Validation schemas

Please see the validation schema guides for an introduction to this API and a list of examples.

Public interface

While the internals are implemented in the streamlink.validate package, streamlink.plugin.api.validate provides the main public interface for plugin implementors.

class streamlink.plugin.api.validate.Schema(*schemas)

Bases: AllSchema

The base class for creating validation schemas.

A wrapper for AllSchema with a wrapper method for validate() which by default raises PluginError on error.

validate(value, name='result', exception=<class 'streamlink.exceptions.PluginError'>)
Parameters:

  • value (Any)

  • name (str)

  • exception (type[Exception])

Return type:

Any

streamlink.plugin.api.validate.validate(schema, value)

The core of the streamlink.plugin.api.validate module.

It validates the given input value and returns a value according to the specific validation rules of the schema.

If the validation fails, a ValidationError is raised with a detailed error message.

The schema can be any kind of object. Depending on the schema, different validation rules apply.

Simple schema objects like "abc" or 123 for example test the equality of value and schema and return value again, while type schema objects like str test whether value is an instance of schema. schema objects which are callable receive value as a single argument and must return a truthy value, otherwise the validation fails. These are just a few examples.

The validate module implements lots of special schemas, like validate.all or validate.any for example, which are schema containers that receive a sequence of sub-schemas as arguments and where each sub-schema then gets validated one after another.

validate.all requires each sub-schema to successfully validate. It passes the return value of each sub-schema to the next one and then returns the return value of the last sub-schema.

validate.any on the other hand requires at least one sub-schema to be valid and returns the return value of the first valid sub-schema. Any validation failures prior will be ignored, but at least one must succeed.

Other special schema cases for example are instances of sequences like list or tuple, or mappings like dict. Here, each sequence item or key-value mapping pair is validated against the input value and a new sequence/mapping object according to the schema validation is returned.

validate() should usually not be called directly when validating schemas. Instead, the wrapper method Schema.validate() of the main Schema class should be called. Other Streamlink APIs like the methods of the HTTPSession or the various streamlink.utils.parse functions for example expect this interface when the schema keyword is set, which allows for immediate validation of the data using a Schema object.

validate() is implemented using the stdlib's functools.singledispatch() decorator, where more specific schemas overload the default implementation with more validation logic.

By default, validate() compares value and schema for equality. This means that simple schema objects like booleans, strings, numbers, None, etc. are validated here, as well as anything unknown.

Example:

schema = validate.Schema(123)
assert schema.validate(123) == 123
assert schema.validate(123.0) == 123.0
schema.validate(456)  # raises ValidationError
schema.validate(None)  # raises ValidationError
Parameters:

  • schema (Any) -- Any kind of object not handled by a more specific validation function

  • value (Any) -- The input value

Raises:

ValidationError -- If value and schema are not equal

Returns:

Unmodified value

streamlink.plugin.api.validate._validate_type(schema, value)

type validation.

Checks if value is an instance of schema.

Example:

schema = validate.Schema(int)
assert schema.validate(123) == 123
assert schema.validate(True) is True  # `bool` is a subclass of `int`
schema.validate("123")  # raises ValidationError

This function is included for documentation purposes only! (singledispatch overload)

Parameters:

  • schema (type) -- A type object

  • value (Any) -- The input value

Raises:

ValidationError -- If value is not an instance of schema

Returns:

Unmodified value

streamlink.plugin.api.validate._validate_callable(schema, value)

Callable validation.

Validates a schema function where value gets passed as a single argument.

Must return a truthy value.

Example:

schema = validate.Schema(
    lambda val: val < 2,
)
assert schema.validate(1) == 1
schema.validate(2)  # raises ValidationError

This function is included for documentation purposes only! (singledispatch overload)

Parameters:

  • schema (Callable) -- A function with one argument

  • value (Any) -- The input value

Raises:

ValidationError -- If schema returns a non-truthy value

Returns:

Unmodified value

streamlink.plugin.api.validate._validate_sequence(schema, value)

list, tuple, set and frozenset validation.

Each item of value gets validated against any of the items of schema.

Please note the difference between list and the ListSchema validation.

Example:

schema = validate.Schema([1, 2, 3])
assert schema.validate([]) == []
assert schema.validate([1, 2]) == [1, 2]
assert schema.validate([3, 2, 1]) == [3, 2, 1]
schema.validate({1, 2, 3})  # raises ValidationError
schema.validate([1, 2, 3, 4])  # raises ValidationError

This function is included for documentation purposes only! (singledispatch overload)

Parameters:

  • schema (Union[list, tuple, set, frozenset]) -- A sequence of validation schemas

  • value (Any) -- The input value

Raises:

ValidationError -- If value is not an instance of the schema's own type

Returns:

A new sequence of the same type as schema with each item of value being validated

streamlink.plugin.api.validate._validate_dict(schema, value)

dict validation.

Each key-value pair of schema gets validated against the respective key-value pair of value.

Additional keys in value are ignored and not included in the validation result.

If a schema key is an instance of OptionalSchema, then value may omit it.

If one of the schema's keys is a type, AllSchema, AnySchema, TransformSchema, or UnionSchema, then all key-value pairs of value are validated against the schema's key-value pair.

Example:

schema = validate.Schema({
    "key": str,
    validate.optional("opt"): 123,
})
assert schema.validate({"key": "val", "other": 123}) == {"key": "val"}
assert schema.validate({"key": "val", "opt": 123}) == {"key": "val", "opt": 123}
schema.validate(None)  # raises ValidationError
schema.validate({})  # raises ValidationError
schema.validate({"key": 123})  # raises ValidationError
schema.validate({"key": "val", "opt": 456})  # raises ValidationError

schema = validate.Schema({
    validate.any("a", "b"): int,
})
assert schema.validate({}) == {}
assert schema.validate({"a": 1}) == {"a": 1}
assert schema.validate({"b": 2}) == {"b": 2}
assert schema.validate({"a": 1, "b": 2}) == {"a": 1, "b": 2}
schema.validate({"a": 1, "b": 2, "other": 0})  # raises ValidationError
schema.validate({"a": None})  # raises ValidationError

This function is included for documentation purposes only! (singledispatch overload)

Parameters:

  • schema (dict) -- A dict

  • value (Any) -- The input value

Raises:
Returns:

A new dict

streamlink.plugin.api.validate._validate_pattern(schema, value)

re.Pattern validation.

Calls the re.Pattern.search() method on the schema pattern.

Please note the difference between re.Pattern and the RegexSchema validation.

Example:

schema = validate.Schema(
    re.compile(r"^Hello, (?P<name>\w+)!$"),
)
assert schema.validate("Does not match") is None
assert schema.validate("Hello, world!")["name"] == "world"
schema.validate(123)  # raises ValidationError
schema.validate(b"Hello, world!")  # raises ValidationError

This function is included for documentation purposes only! (singledispatch overload)

Parameters:

  • schema (re.Pattern) -- A compiled re.Pattern object (re.compile() return value)

  • value (Any) -- The input value

Raises:
Returns:

None if value doesn't match schema, or the resulting re.Match object

streamlink.plugin.api.validate.all

alias of AllSchema

streamlink.plugin.api.validate.any

alias of AnySchema

streamlink.plugin.api.validate.attr

alias of AttrSchema

streamlink.plugin.api.validate.contains(string)

Utility function for checking whether the input string contains another string.

Example:

schema = validate.Schema(
    validate.contains("456"),
)
assert schema.validate("123456789") == "123456789"
schema.validate("987654321")  # raises ValidationError
schema.validate(None)  # raises ValidationError
Raises:
Parameters:

string (str)

Return type:

Callable[[str], bool]

streamlink.plugin.api.validate.endswith(string)

Utility function for checking whether the input string ends with another string.

Example:

schema = validate.Schema(
    validate.endswith("3"),
)
assert schema.validate("123") == "123"
schema.validate("321")  # raises ValidationError
schema.validate(None)  # raises ValidationError
Raises:
Parameters:

string (str)

Return type:

Callable[[str], bool]

streamlink.plugin.api.validate.filter(func)

Utility function for filtering out unwanted items from the input using the specified function via the built-in filter().

Supports iterables, as well as instances of dict where key-value pairs are expanded.

Example:

schema = validate.Schema(
    validate.filter(lambda val: val < 3),
)
assert schema.validate([1, 2, 3, 4]) == [1, 2]

schema = validate.Schema(
    validate.filter(lambda key, val: key > 1 and val < 3),
)
assert schema.validate({0: 0, 1: 1, 2: 2, 3: 3, 4: 4}) == {2: 2}
Parameters:

func (Callable[[...], bool])

Return type:

TransformSchema

streamlink.plugin.api.validate.get

alias of GetItemSchema

streamlink.plugin.api.validate.getattr(attr, default=None)

Utility function for getting an attribute from the input object.

If a default is set, it is returned when the attribute doesn't exist.

Example:

schema = validate.Schema(
    validate.getattr("year", "unknown"),
)
assert schema.validate(datetime.date.fromisoformat("2000-01-01")) == 2000
assert schema.validate("not a date/datetime object") == "unknown"
Parameters:

  • attr (Any)

  • default (Any)

Return type:

TransformSchema

streamlink.plugin.api.validate.hasattr(attr)

Utility function for checking whether an attribute exists on the input object.

Example:

schema = validate.Schema(
    validate.hasattr("year"),
)
date = datetime.date.fromisoformat("2000-01-01")
assert schema.validate(date) is date
schema.validate("not a date/datetime object")  # raises ValidationError
Parameters:

attr (Any)

Return type:

Callable[[Any], bool]

streamlink.plugin.api.validate.length(number, op='ge')

Utility function for checking whether the input has a certain length, by using len(). Checks the minimum length by default (op="ge").

Example:

schema = validate.Schema(
    validate.length(3),
)
assert schema.validate("abc") == "abc"
assert schema.validate([1, 2, 3, 4]) == [1, 2, 3, 4]
schema.validate("a")  # raises ValidationError
schema.validate([1])  # raises ValidationError

schema = validate.Schema(
    validate.length(3, op="lt"),
)
assert schema.validate("ab") == "ab"
schema.validate([1, 2, 3])  # raises ValidationError
Parameters:

  • number (int)

  • op (Literal['lt', 'le', 'eq', 'ge', 'gt'])

Return type:

Callable[[str], bool]

streamlink.plugin.api.validate.list

alias of ListSchema

streamlink.plugin.api.validate.map(func)

Utility function for mapping/transforming items from the input using the specified function, via the built-in map().

Supports iterables, as well as instances of dict where key-value pairs are expanded.

Example:

schema = validate.Schema(
    validate.map(lambda val: val + 1),
)
assert schema.validate([1, 2, 3, 4]) == [2, 3, 4, 5]

schema = validate.Schema(
    validate.map(lambda key, val: (key + 1, val * 2)),
)
assert schema.validate({0: 0, 1: 1, 2: 2, 3: 3, 4: 4}) == {1: 0, 2: 2, 3: 4, 4: 6, 5: 8}
Parameters:

func (Callable[[...], Any])

Return type:

TransformSchema

streamlink.plugin.api.validate.none_or_all

alias of NoneOrAllSchema

streamlink.plugin.api.validate.optional

alias of OptionalSchema

streamlink.plugin.api.validate.parse_html(*args, **kwargs)

Utility function for parsing HTML data using streamlink.utils.parse.parse_html().

Example:

schema = validate.Schema(
    validate.parse_html(),
)
assert schema.validate("""<html lang="en">""").attrib["lang"] == "en"
schema.validate(123)  # raises ValidationError
Raises:

ValidationError -- On parsing error

Return type:

TransformSchema

streamlink.plugin.api.validate.parse_json(*args, **kwargs)

Utility function for parsing JSON data using streamlink.utils.parse.parse_json().

Example:

schema = validate.Schema(
    validate.parse_json(),
)
assert schema.validate("""{"a":[1,2,3],"b":null}""") == {"a": [1, 2, 3], "b": None}
schema.validate(123)  # raises ValidationError
Raises:

ValidationError -- On parsing error

Return type:

TransformSchema

streamlink.plugin.api.validate.parse_qsd(*args, **kwargs)

Utility function for parsing a query string using streamlink.utils.parse.parse_qsd().

Example:

schema = validate.Schema(
    validate.parse_qsd(),
)
assert schema.validate("a=b&a=c&foo=bar") == {"a": "c", "foo": "bar"}
schema.validate(123)  # raises ValidationError
Raises:

ValidationError -- On parsing error

Return type:

TransformSchema

streamlink.plugin.api.validate.parse_xml(*args, **kwargs)

Utility function for parsing XML data using streamlink.utils.parse.parse_xml().

Example:

schema = validate.Schema(
    validate.parse_xml(),
)
assert schema.validate("""<a b="c"/>""").attrib["b"] == "c"
schema.validate(123)  # raises ValidationError
Raises:

ValidationError -- On parsing error

Return type:

TransformSchema

streamlink.plugin.api.validate.regex

alias of RegexSchema

streamlink.plugin.api.validate.startswith(string)

Utility function for checking whether the input string starts with another string.

Example:

schema = validate.Schema(
    validate.startswith("1"),
)
assert schema.validate("123") == "123"
schema.validate("321")  # raises ValidationError
schema.validate(None)  # raises ValidationError
Raises:
Parameters:

string (str)

Return type:

Callable[[str], bool]

streamlink.plugin.api.validate.transform

alias of TransformSchema

streamlink.plugin.api.validate.union

alias of UnionSchema

streamlink.plugin.api.validate.union_get

alias of UnionGetSchema

streamlink.plugin.api.validate.url(**attributes)

Utility function for validating a URL using schemas.

Allows validating all URL attributes returned by urllib.parse.urlparse():

  • scheme - updated to AnySchema("http", "https") if set to "http"

  • netloc

  • path

  • params

  • query

  • fragment

  • username

  • password

  • hostname

  • port

Example:

schema = validate.Schema(
    validate.url(path=validate.endswith(".m3u8")),
)
assert schema.validate("https://host/pl.m3u8?query") == "https://host/pl.m3u8?query"
schema.validate(None)  # raises ValidationError
schema.validate("not a URL")  # raises ValidationError
schema.validate("https://host/no-pl?pl.m3u8")  # raises ValidationError
Raises:
Return type:

Callable[[str], bool]

streamlink.plugin.api.validate.xml_element

alias of XmlElementSchema

streamlink.plugin.api.validate.xml_find(path, namespaces=None)

Utility function for finding an XML element using Element.find().

This method uses the ElementPath query language, which is a subset of XPath.

Example:

schema = validate.Schema(
    validate.xml_find(".//b/c"),
)
assert schema.validate(lxml.etree.XML("<a><b><c>d</c></b></a>")).text == "d"
schema.validate(lxml.etree.XML("<a><b></b></a>"))  # raises ValidationError
schema.validate("<a><b><c>d</c></b></a>")  # raises ValidationError
Raises:
Parameters:

  • path (str)

  • namespaces (Mapping[str, str] | None)

Return type:

TransformSchema

streamlink.plugin.api.validate.xml_findall(path, namespaces=None)

Utility function for finding XML elements using Element.findall().

This method uses the ElementPath query language, which is a subset of XPath.

Example:

schema = validate.Schema(
    validate.xml_findall(".//b"),
    validate.map(lambda elem: elem.text),
)
assert schema.validate(lxml.etree.XML("<a><b>1</b><b>2</b></a>")) == ["1", "2"]
assert schema.validate(lxml.etree.XML("<a><c></c></a>")) == []
schema.validate("<a><b>1</b><b>2</b></a>")  # raises ValidationError
Raises:
Parameters:

  • path (str)

  • namespaces (Mapping[str, str] | None)

Return type:

TransformSchema

streamlink.plugin.api.validate.xml_findtext(path, namespaces=None)

Utility function for finding an XML element using Element.find() and returning its text attribute.

This method uses the ElementPath query language, which is a subset of XPath.

Example:

schema = validate.Schema(
    validate.xml_findtext(".//b/c"),
)
assert schema.validate(lxml.etree.XML("<a><b><c>d</c></b></a>")) == "d"
schema.validate(lxml.etree.XML("<a><b></b></a>"))  # raises ValidationError
schema.validate("<a><b><c>d</c></b></a>")  # raises ValidationError
Raises:
Parameters:

  • path (str)

  • namespaces (Mapping[str, str] | None)

Return type:

AllSchema

streamlink.plugin.api.validate.xml_xpath(xpath, namespaces=None, extensions=None, smart_strings=True, **variables)

Utility function for querying XML elements using XPath (Element.xpath()).

XPath queries always return a result set, but if the result is an empty set, this function instead returns None.

Allows setting XPath variables ($var) as additional keywords.

Example:

schema = validate.Schema(
    validate.xml_xpath(".//b[@c=$c][1]/@d", c="2"),
)
assert schema.validate(lxml.etree.XML("<a><b c='1' d='A'/><b c='2' d='B'/></a>")) == ["B"]
assert schema.validate(lxml.etree.XML("<a></a>")) is None
schema.validate("<a><b c='1' d='A'/><b c='2' d='B'/></a>")  # raises ValidationError
Raises:
Parameters:

  • xpath (str)

  • namespaces (Mapping[str, str] | None)

  • extensions (Mapping[tuple[str | None, str], Callable[[...], Any]] | None)

  • smart_strings (bool)

Return type:

TransformSchema

streamlink.plugin.api.validate.xml_xpath_string(xpath, namespaces=None, extensions=None, **variables)

Utility function for querying XML elements using XPath (Element.xpath()) and turning the result into a string.

XPath queries always return a result set, so be aware when querying multiple elements. If the result is an empty set, this function instead returns None.

Allows setting XPath variables ($var) as additional keywords.

Example:

schema = validate.Schema(
    validate.xml_xpath_string(".//b[2]/text()"),
)
assert schema.validate(lxml.etree.XML("<a><b>A</b><b>B</b><b>C</b></a>")) == "B"
assert schema.validate(lxml.etree.XML("<a></a>")) is None
schema.validate("<a><b>A</b><b>B</b><b>C</b></a>")  # raises ValidationError
Raises:
Parameters:

  • xpath (str)

  • namespaces (Mapping[str, str] | None)

  • extensions (Mapping[tuple[str | None, str], Callable[[...], Any]] | None)

Return type:

TransformSchema

class streamlink.validate._schemas.AllSchema(*schemas)

A collection of schemas where each schema must be valid.

Validates one schema after another with the input value of the return value of the previous one.

Example:

# `validate.Schema` is a subclass of `AllSchema` (`validate.all`)
schema = validate.Schema(
    int,
    validate.transform(lambda val: val + 1),
    lambda val: val < 3,
)
assert schema.validate(1) == 2
schema.validate("a")  # raises ValidationError
schema.validate(2)  # raises ValidationError
Parameters:

*schemas (Any) -- Schemas where each one must be valid

Returns:

The return value of the last schema

class streamlink.validate._schemas.AnySchema(*schemas)

A collection of schemas where at least one schema must be valid.

Validates one schema after another with the same input value until the first one succeeds.

Example:

schema = validate.Schema(
    validate.any(int, float, str),
)
assert schema.validate(123) == 123
assert schema.validate(123.0) == 123.0
assert schema.validate("123") == "123"
schema.validate(None)  # raises ValidationError
Parameters:

*schemas (Any) -- Schemas where at least one must be valid

Raises:

ValidationError -- Error collection of all schema validations if none succeeded

Returns:

The return value of the first valid schema

class streamlink.validate._schemas.NoneOrAllSchema(*schemas)

Similar to AllSchema, but skips the validation if the input value is None.

This is useful for optional validation results, e.g. when validating a potential match of a regular expression.

Example:

schema = validate.Schema(
    validate.none_or_all(
        int,
        lambda val: val < 2,
    ),
)
assert schema.validate(None) is None
assert schema.validate(1) == 1
schema.validate("123")  # raises ValidationError
schema.validate(2)  # raises ValidationError
Parameters:

*schemas (Any) -- Schemas where each one must be valid, unless the input is None

Raises:

ValidationError -- Error wrapper of the failed schema validation

Returns:

None if the input is None, or the return value of the last schema

class streamlink.validate._schemas.TransformSchema(func, *args, **kwargs)

A transform function which receives the input value as the argument, with optional custom arguments and keywords.

Example:

schema = validate.Schema(
    validate.transform(lambda val: val + 1),
    validate.transform(operator.lt, 3),
)
assert schema.validate(1) is True
assert schema.validate(2) is False
Parameters:

  • func (Callable) -- A transform function

  • *args -- Additional arguments

  • **kwargs -- Additional keywords

Raises:

ValidationError -- If the transform function is not callable

Returns:

The return value of the transform function

class streamlink.validate._schemas.OptionalSchema(key)

An optional key set in a dict.

See the dict validation and the UnionSchema.

Parameters:

key (Any)

class streamlink.validate._schemas.ListSchema(*schemas)

A list of schemas where every item must be valid, as well as the input type and length.

Please note the difference between ListSchema and the list validation.

Example:

schema = validate.Schema(
    validate.list(1, 2, int),
)
assert schema.validate([1, 2, 3]) == [1, 2, 3]
schema.validate(None)  # raises ValidationError
schema.validate([1, 2])  # raises ValidationError
schema.validate([3, 2, 1])  # raises ValidationError
Parameters:

*schema (Any) -- Schemas where each one must be valid

Raises:
Returns:

A new list with the validated input

class streamlink.validate._schemas.AttrSchema(schema)

Validate attributes of an input object according to a dict's key-value pairs.

Example:

schema = validate.Schema(
    validate.attr({
        "a": str,
        "b": int,
    }),
)
assert schema.validate(obj) is not obj
schema.validate(obj_without_a)  # raises ValidationError
schema.validate(obj_b_is_str)  # raises ValidationError
Parameters:

schema (dict[str, Any]) -- A dict with attribute validations

Raises:

ValidationError -- If the input doesn't have one of the schema's attributes

Returns:

A copy of the input object with validated attributes

class streamlink.validate._schemas.GetItemSchema(item, default=None, strict=False)

Get an item from the input.

The input can be anything that implements __getitem__(), as well as lxml.etree.Element objects where element attributes are looked up.

Returns the default value if item was not found.

Unless strict is set to True, the item can be a tuple of items for a recursive lookup. In this case, the default value is only returned if the leaf-input-object doesn't contain the current item.

Example:

schema = validate.Schema(
    validate.get("name", default="unknown"),
)
assert schema.validate({"name": "user"}) == "user"
assert schema.validate(re.match(r"Hello, (?P<name>\w+)!", "Hello, user!")) == "user"
assert schema.validate(lxml.etree.XML("""<elem name="abc"/>""")) == "abc"
assert schema.validate({}) == "unknown"
schema.validate(None)  # raises ValidationError

schema = validate.Schema(
    validate.get(("a", "b", "c")),
)
assert schema.validate({"a": {"b": {"c": "d"}}}) == "d"
assert schema.validate({"a": {"b": {}}}) is None
schema.validate({"a": {}})  # raises ValidationError
Parameters:

  • item (Any | tuple) -- The lookup key, or a tuple of recursive lookup keys

  • default (Any) -- Optional custom default value

  • strict (bool) -- If True, don't perform recursive lookups with the tuple item

Raises:

  • ValidationError -- If the input doesn't implement __getitem__()

  • ValidationError -- If the input doesn't have the current item in a recursive non-leaf-input-object lookup

Returns:

The __getitem__() return value, or an lxml.etree.Element attribute

class streamlink.validate._schemas.UnionSchema(schema)

Validate multiple schemas on the same input.

Example:

schema = validate.Schema(
    validate.union((
        validate.transform(str.format, one="abc", two="def"),
        validate.transform(str.format, one="123", two="456"),
    )),
)
assert schema.validate("{one} {two}") == ("abc def", "123 456")

schema = validate.Schema(
    validate.union({
        "one": lambda val: val < 3,
        validate.optional("two"): lambda val: val > 1,
    }),
)
assert schema.validate(1) == {"one": 1}
assert schema.validate(2) == {"one": 2, "two": 2}
schema.validate(3)  # raises ValidationError
Parameters:

schema (Union[tuple, list, set, frozenset, dict]) -- A tuple, list, set, frozenset or dict of schemas

Raises:

ValidationError -- If a sequence item or the value of a non-optional key-value pair doesn't validate

Returns:

A new object of the same type, with each item or key-value pair being validated against the same input value

class streamlink.validate._schemas.UnionGetSchema(*getters, seq=<class 'tuple'>)

Validate multiple GetItemSchema schemas on the same input.

Convenience wrapper for validate.union((validate.get(...), validate.get(...), ...)).

Example:

schema = validate.Schema(
    validate.union_get("a", "b", ("c", "d")),
)
assert schema.validate({"a": 1, "b": 2, "c": {"d": 3}}) == (1, 2, 3)
Parameters:

  • *getters -- Inputs for each GetItemSchema

  • seq (type[tuple | list | set | frozenset])

Returns:

A tuple (default seq type) with items of the respective GetItemSchema validations

class streamlink.validate._schemas.RegexSchema(pattern, method='search')

A re.Pattern that must match.

Allows selecting a different regex pattern method (default is re.Pattern.search()).

Please note the difference between RegexSchema and the re.Pattern validation.

Example:

schema = validate.Schema(
    validate.regex(re.compile(r"Hello, (?P<name>\w+)!")),
)
assert schema.validate("Hello, world!")["name"] == "world"
schema.validate("Does not match")  # raises ValidationError
schema.validate(123)  # raises ValidationError
schema.validate(b"Hello, world!")  # raises ValidationError

schema = validate.Schema(
    validate.regex(re.compile(r"Hello, (?P<name>\w+)!"), method="findall"),
)
assert schema.validate("Hello, userA! Hello, userB!") == ["userA", "userB"]
assert schema.validate("Does not match") == []  # findall does not return None
Parameters:

  • pattern (Pattern) -- A compiled pattern (re.compile() return value)

  • method (Literal['search', 'match', 'fullmatch', 'findall', 'split', 'sub', 'subn']) -- The pattern's method which will be called when validating

Raises:

  • ValidationError -- If the input is not an instance of str or bytes

  • ValidationError -- If the type of the input doesn't match the pattern's str/bytes type

  • ValidationError -- If the return value of the chosen regex pattern method is None

class streamlink.validate._schemas.XmlElementSchema(tag=None, text=None, attrib=None, tail=None)

Validate an XML element.

Example:

schema = validate.Schema(
    validate.xml_element(
        tag="foo",
        attrib={"bar": str},
        text=validate.transform(str.upper),
    ),
)
elem = lxml.etree.XML("""<foo bar="baz">qux</foo>""")
new_elem = schema.validate(elem)
assert new_elem is not elem
assert new_elem.tag == "foo"
assert new_elem.attrib == {"bar": "baz"}
assert new_elem.text == "QUX"
assert new_elem.tail is None
schema.validate(123)  # raises ValidationError
schema.validate(lxml.etree.XML("""<unknown/>"""))  # raises ValidationError
Parameters:

  • tag (Any) -- Optional element tag validation

  • text (Any) -- Optional element text validation

  • attrib (Any) -- Optional element attributes validation

  • tail (Any) -- Optional element tail validation

Raises:

ValidationError -- If value is not an lxml.etree.Element

Returns:

A new lxml.etree.Element object, including a deep-copy of the input's child nodes, with optionally validated tag, attrib mapping, text or tail.

exception streamlink.validate._exception.ValidationError(*errors, schema=None, **errkeywords)

Bases: ValueError

Currently not exposed in the public API.

Parameters:

  • errors (str | Exception | Sequence[str | Exception])

  • schema (str | object | None)