        elements = html.findall(".//*[@property]")
        for element in elements:
            prop = element.get("property")
            val = element.get("content")
            if prop.startswith("og:"):
                prop = prop[3:]
                ogdata[prop] = val

        return ogdata

    def _get_news(self):
        """fetch a set of latest news entries from sources specified in config
        """
        feeds = self.config["newsfeeds"]
        entries = []
        feed_data = {}
        threads = []

        for source in feeds:
            url = source["url"]

            def fetch_feed(url, feed_data):
                """
                get feed data with requests using a timeout
                """
                try:
                    resp = requests.get(url, timeout=20.0)
                    feed_data[url] = io.BytesIO(resp.content)
                except requests.ReadTimeout:
                    self.log.warning("Timeout reading RSS feed %s", url)
                    feed_data[url] = None
                    return

            thread = threading.Thread(target=fetch_feed, args=(url, feed_data))
            threads.append(thread)
            thread.start()

        for thread in threads:
            thread.join()

        for source in feeds:
            feed = feedparser.parse(feed_data[source["url"]])
            if feed is None:
                continue
            num_entries = source["count"]

            # work around if we don't have enough news
            if num_entries > len(feed.entries):
                num_entries = len(feed.entries)

            en_count = 0
            while en_count < num_entries:
                try:
                    entry = feed.entries.pop(0)
                except IndexError:
                    # we are out of entries - quit
                    en_count = num_entries
                    continue

                # ignore the old news we've already seen
                # 
                with self.dbenv.begin(db=self.rev_urldb) as txn:
                    res = txn.get(entry.link.encode())
                    if res is not None:
                        continue

                entry.source = feed.feed.title
                entry.dbhash = self._make_shorturl(entry.link)
                entry.svg = code128.svg("PBr." + entry.dbhash)
                encoded_svg = b64encode(bytes(entry.svg, 'utf-8')).decode()
                encoded_data = "data:image/svg+xml;charset=utf-8;base64," + encoded_svg
                entry.svg = '<img src="%s"/>' % encoded_data

                # skip bogus entries with no text
                if not hasattr(entry, "summary"):
                    continue

                # limit summary to the last space below 500 characters
                if len(entry.summary) > 500:
                    end = entry.summary.rfind(" ", 0, 499)
                    entry.summary = entry.summary[0:end] + "…"

                entry.summary = bleach.clean(entry.summary, strip=True)

                entries.append(entry)
                en_count += 1

        # do this multi-threaded cuz downloads can be slow
        threads = []
        for i in range(len(entries)):
            entry = entries[i]
            def fetch_og(entry):
                """
                get OpenGraph data for entry
                """
                og_data = self._get_ogdata(entry.link)
                if hasattr(entry, "media_thumbnail"):
                    entry.img = entry.media_thumbnail[-1]["url"]
                elif "image" in og_data:
                    entry.img = og_data["image"]
                else:
                    entry.img = " "

            thread = threading.Thread(target=fetch_og, args=(entry,))
            threads.append(thread)
            thread.start()

        # wait till we're done
        for thread in threads:
            thread.join()

        return entries


def main():
    pub = Publications()
    pub.run()


if __name__ == "__main__":
    main()