httplib.py 文件源码

def _set_content_length(self, body, method):
        # Set the content-length based on the body. If the body is "empty", we
        # set Content-Length: 0 for methods that expect a body (RFC 7230,
        # Section 3.3.2). If the body is set for other methods, we set the
        # header provided we can figure out what the length is.
        thelen = None
        if body is None and method.upper() in _METHODS_EXPECTING_BODY:
            thelen = '0'
        elif body is not None:
            try:
                thelen = str(len(body))
            except (TypeError, AttributeError):
                # If this is a file-like object, try to
                # fstat its file descriptor
                try:
                    thelen = str(os.fstat(body.fileno()).st_size)
                except (AttributeError, OSError):
                    # Don't send a length if this failed
                    if self.debuglevel > 0: print "Cannot stat!!"

        if thelen is not None:
            self.putheader('Content-Length', thelen)