### 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/yt-dlp/yt-dlp/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 2021.01.01. 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/yt-dlp/yt-dlp/search?type=Issues) of this repository. If there is an issue, subscribe to it to be notified when there is any progress. Unless you have something useful to add to the conversation, please refrain from commenting.
Additionally, it is also helpful to see if the issue has already been documented in the [youtube-dl issue tracker](https://github.com/ytdl-org/youtube-dl/issues). If similar issues have already been reported in youtube-dl (but not in our issue tracker), links to them can be included in your issue report here.
### Is the website primarily used for piracy?
-We follow [youtube-dl's policy](https://github.com/ytdl-org/youtube-dl#can-you-add-support-for-this-anime-video-site-or-site-which-shows-current-movies-for-free) to not support services that is primarily used for infringing copyright. Additionally, it has been decided to not to support porn sites that specialize in deep fake. We also cannot support any service that serves only [DRM protected content](https://en.wikipedia.org/wiki/Digital_rights_management).
+We follow [youtube-dl's policy](https://github.com/ytdl-org/youtube-dl#can-you-add-support-for-this-anime-video-site-or-site-which-shows-current-movies-for-free) to not support services that is primarily used for infringing copyright. Additionally, it has been decided to not to support porn sites that specialize in fakes. We also cannot support any service that serves only [DRM protected content](https://en.wikipedia.org/wiki/Digital_rights_management).
To run yt-dlp as a developer, you don't need to build anything either. Simply execute
- python -m yt_dlp
+ python3 -m yt_dlp
-To run the test, simply invoke your favorite test runner, or execute a test file directly; any of the following work:
+To run all the available core tests, use:
- python -m unittest discover
- python test/test_download.py
- nosetests
- pytest
+ python3 devscripts/run_tests.py
See item 6 of [new extractor tutorial](#adding-support-for-a-new-site) for how to run extractor specific test cases.
## Adding new feature or making overarching changes
-Before you start writing code for implementing a new feature, open an issue explaining your feature request and atleast one use case. This allows the maintainers to decide whether such a feature is desired for the project in the first place, and will provide an avenue to discuss some implementation details. If you open a pull request for a new feature without discussing with us first, do not be surprised when we ask for large changes to the code, or even reject it outright.
+Before you start writing code for implementing a new feature, open an issue explaining your feature request and at least one use case. This allows the maintainers to decide whether such a feature is desired for the project in the first place, and will provide an avenue to discuss some implementation details. If you open a pull request for a new feature without discussing with us first, do not be surprised when we ask for large changes to the code, or even reject it outright.
The same applies for changes to the documentation, code style, or overarching changes to the architecture
## Adding support for a new site
-If you want to add support for a new site, first of all **make sure** this site is **not dedicated to [copyright infringement](https://www.github.com/ytdl-org/youtube-dl#can-you-add-support-for-this-anime-video-site-or-site-which-shows-current-movies-for-free)**. yt-dlp does **not support** such sites thus pull requests adding support for them **will be rejected**.
+If you want to add support for a new site, first of all **make sure** this site is **not dedicated to [copyright infringement](#is-the-website-primarily-used-for-piracy)**. yt-dlp does **not support** such sites thus pull requests adding support for them **will be rejected**.
After you have ensured this site is distributing its content legally, you can follow this quick list (assuming your service is called `yourextractor`):
'url': 'https://yourextractor.com/watch/42',
'md5': 'TODO: md5 sum of the first 10241 bytes of the video file (use --test)',
'info_dict': {
+ # For videos, only the 'id' and 'ext' fields are required to RUN the test:
'id': '42',
'ext': 'mp4',
- 'title': 'Video title goes here',
- 'thumbnail': r're:^https?://.*\.jpg$',
- # TODO more properties, either as:
- # * A value
- # * MD5 checksum; start the string with md5:
- # * A regular expression; start the string with re:
- # * Any Python type (for example int or float)
+ # Then if the test run fails, it will output the missing/incorrect fields.
+ # Properties can be added as:
+ # * A value, e.g.
+ # 'title': 'Video title goes here',
+ # * MD5 checksum; start the string with 'md5:', e.g.
+ # 'description': 'md5:098f6bcd4621d373cade4e832627b4f6',
+ # * A regular expression; start the string with 're:', e.g.
+ # 'thumbnail': r're:^https?://.*\.jpg$',
+ # * A count of elements in a list; start the string with 'count:', e.g.
+ # 'tags': 'count:10',
+ # * Any Python type, e.g.
+ # 'view_count': int,
}
}]
# TODO more properties (see yt_dlp/extractor/common.py)
}
```
-1. Add an import in [`yt_dlp/extractor/extractors.py`](yt_dlp/extractor/extractors.py).
-1. Run `python test/test_download.py TestDownload.test_YourExtractor` (note that `YourExtractor` doesn't end with `IE`). 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, 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. You can also run all the tests in one go with `TestDownload.test_YourExtractor_all`
-1. Make sure you have atleast one test for your extractor. Even if all videos covered by the extractor are expected to be inaccessible for automated testing, tests should still be added with a `skip` parameter indicating why the particular test is disabled from running.
-1. Have a look at [`yt_dlp/extractor/common.py`](yt_dlp/extractor/common.py) for possible helper methods and a [detailed description of what your extractor should and may return](yt_dlp/extractor/common.py#L91-L426). Add tests and code for as many as you want.
+1. Add an import in [`yt_dlp/extractor/_extractors.py`](yt_dlp/extractor/_extractors.py). Note that the class name must end with `IE`.
+1. Run `python3 devscripts/run_tests.py YourExtractor`. This *may fail* at first, but you can continually re-run it until you're done. Upon failure, it will output the missing fields and/or correct values which you can copy. If you decide to add more than one test, the tests will then be named `YourExtractor`, `YourExtractor_1`, `YourExtractor_2`, etc. Note that tests with an `only_matching` key in the test's dict are not included in the count. You can also run all the tests in one go with `YourExtractor_all`
+1. Make sure you have at least one test for your extractor. Even if all videos covered by the extractor are expected to be inaccessible for automated testing, tests should still be added with a `skip` parameter indicating why the particular test is disabled from running.
+1. Have a look at [`yt_dlp/extractor/common.py`](yt_dlp/extractor/common.py) for possible helper methods and a [detailed description of what your extractor should and may return](yt_dlp/extractor/common.py#L119-L440). Add tests and code for as many as you want.
1. Make sure your code follows [yt-dlp coding conventions](#yt-dlp-coding-conventions) and check the code with [flake8](https://flake8.pycqa.org/en/latest/index.html#quickstart):
$ flake8 yt_dlp/extractor/yourextractor.py
-1. Make sure your code works under all [Python](https://www.python.org/) versions supported by yt-dlp, namely CPython and PyPy for Python 3.6 and above. Backward compatibility is not required for even older versions of Python.
+1. Make sure your code works under all [Python](https://www.python.org/) versions supported by yt-dlp, namely CPython and PyPy for Python 3.8 and above. Backward compatibility is not required for even older versions of Python.
1. When the tests pass, [add](https://git-scm.com/docs/git-add) the new files, [commit](https://git-scm.com/docs/git-commit) them and [push](https://git-scm.com/docs/git-push) the result, like this:
- $ git add yt_dlp/extractor/extractors.py
+ $ git add yt_dlp/extractor/_extractors.py
$ git add yt_dlp/extractor/yourextractor.py
$ git commit -m '[yourextractor] Add extractor'
$ git push origin yourextractor
In any case, thank you very much for your contributions!
-**Tip:** To test extractors that require login information, create a file `test/local_parameters.json` and add `"usenetrc": true` or your username and password in it:
+**Tip:** To test extractors that require login information, create a file `test/local_parameters.json` and add `"usenetrc": true` or your `username`&`password` or `cookiefile`/`cookiesfrombrowser` in it:
```json
{
"username": "your user name",
This section introduces a guide lines for writing idiomatic, robust and future-proof extractor code.
-Extractors are very fragile by nature since they depend on the layout of the source data provided by 3rd party media hosters out of your control and this layout tends to change. As an extractor implementer your task is not only to write code that will extract media links and metadata correctly but also to minimize dependency on the source's layout and even to make the code foresee potential future changes and be ready for that. This is important because it will allow the extractor not to break on minor layout changes thus keeping old yt-dlp versions working. Even though this breakage issue may be easily fixed by a new version of yt-dlp, this could take some time, during which the the extractor will remain broken.
+Extractors are very fragile by nature since they depend on the layout of the source data provided by 3rd party media hosters out of your control and this layout tends to change. As an extractor implementer your task is not only to write code that will extract media links and metadata correctly but also to minimize dependency on the source's layout and even to make the code foresee potential future changes and be ready for that. This is important because it will allow the extractor not to break on minor layout changes thus keeping old yt-dlp versions working. Even though this breakage issue may be easily fixed by a new version of yt-dlp, this could take some time, during which the extractor will remain broken.
### Mandatory and optional metafields
-For extraction to work yt-dlp relies on metadata your extractor extracts and provides to yt-dlp expressed by an [information dictionary](yt_dlp/extractor/common.py#L91-L426) or simply *info dict*. Only the following meta fields in the *info dict* are considered mandatory for a successful extraction process by yt-dlp:
+For extraction to work yt-dlp relies on metadata your extractor extracts and provides to yt-dlp expressed by an [information dictionary](yt_dlp/extractor/common.py#L119-L440) or simply *info dict*. Only the following meta fields in the *info dict* are considered mandatory for a successful extraction process by yt-dlp:
- `id` (media identifier)
- `title` (media title)
For pornographic sites, appropriate `age_limit` must also be returned.
-The extractor is allowed to return the info dict without url or formats in some special cases if it allows the user to extract usefull information with `--ignore-no-formats-error` - Eg: when the video is a live stream that has not started yet.
+The extractor is allowed to return the info dict without url or formats in some special cases if it allows the user to extract useful information with `--ignore-no-formats-error` - e.g. when the video is a live stream that has not started yet.
[Any field](yt_dlp/extractor/common.py#219-L426) 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.
The latter will break extraction process with `KeyError` if `summary` disappears from `meta` at some later time but with the former approach extraction will just go ahead with `description` set to `None` which is perfectly fine (remember `None` is equivalent to the absence of data).
-If the data is nested, do not use `.get` chains, but instead make use of the utility functions `try_get` or `traverse_obj`
+If the data is nested, do not use `.get` chains, but instead make use of `traverse_obj`.
Considering the above `meta` again, assume you want to extract `["user"]["name"]` and put it in the resulting info dict as `uploader`
-```python
-uploader = try_get(meta, lambda x: x['user']['name']) # correct
-```
-or
```python
uploader = traverse_obj(meta, ('user', 'name')) # correct
```
```python
uploader = meta.get('user', {}).get('name') # incorrect
```
+or
+```python
+uploader = try_get(meta, lambda x: x['user']['name']) # old utility
+```
Similarly, you should pass `fatal=False` when extracting optional data from a webpage with `_search_regex`, `_html_search_regex` or similar methods, for instance:
Another thing to remember is not to try to iterate over `None`
-Say you extracted a list of thumbnails into `thumbnail_data` using `try_get` and now want to iterate over them
+Say you extracted a list of thumbnails into `thumbnail_data` and want to iterate over them
```python
-thumbnail_data = try_get(...)
+thumbnail_data = data.get('thumbnails') or []
thumbnails = [{
- 'url': item['url']
-} for item in thumbnail_data or []] # correct
+ 'url': item['url'],
+ 'height': item.get('h'),
+} for item in thumbnail_data if item.get('url')] # correct
```
and not like:
```python
-thumbnail_data = try_get(...)
+thumbnail_data = data.get('thumbnails')
thumbnails = [{
- 'url': item['url']
+ 'url': item['url'],
+ 'height': item.get('h'),
} for item in thumbnail_data] # incorrect
```
-In the later case, `thumbnail_data` will be `None` if the field was not found and this will cause the loop `for item in thumbnail_data` to raise a fatal error. Using `for item in thumbnail_data or []` avoids this error and results in setting an empty list in `thumbnails` instead.
+In this case, `thumbnail_data` will be `None` if the field was not found and this will cause the loop `for item in thumbnail_data` to raise a fatal error. Using `or []` avoids this error and results in setting an empty list in `thumbnails` instead.
+
+Alternately, this can be further simplified by using `traverse_obj`
+
+```python
+thumbnails = [{
+ 'url': item['url'],
+ 'height': item.get('h'),
+} for item in traverse_obj(data, ('thumbnails', lambda _, v: v['url']))]
+```
+
+or, even better,
+```python
+thumbnails = traverse_obj(data, ('thumbnails', ..., {'url': 'url', 'height': 'h'}))
+```
### Provide fallbacks
#### Example
-Say `meta` from the previous example has a `title` and you are about to extract it. Since `title` is a mandatory meta field you should end up with something like:
+Say `meta` from the previous example has a `title` and you are about to extract it like:
```python
-title = meta['title']
+title = meta.get('title')
```
-If `title` disappears from `meta` in future due to some changes on the hoster's side the extraction would fail since `title` is mandatory. That's expected.
+If `title` disappears from `meta` in future due to some changes on the hoster's side the title extraction would fail.
-Assume that you have some another source you can extract `title` from, for example `og:title` HTML meta of a `webpage`. In this case you can provide a fallback scenario:
+Assume that you have some another source you can extract `title` from, for example `og:title` HTML meta of a `webpage`. In this case you can provide a fallback like:
```python
title = meta.get('title') or self._og_search_title(webpage)
```
-This code will try to extract from `meta` first and if it fails it will try extracting `og:title` from a `webpage`.
+This code will try to extract from `meta` first and if it fails it will try extracting `og:title` from a `webpage`, making the extractor more robust.
### Regular expressions
r'<span[^>]+class="title"[^>]*>([^<]+)', webpage, 'title')
```
-Or even better:
+which tolerates potential changes in the `style` attribute's value. Or even better:
```python
title = self._search_regex( # correct
webpage, 'title', group='title')
```
-Note how you tolerate potential changes in the `style` attribute's value or switch from using double quotes to single for `class` attribute:
+which also handles both single quotes in addition to double quotes.
The code definitely should not look like:
webpage, 'title', group='title')
```
-Here the presence or absence of other attributes including `style` is irrelevent for the data we need, and so the regex must not depend on it
+Here the presence or absence of other attributes including `style` is irrelevant for the data we need, and so the regex must not depend on it
+
+
+#### Keep the regular expressions as simple as possible, but no simpler
+
+Since many extractors deal with unstructured data provided by websites, we will often need to use very complex regular expressions. You should try to use the *simplest* regex that can accomplish what you want. In other words, each part of the regex must have a reason for existing. If you can take out a symbol and the functionality does not change, the symbol should not be there.
+
+##### Example
+
+Correct:
+
+```python
+_VALID_URL = r'https?://(?:www\.)?website\.com/(?:[^/]+/){3,4}(?P<display_id>[^/]+)_(?P<id>\d+)'
+```
+
+Incorrect:
+
+```python
+_VALID_URL = r'https?:\/\/(?:www\.)?website\.com\/[^\/]+/[^\/]+/[^\/]+(?:\/[^\/]+)?\/(?P<display_id>[^\/]+)_(?P<id>\d+)'
+```
+
+#### Do not misuse `.` and use the correct quantifiers (`+*?`)
+
+Avoid creating regexes that over-match because of wrong use of quantifiers. Also try to avoid non-greedy matching (`?`) where possible since they could easily result in [catastrophic backtracking](https://www.regular-expressions.info/catastrophic.html)
+
+Correct:
+
+```python
+title = self._search_regex(r'<span\b[^>]+class="title"[^>]*>([^<]+)', webpage, 'title')
+```
+
+Incorrect:
+
+```python
+title = self._search_regex(r'<span\b.*class="title".*>(.+?)<', webpage, 'title')
+```
### Long lines policy
For example, you should **never** split long string literals like URLs or some other often copied entities over multiple lines to fit this limit:
-Conversely, don't unecessarily split small lines further. As a rule of thumb, if removing the line split keeps the code under 80 characters, it should be a single line.
+Conversely, don't unnecessarily split small lines further. As a rule of thumb, if removing the line split keeps the code under 80 characters, it should be a single line.
##### Examples
### Quotes
-Always use single quotes for strings (even if the string has `'`) and double quotes for docstrings. Use `'''` only for multi-line strings. An exception can be made if a string has multiple single quotes in it and escaping makes it significantly harder to read. For f-strings, use you can use double quotes on the inside. But avoid f-strings that have too many quotes inside.
+Always use single quotes for strings (even if the string has `'`) and double quotes for docstrings. Use `'''` only for multi-line strings. An exception can be made if a string has multiple single quotes in it and escaping makes it *significantly* harder to read. For f-strings, use you can use double quotes on the inside. But avoid f-strings that have too many quotes inside.
### 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
+#### Examples
Correct:
```python
-title = self._html_search_regex(r'<h1>([^<]+)</h1>', webpage, 'title')
+return {
+ 'title': self._html_search_regex(r'<h1>([^<]+)</h1>', webpage, 'title'),
+ # ...some lines of code...
+}
```
Incorrect:
TITLE_RE = r'<h1>([^<]+)</h1>'
# ...some lines of code...
title = self._html_search_regex(TITLE_RE, webpage, 'title')
+# ...some lines of code...
+return {
+ 'title': title,
+ # ...some lines of code...
+}
```
### Trailing parentheses
-Always move trailing parentheses used for grouping/functions after the last argument. On the other hand, literal list/tuple/dict/set should closed be in a new line. Generators and list/dict comprehensions may use either style
+Always move trailing parentheses used for grouping/functions after the last argument. On the other hand, multi-line literal list/tuple/dict/set should closed be in a new line. Generators and list/dict comprehensions may use either style
#### Examples
Correct:
```python
-url = try_get(
- info,
- lambda x: x['ResultSet']['Result'][0]['VideoUrlSet']['VideoUrl'],
- list)
+url = traverse_obj(info, (
+ 'context', 'dispatcher', 'stores', 'VideoTitlePageStore', 'data', 'video', 0, 'VideoUrlSet', 'VideoUrl'), list)
```
Correct:
```python
-url = try_get(info,
- lambda x: x['ResultSet']['Result'][0]['VideoUrlSet']['VideoUrl'],
- list)
+url = traverse_obj(
+ info,
+ ('context', 'dispatcher', 'stores', 'VideoTitlePageStore', 'data', 'video', 0, 'VideoUrlSet', 'VideoUrl'),
+ list)
```
Incorrect:
```python
-url = try_get(
+url = traverse_obj(
info,
- lambda x: x['ResultSet']['Result'][0]['VideoUrlSet']['VideoUrl'],
- list,
+ ('context', 'dispatcher', 'stores', 'VideoTitlePageStore', 'data', 'video', 0, 'VideoUrlSet', 'VideoUrl'),
+ list
)
```
### Use convenience conversion and parsing functions
-Wrap all extracted numeric data into safe functions from [`yt_dlp/utils.py`](yt_dlp/utils.py): `int_or_none`, `float_or_none`. Use them for string to number conversions as well.
+Wrap all extracted numeric data into safe functions from [`yt_dlp/utils/`](yt_dlp/utils/): `int_or_none`, `float_or_none`. Use them for string to number conversions as well.
Use `url_or_none` for safe URL processing.
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 [`yt_dlp/utils.py`](yt_dlp/utils.py) for more useful convenience functions.
+Explore [`yt_dlp/utils/`](yt_dlp/utils/) for more useful convenience functions.
-#### More examples
+#### Examples
-##### Safely extract optional description from parsed JSON
```python
description = traverse_obj(response, ('result', 'video', 'summary'), expected_type=str)
-```
-
-##### Safely extract more optional metadata
-```python
+thumbnails = traverse_obj(response, ('result', 'thumbnails', ..., 'url'), expected_type=url_or_none)
video = traverse_obj(response, ('result', 'video', 0), default={}, expected_type=dict)
-description = video.get('summary')
duration = float_or_none(video.get('durationMs'), scale=1000)
view_count = int_or_none(video.get('views'))
```
+
# My pull request is labeled pending-fixes
The `pending-fixes` label is added when there are changes requested to a PR. When the necessary changes are made, the label should be removed. However, despite our best efforts, it may sometimes happen that the maintainer did not see the changes or forgot to remove the label. If your PR is still marked as `pending-fixes` a few days after all requested changes have been made, feel free to ping the maintainer who labeled your issue and ask them to re-review and remove the label.
projects / yt-dlp.git / blobdiff