downloading each video. The special sequences may be formatted according
to python string formatting operations. For example, %(NAME)s or
%(NAME)05d. To clarify, that is a percent symbol followed by a name in
-parentheses, followed by a formatting operations. Allowed names along
-with sequence type are:
+parentheses, followed by formatting operations. Allowed names along with
+sequence type are:
- id (string): Video identifier
- title (string): Video title
available
- upload_date (string): Video upload date (YYYYMMDD)
- uploader_id (string): Nickname or id of the video uploader
+- channel (string): Full name of the channel the video is uploaded on
+- channel_id (string): Id of the channel
- location (string): Physical location where the video was filmed
- duration (numeric): Length of the video in seconds
- view_count (numeric): How many users have watched the video on the
methods and a detailed description of what your extractor should and
may return. Add tests and code for as many as you want.
8. Make sure your code follows youtube-dl coding conventions and check
- the code with flake8. Also make sure your code works under all
- Python versions claimed supported by youtube-dl, namely 2.6, 2.7,
- and 3.2+.
-9. When the tests pass, add the new files and commit them and push the
+ the code with flake8:
+
+ $ flake8 youtube_dl/extractor/yourextractor.py
+
+9. Make sure your code works under all Python versions claimed
+ supported by youtube-dl, namely 2.6, 2.7, and 3.2+.
+10. When the tests pass, add the new files and commit them and push the
result, like this:
- $ git add youtube_dl/extractor/extractors.py
- $ git add youtube_dl/extractor/yourextractor.py
- $ git commit -m '[yourextractor] Add new extractor'
- $ git push origin yourextractor
+ $ git add youtube_dl/extractor/extractors.py
+ $ git add youtube_dl/extractor/yourextractor.py
+ $ git commit -m '[yourextractor] Add new extractor'
+ $ git push origin yourextractor
-10. Finally, create a pull request. We'll then review and merge it.
+11. Finally, create a pull request. We'll then review and merge it.
In any case, thank you very much for your contributions!
This code will try to extract from meta first and if it fails it will
try extracting og:title from a webpage.
-Make regular expressions flexible
+Regular expressions
+
+Don't capture groups you don't use
+
+Capturing group must be an indication that it's used somewhere in the
+code. Any group that is not used must be non capturing.
+
+Example
+
+Don't capture id attribute name here since you can't use it for anything
+anyway.
-When using regular expressions try to write them fuzzy and flexible.
+Correct:
+
+ r'(?:id|ID)=(?P<id>\d+)'
+
+Incorrect:
+
+ r'(id|ID)=(?P<id>\d+)'
+
+Make regular expressions relaxed and flexible
+
+When using regular expressions try to write them fuzzy, relaxed and
+flexible, skipping insignificant parts that are more likely to change,
+allowing both single and double quotes for quoted values and so on.
Example
r'<span style="position: absolute; left: 910px; width: 90px; float: right; z-index: 9999;" class="title">(.*?)</span>',
webpage, 'title', group='title')
+Long lines policy
+
+There is a soft limit to keep lines of code under 80 characters long.
+This means it should be respected if possible and if it does not make
+readability and code maintenance worse.
+
+For example, you should NEVER split long string literals like URLs or
+some other often copied entities over multiple lines to fit this limit:
+
+Correct:
+
+ 'https://www.youtube.com/watch?v=FqZTN594JQw&list=PLMYEtVRpaqY00V9W81Cwmzp6N6vZqfUKD4'
+
+Incorrect:
+
+ 'https://www.youtube.com/watch?v=FqZTN594JQw&list='
+ 'PLMYEtVRpaqY00V9W81Cwmzp6N6vZqfUKD4'
+
Use safe conversion functions
-Wrap all extracted numeric data into safe functions from utils:
-int_or_none, float_or_none. Use them for string to number conversions as
-well.
+Wrap all extracted numeric data into safe functions from
+youtube_dl/utils.py: int_or_none, float_or_none. Use them for string to
+number conversions as well.
+
+Use url_or_none for safe URL processing.
+
+Use try_get for safe metadata extraction from parsed JSON.
+
+Explore youtube_dl/utils.py for more useful convenience functions.
+
+More examples
+
+Safely extract optional description from parsed JSON
+
+ description = try_get(response, lambda x: x['result']['video'][0]['summary'], compat_str)
+
+Safely extract more optional metadata
+
+ video = try_get(response, lambda x: x['result']['video'][0], dict) or {}
+ description = video.get('summary')
+ duration = float_or_none(video.get('durationMs'), scale=1000)
+ view_count = int_or_none(video.get('views'))
Rapsys Git / youtubedl / blobdiff