### Is the issue already documented?
-Make sure that someone has not already opened the issue you're trying to open. Search at the top of the window or browse the [GitHub Issues](https://github.com/rg3/youtube-dl/search?type=Issues) of this repository. If there is an issue, feel free to write something along the lines of "This affects me as well, with version 2015.01.01. Here is some more information on the issue: ...". While some issues may be old, a new post into them often spurs rapid activity.
+Make sure that someone has not already opened the issue you're trying to open. Search at the top of the window or browse the [GitHub Issues](https://github.com/ytdl-org/youtube-dl/search?type=Issues) of this repository. If there is an issue, feel free to write something along the lines of "This affects me as well, with version 2015.01.01. Here is some more information on the issue: ...". While some issues may be old, a new post into them often spurs rapid activity.
### Why are existing options not enough?
-Before requesting a new feature, please have a quick peek at [the list of supported options](https://github.com/rg3/youtube-dl/blob/master/README.md#options). Many feature requests are for features that actually exist already! Please, absolutely do show off your work in the issue report and detail how the existing similar options do *not* solve your problem.
+Before requesting a new feature, please have a quick peek at [the list of supported options](https://github.com/ytdl-org/youtube-dl/blob/master/README.md#options). Many feature requests are for features that actually exist already! Please, absolutely do show off your work in the issue report and detail how the existing similar options do *not* solve your problem.
### Is there enough context in your bug report?
# DEVELOPER INSTRUCTIONS
-Most users do not need to build youtube-dl and can [download the builds](https://rg3.github.io/youtube-dl/download.html) or get them from their distribution.
+Most users do not need to build youtube-dl and can [download the builds](https://ytdl-org.github.io/youtube-dl/download.html) or get them from their distribution.
To run youtube-dl as a developer, you don't need to build anything either. Simply execute
After you have ensured this site is distributing its content legally, you can follow this quick list (assuming your service is called `yourextractor`):
-1. [Fork this repository](https://github.com/rg3/youtube-dl/fork)
+1. [Fork this repository](https://github.com/ytdl-org/youtube-dl/fork)
2. Check out the source code with:
git clone git@github.com:YOUR_GITHUB_USERNAME/youtube-dl.git
# TODO more properties (see youtube_dl/extractor/common.py)
}
```
-5. Add an import in [`youtube_dl/extractor/extractors.py`](https://github.com/rg3/youtube-dl/blob/master/youtube_dl/extractor/extractors.py).
+5. Add an import in [`youtube_dl/extractor/extractors.py`](https://github.com/ytdl-org/youtube-dl/blob/master/youtube_dl/extractor/extractors.py).
6. Run `python test/test_download.py TestDownload.test_YourExtractor`. This *should fail* at first, but you can continually re-run it until you're done. If you decide to add more than one test, then rename ``_TEST`` to ``_TESTS`` and make it into a list of dictionaries. The tests will then be named `TestDownload.test_YourExtractor`, `TestDownload.test_YourExtractor_1`, `TestDownload.test_YourExtractor_2`, etc. Note that tests with `only_matching` key in test's dict are not counted in.
-7. Have a look at [`youtube_dl/extractor/common.py`](https://github.com/rg3/youtube-dl/blob/master/youtube_dl/extractor/common.py) for possible helper methods and a [detailed description of what your extractor should and may return](https://github.com/rg3/youtube-dl/blob/master/youtube_dl/extractor/common.py#L74-L252). Add tests and code for as many as you want.
-8. Make sure your code follows [youtube-dl coding conventions](#youtube-dl-coding-conventions) and check the code with [flake8](https://pypi.python.org/pypi/flake8). Also make sure your code works under all [Python](https://www.python.org/) versions claimed supported by youtube-dl, namely 2.6, 2.7, and 3.2+.
-9. When the tests pass, [add](https://git-scm.com/docs/git-add) the new files and [commit](https://git-scm.com/docs/git-commit) them and [push](https://git-scm.com/docs/git-push) the result, like this:
+7. Have a look at [`youtube_dl/extractor/common.py`](https://github.com/ytdl-org/youtube-dl/blob/master/youtube_dl/extractor/common.py) for possible helper methods and a [detailed description of what your extractor should and may return](https://github.com/ytdl-org/youtube-dl/blob/7f41a598b3fba1bcab2817de64a08941200aa3c8/youtube_dl/extractor/common.py#L94-L303). Add tests and code for as many as you want.
+8. Make sure your code follows [youtube-dl coding conventions](#youtube-dl-coding-conventions) and check the code with [flake8](https://flake8.pycqa.org/en/latest/index.html#quickstart):
+
+ $ flake8 youtube_dl/extractor/yourextractor.py
+
+9. Make sure your code works under all [Python](https://www.python.org/) versions claimed supported by youtube-dl, namely 2.6, 2.7, and 3.2+.
+10. When the tests pass, [add](https://git-scm.com/docs/git-add) the new files and [commit](https://git-scm.com/docs/git-commit) them and [push](https://git-scm.com/docs/git-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
-10. Finally, [create a pull request](https://help.github.com/articles/creating-a-pull-request). We'll then review and merge it.
+11. Finally, [create a pull request](https://help.github.com/articles/creating-a-pull-request). We'll then review and merge it.
In any case, thank you very much for your contributions!
### Mandatory and optional metafields
-For extraction to work youtube-dl relies on metadata your extractor extracts and provides to youtube-dl expressed by an [information dictionary](https://github.com/rg3/youtube-dl/blob/master/youtube_dl/extractor/common.py#L75-L257) or simply *info dict*. Only the following meta fields in the *info dict* are considered mandatory for a successful extraction process by youtube-dl:
+For extraction to work youtube-dl relies on metadata your extractor extracts and provides to youtube-dl expressed by an [information dictionary](https://github.com/ytdl-org/youtube-dl/blob/7f41a598b3fba1bcab2817de64a08941200aa3c8/youtube_dl/extractor/common.py#L94-L303) or simply *info dict*. Only the following meta fields in the *info dict* are considered mandatory for a successful extraction process by youtube-dl:
- `id` (media identifier)
- `title` (media title)
In fact only the last option is technically mandatory (i.e. if you can't figure out the download location of the media the extraction does not make any sense). But by convention youtube-dl also treats `id` and `title` as mandatory. Thus the aforementioned metafields are the critical data that the extraction does not make any sense without and if any of them fail to be extracted then the extractor is considered completely broken.
-[Any field](https://github.com/rg3/youtube-dl/blob/master/youtube_dl/extractor/common.py#L149-L257) apart from the aforementioned ones are considered **optional**. That means that extraction should be **tolerant** to situations when sources for these fields can potentially be unavailable (even if they are always available at the moment) and **future-proof** in order not to break the extraction of general purpose mandatory fields.
+[Any field](https://github.com/ytdl-org/youtube-dl/blob/7f41a598b3fba1bcab2817de64a08941200aa3c8/youtube_dl/extractor/common.py#L188-L303) apart from the aforementioned ones are considered **optional**. That means that extraction should be **tolerant** to situations when sources for these fields can potentially be unavailable (even if they are always available at the moment) and **future-proof** in order not to break the extraction of general purpose mandatory fields.
#### Example
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.
+
+Correct:
+
+```python
+r'(?:id|ID)=(?P<id>\d+)'
+```
-When using regular expressions try to write them fuzzy and flexible.
+Incorrect:
+```python
+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
+##### Example
Say you need to extract `title` from the following HTML code:
webpage, 'title', group='title')
```
-### Use safe conversion functions
+### 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:
+
+```python
+'https://www.youtube.com/watch?v=FqZTN594JQw&list=PLMYEtVRpaqY00V9W81Cwmzp6N6vZqfUKD4'
+```
+
+Incorrect:
+
+```python
+'https://www.youtube.com/watch?v=FqZTN594JQw&list='
+'PLMYEtVRpaqY00V9W81Cwmzp6N6vZqfUKD4'
+```
+
+### Inline values
+
+Extracting variables is acceptable for reducing code duplication and improving readability of complex expressions. However, you should avoid extracting variables used only once and moving them to opposite parts of the extractor file, which makes reading the linear flow difficult.
+
+#### Example
+
+Correct:
+
+```python
+title = self._html_search_regex(r'<title>([^<]+)</title>', webpage, 'title')
+```
+
+Incorrect:
+
+```python
+TITLE_RE = r'<title>([^<]+)</title>'
+# ...some lines of code...
+title = self._html_search_regex(TITLE_RE, webpage, 'title')
+```
+
+### Collapse fallbacks
+
+Multiple fallback values can quickly become unwieldy. Collapse multiple fallback values into a single expression via a list of patterns.
+
+#### Example
+
+Good:
+
+```python
+description = self._html_search_meta(
+ ['og:description', 'description', 'twitter:description'],
+ webpage, 'description', default=None)
+```
+
+Unwieldy:
+
+```python
+description = (
+ self._og_search_description(webpage, default=None)
+ or self._html_search_meta('description', webpage, default=None)
+ or self._html_search_meta('twitter:description', webpage, default=None))
+```
+
+Methods supporting list of patterns are: `_search_regex`, `_html_search_regex`, `_og_search_property`, `_html_search_meta`.
+
+### Trailing parentheses
+
+Always move trailing parentheses after the last argument.
+
+#### Example
+
+Correct:
+
+```python
+ lambda x: x['ResultSet']['Result'][0]['VideoUrlSet']['VideoUrl'],
+ list)
+```
+
+Incorrect:
+
+```python
+ lambda x: x['ResultSet']['Result'][0]['VideoUrlSet']['VideoUrl'],
+ list,
+)
+```
+
+### Use convenience conversion and parsing functions
+
+Wrap all extracted numeric data into safe functions from [`youtube_dl/utils.py`](https://github.com/ytdl-org/youtube-dl/blob/master/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.
-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.
+Use `try_get` for safe metadata extraction from parsed JSON.
+
+Use `unified_strdate` for uniform `upload_date` or any `YYYYMMDD` meta field extraction, `unified_timestamp` for uniform `timestamp` extraction, `parse_filesize` for `filesize` extraction, `parse_count` for count meta fields extraction, `parse_resolution`, `parse_duration` for `duration` extraction, `parse_age_limit` for `age_limit` extraction.
+
+Explore [`youtube_dl/utils.py`](https://github.com/ytdl-org/youtube-dl/blob/master/youtube_dl/utils.py) for more useful convenience functions.
+
+#### More examples
+
+##### Safely extract optional description from parsed JSON
+```python
+description = try_get(response, lambda x: x['result']['video'][0]['summary'], compat_str)
+```
+
+##### Safely extract more optional metadata
+```python
+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'))
+```
projects / youtube-dl / blobdiff