Python IRequest.finish方法代码示例

# 需要导入模块: from nevow.inevow import IRequest [as 别名]
# 或者: from nevow.inevow.IRequest import finish [as 别名]
    def renderHTTP(self, ctx):
        req = IRequest(ctx)
        gte = static.getTypeAndEncoding
        ctype, encoding = gte(
            self.filename, static.File.contentTypes, static.File.contentEncodings, defaultType="text/plain"
        )
        req.setHeader("content-type", ctype)
        if encoding:
            req.setHeader("content-encoding", encoding)

        if boolean_of_arg(get_arg(req, "save", "False")):
            # tell the browser to save the file rather display it we don't
            # try to encode the filename, instead we echo back the exact same
            # bytes we were given in the URL. See the comment in
            # FileNodeHandler.render_GET for the sad details.
            req.setHeader("content-disposition", 'attachment; filename="%s"' % self.filename)

        filesize = self.filenode.get_size()
        assert isinstance(filesize, (int, long)), filesize
        first, size = 0, None
        contentsize = filesize
        req.setHeader("accept-ranges", "bytes")
        if not self.filenode.is_mutable():
            # TODO: look more closely at Request.setETag and how it interacts
            # with a conditional "if-etag-equals" request, I think this may
            # need to occur after the setResponseCode below
            si = self.filenode.get_storage_index()
            if si:
                req.setETag(base32.b2a(si))
        # TODO: for mutable files, use the roothash. For LIT, hash the data.
        # or maybe just use the URI for CHK and LIT.
        rangeheader = req.getHeader("range")
        if rangeheader:
            ranges = self.parse_range_header(rangeheader)

            # ranges = None means the header didn't parse, so ignore
            # the header as if it didn't exist.  If is more than one
            # range, then just return the first for now, until we can
            # generate multipart/byteranges.
            if ranges is not None:
                first, last = ranges[0]

                if first >= filesize:
                    raise WebError("First beyond end of file", http.REQUESTED_RANGE_NOT_SATISFIABLE)
                else:
                    first = max(0, first)
                    last = min(filesize - 1, last)

                    req.setResponseCode(http.PARTIAL_CONTENT)
                    req.setHeader("content-range", "bytes %s-%s/%s" % (str(first), str(last), str(filesize)))
                    contentsize = last - first + 1
                    size = contentsize

        req.setHeader("content-length", str(contentsize))
        if req.method == "HEAD":
            return ""
        d = self.filenode.read(req, first, size)

        def _error(f):
            log.msg("error during GET", facility="tahoe.webish", failure=f, level=log.UNUSUAL, umid="xSiF3w")
            req._tahoe_request_had_error = f  # for HTTP-style logging
            if req.startedWriting:
                # The content-type is already set, and the response code has
                # already been sent, so we can't provide a clean error
                # indication. We can emit text (which a browser might
                # interpret as something else), and if we sent a Size header,
                # they might notice that we've truncated the data. Keep the
                # error message small to improve the chances of having our
                # error response be shorter than the intended results.
                #
                # We don't have a lot of options, unfortunately.
                req.write("problem during download\n")
                req.finish()
            else:
                # We haven't written anything yet, so we can provide a
                # sensible error message.
                eh = MyExceptionHandler()
                eh.renderHTTP_exception(ctx, f)

        d.addCallbacks(lambda ign: req.finish(), _error)
        return req.deferred