add code for analysis of data

1 files changed, 439 insertions, 0 deletions

diff --git a/venv/lib/python3.8/site-packages/werkzeug/middleware/lint.py b/venv/lib/python3.8/site-packages/werkzeug/middleware/lint.py
new file mode 100644
index 0000000..de93b52
--- /dev/null
+++ b/venv/lib/python3.8/site-packages/werkzeug/middleware/lint.py
@@ -0,0 +1,439 @@
+"""
+WSGI Protocol Linter
+====================
+
+This module provides a middleware that performs sanity checks on the
+behavior of the WSGI server and application. It checks that the
+:pep:`3333` WSGI spec is properly implemented. It also warns on some
+common HTTP errors such as non-empty responses for 304 status codes.
+
+.. autoclass:: LintMiddleware
+
+:copyright: 2007 Pallets
+:license: BSD-3-Clause
+"""
+
+from __future__ import annotations
+
+import typing as t
+from types import TracebackType
+from urllib.parse import urlparse
+from warnings import warn
+
+from ..datastructures import Headers
+from ..http import is_entity_header
+from ..wsgi import FileWrapper
+
+if t.TYPE_CHECKING:
+    from _typeshed.wsgi import StartResponse
+    from _typeshed.wsgi import WSGIApplication
+    from _typeshed.wsgi import WSGIEnvironment
+
+
+class WSGIWarning(Warning):
+    """Warning class for WSGI warnings."""
+
+
+class HTTPWarning(Warning):
+    """Warning class for HTTP warnings."""
+
+
+def check_type(context: str, obj: object, need: type = str) -> None:
+    if type(obj) is not need:
+        warn(
+            f"{context!r} requires {need.__name__!r}, got {type(obj).__name__!r}.",
+            WSGIWarning,
+            stacklevel=3,
+        )
+
+
+class InputStream:
+    def __init__(self, stream: t.IO[bytes]) -> None:
+        self._stream = stream
+
+    def read(self, *args: t.Any) -> bytes:
+        if len(args) == 0:
+            warn(
+                "WSGI does not guarantee an EOF marker on the input stream, thus making"
+                " calls to 'wsgi.input.read()' unsafe. Conforming servers may never"
+                " return from this call.",
+                WSGIWarning,
+                stacklevel=2,
+            )
+        elif len(args) != 1:
+            warn(
+                "Too many parameters passed to 'wsgi.input.read()'.",
+                WSGIWarning,
+                stacklevel=2,
+            )
+        return self._stream.read(*args)
+
+    def readline(self, *args: t.Any) -> bytes:
+        if len(args) == 0:
+            warn(
+                "Calls to 'wsgi.input.readline()' without arguments are unsafe. Use"
+                " 'wsgi.input.read()' instead.",
+                WSGIWarning,
+                stacklevel=2,
+            )
+        elif len(args) == 1:
+            warn(
+                "'wsgi.input.readline()' was called with a size hint. WSGI does not"
+                " support this, although it's available on all major servers.",
+                WSGIWarning,
+                stacklevel=2,
+            )
+        else:
+            raise TypeError("Too many arguments passed to 'wsgi.input.readline()'.")
+        return self._stream.readline(*args)
+
+    def __iter__(self) -> t.Iterator[bytes]:
+        try:
+            return iter(self._stream)
+        except TypeError:
+            warn("'wsgi.input' is not iterable.", WSGIWarning, stacklevel=2)
+            return iter(())
+
+    def close(self) -> None:
+        warn("The application closed the input stream!", WSGIWarning, stacklevel=2)
+        self._stream.close()
+
+
+class ErrorStream:
+    def __init__(self, stream: t.IO[str]) -> None:
+        self._stream = stream
+
+    def write(self, s: str) -> None:
+        check_type("wsgi.error.write()", s, str)
+        self._stream.write(s)
+
+    def flush(self) -> None:
+        self._stream.flush()
+
+    def writelines(self, seq: t.Iterable[str]) -> None:
+        for line in seq:
+            self.write(line)
+
+    def close(self) -> None:
+        warn("The application closed the error stream!", WSGIWarning, stacklevel=2)
+        self._stream.close()
+
+
+class GuardedWrite:
+    def __init__(self, write: t.Callable[[bytes], object], chunks: list[int]) -> None:
+        self._write = write
+        self._chunks = chunks
+
+    def __call__(self, s: bytes) -> None:
+        check_type("write()", s, bytes)
+        self._write(s)
+        self._chunks.append(len(s))
+
+
+class GuardedIterator:
+    def __init__(
+        self,
+        iterator: t.Iterable[bytes],
+        headers_set: tuple[int, Headers],
+        chunks: list[int],
+    ) -> None:
+        self._iterator = iterator
+        self._next = iter(iterator).__next__
+        self.closed = False
+        self.headers_set = headers_set
+        self.chunks = chunks
+
+    def __iter__(self) -> GuardedIterator:
+        return self
+
+    def __next__(self) -> bytes:
+        if self.closed:
+            warn("Iterated over closed 'app_iter'.", WSGIWarning, stacklevel=2)
+
+        rv = self._next()
+
+        if not self.headers_set:
+            warn(
+                "The application returned before it started the response.",
+                WSGIWarning,
+                stacklevel=2,
+            )
+
+        check_type("application iterator items", rv, bytes)
+        self.chunks.append(len(rv))
+        return rv
+
+    def close(self) -> None:
+        self.closed = True
+
+        if hasattr(self._iterator, "close"):
+            self._iterator.close()
+
+        if self.headers_set:
+            status_code, headers = self.headers_set
+            bytes_sent = sum(self.chunks)
+            content_length = headers.get("content-length", type=int)
+
+            if status_code == 304:
+                for key, _value in headers:
+                    key = key.lower()
+                    if key not in ("expires", "content-location") and is_entity_header(
+                        key
+                    ):
+                        warn(
+                            f"Entity header {key!r} found in 304 response.",
+                            HTTPWarning,
+                            stacklevel=2,
+                        )
+                if bytes_sent:
+                    warn(
+                        "304 responses must not have a body.",
+                        HTTPWarning,
+                        stacklevel=2,
+                    )
+            elif 100 <= status_code < 200 or status_code == 204:
+                if content_length != 0:
+                    warn(
+                        f"{status_code} responses must have an empty content length.",
+                        HTTPWarning,
+                        stacklevel=2,
+                    )
+                if bytes_sent:
+                    warn(
+                        f"{status_code} responses must not have a body.",
+                        HTTPWarning,
+                        stacklevel=2,
+                    )
+            elif content_length is not None and content_length != bytes_sent:
+                warn(
+                    "Content-Length and the number of bytes sent to the"
+                    " client do not match.",
+                    WSGIWarning,
+                    stacklevel=2,
+                )
+
+    def __del__(self) -> None:
+        if not self.closed:
+            try:
+                warn(
+                    "Iterator was garbage collected before it was closed.",
+                    WSGIWarning,
+                    stacklevel=2,
+                )
+            except Exception:
+                pass
+
+
+class LintMiddleware:
+    """Warns about common errors in the WSGI and HTTP behavior of the
+    server and wrapped application. Some of the issues it checks are:
+
+    -   invalid status codes
+    -   non-bytes sent to the WSGI server
+    -   strings returned from the WSGI application
+    -   non-empty conditional responses
+    -   unquoted etags
+    -   relative URLs in the Location header
+    -   unsafe calls to wsgi.input
+    -   unclosed iterators
+
+    Error information is emitted using the :mod:`warnings` module.
+
+    :param app: The WSGI application to wrap.
+
+    .. code-block:: python
+
+        from werkzeug.middleware.lint import LintMiddleware
+        app = LintMiddleware(app)
+    """
+
+    def __init__(self, app: WSGIApplication) -> None:
+        self.app = app
+
+    def check_environ(self, environ: WSGIEnvironment) -> None:
+        if type(environ) is not dict:  # noqa: E721
+            warn(
+                "WSGI environment is not a standard Python dict.",
+                WSGIWarning,
+                stacklevel=4,
+            )
+        for key in (
+            "REQUEST_METHOD",
+            "SERVER_NAME",
+            "SERVER_PORT",
+            "wsgi.version",
+            "wsgi.input",
+            "wsgi.errors",
+            "wsgi.multithread",
+            "wsgi.multiprocess",
+            "wsgi.run_once",
+        ):
+            if key not in environ:
+                warn(
+                    f"Required environment key {key!r} not found",
+                    WSGIWarning,
+                    stacklevel=3,
+                )
+        if environ["wsgi.version"] != (1, 0):
+            warn("Environ is not a WSGI 1.0 environ.", WSGIWarning, stacklevel=3)
+
+        script_name = environ.get("SCRIPT_NAME", "")
+        path_info = environ.get("PATH_INFO", "")
+
+        if script_name and script_name[0] != "/":
+            warn(
+                f"'SCRIPT_NAME' does not start with a slash: {script_name!r}",
+                WSGIWarning,
+                stacklevel=3,
+            )
+
+        if path_info and path_info[0] != "/":
+            warn(
+                f"'PATH_INFO' does not start with a slash: {path_info!r}",
+                WSGIWarning,
+                stacklevel=3,
+            )
+
+    def check_start_response(
+        self,
+        status: str,
+        headers: list[tuple[str, str]],
+        exc_info: None | (tuple[type[BaseException], BaseException, TracebackType]),
+    ) -> tuple[int, Headers]:
+        check_type("status", status, str)
+        status_code_str = status.split(None, 1)[0]
+
+        if len(status_code_str) != 3 or not status_code_str.isdecimal():
+            warn("Status code must be three digits.", WSGIWarning, stacklevel=3)
+
+        if len(status) < 4 or status[3] != " ":
+            warn(
+                f"Invalid value for status {status!r}. Valid status strings are three"
+                " digits, a space and a status explanation.",
+                WSGIWarning,
+                stacklevel=3,
+            )
+
+        status_code = int(status_code_str)
+
+        if status_code < 100:
+            warn("Status code < 100 detected.", WSGIWarning, stacklevel=3)
+
+        if type(headers) is not list:  # noqa: E721
+            warn("Header list is not a list.", WSGIWarning, stacklevel=3)
+
+        for item in headers:
+            if type(item) is not tuple or len(item) != 2:
+                warn("Header items must be 2-item tuples.", WSGIWarning, stacklevel=3)
+            name, value = item
+            if type(name) is not str or type(value) is not str:  # noqa: E721
+                warn(
+                    "Header keys and values must be strings.", WSGIWarning, stacklevel=3
+                )
+            if name.lower() == "status":
+                warn(
+                    "The status header is not supported due to"
+                    " conflicts with the CGI spec.",
+                    WSGIWarning,
+                    stacklevel=3,
+                )
+
+        if exc_info is not None and not isinstance(exc_info, tuple):
+            warn("Invalid value for exc_info.", WSGIWarning, stacklevel=3)
+
+        headers_obj = Headers(headers)
+        self.check_headers(headers_obj)
+
+        return status_code, headers_obj
+
+    def check_headers(self, headers: Headers) -> None:
+        etag = headers.get("etag")
+
+        if etag is not None:
+            if etag.startswith(("W/", "w/")):
+                if etag.startswith("w/"):
+                    warn(
+                        "Weak etag indicator should be upper case.",
+                        HTTPWarning,
+                        stacklevel=4,
+                    )
+
+                etag = etag[2:]
+
+            if not (etag[:1] == etag[-1:] == '"'):
+                warn("Unquoted etag emitted.", HTTPWarning, stacklevel=4)
+
+        location = headers.get("location")
+
+        if location is not None:
+            if not urlparse(location).netloc:
+                warn(
+                    "Absolute URLs required for location header.",
+                    HTTPWarning,
+                    stacklevel=4,
+                )
+
+    def check_iterator(self, app_iter: t.Iterable[bytes]) -> None:
+        if isinstance(app_iter, str):
+            warn(
+                "The application returned a string. The response will send one"
+                " character at a time to the client, which will kill performance."
+                " Return a list or iterable instead.",
+                WSGIWarning,
+                stacklevel=3,
+            )
+
+    def __call__(self, *args: t.Any, **kwargs: t.Any) -> t.Iterable[bytes]:
+        if len(args) != 2:
+            warn("A WSGI app takes two arguments.", WSGIWarning, stacklevel=2)
+
+        if kwargs:
+            warn(
+                "A WSGI app does not take keyword arguments.", WSGIWarning, stacklevel=2
+            )
+
+        environ: WSGIEnvironment = args[0]
+        start_response: StartResponse = args[1]
+
+        self.check_environ(environ)
+        environ["wsgi.input"] = InputStream(environ["wsgi.input"])
+        environ["wsgi.errors"] = ErrorStream(environ["wsgi.errors"])
+
+        # Hook our own file wrapper in so that applications will always
+        # iterate to the end and we can check the content length.
+        environ["wsgi.file_wrapper"] = FileWrapper
+
+        headers_set: list[t.Any] = []
+        chunks: list[int] = []
+
+        def checking_start_response(
+            *args: t.Any, **kwargs: t.Any
+        ) -> t.Callable[[bytes], None]:
+            if len(args) not in {2, 3}:
+                warn(
+                    f"Invalid number of arguments: {len(args)}, expected 2 or 3.",
+                    WSGIWarning,
+                    stacklevel=2,
+                )
+
+            if kwargs:
+                warn(
+                    "'start_response' does not take keyword arguments.",
+                    WSGIWarning,
+                    stacklevel=2,
+                )
+
+            status: str = args[0]
+            headers: list[tuple[str, str]] = args[1]
+            exc_info: (
+                None | (tuple[type[BaseException], BaseException, TracebackType])
+            ) = args[2] if len(args) == 3 else None
+
+            headers_set[:] = self.check_start_response(status, headers, exc_info)
+            return GuardedWrite(start_response(status, headers, exc_info), chunks)
+
+        app_iter = self.app(environ, t.cast("StartResponse", checking_start_response))
+        self.check_iterator(app_iter)
+        return GuardedIterator(
+            app_iter, t.cast(t.Tuple[int, Headers], headers_set), chunks
+        )