unable to compile python program using jython

Question

I'm trying to compile a python program using jython and it's throwing below error

C:\jython2.2.1>jython test.py
Traceback (innermost last):
 (no code object) at line 0
 File "test.py", line 30
 html = html if html else download(url, user_agent).read()
 ^
SyntaxError: invalid syntax

Below is my python program. Please let me know how to resolve this.

---

import sys
import re
import urllib2
import urlparse
from optparse import OptionParser
# regular expression data for each website
VIDEO_DATA = [
 ('youtube.com', '%7C(.*?videoplayback.*?)%2C'),
 ('metacafe.com', '&mediaURL=(.*?)&'),
]
# default user agent to use when downloading
USER_AGENT = 'pytube'
# size of file to download
CHUNK_SIZE = 1024 * 1024
def scrape(url, html=None, user_agent=None, output=None):
 """Scrape video location from given url. 
 Use html instead of downloading if passed.
 Download file to output if passed.
 Return url of video if found, else None
 """
 netloc = urlparse.urlsplit(url).netloc
 for domain, video_re in VIDEO_DATA:
 if domain in netloc:
 html = html if html else download(url, user_agent).read()
 search = re.search(video_re, html)
 if search:
 flash_url = urllib2.unquote(search.group(1))
 if output:
 print "Downloading flash to `%s'" % output,
 #open(output, 'wb').write(download(flash_url, user_agent).read())
 req = download(flash_url, user_agent)
 # testing with keyword in python
 with open(output, 'wb') as fp:
 chunk = True
 while chunk:
 chunk = req.read(CHUNK_SIZE)
 if chunk:
 fp.write(chunk)
 #fp.flush()
 print '.',
 sys.stdout.flush()
 print
 return flash_url
 else:
 raise PyTubeException('Failed to locate video regular expression in downloaded HTML')
 raise PyTubeException('URL did not match available domains')
def download(url, user_agent=None):
 """Download url and return data
 """
 headers = {'User-Agent' : user_agent}
 req = urllib2.Request(url, None, headers)
 return urllib2.urlopen(req)
class PyTubeException(Exception):
 pass
if __name__ == '__main__':
 # parse command line options
 parser = OptionParser(usage='usage: %prog, [-o <file.flv> -a <user_agent> -s -h] url')
 parser.add_option('-o', '--output', dest='output', help='Output file to download flash file to. If this is not specified file will not be downloaded.')
 parser.add_option('-s', '--sites', action='store_true', default=False, dest='sites', help='Display sites that pytube supports, then quit.')
 parser.add_option('-a', '--agent', dest='user_agent', default=USER_AGENT, help='Set user-agent for downloads.') 
 options, args = parser.parse_args()
 if options.sites:
 print '\n'.join(domain for (domain, reg) in VIDEO_DATA)
 else:
 if args:
 flash_url = scrape(args[0], user_agent=options.user_agent, output=options.output)
 if flash_url:
 print flash_url
 else:
 print 'Need to pass the url of the video you want to download'
 parser.print_help()

---

• JavaGeek: after changing the code as you said then it's showing below error C:\jython2.2.1>jython test.py Traceback (innermost last): (no code object) at line 0 File "test.py", line 30 html = (html) ? "html" : download(url, user_agent).read() ^ SyntaxError: inconsistent dedent

Answer 1

Jython 2.2.1 is (AFAIK) equivalent to Cpython 2.2.1 as far as syntax is concerned. The line that causes the problem uses the ternary operator which was introduced later. the solution is to replace it with an if statement.

if not html:
 html = download(url, user_agent).read() 

That should take care of that syntax error. There is also a with clause that you will need to replace.

with open(output, 'wb') as fp:
 chunk = True
 while chunk:
 chunk = req.read(CHUNK_SIZE)
 if chunk:
 fp.write(chunk)
 #fp.flush()
 print '.',
 sys.stdout.flush()

You can replace this with

try:
 fp = open(output, 'w')
 chunk = True
 while chunk:
 chunk = req.read(CHUNK_SIZE)
 if chunk:
 fp.write(chunk)
 #fp.flush()
 print '.',
 sys.stdout.flush()
finally:
 fp.close()

• JavaGeek: Now It's throwing error like ^ SyntaxError: inconsistent dedent C:\jython2.2.1>jython test.py Traceback (innermost last): (no code object) at line 0 File "test.py", line 30 if not html: html = download(url, user_agent).read() ^ SyntaxError: inconsistent dedent
• Wooble: Sukumar: in Python, indentation is important. You're not indenting something correctly.
• JavaGeek: Actually i'm new to python and still trying to figure it out what's going wrong with this..no luck yet..giving the same error
• aaronasterling: @Sukumar Porting from CPython to Jython might be a little ambitious. You need to study python indentation and learn to read the error messages. here is a link to help with the indentation:secnetix.de/~olli/Python/block_indentation.hawk
• JavaGeek: @AaronMcSmooth Thanks a lot. I will study Identation and try to resolve. I'll let you know if i face any problem.