def __init__(self, dbname="index.db"):
""" Initial indexer.
Warning: when initial indexer, it will overwrite existed index database in current dircetory. """
if os.path.exists(dbname):
os.remove(dbname)
self.analyzer = NaiveAnalyzer()
self.conn = sqlite3.connect(dbname)
self.cur = self.conn.cursor()
# create tables to store information
sqls = []
sqls.append("create table urllist(url text)")
sqls.append("create table wordlist(word text)")
sqls.append("create table urltitle(urlid integer, title text)")
sqls.append("create table wordlocation(urlid integer, wordid integer, location integer)");
sqls.append("create table wordinfo(urlid integer, wordid integer, tf real)");
sqls.append("create table linkwords(wordid integer, linkid integer)")
sqls.append("create index urlidx on urllist(url)")
sqls.append("create index wordidx on wordlist(word)")
sqls.append("create index wordurlidx on wordlocation(wordid)")
sqls.append("create index tfidx on wordinfo(tf)")
for sql in sqls:
self.cur.execute(sql)
self.conn.commit()
class Indexer(object):
""" Indexer class. """
def __init__(self, dbname="index.db"):
""" Initial indexer.
Warning: when initial indexer, it will overwrite existed index database in current dircetory. """
if os.path.exists(dbname):
os.remove(dbname)
self.analyzer = NaiveAnalyzer()
self.conn = sqlite3.connect(dbname)
self.cur = self.conn.cursor()
# create tables to store information
sqls = []
sqls.append("create table urllist(url text)")
sqls.append("create table wordlist(word text)")
sqls.append("create table urltitle(urlid integer, title text)")
sqls.append("create table wordlocation(urlid integer, wordid integer, location integer)");
sqls.append("create table wordinfo(urlid integer, wordid integer, tf real)");
sqls.append("create table linkwords(wordid integer, linkid integer)")
sqls.append("create index urlidx on urllist(url)")
sqls.append("create index wordidx on wordlist(word)")
sqls.append("create index wordurlidx on wordlocation(wordid)")
sqls.append("create index tfidx on wordinfo(tf)")
for sql in sqls:
self.cur.execute(sql)
self.conn.commit()
def __del__(self):
self.conn.commit()
self.cur.close()
def getitems(self, html):
""" Analyze the original webpage, and extract the valuable info.
Here only extract the page title and all page contents. """
try:
p = Parser()
p.feed(html)
except:
ferrmsg('Error: feed error!', 'Index')
items = {}
title = p.get_title()
items['title'] = title
content = p.get_content()
items['content'] = content
return items
def getid(self, table, field, value):
""" Get given field's index-value from the tabel,
if the field is not exist, create a new one and return the newly added index. """
sql = "select rowid from %s where %s='%s'" % (table, field, value)
res = self.cur.execute(sql).fetchone()
if res is None:
sql = "insert into %s (%s) values('%s')" % (table, field, value)
return self.cur.execute(sql).lastrowid
else:
return res[0]
def index(self, db):
""" Index the given database.
Index steps consist of:
1, seperate the content into individual words.
2, record each word.
3, calculate the term frequency in current page.
Note: index process is time-wasting. """
conn = sqlite3.connect(db)
cur = conn.cursor()
conn.text_factory = str
dbname = db[:-3]
sql = "select url from %s" % dbname
urls = [ url[0] for url in cur.execute(sql).fetchall()]
progress = ProgressMeter(total=len(urls))
# traverse all webpages
for (cnt, url) in enumerate(urls):
urlid = self.getid('urllist','url',url)
sql = "select content from %s where url='%s'" % (dbname, url)
html = cur.execute(sql).fetchone()[0]
items = self.getitems(html)
title = replace_quote(items['title'])
sql = "insert into urltitle values(%d,'%s')" % (urlid, title)
self.cur.execute(sql)
content = items['content']
words = self.analyzer.run(content)
tfdir = {}
# traverse all words in current webpage
for i in range(len(words)):
word = words[i]
if word not in tfdir:
tfdir[word] = 1
else:
tfdir[word] += 1
wordid = self.getid('wordlist','word',word)
sql = "insert into wordlocation values(%d,%d,%d)" % (urlid, wordid, i)
self.cur.execute(sql)
for (word, tf) in tfdir.items():
wordid = self.getid('wordlist','word',word)
sql = "insert into wordinfo values(%d,%d,%f)" % \
(urlid, wordid, float(tf)/len(words))
self.cur.execute(sql)
# update the progress
if (cnt % REFRESH_CNT) == 0 or cnt == progress.total-1:
progress.update(cnt+1)
del progress
cur.close()
