add cgitb.py & test_cgitb.py from cpython 3.8

Snowapril · Snowapril · commit ab9fd92e7e13 · 2021-09-06T18:55:23.000+09:00
Signed-off-by: snowapril &lt;sinjihng@gmail.com&gt;
diff --git a/Lib/cgitb.py b/Lib/cgitb.py
@@ -0,0 +1,321 @@
+"""More comprehensive traceback formatting for Python scripts.
+
+To enable this module, do:
+
+    import cgitb; cgitb.enable()
+
+at the top of your script.  The optional arguments to enable() are:
+
+    display     - if true, tracebacks are displayed in the web browser
+    logdir      - if set, tracebacks are written to files in this directory
+    context     - number of lines of source code to show for each stack frame
+    format      - 'text' or 'html' controls the output format
+
+By default, tracebacks are displayed but not saved, the context is 5 lines
+and the output format is 'html' (for backwards compatibility with the
+original use of this module)
+
+Alternatively, if you have caught an exception and want cgitb to display it
+for you, call cgitb.handler().  The optional argument to handler() is a
+3-item tuple (etype, evalue, etb) just like the value of sys.exc_info().
+The default handler displays output as HTML.
+
+"""
+import inspect
+import keyword
+import linecache
+import os
+import pydoc
+import sys
+import tempfile
+import time
+import tokenize
+import traceback
+
+def reset():
+    """Return a string that resets the CGI and browser to a known state."""
+    return '''<!--: spam
+Content-Type: text/html
+
+<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> -->
+<body bgcolor="#f0f0f8"><font color="#f0f0f8" size="-5"> --> -->
+</font> </font> </font> </script> </object> </blockquote> </pre>
+</table> </table> </table> </table> </table> </font> </font> </font>'''
+
+__UNDEF__ = []                          # a special sentinel object
+def small(text):
+    if text:
+        return '<small>' + text + '</small>'
+    else:
+        return ''
+
+def strong(text):
+    if text:
+        return '<strong>' + text + '</strong>'
+    else:
+        return ''
+
+def grey(text):
+    if text:
+        return '<font color="#909090">' + text + '</font>'
+    else:
+        return ''
+
+def lookup(name, frame, locals):
+    """Find the value for a given name in the given environment."""
+    if name in locals:
+        return 'local', locals[name]
+    if name in frame.f_globals:
+        return 'global', frame.f_globals[name]
+    if '__builtins__' in frame.f_globals:
+        builtins = frame.f_globals['__builtins__']
+        if type(builtins) is type({}):
+            if name in builtins:
+                return 'builtin', builtins[name]
+        else:
+            if hasattr(builtins, name):
+                return 'builtin', getattr(builtins, name)
+    return None, __UNDEF__
+
+def scanvars(reader, frame, locals):
+    """Scan one logical line of Python and look up values of variables used."""
+    vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__
+    for ttype, token, start, end, line in tokenize.generate_tokens(reader):
+        if ttype == tokenize.NEWLINE: break
+        if ttype == tokenize.NAME and token not in keyword.kwlist:
+            if lasttoken == '.':
+                if parent is not __UNDEF__:
+                    value = getattr(parent, token, __UNDEF__)
+                    vars.append((prefix + token, prefix, value))
+            else:
+                where, value = lookup(token, frame, locals)
+                vars.append((token, where, value))
+        elif token == '.':
+            prefix += lasttoken + '.'
+            parent = value
+        else:
+            parent, prefix = None, ''
+        lasttoken = token
+    return vars
+
+def html(einfo, context=5):
+    """Return a nice HTML document describing a given traceback."""
+    etype, evalue, etb = einfo
+    if isinstance(etype, type):
+        etype = etype.__name__
+    pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
+    date = time.ctime(time.time())
+    head = '<body bgcolor="#f0f0f8">' + pydoc.html.heading(
+        '<big><big>%s</big></big>' %
+        strong(pydoc.html.escape(str(etype))),
+        '#ffffff', '#6622aa', pyver + '<br>' + date) + '''
+<p>A problem occurred in a Python script.  Here is the sequence of
+function calls leading up to the error, in the order they occurred.</p>'''
+
+    indent = '<tt>' + small('&nbsp;' * 5) + '&nbsp;</tt>'
+    frames = []
+    records = inspect.getinnerframes(etb, context)
+    for frame, file, lnum, func, lines, index in records:
+        if file:
+            file = os.path.abspath(file)
+            link = '<a href="file://%s">%s</a>' % (file, pydoc.html.escape(file))
+        else:
+            file = link = '?'
+        args, varargs, varkw, locals = inspect.getargvalues(frame)
+        call = ''
+        if func != '?':
+            call = 'in ' + strong(pydoc.html.escape(func))
+            if func != "<module>":
+                call += inspect.formatargvalues(args, varargs, varkw, locals,
+                    formatvalue=lambda value: '=' + pydoc.html.repr(value))
+
+        highlight = {}
+        def reader(lnum=[lnum]):
+            highlight[lnum[0]] = 1
+            try: return linecache.getline(file, lnum[0])
+            finally: lnum[0] += 1
+        vars = scanvars(reader, frame, locals)
+
+        rows = ['<tr><td bgcolor="#d8bbff">%s%s %s</td></tr>' %
+                ('<big>&nbsp;</big>', link, call)]
+        if index is not None:
+            i = lnum - index
+            for line in lines:
+                num = small('&nbsp;' * (5-len(str(i))) + str(i)) + '&nbsp;'
+                if i in highlight:
+                    line = '<tt>=&gt;%s%s</tt>' % (num, pydoc.html.preformat(line))
+                    rows.append('<tr><td bgcolor="#ffccee">%s</td></tr>' % line)
+                else:
+                    line = '<tt>&nbsp;&nbsp;%s%s</tt>' % (num, pydoc.html.preformat(line))
+                    rows.append('<tr><td>%s</td></tr>' % grey(line))
+                i += 1
+
+        done, dump = {}, []
+        for name, where, value in vars:
+            if name in done: continue
+            done[name] = 1
+            if value is not __UNDEF__:
+                if where in ('global', 'builtin'):
+                    name = ('<em>%s</em> ' % where) + strong(name)
+                elif where == 'local':
+                    name = strong(name)
+                else:
+                    name = where + strong(name.split('.')[-1])
+                dump.append('%s&nbsp;= %s' % (name, pydoc.html.repr(value)))
+            else:
+                dump.append(name + ' <em>undefined</em>')
+
+        rows.append('<tr><td>%s</td></tr>' % small(grey(', '.join(dump))))
+        frames.append('''
+<table width="100%%" cellspacing=0 cellpadding=0 border=0>
+%s</table>''' % '\n'.join(rows))
+
+    exception = ['<p>%s: %s' % (strong(pydoc.html.escape(str(etype))),
+                                pydoc.html.escape(str(evalue)))]
+    for name in dir(evalue):
+        if name[:1] == '_': continue
+        value = pydoc.html.repr(getattr(evalue, name))
+        exception.append('\n<br>%s%s&nbsp;=\n%s' % (indent, name, value))
+
+    return head + ''.join(frames) + ''.join(exception) + '''
+
+
+<!-- The above is a description of an error in a Python program, formatted
+     for a Web browser because the 'cgitb' module was enabled.  In case you
+     are not reading this in a Web browser, here is the original traceback:
+
+%s
+-->
+''' % pydoc.html.escape(
+          ''.join(traceback.format_exception(etype, evalue, etb)))
+
+def text(einfo, context=5):
+    """Return a plain text document describing a given traceback."""
+    etype, evalue, etb = einfo
+    if isinstance(etype, type):
+        etype = etype.__name__
+    pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
+    date = time.ctime(time.time())
+    head = "%s\n%s\n%s\n" % (str(etype), pyver, date) + '''
+A problem occurred in a Python script.  Here is the sequence of
+function calls leading up to the error, in the order they occurred.
+'''
+
+    frames = []
+    records = inspect.getinnerframes(etb, context)
+    for frame, file, lnum, func, lines, index in records:
+        file = file and os.path.abspath(file) or '?'
+        args, varargs, varkw, locals = inspect.getargvalues(frame)
+        call = ''
+        if func != '?':
+            call = 'in ' + func
+            if func != "<module>":
+                call += inspect.formatargvalues(args, varargs, varkw, locals,
+                    formatvalue=lambda value: '=' + pydoc.text.repr(value))
+
+        highlight = {}
+        def reader(lnum=[lnum]):
+            highlight[lnum[0]] = 1
+            try: return linecache.getline(file, lnum[0])
+            finally: lnum[0] += 1
+        vars = scanvars(reader, frame, locals)
+
+        rows = [' %s %s' % (file, call)]
+        if index is not None:
+            i = lnum - index
+            for line in lines:
+                num = '%5d ' % i
+                rows.append(num+line.rstrip())
+                i += 1
+
+        done, dump = {}, []
+        for name, where, value in vars:
+            if name in done: continue
+            done[name] = 1
+            if value is not __UNDEF__:
+                if where == 'global': name = 'global ' + name
+                elif where != 'local': name = where + name.split('.')[-1]
+                dump.append('%s = %s' % (name, pydoc.text.repr(value)))
+            else:
+                dump.append(name + ' undefined')
+
+        rows.append('\n'.join(dump))
+        frames.append('\n%s\n' % '\n'.join(rows))
+
+    exception = ['%s: %s' % (str(etype), str(evalue))]
+    for name in dir(evalue):
+        value = pydoc.text.repr(getattr(evalue, name))
+        exception.append('\n%s%s = %s' % (" "*4, name, value))
+
+    return head + ''.join(frames) + ''.join(exception) + '''
+
+The above is a description of an error in a Python program.  Here is
+the original traceback:
+
+%s
+''' % ''.join(traceback.format_exception(etype, evalue, etb))
+
+class Hook:
+    """A hook to replace sys.excepthook that shows tracebacks in HTML."""
+
+    def __init__(self, display=1, logdir=None, context=5, file=None,
+                 format="html"):
+        self.display = display          # send tracebacks to browser if true
+        self.logdir = logdir            # log tracebacks to files if not None
+        self.context = context          # number of source code lines per frame
+        self.file = file or sys.stdout  # place to send the output
+        self.format = format
+
+    def __call__(self, etype, evalue, etb):
+        self.handle((etype, evalue, etb))
+
+    def handle(self, info=None):
+        info = info or sys.exc_info()
+        if self.format == "html":
+            self.file.write(reset())
+
+        formatter = (self.format=="html") and html or text
+        plain = False
+        try:
+            doc = formatter(info, self.context)
+        except:                         # just in case something goes wrong
+            doc = ''.join(traceback.format_exception(*info))
+            plain = True
+
+        if self.display:
+            if plain:
+                doc = pydoc.html.escape(doc)
+                self.file.write('<pre>' + doc + '</pre>\n')
+            else:
+                self.file.write(doc + '\n')
+        else:
+            self.file.write('<p>A problem occurred in a Python script.\n')
+
+        if self.logdir is not None:
+            suffix = ['.txt', '.html'][self.format=="html"]
+            (fd, path) = tempfile.mkstemp(suffix=suffix, dir=self.logdir)
+
+            try:
+                with os.fdopen(fd, 'w') as file:
+                    file.write(doc)
+                msg = '%s contains the description of this error.' % path
+            except:
+                msg = 'Tried to save traceback to %s, but failed.' % path
+
+            if self.format == 'html':
+                self.file.write('<p>%s</p>\n' % msg)
+            else:
+                self.file.write(msg + '\n')
+        try:
+            self.file.flush()
+        except: pass
+
+handler = Hook().handle
+def enable(display=1, logdir=None, context=5, format="html"):
+    """Install an exception handler that formats tracebacks as HTML.
+
+    The optional argument 'display' can be set to 0 to suppress sending the
+    traceback to the browser, and 'logdir' can be set to a directory to cause
+    tracebacks to be written to files there."""
+    sys.excepthook = Hook(display=display, logdir=logdir,
+                          context=context, format=format)
diff --git a/Lib/test/test_cgitb.py b/Lib/test/test_cgitb.py
@@ -0,0 +1,68 @@
+from test.support import temp_dir
+from test.support.script_helper import assert_python_failure
+import unittest
+import sys
+import cgitb
+
+class TestCgitb(unittest.TestCase):
+
+    def test_fonts(self):
+        text = "Hello Robbie!"
+        self.assertEqual(cgitb.small(text), "<small>{}</small>".format(text))
+        self.assertEqual(cgitb.strong(text), "<strong>{}</strong>".format(text))
+        self.assertEqual(cgitb.grey(text),
+                         '<font color="#909090">{}</font>'.format(text))
+
+    def test_blanks(self):
+        self.assertEqual(cgitb.small(""), "")
+        self.assertEqual(cgitb.strong(""), "")
+        self.assertEqual(cgitb.grey(""), "")
+
+    def test_html(self):
+        try:
+            raise ValueError("Hello World")
+        except ValueError as err:
+            # If the html was templated we could do a bit more here.
+            # At least check that we get details on what we just raised.
+            html = cgitb.html(sys.exc_info())
+            self.assertIn("ValueError", html)
+            self.assertIn(str(err), html)
+
+    def test_text(self):
+        try:
+            raise ValueError("Hello World")
+        except ValueError as err:
+            text = cgitb.text(sys.exc_info())
+            self.assertIn("ValueError", text)
+            self.assertIn("Hello World", text)
+
+    def test_syshook_no_logdir_default_format(self):
+        with temp_dir() as tracedir:
+            rc, out, err = assert_python_failure(
+                  '-c',
+                  ('import cgitb; cgitb.enable(logdir=%s); '
+                   'raise ValueError("Hello World")') % repr(tracedir))
+        out = out.decode(sys.getfilesystemencoding())
+        self.assertIn("ValueError", out)
+        self.assertIn("Hello World", out)
+        self.assertIn("<strong>&lt;module&gt;</strong>", out)
+        # By default we emit HTML markup.
+        self.assertIn('<p>', out)
+        self.assertIn('</p>', out)
+
+    def test_syshook_no_logdir_text_format(self):
+        # Issue 12890: we were emitting the <p> tag in text mode.
+        with temp_dir() as tracedir:
+            rc, out, err = assert_python_failure(
+                  '-c',
+                  ('import cgitb; cgitb.enable(format="text", logdir=%s); '
+                   'raise ValueError("Hello World")') % repr(tracedir))
+        out = out.decode(sys.getfilesystemencoding())
+        self.assertIn("ValueError", out)
+        self.assertIn("Hello World", out)
+        self.assertNotIn('<p>', out)
+        self.assertNotIn('</p>', out)
+
+
+if __name__ == "__main__":
+    unittest.main()
