From 65cd34c5d735f968b03c6e618db4e177ed80f1ac Mon Sep 17 00:00:00 2001 From: Ricardo Garcia Date: Sun, 27 Jul 2008 12:13:49 +0200 Subject: [PATCH] Add initial version of postprocessing framework --- youtube-dl | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) diff --git a/youtube-dl b/youtube-dl index 3f20da590a..7690898b2e 100755 --- a/youtube-dl +++ b/youtube-dl @@ -42,6 +42,14 @@ class SameFileError(Exception): """ pass +class PostProcessingError(Exception): + """Post Processing exception. + + This exception may be raised by PostProcessor's .run() method to + indicate an error in the postprocessing task. + """ + pass + class FileDownloader(object): """File Downloader class. @@ -83,10 +91,12 @@ class FileDownloader(object): _params = None _ies = [] + _pps = [] def __init__(self, params): """Create a FileDownloader object with the given options.""" self._ies = [] + self._pps = [] self.set_params(params) @staticmethod @@ -176,6 +186,11 @@ class FileDownloader(object): self._ies.append(ie) ie.set_downloader(self) + def add_post_processor(self, pp): + """Add a PostProcessor object to the end of the chain.""" + self._pps.append(pp) + pp.set_downloader(self) + def to_stdout(self, message, skip_eol=False): """Print message to stdout if not in quiet mode.""" if not self._params.get('quiet', False): @@ -288,11 +303,26 @@ class FileDownloader(object): except (urllib2.URLError, httplib.HTTPException, socket.error), err: retcode = self.trouble('ERROR: unable to download video data: %s' % str(err)) continue + try: + self.post_process(filename, result) + except (PostProcessingError), err: + retcode = self.trouble('ERROR: postprocessing: %s' % str(err)) + continue + break if not suitable_found: retcode = self.trouble('ERROR: no suitable InfoExtractor: %s' % url) return retcode + + def post_process(self, filename, ie_info): + """Run the postprocessing chain on the given file.""" + info = dict(ie_info) + info['filepath'] = filename + for pp in self._pps: + info = pp.run(info) + if info is None: + break def _do_download(self, stream, url): request = urllib2.Request(url, None, std_headers) @@ -736,6 +766,62 @@ class YoutubePlaylistIE(InfoExtractor): information.extend(self._youtube_ie.extract('http://www.youtube.com/watch?v=%s' % id)) return information +class PostProcessor(object): + """Post Processor class. + + PostProcessor objects can be added to downloaders with their + add_post_processor() method. When the downloader has finished a + successful download, it will take its internal chain of PostProcessors + and start calling the run() method on each one of them, first with + an initial argument and then with the returned value of the previous + PostProcessor. + + The chain will be stopped if one of them ever returns None or the end + of the chain is reached. + + PostProcessor objects follow a "mutual registration" process similar + to InfoExtractor objects. + """ + + _downloader = None + + def __init__(self, downloader=None): + self._downloader = downloader + + def to_stdout(self, message): + """Print message to stdout if downloader is not in quiet mode.""" + if self._downloader is None or not self._downloader.get_params().get('quiet', False): + print message + + def to_stderr(self, message): + """Print message to stderr.""" + print >>sys.stderr, message + + def set_downloader(self, downloader): + """Sets the downloader for this PP.""" + self._downloader = downloader + + def run(self, information): + """Run the PostProcessor. + + The "information" argument is a dictionary like the ones + returned by InfoExtractors. The only difference is that this + one has an extra field called "filepath" that points to the + downloaded file. + + When this method returns None, the postprocessing chain is + stopped. However, this method may return an information + dictionary that will be passed to the next postprocessing + object in the chain. It can be the one it received after + changing some fields. + + In addition, this method may raise a PostProcessingError + exception that will be taken into account by the downloader + it was called from. + """ + return information # by default, do nothing + +### MAIN PROGRAM ### if __name__ == '__main__': try: # Modules needed only when running the main program