Luiz Capitulino <lcapitul...@redhat.com> writes: > On Sun, 24 Jan 2010 18:35:14 +0000 > Jamie Lokier <ja...@shareable.org> wrote: > >> Anthony Liguori wrote: >> > >I'd like to be able to connect and be sure not to receive any async >> > >messages, from simple scripts with simple output parsing. >> > >> > You can't have simple output parsing with QMP. You need a full JSON >> > stack. The simplest script would be a python script that uses the >> > builtin json support. Having async messages means that you'll have to >> > loop on recv in order make sure that the response is a command response >> > vs. an async message. It's just a few lines more of code so I have a >> > hard time believing it's really a problem. >> > >> > But what you probably want is a python QMP library and that would mean >> > you wouldn't need the few more lines of code. >> >> You're right. To be honest, parsing JSON can be done in a single Perl >> regexp; a "full JSON stack" isn't much. >> >> On that note, it'd be good if the end of a QMP message is framed with >> something that can't appear inside the JSON value, without having to >> parse the JSON incrementally on each partial read(). There are plenty >> of short character sequences to choose from that can't appear. Some >> JSON parsers expect a whole well-formed expression or throw a parse >> error - it's what people do over HTTP after all. So you wait until >> you think you've read a whole one, then pass it to the JSON parser. > > The Monitor sends a CRLF sequence at the end of each line and I have > maintained that behaivor for QMP, but it's hard to _guarantee_ that this > sequence won't appear inside a json-string.
JSON requires control characters in strings to be escaped. RFC 4627 section 2.5: A string begins and ends with quotation marks. All Unicode characters may be placed within the quotation marks except for the characters that must be escaped: quotation mark, reverse solidus, and the control characters (U+0000 through U+001F). > In practice it doesn't, afaik. If it doesn't, then it's not proper JSON, is it?
