Renamed package itself

1 files changed, 259 insertions, 0 deletions

diff --git a/paste/lint.py b/paste/lint.py
new file mode 100644
index 0000000..0eac637
--- /dev/null
+++ b/paste/lint.py
@@ -0,0 +1,259 @@
+"""
+A lint of sorts; an anal middleware that checks for WSGI compliance
+both in the server and the application (but otherwise does not effect
+the request, it just looks at the communication).
+"""
+
+import re
+import sys
+from types import *
+
+header_re = re.compile(r'^[a-zA-Z][a-zA-Z0-9\-_]*$')
+bad_header_value_re = re.compile(r'[\000-\037]')
+
+def middleware(application):
+    def lint_app(*args, **kw):
+        assert len(args) == 2, "Two arguments required"
+        assert not kw, "No keyword arguments allowed"
+        environ, start_response = args
+
+        check_environ(environ)
+
+        # We use this to check if the application returns without
+        # calling start_response:
+        start_response_started = []
+
+        def start_response_wrapper(*args, **kw):
+            assert len(args) == 2 or len(args) == 3, "Invalid number of arguments: %s" % args
+            assert not kw, "No keyword arguments allowed"
+            status = args[0]
+            headers = args[1]
+            if len(args) == 3:
+                exc_info = args[2]
+            else:
+                exc_info = None
+
+            check_status(status)
+            check_headers(headers)
+            check_content_type(status, headers)
+            check_exc_info(exc_info)
+
+            start_response_started.append(None)
+            return WriteWrapper(start_response(*args))
+
+        environ['wsgi.input'] = InputWrapper(environ['wsgi.input'])
+        environ['wsgi.errors'] = ErrorWrapper(environ['wsgi.errors'])
+
+        iterator = application(environ, start_response_wrapper)
+        assert start_response_started, (
+            "The application returned, but did not call start_response()")
+        assert iterator is not None and iterator != False, \
+               "The application must return an iterator, if only an empty list"
+
+        check_iterator(iterator)
+
+        return IteratorWrapper(iterator)
+
+    return lint_app
+
+class InputWrapper:
+
+    def __init__(self, wsgi_input):
+        self.input = wsgi_input
+
+    def read(self, *args):
+        assert len(args) <= 1
+        v = self.input.read(*args)
+        assert type(v) is type("")
+        return v
+
+    def readline(self):
+        v = self.input.readline()
+        assert type(v) is type("")
+        return v
+
+    def readlines(self, *args):
+        assert len(args) <= 1
+        lines = self.input.readlines(*args)
+        assert type(lines) is type([])
+        for line in lines:
+            assert type(line) is type("")
+        return lines
+    
+    def __iter__(self):
+        while 1:
+            line = self.readline()
+            if not line:
+                return
+            yield line
+
+    def close(self):
+        assert 0, "input.close() must not be called"
+
+class ErrorWrapper:
+
+    def __init__(self, wsgi_errors):
+        self.errors = wsgi_errors
+
+    def write(self, s):
+        assert type(s) is type("")
+        self.errors.write(s)
+
+    def flush(self):
+        self.errors.flush()
+
+    def writelines(self, seq):
+        for line in seq:
+            self.write(line)
+
+    def close(self):
+        assert 0, "errors.close() must not be called"
+
+class WriteWrapper:
+
+    def __init__(self, wsgi_writer):
+        self.writer = wsgi_writer
+
+    def __call__(self, s):
+        assert type(s) is type("")
+        self.writer(s)
+
+class PartialIteratorWrapper:
+
+    def __init__(self, wsgi_iterator):
+        self.iterator = iterator
+
+    def __iter__(self):
+        # We want to make sure __iter__ is called
+        return IteratorWrapper(self.iterator)
+
+class IteratorWrapper:
+
+    def __init__(self, wsgi_iterator):
+        self.original_iterator = wsgi_iterator
+        self.iterator = iter(wsgi_iterator)
+        self.closed = False
+
+    def __iter__(self):
+        return self
+
+    def next(self):
+        assert not self.closed, \
+               "Iterator read after closed"
+        return self.iterator.next()
+
+    def close(self):
+        self.closed = True
+        if hasattr(self.original_iterator, 'close'):
+            self.original_iterator.close()
+
+    def __del__(self):
+        if not self.closed:
+            sys.stderr.write("Iterator garbage collected without being closed")
+        assert self.closed, \
+               "Iterator garbage collected without being closed"
+
+def check_environ(environ):
+    assert type(environ) is DictType, \
+           "Environment is not of the right type: %r (environment: %r)" % (type(environ), environ)
+    
+    for key in ['REQUEST_METHOD', 'SERVER_NAME', 'SERVER_PORT',
+                'wsgi.version', 'wsgi.input', 'wsgi.errors',
+                'wsgi.multithread', 'wsgi.multiprocess',
+                'wsgi.run_once']:
+        assert environ.has_key(key), \
+               "Environment missing required key: %r" % key
+        
+    for key in environ.keys():
+        if '.' in key:
+            # Extension, we don't care about its type
+            continue
+        assert type(environ[key]) is StringType, \
+               "Environmental variable %s is not a string: %r (value: %r)" % (type(environ[key]), environ[key])
+        
+    assert type(environ['wsgi.version']) is TupleType, \
+           "wsgi.version should be a tuple (%r)" % environ['wsgi.version']
+    assert environ['wsgi.url_scheme'] in ('http', 'https'), \
+           "wsgi.url_scheme unknown: %r" % environ['wsgi.url_scheme']
+
+    check_input(environ['wsgi.input'])
+    check_errors(environ['wsgi.errors'])
+
+    # @@: these need filling out:
+    assert environ['REQUEST_METHOD'] in ('GET', 'HEAD', 'POST'), "Unknown REQUEST_METHOD: %r" % environ['REQUEST_METHOD']
+
+    assert (not environ.get('SCRIPT_NAME')
+            or environ['SCRIPT_NAME'].startswith('/')), \
+           "SCRIPT_NAME doesn't start with /: %r" % environ['SCRIPT_NAME']
+    assert (not environ.get('PATH_INFO')
+            or environ['PATH_INFO'].startswith('/')), \
+           "PATH_INFO doesn't start with /: %s" % environ['PATH_INFO']
+    if environ.get('CONTENT_LENGTH'):
+        assert int(environ['CONTENT_LENGTH']) >= 0, "Invalid CONTENT_LENGTH: %r" % environ['CONTENT_LENGTH']
+
+    if not environ.get('SCRIPT_NAME'):
+        assert environ.has_key('PATH_INFO'), \
+               "One of SCRIPT_NAME or PATH_INFO are required (PATH_INFO should at least be '/' if SCRIPT_NAME is empty)"
+    assert environ.get('SCRIPT_NAME') != '/', \
+           "SCRIPT_NAME cannot be '/'; it should instead be '', and PATH_INFO should be '/'"
+
+def check_input(wsgi_input):
+    for attr in ['read', 'readline', 'readlines', '__iter__']:
+        assert hasattr(wsgi_input, attr), \
+               "wsgi.input (%r) doesn't have the attribute %s" % (wsgi_input, attr)
+
+def check_errors(wsgi_errors):
+    for attr in ['flush', 'write', 'writelines']:
+        assert hasattr(wsgi_errors, attr), \
+               "wsgi.errors (%r) doesn't have the attributes %s" % (wsgi_errors, attr)
+
+def check_status(status):
+    assert type(status) is StringType, \
+           "Status must be a string (not %r)" % status
+    # Implicitly check that we can turn it into an integer:
+    status_int = int(status.split(None, 1)[0])
+    assert status_int >= 100, "Status code is invalid: %r" % status_int
+
+def check_headers(headers):
+    assert type(headers) is ListType, \
+           "Headers (%r) must be of type list: %r" % (headers, type(headers))
+    header_names = {}
+    for item in headers:
+        assert type(item) is TupleType, \
+               "Individual headers (%r) must be of type tuple: %r" % (item, type(item))
+        assert len(item) == 2
+        name, value = item
+        assert name.lower() != 'status', \
+               "The Status header cannot be used; it conflicts with CGI script, and HTTP status is not given through headers (value: %r)." % value
+        header_names[name.lower()] = None
+        assert '\n' not in name and ':' not in name, \
+               "Header names may not contain ':' or '\\n': %r" % name
+        assert header_re.search(name), "Bad header name: %r" % name
+        assert not name.endswith('-') and not name.endswith('_'), \
+               "Names may not end in '-' or '_': %r" % name
+        assert not bad_header_value_re.search(value), \
+               "Bad header value: %r (bad char: %r)" % (value, bad_header_value_re.search(value).group(0))
+
+def check_content_type(status, headers):
+    code = int(status.split(None, 1)[0])
+    if code == 204:
+        # 204 No Content is the only code where there's no body,
+        # and so it doesn't need a content-type header.
+        # @@: Not 100% sure this is the only case where a content-type
+        # header can be left out
+        return
+    for name, value in headers:
+        if name.lower() == 'content-type':
+            return
+    assert 0, "No Content-Type header found in headers (%s)" % headers
+
+def check_exc_info(exc_info):
+    assert not exc_info or type(exc_info) is type(()), "exc_info (%r) is not a tuple: %r" % (exc_info, type(exc_info))
+    # More exc_info checks?
+
+def check_iterator(iterator):
+    # Technically a string is legal, which is why it's a really bad
+    # idea, because it may cause the response to be returned
+    # character-by-character
+    assert not isinstance(iterator, str), \
+           "You should not return a string as your application iterator, instead return a single-item list containing that string."